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Posted: 5/13/2011 2:44:54 PM EDT
[Last Edit: 5/13/2011 2:47:00 PM EDT by w12x40]
Inspired by the CJan_NH post, I decided to build a battery box, initially because I thought it would be a wonderful way to run my sump pump in case the power goes out during a rain storm. I remembered that half the time when the power goes out, it's a hot and sticky evening, so this should do nicely to run a fan and a lamp.

I'm a structural engineer. My college experience with electronics was a single required course where we never got past Thevenin whatchamacallits and the oscilloscopes never worked right. In every day life, I know one thing: if you don't touch it, it won't shock you. This project presented a dandy way to do some wiring and get something useful.

A few things I learned:

1. The copper battery cable lugs are discontinued at Autozone. I did everything out of crimp-on ring terminals.
2. Those powerpole things are expensive. Getting the wires into them and then making them connect is kind of a pain in the ass.
3. It seemed like a really good idea, so I bought the crimper that goes with the powerpole connectors. One crimp and I sheared a pin in the tool. I sent it back to Powerwerx.com, and we'll see how their customer service does.
4. The Optima batteries suggest a 1-amp maximum trickle charge for maintenance. The charger I bought only did 2-amps. So I bought a trickle charger that does 1-amp.
5. I had no raw materials. 10-gage wire is expensive, too.
6. You can't plug your iphone directly into the USB port on that model inverter. Well, you can, but it won't charge the phone. If you plug the AC wall wart into the inverter, it charges as expected.
7. I didn't realize the inverter had a power switch, I thought it would start right up when I plugged it in like the charger. This led me to go dig out my multimeter, whereupon I discovered that the batteries in it were dead.
8. The breaker that doubles as an on-off switch took me forever to find. You have to look for a surface-mount marine battery. Conveniently, Powerwerx sold it, too.
9. I have two stripper/crimper tools. One wouldn't strip wire worth a damn, but it did OK crimping. The other was a great stripper (I nicknamed it "Miss Nude Pennsylvania") but didn't crimp worth a crap. Neither one would cut 10-gage.
10. Surprisingly, there weren't a whole lot of parts and pieces available at either Autozone or Pep Boys. I was expecting more.
11. The nylon strap that comes with the battery box sucks. It is hard to tighten and impossible to undo. I went into my tactical nylon box and got a piece of 1" web and a ladder buckle. Now I can open it up easily.
12. I bought the battery box that was bigger (group 28-34, I think) than the battery so I could use the extra compartment for storage. Pigtails, fuses, inverter and charger instructions.

I don't even want to count how much I spent. I had nothing, so everything was an acquisition. I paid shipping on a lot of it die to internet ordering. My wife will see the credit card statement and complain, she'll see the box and complain, she'll see the charger and complain, she'll complain that I built a box instead of doing laundry, and the first time the power goes out, I'll rub her nose in it.

So, thanks to CJan_NH for the writeup.



Link Posted: 5/13/2011 3:50:02 PM EDT
Sounds like you're off to a good start!

Now start planning on a refined version.

Be sure you have FUSED THE BATTERY at the battery, I'd hate to see your next project be repairing a fire damaged house.

Ebay has every part you could possibly need for battery backup supplies, at excellent prices.
Link Posted: 5/13/2011 4:22:03 PM EDT
I put a fuse in the circuit for the charging pigtail. The circuit for the inverter runs through a breaker. The wiring is exactly like the one in the original thread. Does it need a fuse as well in the inverter circuit?
Link Posted: 5/13/2011 4:49:29 PM EDT
Originally Posted By w12x40:
Inspired by the CJan_NH post, I decided to build a battery box, initially because I thought it would be a wonderful way to run my sump pump in case the power goes out during a rain storm. I remembered that half the time when the power goes out, it's a hot and sticky evening, so this should do nicely to run a fan and a lamp.

I'm a structural engineer. My college experience with electronics was a single required course where we never got past Thevenin whatchamacallits and the oscilloscopes never worked right. In every day life, I know one thing: if you don't touch it, it won't shock you. This project presented a dandy way to do some wiring and get something useful.

A few things I learned:

1. The copper battery cable lugs are discontinued at Autozone. I did everything out of crimp-on ring terminals.
2. Those powerpole things are expensive. Getting the wires into them and then making them connect is kind of a pain in the ass.
3. It seemed like a really good idea, so I bought the crimper that goes with the powerpole connectors. One crimp and I sheared a pin in the tool. I sent it back to Powerwerx.com, and we'll see how their customer service does.
4. The Optima batteries suggest a 1-amp maximum trickle charge for maintenance. The charger I bought only did 2-amps. So I bought a trickle charger that does 1-amp.
5. I had no raw materials. 10-gage wire is expensive, too.
6. You can't plug your iphone directly into the USB port on that model inverter. Well, you can, but it won't charge the phone. If you plug the AC wall wart into the inverter, it charges as expected.
7. I didn't realize the inverter had a power switch, I thought it would start right up when I plugged it in like the charger. This led me to go dig out my multimeter, whereupon I discovered that the batteries in it were dead.
8. The breaker that doubles as an on-off switch took me forever to find. You have to look for a surface-mount marine battery. Conveniently, Powerwerx sold it, too.
9. I have two stripper/crimper tools. One wouldn't strip wire worth a damn, but it did OK crimping. The other was a great stripper (I nicknamed it "Miss Nude Pennsylvania") but didn't crimp worth a crap. Neither one would cut 10-gage.
10. Surprisingly, there weren't a whole lot of parts and pieces available at either Autozone or Pep Boys. I was expecting more.
11. The nylon strap that comes with the battery box sucks. It is hard to tighten and impossible to undo. I went into my tactical nylon box and got a piece of 1" web and a ladder buckle. Now I can open it up easily.
12. I bought the battery box that was bigger (group 28-34, I think) than the battery so I could use the extra compartment for storage. Pigtails, fuses, inverter and charger instructions.

