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Posted: 6/1/2007 12:59:37 AM EDT
Me and my roomate are talking about getting a generator.
This is something I know noting about. Are the ones you get at Lowes/HomeDepot good or good enough, or should one look elsewhere for a better deal/better product?

Any general guidlnes, suggestions, recommendations?
Link Posted: 6/1/2007 1:07:03 AM EDT
Depends entirely on what you wish to power.... have you calculated how much wattage you need?

I'm assuming you want portable? "Roommate" implies (at least to me) that you're a renter.

What are you going to do about fuel storage? A larger generator will consume a fair amount of gasoline, which doesn't store very well, and will be in very short supply once disaster strikes.

Are you planning on running extension cords, or is there a twist-lock generator receptable at your home? When you're using your generator, you'll need to either turn off grid power, or use a transfer switch. You don't want to just plug it into the wall... you'll be backfeeding current into the grid, and may kill the power-company guy who's trying to get your power back on.

You're in Florida, so I assume this is for hurricane preparedness, yes?
Link Posted: 6/1/2007 1:29:30 AM EDT
yes, hurricane prep. I am a renter.

I do know a thing or two about ele. In fact i work in the field, but I really don't deal w/ little gas gennys.

What about little single cylinder aircooled dielsel generators? Can those be had?

I guess this would be for powering the house w/ drop cords. I do realize the dangers of backfeeding.

As for the load, probably just 120 stuff, but we may want to run the AC. so we might have to work up some sort of L-L scheme.

Does anyone know of any powerful fans, probably 240v that can fit into the scuttle hole going into the atic to act as a whole house attic fan, but not a permanant one?

Link Posted: 6/1/2007 1:50:14 AM EDT
[Last Edit: 6/1/2007 1:52:39 AM EDT by TheGrayMan]

s for the load, probably just 120 stuff, but we may want to run the AC


Powering AC units takes a very large generator, since AC units pull an enormous amount of current when they start up; 5-6x their nominal running amperage.

Go outside and take a look at your AC unit. The metal plate on the side should have a field labeled "LRA" (stands for "Locked Rotor Amps"). That's the maximum amount of current that your unit can draw at startup... for a standard residential 4-ton AC unit, it can be well over 100 amps. Multiple that by 120v and you've got the total wattage that your AC unit can potentially pull. You're going to find very few portable generators that can supply 12kW (that's just to start your AC... that doesn't include fridge, lights, computers, fans, etc)

You're going to find that running AC units (with their associated blowers) takes a mighty big genset (unless you've got a dinky window unit that's going to be cooling one room).

You might just want to open the windows and turn on some fans... at least that way you could keep your fridge cold, and a few lights on. Most portable generators aren't designed for much more than that.

I don't think a single-cylinder diesel (though I am fond of diesels) is going to do what you want.
Link Posted: 6/1/2007 3:07:58 AM EDT
Thanks for the info about the startup load. What we need to do is get the attic well ventalatted and install a good whole house attic ceiling fan that we could run w/ the genny.

WHy not the diesels? Do you know anything about them or are you just stating that they are kind of obsuce and specialized.

Link Posted: 6/1/2007 4:27:22 AM EDT
I have a 5200 watt gen. (6.5K surge) and bought a 6000 BTU window unit for my bedroom. It only draws about 7 amps, so at least we can sleep at night. I can run the a/c, refrigerator, lights (as needed), and TV. The down side.....it's as loud as a freight train (10 HP), and burns about a tank of gas (7 gal.) in about 12-14 hours.

a-bare
Link Posted: 6/1/2007 4:42:13 AM EDT
I just picked up a 5K unit from HD this morning. The best part was that I got the genny, 4 5-gal cans, and a carbon monoxide detector for less than the sticker price on the genny. It's got a Suburu engine that's supposed to be pretty quiet. We'll see. Hopefully I'll get her checked out tonight after work.

I'd recommend buying a Kill-a-Watt to check that actual pull the items you want to run have (both wattage and amperage).
Link Posted: 6/1/2007 5:04:48 AM EDT
[Last Edit: 6/1/2007 5:05:10 AM EDT by N_FL_Mountaineer]
Some of you have seen this in another thread but it bears repeating...I use battery powered inverters for a window A/C unit and my refrigerator...have APC ups units that are backed up my some beefy external batts for computer, entertainment, communications, etc.



The batts all have the quick connect plugs that I can hook up on my truck to charge...
I intend to get a small generator this year to run some 240V stuff in the house for a few hours a day.
Link Posted: 6/1/2007 6:22:07 AM EDT

Originally Posted By N_FL_Mountaineer:
Some of you have seen this in another thread but it bears repeating...I use battery powered inverters for a window A/C unit and my refrigerator...have APC ups units that are backed up my some beefy external batts for computer, entertainment, communications, etc.

www.imagestation.com/picture/sraid223/pb59c2aac53465246fab1c3f86f87f226/eac5f0ae.jpg

The batts all have the quick connect plugs that I can hook up on my truck to charge...
I intend to get a small generator this year to run some 240V stuff in the house for a few hours a day.


So the unit in the picture is for your fridge and AC, and then you have some APC units for other stuff? If so, how long can you run a window unit on a hot day on those two 12V batteries?
Link Posted: 6/1/2007 6:23:14 AM EDT

Originally Posted By rightwingnut:
Does anyone know of any powerful fans, probably 240v that can fit into the scuttle hole going into the atic to act as a whole house attic fan, but not a permanant one?


All the whole-house fans I've looked at are 120 VAC only, and are way too big to fit in the average attic access hole. However, it shouldn't be too hard to build your own, using either a through-the-roof attic fan or a table fan mounted to a piece of plywood cut to fit the scuttle hole opening. (Although an attic fan would probably pull more air, a table fan gives you the option of running several, quieter speeds).

120 VAC should be just fine for this application.
Link Posted: 6/1/2007 6:36:53 AM EDT

Originally Posted By rightwingnut:

Originally Posted By N_FL_Mountaineer:
Some of you have seen this in another thread but it bears repeating...I use battery powered inverters for a window A/C unit and my refrigerator...have APC ups units that are backed up my some beefy external batts for computer, entertainment, communications, etc.

www.imagestation.com/picture/sraid223/pb59c2aac53465246fab1c3f86f87f226/eac5f0ae.jpg

The batts all have the quick connect plugs that I can hook up on my truck to charge...
I intend to get a small generator this year to run some 240V stuff in the house for a few hours a day.


So the unit in the picture is for your fridge and AC, and then you have some APC units for other stuff? If so, how long can you run a window unit on a hot day on those two 12V batteries?



We have so far run the window A/C unit for an entire weekend without recharging...have a separate unit just like one shown for the refrigerator
Link Posted: 6/1/2007 6:39:55 AM EDT
That is quite impressive! Those are just some big deep cycle 12 volt batteries? Two of them?

Do you work in the critical powerfield to have come by those APC units? I work on UPS's myself.
Link Posted: 6/1/2007 8:46:58 AM EDT

Originally Posted By N_FL_Mountaineer:
We have so far run the window A/C unit for an entire weekend without recharging...have a separate unit just like one shown for the refrigerator


How many amp hours is that rated for?


Link Posted: 6/1/2007 9:10:15 AM EDT
Im in Biomedical Engineering, actually...have some USER experience with UPS units...The batts are deep cycle gel batteries made by Optima and I am unsure of the a/h rating.

My ups' are backed up by various types of gel cels obtained from many different sources, my favorite setup being the rackmount set of 8 ea 12v 7ah cells.

Inverters and batteries are WAY cheaper than running a generator round the clock.

Bryan
Link Posted: 6/1/2007 12:25:43 PM EDT
Interesting.