I don't even want to count how much I spent. I had nothing, so everything was an acquisition. I paid shipping on a lot of it die to internet ordering. My wife will see the credit card statement and complain, she'll see the box and complain, she'll see the charger and complain, she'll complain that I built a box instead of doing laundry, and the first time the power goes out, I'll rub her nose in it.

So, thanks to CJan_NH for the writeup.




my iphone wouldn't charge on mine either. the droid did though
Link Posted: 5/13/2011 8:10:46 PM EDT
Originally Posted By hootch13:
Originally Posted By w12x40:





my iphone wouldn't charge on mine either. the droid did though


I didn't try anything else (the iphone is insured via work, so I didn't feel bad about testing with it), but I'm disappointed.
Link Posted: 5/13/2011 10:03:50 PM EDT
[Last Edit: 5/13/2011 10:04:31 PM EDT by EXPY37]
Originally Posted By w12x40:
I put a fuse in the circuit for the charging pigtail. The circuit for the inverter runs through a breaker. The wiring is exactly like the one in the original thread. Does it need a fuse as well in the inverter circuit?


The inverter likely has internal fuses, but check the user manual. The wires to the inverter should be very short and protected from abrasion and shorting. Sometimes that's the best you can do.

The other wires all should be protected, usually on the positive side, because thinner wires can light up like a Christmas tree.

Link Posted: 5/13/2011 11:10:46 PM EDT
Originally Posted By w12x40:
Originally Posted By hootch13:
Originally Posted By w12x40:



my iphone wouldn't charge on mine either. the droid did though


I didn't try anything else (the iphone is insured via work, so I didn't feel bad about testing with it), but I'm disappointed.


i've read elsewhere that they are "finicky" with charging apparatus, but i've not figured out a solution.

sorry. </hijack>

got a pic of your battery box??
Link Posted: 5/15/2011 9:09:38 AM EDT
Pictures:






Link Posted: 5/15/2011 10:17:16 AM EDT
Let me apologize in advance.  I'm not trying to be a jerk...

w12x40, your setup is very nicely done, but the wires that connect your inverter to your battery are way too small.  Based on the sticker on the inverter, I expect it will draw 65-70A when running at its full 750W capacity.  Apparently you do too, since you've installed what appears to be a 70A circuit breaker between the battery and inverter (nicely done).  Unfortunately, based on the pictures, I think you're using 14 gauge wire to connect the battery and inverter.  That's a problem; 14 gauge wire is only rated for 15 amps. Based on the table here you need a minimum of 4 gauge wire to safely carry the current the inverter will draw at full power.  If you try to pull 65 amps through the wire you're using now, it will probably melt; the circuit breaker won't help you.  In addition, the skinny wire you're using will likely "drop" enough voltage that your inverter probably won't operate at high power anyway.

I'm just trying to help
Link Posted: 5/15/2011 10:41:48 AM EDT
Link Posted: 5/15/2011 11:33:09 AM EDT
Originally Posted By ALKVA:
Let me apologize in advance.  I'm not trying to be a jerk...

w12x40, your setup is very nicely done, but the wires that connect your inverter to your battery are way too small.  Based on the sticker on the inverter, I expect it will draw 65-70A when running at its full 750W capacity.  Apparently you do too, since you've installed what appears to be a 70A circuit breaker between the battery and inverter (nicely done).  Unfortunately, based on the pictures, I think you're using 14 gauge wire to connect the battery and inverter.  That's a problem; 14 gauge wire is only rated for 15 amps. Based on the table here you need a minimum of 4 gauge wire to safely carry the current the inverter will draw at full power.  If you try to pull 65 amps through the wire you're using now, it will probably melt; the circuit breaker won't help you.  In addition, the skinny wire you're using will likely "drop" enough voltage that your inverter probably won't operate at high power anyway.

I'm just trying to help


Not at all. If you didn't tell me, I wouldn't know.

It is all 10-gage stuff. I know that a larger wire is required for larger current, but I think it also has larger resistance.

The inverter is 6.52 amps and has an internal 35 amp fuse.

The breaker seems to be too big for the operation. Powerwerx has 50, 70, 120 and 150 amp breakers. I thought I ordered the 50, but when it came, it was a 70. I doubt it will ever trip, but it makes a really hand off switch. I used it because it looked like a good idea in the original tutorial. He used a 100 amp breaker.

For the next one, I'll probably measure voltages and currents and try some load mathematics to better size the components.

Link Posted: 5/15/2011 11:38:21 AM EDT
[Last Edit: 5/15/2011 11:55:06 AM EDT by w12x40]
Originally Posted By The_Beer_Slayer:
125ah battery from walmart... New 89.00
100amp breaker on amazon   15.00 shipped
1k inverter from big lots .... 50.00
battery box  8.00
batttery cables 20.00 from walmart

total... 182.00 at retail prices.

if you shop around and scrap used parts i built one for about 125.00 including a NEW battery



I went way over budget on the battery. I bought an Optima from Pep Boys for 189. Everything else is pretty much in line for the basic box. I had no charger, no terminals, no connectors.

Why is the optima so much more than the Walmart battery? Warranty?

And let me add to the list a brand-new set of Channellock cutting pliers that my kid absconded with. I'll find them in a year.
Link Posted: 5/15/2011 12:27:39 PM EDT
Originally Posted By w12x40:
Originally Posted By ALKVA:
Let me apologize in advance.  I'm not trying to be a jerk...

w12x40, your setup is very nicely done, but the wires that connect your inverter to your battery are way too small.  Based on the sticker on the inverter, I expect it will draw 65-70A when running at its full 750W capacity.  Apparently you do too, since you've installed what appears to be a 70A circuit breaker between the battery and inverter (nicely done).  Unfortunately, based on the pictures, I think you're using 14 gauge wire to connect the battery and inverter.  That's a problem; 14 gauge wire is only rated for 15 amps. Based on the table here you need a minimum of 4 gauge wire to safely carry the current the inverter will draw at full power.  If you try to pull 65 amps through the wire you're using now, it will probably melt; the circuit breaker won't help you.  In addition, the skinny wire you're using will likely "drop" enough voltage that your inverter probably won't operate at high power anyway.

I'm just trying to help


Not at all. If you didn't tell me, I wouldn't know.

It is all 10-gage stuff. I know that a larger wire is required for larger current, but I think it also has larger resistance. Bigger wire has a lower resistance = handles more current and drops less voltage

The inverter is 6.52 amps at 120VAC and 65-70A at 12VDC from the battery and probably has a pair ofn internal 35 amp fuses.

The breaker seems to be too big for the operation wires. Powerwerx has 50, 70, 120 and 150 amp breakers. I thought I ordered the 50, but when it came, it was a 70. I doubt it will ever trip, but it makes a really hand off switch. I used it because it looked like a good idea in the original tutorial. He used a 100 amp breaker.

For the next one, I'll probably measure voltages and currents and try some load mathematics to better size the components.



Can you double-up the 10 gauge wires between the battery and the circuit breaker and inverter?

Once again, not trying to be a jerk...
Link Posted: 5/15/2011 1:53:16 PM EDT
Originally Posted By w12x40:
Originally Posted By The_Beer_Slayer:
125ah battery from walmart... New 89.00
100amp breaker on amazon   15.00 shipped
1k inverter from big lots .... 50.00
battery box  8.00
batttery cables 20.00 from walmart

total... 182.00 at retail prices.

if you shop around and scrap used parts i built one for about 125.00 including a NEW battery



I went way over budget on the battery. I bought an Optima from Pep Boys for 189. Everything else is pretty much in line for the basic box. I had no charger, no terminals, no connectors.

Why is the optima so much more than the Walmart battery? Warranty?

And let me add to the list a brand-new set of Channellock cutting pliers that my kid absconded with. I'll find them in a year.


wish you had asked here first. optima battery quality has gone down the shitter the last few years since they sold out. i have seen them last 5+ years but also seen them last as little as a few months. its really a crap shoot. the walmart battery is the best bang for the buck and they are easy to find as well as replace if you have a problem.
Link Posted: 5/15/2011 5:14:00 PM EDT
[Last Edit: 5/15/2011 5:15:32 PM EDT by Skibane]
As ALKVA mentioned, the inverter may be supplying up 6.52 amps at its 120VAC output receptacles, but it will be drawing around 65-70A from the 12 volt input in order to do it - which is why you probably need thicker wiring for the 12 volt connections between the inverter and battery.

One source of relatively cheap thick-gauge wire is a set of battery jumper cables. You can buy 'em with 6, 4 or 2 gauge wire at any Wal-Mart or auto parts store.
Link Posted: 5/15/2011 6:57:28 PM EDT
[Last Edit: 5/15/2011 6:58:20 PM EDT by Badfish25]





Originally Posted By Skibane:



As ALKVA mentioned, the inverter may be supplying up 6.52 amps at its 120VAC output receptacles, but it will be drawing around 65-70A from the 12 volt input in order to do it - which is why you probably need thicker wiring for the 12 volt connections between the inverter and battery.





One source of relatively cheap thick-gauge wire is a set of battery jumper cables. You can buy 'em with 6, 4 or 2 gauge wire at any Wal-Mart or auto parts store.



So the piece of wire between the battery and the inverter could melt since it is under sized?





 
Link Posted: 5/15/2011 7:40:23 PM EDT
[Last Edit: 5/15/2011 7:53:56 PM EDT by dablues]
So the piece of wire between the battery and the inverter could melt since it is under sized?


Yep.  I can pull 100amps to an inverter and even 2 gauge wire gets warm.  http://wiki.xtronics.com/index.php/Wire-Gauge_Ampacity

I've had good luck with Optimas, but one caution, sealed batteries do not tolerate an improper charge.  Overcharge and boil off the electrolyte, you can't add any more.  So they cannot just be left on a constant current charge.  They want a 3 stage charger.

Another source of heavy duty connectors is battery cables from  Autozone.  They sell premade starter motor cables in 4 and 2 guage of varying lengths with both post mount or terminal mount connectors.

http://www.autozone.com/autozone/parts/Duralast-Battery-Cable/_/N-acy22?counter=18&itemIdentifier=570476_0_0_

Link Posted: 5/15/2011 8:33:00 PM EDT
Be careful buying jumper cables for a source of wire.

[A good idea I'll agree]

Some of the recent cables I've looked at are copper plated aluminium stranded wire.