I've seen some 6v golf cart type batteries at sam's club.

They're Energizer brand, 220 AH. Is that a decent output/capacity?

Link Posted: 6/1/2007 12:43:11 PM EDT
While we're on the subject, perhaps somebody can tell me how much generator I need. My goal would be to run 2 refridgerators, lights and the ham radio. To me, that doesn't seem like a lot, but I also don't want to snake by with the "minimum".
Link Posted: 6/1/2007 12:45:43 PM EDT
[Last Edit: 6/1/2007 12:47:08 PM EDT by Skibane]

Originally Posted By N_FL_Mountaineer:
We have so far run the window A/C unit for an entire weekend without recharging...have a separate unit just like one shown for the refrigerator


Generously assuming that each battery is capable of supplying 1 KWH of power...
And generously assuming that your window air conditioner is the smallest model available (5,000 BTU)...
And generously assuming that your window air conditioner has the highest efficiency available (EER=10)...
And generously assuming that your inverter is 100 percent efficient...

The 500 watts of power consumed by your AC could be provided by one of your batteries for 2 hours, or 4 hours total for the pair of batteries.

Since when is a weekend 4 hours long?
Link Posted: 6/1/2007 1:02:01 PM EDT

Originally Posted By Skibane:

Originally Posted By N_FL_Mountaineer:
We have so far run the window A/C unit for an entire weekend without recharging...have a separate unit just like one shown for the refrigerator


Generously assuming that each battery is capable of supplying 1 KWH of power...
And generously assuming that your window air conditioner is the smallest model available (5,000 BTU)...
And generously assuming that your window air conditioner has the highest efficiency available (EER=10)...
And generously assuming that your inverter is 100 percent efficient...

The 500 watts of power consumed by your AC could be provided by one of your batteries for 2 hours, or 4 hours total for the pair of batteries.



Since when is a weekend 4 hours long?




Thanks for your generosity????????

Hmmm,

from Friday evening to Sunday evening, the A/C unit is 8,000 btu and the batteries were still very strong when I unplugged the unit...nowhere near fully discharged.
I didn't just find this on the internet, I built the cart and assembled the whole deal from scratch to provide emergency cooling in case of power outage...

but thanks for calling me out publicly...that was very brave.
Link Posted: 6/1/2007 1:18:10 PM EDT

My goal would be to run 2 refridgerators, lights and the ham radio. To me, that doesn't seem like a lot, but I also don't want to snake by with the "minimum".



That's NOT a lot, actually. You might be able to get by with one of the thrifty little honda generators, particularly if you alternate plugging in your two fridges (and don't open them much).

Generally you want to calculate your loads based on everything starting up at the same time. Check out the max current draw on your refrigerators, figure 100 watts per light bulb, and whatever wattage your Ham rig pulls.

Add it all together and then add 20%.

Calculate your fuel consumption by reading your generator manual... it should give you Gal/hr figures for various loads (eg. .5 Gal/hr @ half-load).

After that, it's all a matter of stocking enough gas to get you through your predicted outage period.

Important Note: When stockpiling gas, also plan on stocking oil to change the generator's engine oil. Some portable home generators recommend an oil change every 100 hours (about four days). You don't want to burn up a 2-3000 dollar generator because you forgot to get oil ahead of time.
Link Posted: 6/1/2007 1:36:21 PM EDT
[Last Edit: 6/1/2007 2:15:42 PM EDT by dablues]

Originally Posted By Primos:
Interesting.

I've seen some 6v golf cart type batteries at sam's club.

They're Energizer brand, 220 AH. Is that a decent output/capacity?



That's pretty standard. Here's what I do to compare apples to apples. 6v * 220AH = 1320watt-hours.

By comparison, an Optima type 31 sealed glass mat battery is 12v at 75AH or 900watt-hours.

I run a bank of six, type 31 would be 5400watt-hours.

4 of the Energizer you talked about would be 5280 watt-hours. Roughly the same total power.