Probably will work, but copper wire is arguably better.
Link Posted: 5/16/2011 6:01:16 AM EDT
So the box only gives you arnd 7 ams on the inverter side? That's really low if I want to plug in a fridge or a TV. I thought I'd be getting close to 20 amps.
Link Posted: 5/16/2011 6:09:22 AM EDT
[Last Edit: 5/16/2011 6:10:29 AM EDT by Skibane]
Originally Posted By batjka104:
So the box only gives you arnd 7 ams on the inverter side? That's really low if I want to plug in a fridge or a TV. I thought I'd be getting close to 20 amps.


The inverter is rated to provide 750 watts continuously, which is  6.25 amps at 120 volts:

750 watts /  120 volts = 6.25 amps.

To get 20 amps at 120 volts, you would need a 2,400 watt inverter - and a HUGE battery if you were expecting to get that 20 amps for more than a few minutes between recharges.

The whole purpose of building a battery box with an inverter is to operate SMALL loads for extended periods, so you don't have to run your generator all the time. It's not intended to replace a generator by running LARGE loads for extended periods.
Link Posted: 5/16/2011 6:20:35 AM EDT
BRB - 2gage.
Link Posted: 5/16/2011 7:41:17 AM EDT
[Last Edit: 5/16/2011 7:53:33 AM EDT by batjka104]
Originally Posted By Skibane:
Originally Posted By batjka104:
So the box only gives you arnd 7 ams on the inverter side? That's really low if I want to plug in a fridge or a TV. I thought I'd be getting close to 20 amps.


The inverter is rated to provide 750 watts continuously, which is  6.25 amps at 120 volts:

750 watts /  120 volts = 6.25 amps.

To get 20 amps at 120 volts, you would need a 2,400 watt inverter - and a HUGE battery if you were expecting to get that 20 amps for more than a few minutes between recharges.

The whole purpose of building a battery box with an inverter is to operate SMALL loads for extended periods, so you don't have to run your generator all the time. It's not intended to replace a generator by running LARGE loads for extended periods.


Got it. How much does a fridge draw? I thought I'd be able to run it until it cools down and then disconnect. I've seen a number as 170W for compressor to run. So by your formula the fridge would be 170W/120V=1.42 A. Correct?

Starting a compressor would be another issue, because that draws a lot more.  

Link Posted: 5/16/2011 8:43:44 AM EDT
Originally Posted By batjka104:
Originally Posted By Skibane:
Originally Posted By batjka104:
So the box only gives you arnd 7 ams on the inverter side? That's really low if I want to plug in a fridge or a TV. I thought I'd be getting close to 20 amps.


The inverter is rated to provide 750 watts continuously, which is  6.25 amps at 120 volts:

750 watts /  120 volts = 6.25 amps.

To get 20 amps at 120 volts, you would need a 2,400 watt inverter - and a HUGE battery if you were expecting to get that 20 amps for more than a few minutes between recharges.

The whole purpose of building a battery box with an inverter is to operate SMALL loads for extended periods, so you don't have to run your generator all the time. It's not intended to replace a generator by running LARGE loads for extended periods.


Got it. How much does a fridge draw? I thought I'd be able to run it until it cools down and then disconnect. I've seen a number as 170W for compressor to run. So by your formula the fridge would be 170W/120V=1.42 A. Correct?

Starting a compressor would be another issue, because that draws a lot more.  



1.4 amps from the inverter which would in turn draw something like 15 amps from a battery.  If you used a typical marine deep cycle battery from Walmart/Costco/etc. (rated at 115 Ah) you get on the order of three hours of compressor run-time.  Note, you can't expect to use the battery's full capacity, you'll kill it quickly if you do.  I assumed 50% of capacity in this example.  BTW, battery capacity is rated using a current that would discharge the battery in 20 hours.  Heavier current drains result in a lower capacity.
Link Posted: 5/16/2011 9:11:16 AM EDT
If you need a source for larger gauge wire and terminals, go to a welding supply store.

Ace hardware also sells the copper terminals.

DC current ratings are different for wire ampacity than AC.  Be sure to use a proper chart and consider wire length.
Link Posted: 5/16/2011 9:24:44 AM EDT
Link Posted: 5/16/2011 9:45:52 AM EDT
[Last Edit: 5/16/2011 9:46:32 AM EDT by shortround]
Marine supply stores are also a great place to buy larger size wire copper lugs and electrical fittings.  If you think about it, most bigger boats are set up to do just what you are trying to accomplish.
Link Posted: 5/16/2011 10:29:26 AM EDT
Thank you for your clarification. I imagine same goes for a small AC? It would suck to run the generator at night for AC making noise and preventing people from sleeping. But I guess it is what it is.

Another question:

If I'm using 2 ga wire from battery to inverter, do I still need a breaker on the hot leg? The wire is pretty sizable...
Link Posted: 5/16/2011 10:47:09 AM EDT
Originally Posted By batjka104:
Thank you for your clarification. I imagine same goes for a small AC? It would suck to run the generator at night for AC making noise and preventing people from sleeping. But I guess it is what it is.

Another question:

If I'm using 2 ga wire from battery to inverter, do I still need a breaker on the hot leg? The wire is pretty sizable...


Yes you absolutely have to have a breaker or fuse!  A decent sized battery like we're talking about here can deliver a short circuit current of 10's of thousands of amps!  Even 2 gauge wire will melt under those conditions.  Ideally the breaker/fuse should be mounted as close to the battery as possible.