Mind you, most companies rate their batteries over a 20 hour period, so I would *not* get near 5400watt-hours if I drained the batteries in just a couple hours, and conversely, I could get a lot more total energy if I could load the battery with only a few watts drain.

I went with the glass mat batteries for low maintenance *and* the fact the batteries are still light weight enough I can pick them up single handedly.

There are some really honking big batteries available that weigh hundreds of pounds per battery.

I am curious what the Optima batteries shown above are? They look substantially bigger than the ones I've got.

In any case, get a Kill-A-Watt meter!

Plug in the stuff you intend to run and find out how much energy it really uses, say, over 12 hours. Case in point, Sears chest freezer I have says 120volts * 5 amps.

Hmmm..that suggests 600 watts.

However, running watts is really about 120 watts, and averaged out with start and stop cycle, my 15 cubic foot freezer uses about *75* watts an hour to run all day.

So, if all I wanted to do was maintain my deep freeze, 5400watt-hours divided by 75 watts equals 72 hours.....theoretically.

However, my particular inverter (Xantrex Prosine 2000) is about 85% efficient, and that knocks it down to 61 hours. And then ideally, a lead acid battery shouldn't be drained more than 50%, so I can get about 30 hours of practical runtime with the setup I've got before I recharge them with a 100 amp charge for about 2 to 3 hours.

That's the numbers that my setup has.

My design was to avoid running a generator 24x7 for security reasons and quiet hours and wear and tear on the genset.
Link Posted: 6/1/2007 3:02:57 PM EDT
[Last Edit: 6/1/2007 3:15:51 PM EDT by Tight-group]

Originally Posted By rightwingnut:
yes, hurricane prep. I am a renter.

I do know a thing or two about ele. In fact i work in the field, but I really don't deal w/ little gas gennys.

What about little single cylinder aircooled dielsel generators? Can those be had?
Yes but are the're noise and weight considerations + cost?
I guess this would be for powering the house w/ drop cords. I do realize the dangers of backfeeding.

As for the load, probably just 120 stuff, but we may want to run the AC. so we might have to work up some sort of L-L scheme.

Does anyone know of any powerful fans, probably 240v that can fit into the scuttle hole going into the atic to act as a whole house attic fan, but not a permanant one?
You could get one of those black and decker tornado fans and get it to mount in your scuttle they move an amazeing amount of air they pull about 170 watts on high


How much are you going to invest? There are some quiet enclosed diesels out there. Your fuel storage issues are greatly reduced

I have two and love em one is 4.2K @3600 rpm the other is 15K @1800rpm

the small one goes thru about 3 gallons at 1/2 load in 20 hrs

the big one goes thru about .375 gal an hr at 4K load
Link Posted: 6/1/2007 3:50:31 PM EDT
[Last Edit: 6/1/2007 3:51:22 PM EDT by Skibane]

Originally Posted By N_FL_Mountaineer:
from Friday evening to Sunday evening, the A/C unit is 8,000 btu and the batteries were still very strong when I unplugged the unit...nowhere near fully discharged.


No need for offense - I'm just trying to understand how you managed to stretch 4 hours of A/C operation into 48...

Was the thermostat set so high (or the ambient temperature so low) that the compressor never kicked on?
Does this A/C have an "energy saver" switch that also shuts off the fan whenever the compressor isn't running?
Link Posted: 6/1/2007 5:14:40 PM EDT
The A/C unit was put into use because we had no power for the heat pump. We were able to bring the temp in the living room down to about 75 degrees at which point the power saver funcion of the A/C kicked in...no offense taken....consider that you are using 12 volt batts to power the inverter which makes ac for the air conditioner or other load. I ran a single bettery on an inverter for my garage window a/c for about 18 hours before it gave up the ghost...it was a regular car battery, not the deep cycle Optima...

Bryan
Link Posted: 6/2/2007 10:44:40 AM EDT
[Last Edit: 6/2/2007 10:46:02 AM EDT by rightwingnut]

Originally Posted By Tight-group:

Originally Posted By rightwingnut:
yes, hurricane prep. I am a renter.

I do know a thing or two about ele. In fact i work in the field, but I really don't deal w/ little gas gennys.

What about little single cylinder aircooled dielsel generators? Can those be had?
Yes but are the're noise and weight considerations + cost?
I guess this would be for powering the house w/ drop cords. I do realize the dangers of backfeeding.

As for the load, probably just 120 stuff, but we may want to run the AC. so we might have to work up some sort of L-L scheme.

Does anyone know of any powerful fans, probably 240v that can fit into the scuttle hole going into the atic to act as a whole house attic fan, but not a permanant one?
You could get one of those black and decker tornado fans and get it to mount in your scuttle they move an amazeing amount of air they pull about 170 watts on high


How much are you going to invest? There are some quiet enclosed diesels out there. Your fuel storage issues are greatly reduced

I have two and love em one is 4.2K @3600 rpm the other is 15K @1800rpm

the small one goes thru about 3 gallons at 1/2 load in 20 hrs

the big one goes thru about .375 gal an hr at 4K load


Honestly, I am probably going to be trying to get by on the cheap, at least for now so the diesel is probably out of the question, but what about those little ones ones that some truckers have to run stuff when they are parked, I believe they are little single cylinder ones and they are not too loud. I dont know how those work exactly either. I suspect they may be hooked up to their own alternater to charge the truck battery??? I dunno, how how woudl they run climate control in their truck, I guess they have to have another ac unit besides the one on the accessory belt of the truck engine???

Anybody know how this works?

Anyway, I might just try to combine a very small honda gas genny w/ some inverteirs and batteiries like N FL is doing?
Link Posted: 6/2/2007 10:51:51 AM EDT
I am a little suprised that those batteries can run that AC for so long. Of course theere a a bunch of little variable like how hot is outside, how much space, how well insulated etc that matter, but still.

NFL Mounttaineer. I am curious about what your scheme is for keeping from over dischargeing your Optima Gel Batteries? Do you just have to remember to go check them every so often, or is the inverter set to shut off when DC voltages drops below a certain threshhold? Just how sensitive are these "gel batteries" to deep discharging?

What kind of money are we talking about for those gel batteries?

I really haven't had any experience w/ gel batteries. They are always either regular or non-spillable lead acid as in most applications battery weight is not a big concern in a UPS scheme.

Are those APC units you have just little standby units that you plug in inbetween the wall jack and the device?
Link Posted: 6/2/2007 10:56:17 AM EDT
so I was at a Dr yesterday, waiting and waiting of course, & I came across mother earth news in the magazine rack??? Anyway, I saw a little add in the back for some company that sells trailer solar power units. One was a little car trailer unit, the other was a big ass unit, like a 30' trailer that had exide batteries and a generaor inside beneath the solar panels. It was said that that unit could power a whole houlse and was all set up ready to go. The portability of them was pretty cool.

Can you imagnine trying to bug out w/ that thing?

I'll did commandeer that magazine b/c of that and an article I saw about a couple that built a one room shed to live in in the country while they gradually built their house that I want to show my girlfriend.
Link Posted: 6/2/2007 12:18:34 PM EDT

Originally Posted By rightwingnut:
NFL Mounttaineer. I am curious about what your scheme is for keeping from over dischargeing your Optima Gel Batteries? Do you just have to remember to go check them every so often, or is the inverter set to shut off when DC voltages drops below a certain threshhold? Just how sensitive are these "gel batteries" to deep discharging?

I bought a Battery Tender for mine. It comes with a quick-disconnect cable to attach to the terminal posts. It also has alligator clips. So you can use whatever's right for you or swap them out easily.



What kind of money are we talking about for those gel batteries?