Another reason to use large cables is to reduce the voltage drop when the inverter is heavily loaded.  All wires have resistance but larger wires have less resistance.  When flowing current, the wire's resistance causes a voltage drop (voltage out < voltage in).  When we're talking about currents of 65A, even a small voltage drop can reduce the voltage available to the inverter below what it takes to operate.  But my refigerator or air conditioner only pulls 200W, what's the big deal?  Well it may only draw 150-200W when its running but it's compressor takes 5-10 times that much for a short itme when it tries to start.  Even if you've got a huge battery bank if you use wires to your inverter that are too small you'll lose enough voltage to prevent the inverter from supplying enough current to start the compressor.
Link Posted: 5/16/2011 3:54:25 PM EDT
[Last Edit: 5/16/2011 3:56:03 PM EDT by bikejunky]
Not to high jack this thread but if one where to use the 1000WBlack and Decker inverter


and use 4 gauge battery cables, would the 70 amp circuit breaker be a good choice


Or should one move up to the 100amp?

Thanks
bikejunky
Link Posted: 5/16/2011 5:14:08 PM EDT
Originally Posted By bikejunky:
Not to high jack this thread but if one where to use the 1000WBlack and Decker inverter


and use 4 gauge battery cables, would the 70 amp circuit breaker be a good choice


Or should one move up to the 100amp?

Thanks
bikejunky


1000W @ 12V = 83A assuming 100% conversion efficiency, which is unrealistic, so call it 90 amps.

The purpose of the circuit breaker is to protect the wire from melting in the event of a catastrophic short circuit.  So by the book, given the choices of circuit breakers, you should go with a 100A breaker and 1 gauge wire which is rated for 110 amps.

Link Posted: 5/16/2011 5:15:33 PM EDT
Originally Posted By bikejunky:
Not to high jack this thread but if one where to use the 1000WBlack and Decker inverter


and use 4 gauge battery cables, would the 70 amp circuit breaker be a good choice


Or should one move up to the 100amp?

Thanks
bikejunky


From what I've learned, watts divided by volts gives amps. Thus 1000/12 = 83.3 amps.
Link Posted: 5/16/2011 5:59:34 PM EDT
Originally Posted By shortround:
Marine supply stores are also a great place to buy larger size wire copper lugs and electrical fittings.  If you think about it, most bigger boats are set up to do just what you are trying to accomplish.


problem is your going to pay a premium for anything at a marine shop.
Link Posted: 5/16/2011 6:10:56 PM EDT
[Last Edit: 5/16/2011 6:14:52 PM EDT by Skibane]
Originally Posted By bikejunky:
Not to high jack this thread but if one where to use the 1000WBlack and Decker inverter


and use 4 gauge battery cables, would the 70 amp circuit breaker be a good choice


Or should one move up to the 100amp?


The B&D owner's manual recommends a 200 amp fuse. It also recommends using 2 gauge wire for "permanent" installation.

Consider that this model is capable of supplying 2000 watts for brief periods - which would be around 167 amps at 12 volts. Add in the fact that the inverter is probably only around 80 percent efficient at that kind of power level, and it could easily be drawing 200 amps!

So - It's probably best to "go large" on your fuse or circuit breaker.

Note that using an oversized fuse or circuit breaker also has the advantage of typically having less voltage drop when carrying normal amounts of current.

Personally, I'm using the "ANL" fuses that are commonly sold for auto sound systems - They're cheap and readily available on ebay and Amazon.

Also - Have you seen this thread about the same inverter being sold at Big Lots for 50 bucks?
Link Posted: 5/17/2011 1:55:36 PM EDT
Some good info in this thread.  

My wife and I are setting up something similar for her sister in Huntsville AL.

One quick question and a small hijack..  I am sitting up a large scale battery box.  I have four 100 amp hour 12v batteries.  I am looking for some type of power distribution block where I can bring all 4 battery feeds in at one point and then have one power out port to feed my Saratoga Rig Runner.  I want to be able to charge the batteries from one common point through equal length cables so all batteries receive a charge..

Semper Fi
Link Posted: 5/18/2011 12:29:28 AM EDT
Originally Posted By dave5339:
Some good info in this thread.  

My wife and I are setting up something similar for her sister in Huntsville AL.

One quick question and a small hijack..  I am sitting up a large scale battery box.  I have four 100 amp hour 12v batteries.  I am looking for some type of power distribution block where I can bring all 4 battery feeds in at one point and then have one power out port to feed my Saratoga Rig Runner.  I want to be able to charge the batteries from one common point through equal length cables so all batteries receive a charge..

Semper Fi


http://shop.ebay.com/i.html?_trkparms=65%253A10%257C66%253A2%257C39%253A1&rt=nc&_nkw=power%20distribution%20block&_trksid=p3286.c0.m14.l1513&_pgn=1

Link Posted: 5/18/2011 6:51:36 AM EDT



Originally Posted By wildearp:


If you need a source for larger gauge wire and terminals, go to a welding supply store.



Ace hardware also sells the copper terminals.



DC current ratings are different for wire ampacity than AC.  Be sure to use a proper chart and consider wire length.


I was going to mention this. Welding cable is much more flexible than typical battery cables, and uses more strands of smaller wire. It's much better quality(IMO) than battery cables or large A/C wires.



 
Link Posted: 5/21/2011 9:49:48 AM EDT
Lets say I have a battery rated at 22 amp/h and I am charging a cell phone which requires 6 watts.

Can anyone tell me how long I can charge the phone til the battery is completely discharged?
Link Posted: 5/21/2011 11:18:37 AM EDT
Originally Posted By molar:
Lets say I have a battery rated at 22 amp/h and I am charging a cell phone which requires 6 watts.

Can anyone tell me how long I can charge the phone til the battery is completely discharged?


Volts X Amps = Watts, or

Watts / Volts = Amps.

So, if your cell phone charger consumes 6 watts, it will be drawing

6 watts / 12 volts = 0.5 Amps of current out of your battery...

Which means that your 22 Amp-Hour battery could theoretically operate it for

22 Amp-Hours  / 0.5 Amps  = 44 hours.

Link Posted: 5/21/2011 5:30:43 PM EDT
Very nicely done w12x40! It warms my heart every time I see one of these boxes come to life
Link Posted: 6/15/2011 6:53:50 AM EDT
I will not let this thread die until my battery box is in place!

So far I have acquired some 2-gauge wire and a 3-pole 100 amp circuit breaker. If I rig 2 polls, it will give me 200A.

Question on inverters. I have no Big Lots by me, so ebay's going to be my friend. There are many Chinese inverters there, some go for as little as 30-40 bucks for a 1000W model. Are they any good? Don't know power characteristics. I also saw a Cobra modified sin wave 1000W for $65 shipped. Which one should I go with without spending much money? Which electronics are sensitive that might be ruined?

Next on my list, after the inverter, is a trip to Costco to get a deep cycle battery.
Also, I saw some 12V 18ah Li-ion batteries on ebay for $100. They only weigh 3 lbs. Maybe those are worth it if I wanted to get some portability to the system at cost of power and duration. On a positive side, these recharge very quickly and can be drained totally without ruining the battery.

And last but not least - chargers. Like I said above, I have no Big Lots by me, so those 40-amp automatic chargers for $50 are not an option. What would be the most cost-effective solution?

Thank you all for your help.
Link Posted: 6/15/2011 9:55:25 AM EDT
This is the Li-ion battery I was talking about. If there's a way to rig it to an inverter (probably have to open to get to the terminals), it would provide a really lightweight power supply for portability. Don't know if anyone had tried it.

http://item.mobileweb.ebay.com/viewitem?itemId=120700143448&index=22&nav=SEARCH&nid=78229851808

18000 mah is 18 ah, correct?
Link Posted: 6/15/2011 4:20:23 PM EDT
Selfish bump.
Link Posted: 6/15/2011 4:27:19 PM EDT
tag
Link Posted: 6/15/2011 5:03:08 PM EDT
[Last Edit: 6/15/2011 5:05:10 PM EDT by mylt1]
Originally Posted By batjka104:
This is the Li-ion battery I was talking about. If there's a way to rig it to an inverter (probably have to open to get to the terminals), it would provide a really lightweight power supply for portability. Don't know if anyone had tried it.

http://item.mobileweb.ebay.com/viewitem?itemId=120700143448&index=22&nav=SEARCH&nid=78229851808

18000 mah is 18 ah, correct?


18ah's isnt that much. you really need to look into larger batteries, either automotive or deep cell would be your best bet. that being said, if you wanted to build a small solar battery back up for charging things like cell or even running a clock or some 12v lights then 1 or 2 of those batteries and a small panel with charge controller would provide you with a nice little charging station for your small devices.
Link Posted: 6/15/2011 5:53:06 PM EDT
Originally Posted By w12x40:
Inspired by the CJan_NH post, I decided to build a battery box, initially because I thought it would be a wonderful way to run my sump pump in case the power goes out during a rain storm. I remembered that half the time when the power goes out, it's a hot and sticky evening, so this should do nicely to run a fan and a lamp.

I'm a structural engineer. My college experience with electronics was a single required course where we never got past Thevenin whatchamacallits and the oscilloscopes never worked right. In every day life, I know one thing: if you don't touch it, it won't shock you. This project presented a dandy way to do some wiring and get something useful.

A few things I learned:

1. The copper battery cable lugs are discontinued at Autozone. I did everything out of crimp-on ring terminals.
2. Those powerpole things are expensive. Getting the wires into them and then making them connect is kind of a pain in the ass.
3. It seemed like a really good idea, so I bought the crimper that goes with the powerpole connectors. One crimp and I sheared a pin in the tool. I sent it back to Powerwerx.com, and we'll see how their customer service does.
4. The Optima batteries suggest a 1-amp maximum trickle charge for maintenance. The charger I bought only did 2-amps. So I bought a trickle charger that does 1-amp.
5. I had no raw materials. 10-gage wire is expensive, too.
6. You can't plug your iphone directly into the USB port on that model inverter. Well, you can, but it won't charge the phone. If you plug the AC wall wart into the inverter, it charges as expected.
7. I didn't realize the inverter had a power switch, I thought it would start right up when I plugged it in like the charger. This led me to go dig out my multimeter, whereupon I discovered that the batteries in it were dead.
8. The breaker that doubles as an on-off switch took me forever to find. You have to look for a surface-mount marine battery. Conveniently, Powerwerx sold it, too.
9. I have two stripper/crimper tools. One wouldn't strip wire worth a damn, but it did OK crimping. The other was a great stripper (I nicknamed it "Miss Nude Pennsylvania") but didn't crimp worth a crap. Neither one would cut 10-gage.
10. Surprisingly, there weren't a whole lot of parts and pieces available at either Autozone or Pep Boys. I was expecting more.
11. The nylon strap that comes with the battery box sucks. It is hard to tighten and impossible to undo. I went into my tactical nylon box and got a piece of 1" web and a ladder buckle. Now I can open it up easily.
12. I bought the battery box that was bigger (group 28-34, I think) than the battery so I could use the extra compartment for storage. Pigtails, fuses, inverter and charger instructions.