I paid $170 on sale for my Optima 34/78 yellow top. It's a 55Ah battery.
Link Posted: 6/2/2007 6:25:09 PM EDT
[Last Edit: 6/2/2007 6:33:21 PM EDT by rightwingnut]

Originally Posted By JaxShooter:

Originally Posted By rightwingnut:
NFL Mounttaineer. I am curious about what your scheme is for keeping from over dischargeing your Optima Gel Batteries? Do you just have to remember to go check them every so often, or is the inverter set to shut off when DC voltages drops below a certain threshhold? Just how sensitive are these "gel batteries" to deep discharging?

I bought a Battery Tender for mine. It comes with a quick-disconnect cable to attach to the terminal posts. It also has alligator clips. So you can use whatever's right for you or swap them out easily.



What kind of money are we talking about for those gel batteries?

I paid $170 on sale for my Optima 34/78 yellow top. It's a 55Ah battery.


How does this battery tender work exactly, particularly when you are running an inverter w/ load and w/o a chargeing input? Does it somehow shut the inverter down at a certain point or somethign?
Link Posted: 6/2/2007 6:32:00 PM EDT
here is a link to that company that makes the solar/generator power trailer units:

Independent Energy Systems
Link Posted: 6/2/2007 6:36:06 PM EDT
How much were those Golf cart batteries that guy saw at sams club or costco? How many amp hours were they?

How quickly do those gel batteries recharge compared to non-spillable lead acid types?
Link Posted: 6/3/2007 4:15:43 AM EDT
[Last Edit: 6/3/2007 4:18:11 AM EDT by N_FL_Mountaineer]
Wow! I only have a few minutes, I'll try to answer a few of these questions...

I started out with the cheapest hand truck I could find since it needed modified anyway. I welded some extra support for the batteries, the inverter mount, and the "dashboard" mount.

My thought was to be able to provide a portable aux power source quickly and quietly wherever needed.

Coleman 2000 Watt inverter, auto shuts off when betteries are drained to a safe voltage level. small charger to occasionally trickle charge in the house.

I chose the Optima batteries for many reasons...It's what I wanted to run in my vehicles and in fact is exactly what is in all but my 2005 Silverado 2500HD. That will get a matched pair of them eventually.

The big dollar plugs are from Anderson Power Products, they are used in a lot of stuff, golf carts, forklifts, NASCAR, etc. I wanted to swap these batteries from the house to the vehicles with as little fuss as possible, that for me meant ponying up for some fancy plugs.

When you are figuring out your potential runtime, it's difficult to calculate how much "bounce back" the batteries will have when they are in great shape. As in my case when the window A/C unit's compressor and fan cycle off the batteries recover more than I ever would have imagined. Now, I'm no expert in battery technology but have been working on battery-powered medical equipment for nearly 30 years, from small portable stuff to portable X-rays that used 90 each 1.5 volt wet lead acid cells that would provide unlimited instantaneous current...nearly no measurable internal resistance.

Anyway...one alternate plan might be to set this rig up in a little red wagon...really anything with wheels would do.

This kind of project would stretch a lot of handyman-types' capabilities to the danger point, I have to stress safety when working with high-discharge batteries.

A word on the UPS units...mine are standard battery back up units like you can buy for computers....I opened them up and brought attachment ponts to the outside of the case...to which I can connect an external battery in the case of an extended power outage. Most people should not attempt this, it requires internal modifacations that would void the warranty make your insurance agent cringe.

That's all for now..

Later

Bryan
Link Posted: 6/3/2007 3:48:00 PM EDT

Originally Posted By rightwingnut:
How does this battery tender work exactly, particularly when you are running an inverter w/ load and w/o a chargeing input? Does it somehow shut the inverter down at a certain point or somethign?