I don't even want to count how much I spent. I had nothing, so everything was an acquisition. I paid shipping on a lot of it die to internet ordering. My wife will see the credit card statement and complain, she'll see the box and complain, she'll see the charger and complain, she'll complain that I built a box instead of doing laundry, and the first time the power goes out, I'll rub her nose in it.

So, thanks to CJan_NH for the writeup.




................WARNING......... TRICKLE CHARGER WILL DESTROY AN OPTIMA BATTERY.....

Link Posted: 6/15/2011 6:27:23 PM EDT
Just in case you missed the other guy's comment, larger wires have less resistance.  

Originally Posted By w12x40:
It is all 10-gage stuff. I know that a larger wire is required for larger current, but I think it also has larger resistance.


Link Posted: 6/15/2011 6:44:31 PM EDT
Originally Posted By Fullpower:
Originally Posted By w12x40:
Inspired by the CJan_NH post, I decided to build a battery box, initially because I thought it would be a wonderful way to run my sump pump in case the power goes out during a rain storm. I remembered that half the time when the power goes out, it's a hot and sticky evening, so this should do nicely to run a fan and a lamp.

I'm a structural engineer. My college experience with electronics was a single required course where we never got past Thevenin whatchamacallits and the oscilloscopes never worked right. In every day life, I know one thing: if you don't touch it, it won't shock you. This project presented a dandy way to do some wiring and get something useful.

A few things I learned:

1. The copper battery cable lugs are discontinued at Autozone. I did everything out of crimp-on ring terminals.
2. Those powerpole things are expensive. Getting the wires into them and then making them connect is kind of a pain in the ass.
3. It seemed like a really good idea, so I bought the crimper that goes with the powerpole connectors. One crimp and I sheared a pin in the tool. I sent it back to Powerwerx.com, and we'll see how their customer service does.
4. The Optima batteries suggest a 1-amp maximum trickle charge for maintenance. The charger I bought only did 2-amps. So I bought a trickle charger that does 1-amp.
5. I had no raw materials. 10-gage wire is expensive, too.
6. You can't plug your iphone directly into the USB port on that model inverter. Well, you can, but it won't charge the phone. If you plug the AC wall wart into the inverter, it charges as expected.
7. I didn't realize the inverter had a power switch, I thought it would start right up when I plugged it in like the charger. This led me to go dig out my multimeter, whereupon I discovered that the batteries in it were dead.
8. The breaker that doubles as an on-off switch took me forever to find. You have to look for a surface-mount marine battery. Conveniently, Powerwerx sold it, too.
9. I have two stripper/crimper tools. One wouldn't strip wire worth a damn, but it did OK crimping. The other was a great stripper (I nicknamed it "Miss Nude Pennsylvania") but didn't crimp worth a crap. Neither one would cut 10-gage.
10. Surprisingly, there weren't a whole lot of parts and pieces available at either Autozone or Pep Boys. I was expecting more.
11. The nylon strap that comes with the battery box sucks. It is hard to tighten and impossible to undo. I went into my tactical nylon box and got a piece of 1" web and a ladder buckle. Now I can open it up easily.
12. I bought the battery box that was bigger (group 28-34, I think) than the battery so I could use the extra compartment for storage. Pigtails, fuses, inverter and charger instructions.

I don't even want to count how much I spent. I had nothing, so everything was an acquisition. I paid shipping on a lot of it die to internet ordering. My wife will see the credit card statement and complain, she'll see the box and complain, she'll see the charger and complain, she'll complain that I built a box instead of doing laundry, and the first time the power goes out, I'll rub her nose in it.

So, thanks to CJan_NH for the writeup.




................WARNING......... TRICKLE CHARGER WILL DESTROY AN OPTIMA BATTERY.....



WARNING, optimas are over rated and are now POS's since they sold out. i wouldnt waste my time or money on them. there are more and more people having problems with the newer optimas then arent. there is NO reason a trickle charger should/would kill any battery.
Link Posted: 6/15/2011 11:29:22 PM EDT
Originally Posted By batjka104:
Question on inverters. I have no Big Lots by me, so ebay's going to be my friend. There are many Chinese inverters there, some go for as little as 30-40 bucks for a 1000W model. Are they any good? Don't know power characteristics. I also saw a Cobra modified sin wave 1000W for $65 shipped. Which one should I go with without spending much money?


On some of the no-name Chinese stuff, they cut corners on circuit design and the quality of the individual electronic components. Also, you probably won't get a usable warranty. For this reason, I would go with the Cobra, or some other name brand.

Which electronics are sensitive that might be ruined?


Cordless tool battery chargers are probably the item most likely to be damaged by using a modified sine wave inverter - Most of them don't like anything other than true sine wave AC. Also, some AC motors (i.e., table fans, box fans, etc.) will run slow and noisy with MSW power, and some audio equipment has a hum problem with it.
Link Posted: 6/16/2011 4:20:03 AM EDT
My take on this battery box deal while cool and all that is why take something so simple and spend money to complicate the issue? The first problem I see is all the fuses, you do not need a fuse from the charger to the battery. Battery chargers are made to charge battery's just fine the way they are. The other fuse between the inverter and battery is also not needed, the inverter is going to draw what it draws nothing more. The inverter comes with a cable and alligator clips for a reason, its all that is needed, its quick, and the clips will hook to any battery with no tools required. All this extra hard wire and what not just makes it hard to swap out battery's and makes an already heavy battery even heaver with the inverter and all the other stuff hooked on.