Well, I can't find anything specific about that in any documentation so I'd say it's up to you to monitor the load. I do know that if you're power something (like my ham rigs) then the load just makes the charger figure it needs to go to work. I don't see how it would be able to shut down your inverter.
Link Posted: 6/4/2007 12:11:11 AM EDT
I guess when people say a "battery tender" they mean a charger that turns on and off based on high and low voltage thresholds. Since it is generally bad on non wet batteries to be fully discharged, and it is also bad on batteries to have a constanst trickle charge when the batteries are full, the tender switches on and off approptiately. This is apposed to a trickle charger that has no logic beside the on/off switch and constantly charges batteries whether they need it or not.

When you mentioned them before, I thought you were referring to some sort of device that regulated discharge when utility power is not present to power the battery charger.

N-FL, I am well aware of anderson connectors. When you originally mentioned your truck & the batteries, I didn't realized that you were saying that you actually swap batteries b/t the unit and your truck, I thought that you were saying that just wheeled the cart outside and made a connectinon b/t the cart and your truck's ele system.
Link Posted: 6/4/2007 4:20:06 AM EDT
I was referring to the Battery Tender Plus.
Link Posted: 6/4/2007 4:25:14 AM EDT
thanks for the link.
Link Posted: 6/4/2007 5:07:26 AM EDT
It's been mentioned before, but is worth repeating:

After every significant "event" that I've been through (hurricane, etc.), it was so quiet in the neighborhood that you could hear a pin drop.

Running a generator under those circumstances draws a lot of attention. Not all of it welcomed.
Link Posted: 6/4/2007 5:16:12 AM EDT
The first thing I did was walk to the front of the house. I couldn't hear mine. I'm sure the neighbors on either side probably could but I doubt anyone else could. Perhaps if they were specifically listening for it. I've thought about the feasibility of building a sound baffled enclosure for it.
Link Posted: 6/4/2007 6:03:46 AM EDT
u one of them there smrt guys huh
Link Posted: 6/4/2007 6:29:26 AM EDT
Not as smart as this guy.
Link Posted: 6/4/2007 6:51:24 AM EDT
I don't see how it takes 20 ppages to discuss that stuff.
Link Posted: 6/4/2007 7:14:25 AM EDT
20? It's 84!! Looks like it was a PhD thesis or something.
Link Posted: 6/10/2007 5:25:00 AM EDT

Originally Posted By TheGrayMan:

s for the load, probably just 120 stuff, but we may want to run the AC


Powering AC units takes a very large generator, since AC units pull an enormous amount of current when they start up; 5-6x their nominal running amperage.

Go outside and take a look at your AC unit. The metal plate on the side should have a field labeled "LRA" (stands for "Locked Rotor Amps"). That's the maximum amount of current that your unit can draw at startup... for a standard residential 4-ton AC unit, it can be well over 100 amps. Multiple that by 120v and you've got the total wattage that your AC unit can potentially pull. You're going to find very few portable generators that can supply 12kW (that's just to start your AC... that doesn't include fridge, lights, computers, fans, etc)
.


The LRA on the central AC unit is 84.4amps. But wouldn't you take that times 240 since it is a line to line device rather than single line? Is it the case that they list the LRA in 120 volt amps as some sort of standard or something?
Link Posted: 6/10/2007 7:14:20 AM EDT
Good info
Link Posted: 6/10/2007 8:24:19 PM EDT
[Last Edit: 6/10/2007 8:28:28 PM EDT by Primos]

Originally Posted By rightwingnut:
How much were those Golf cart batteries that guy saw at sams club or costco? How many amp hours were they?

How quickly do those gel batteries recharge compared to non-spillable lead acid types?


The 6 volt golf cart batteries at Sam's Club are about $62 each.
220 Amp Hour.

I just bought two of them yesterday, myself.
Link Posted: 6/10/2007 9:29:50 PM EDT
[Last Edit: 6/10/2007 9:35:26 PM EDT by TomJefferson]
Link Posted: 6/16/2007 4:27:47 PM EDT
[Last Edit: 6/16/2007 4:55:31 PM EDT by dread-pirate]

Originally Posted By N_FL_Mountaineer:
Wow! I only have a few minutes, I'll try to answer a few of these questions...