Here is an example. Power goes out due to a ice storm and I need to run a few lights and tv to see whats going on and I eventually discharge the battery. The next day or so say I need to run the generator for the fridge, freezer and say heater and I also need to charge the cell phones as everyone I know has been calling the wife and I to see if we are alive. Well no problem I plug my charger into the generator as its big enough to handle all this load and charge the battery, in the mean time I go grab another battery and hook up the inverter and charge my phones or what ever. While you are still taking off all the wire set up and pulling your battery out of the box to set up another one I am having a hot tottie and watching the tv. There is also the portability of just a inverter as battery's are not hard to find I can just grab the inverter and go knowing that the car battery will take car of any issues I might need.

Just seams like the money spent on all the unnecessary stuff could be used for a bigger battery or another battery if you are battery deficient.
Link Posted: 6/16/2011 5:31:10 AM EDT
Originally Posted By mylt1:
Originally Posted By Fullpower:
Originally Posted By w12x40:
Inspired by the CJan_NH post, I decided to build a battery box, initially because I thought it would be a wonderful way to run my sump pump in case the power goes out during a rain storm. I remembered that half the time when the power goes out, it's a hot and sticky evening, so this should do nicely to run a fan and a lamp.

I'm a structural engineer. My college experience with electronics was a single required course where we never got past Thevenin whatchamacallits and the oscilloscopes never worked right. In every day life, I know one thing: if you don't touch it, it won't shock you. This project presented a dandy way to do some wiring and get something useful.

A few things I learned:

1. The copper battery cable lugs are discontinued at Autozone. I did everything out of crimp-on ring terminals.
2. Those powerpole things are expensive. Getting the wires into them and then making them connect is kind of a pain in the ass.
3. It seemed like a really good idea, so I bought the crimper that goes with the powerpole connectors. One crimp and I sheared a pin in the tool. I sent it back to Powerwerx.com, and we'll see how their customer service does.
4. The Optima batteries suggest a 1-amp maximum trickle charge for maintenance. The charger I bought only did 2-amps. So I bought a trickle charger that does 1-amp.
5. I had no raw materials. 10-gage wire is expensive, too.
6. You can't plug your iphone directly into the USB port on that model inverter. Well, you can, but it won't charge the phone. If you plug the AC wall wart into the inverter, it charges as expected.
7. I didn't realize the inverter had a power switch, I thought it would start right up when I plugged it in like the charger. This led me to go dig out my multimeter, whereupon I discovered that the batteries in it were dead.
8. The breaker that doubles as an on-off switch took me forever to find. You have to look for a surface-mount marine battery. Conveniently, Powerwerx sold it, too.
9. I have two stripper/crimper tools. One wouldn't strip wire worth a damn, but it did OK crimping. The other was a great stripper (I nicknamed it "Miss Nude Pennsylvania") but didn't crimp worth a crap. Neither one would cut 10-gage.
10. Surprisingly, there weren't a whole lot of parts and pieces available at either Autozone or Pep Boys. I was expecting more.
11. The nylon strap that comes with the battery box sucks. It is hard to tighten and impossible to undo. I went into my tactical nylon box and got a piece of 1" web and a ladder buckle. Now I can open it up easily.
12. I bought the battery box that was bigger (group 28-34, I think) than the battery so I could use the extra compartment for storage. Pigtails, fuses, inverter and charger instructions.

I don't even want to count how much I spent. I had nothing, so everything was an acquisition. I paid shipping on a lot of it die to internet ordering. My wife will see the credit card statement and complain, she'll see the box and complain, she'll see the charger and complain, she'll complain that I built a box instead of doing laundry, and the first time the power goes out, I'll rub her nose in it.

So, thanks to CJan_NH for the writeup.




................WARNING......... TRICKLE CHARGER WILL DESTROY AN OPTIMA BATTERY.....



WARNING, optimas are over rated and are now POS's since they sold out. i wouldnt waste my time or money on them. there are more and more people having problems with the newer optimas then arent. there is NO reason a trickle charger should/would kill any battery.


I read the instruction manual that came with the Optima. It said a trickle charge was OK as long as it was 1 amp or less. My next box won't be an optima, though.
Link Posted: 6/16/2011 5:32:09 AM EDT
Originally Posted By Muddydogs:
My take on this battery box deal while cool and all that is why take something so simple and spend money to complicate the issue? The first problem I see is all the fuses, you do not need a fuse from the charger to the battery. Battery chargers are made to charge battery's just fine the way they are. The other fuse between the inverter and battery is also not needed, the inverter is going to draw what it draws nothing more. The inverter comes with a cable and alligator clips for a reason, its all that is needed, its quick, and the clips will hook to any battery with no tools required. All this extra hard wire and what not just makes it hard to swap out battery's and makes an already heavy battery even heaver with the inverter and all the other stuff hooked on.

Here is an example. Power goes out due to a ice storm and I need to run a few lights and tv to see whats going on and I eventually discharge the battery. The next day or so say I need to run the generator for the fridge, freezer and say heater and I also need to charge the cell phones as everyone I know has been calling the wife and I to see if we are alive. Well no problem I plug my charger into the generator as its big enough to handle all this load and charge the battery, in the mean time I go grab another battery and hook up the inverter and charge my phones or what ever. While you are still taking off all the wire set up and pulling your battery out of the box to set up another one I am having a hot tottie and watching the tv. There is also the portability of just a inverter as battery's are not hard to find I can just grab the inverter and go knowing that the car battery will take car of any issues I might need.

Just seams like the money spent on all the unnecessary stuff could be used for a bigger battery or another battery if you are battery deficient.


You're probably right. It was fun, though.
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