I started out with the cheapest hand truck I could find since it needed modified anyway. I welded some extra support for the batteries, the inverter mount, and the "dashboard" mount.

My thought was to be able to provide a portable aux power source quickly and quietly wherever needed.

Coleman 2000 Watt inverter, auto shuts off when betteries are drained to a safe voltage level. small charger to occasionally trickle charge in the house.

I chose the Optima batteries for many reasons...It's what I wanted to run in my vehicles and in fact is exactly what is in all but my 2005 Silverado 2500HD. That will get a matched pair of them eventually.

The big dollar plugs are from Anderson Power Products, they are used in a lot of stuff, golf carts, forklifts, NASCAR, etc. I wanted to swap these batteries from the house to the vehicles with as little fuss as possible, that for me meant ponying up for some fancy plugs.

When you are figuring out your potential runtime, it's difficult to calculate how much "bounce back" the batteries will have when they are in great shape. As in my case when the window A/C unit's compressor and fan cycle off the batteries recover more than I ever would have imagined. Now, I'm no expert in battery technology but have been working on battery-powered medical equipment for nearly 30 years, from small portable stuff to portable X-rays that used 90 each 1.5 volt wet lead acid cells that would provide unlimited instantaneous current...nearly no measurable internal resistance.

Anyway...one alternate plan might be to set this rig up in a little red wagon...really anything with wheels would do.

This kind of project would stretch a lot of handyman-types' capabilities to the danger point, I have to stress safety when working with high-discharge batteries.

A word on the UPS units...mine are standard battery back up units like you can buy for computers....I opened them up and brought attachment ponts to the outside of the case...to which I can connect an external battery in the case of an extended power outage. Most people should not attempt this, it requires internal modifacations that would void the warranty make your insurance agent cringe.

That's all for now..

Later

Bryan


What are "plugs" you are referring to from Anderson? Are these just so you can also use it to jump start your cars? Or are there other uses for them?

I am going to build a similar system for the same reasons. I also like the idea with the handcart, takes up little space and is easy to wheel around.

Is there a thread or web page with more step by step directions and safety precautions to build a similar rig?

Link Posted: 6/16/2007 4:32:14 PM EDT

Originally Posted By dread-pirate:
What are "plugs" you are referring to from Anderson? Are these just so you can also use it to jump start your carss? Or are there other uses for them?

Anderson Powerpoles (generally the 30A variety) are used by a lot of folks to standardize on a plug type. They're very easy to connect/disconnect and installation is generally a breeze as long as you crimp correctly. My and my wife's cars are both wired with Powerpoles as well as my mom's.
Link Posted: 6/16/2007 4:59:50 PM EDT

Originally Posted By JaxShooter:

Originally Posted By dread-pirate:
What are "plugs" you are referring to from Anderson? Are these just so you can also use it to jump start your carss? Or are there other uses for them?

Anderson Powerpoles (generally the 30A variety) are used by a lot of folks to standardize on a plug type. They're very easy to connect/disconnect and installation is generally a breeze as long as you crimp correctly. My and my wife's cars are both wired with Powerpoles as well as my mom's.


I'm probably being dense so let me see if I understand. These are used as couplings to quickly and easilly hook up 2 cables for what ever purpose?

I'm not sure how this would relate to a car, maybe with stereos, CB's/HAM, audio equipment etc? I assume you are not putting them on the terminials or jump starting purposes?

In regards to this project, they are being used to securly and easilly hook the cables to the various parts of the inverter/charger/batteries? Right?

I'd be interested in seeing some large pictures of the unit and a step by step and safety precautions (I never knew there were dangers with working with these batteries).
Link Posted: 6/16/2007 5:24:49 PM EDT
[Last Edit: 6/16/2007 5:26:31 PM EDT by JaxShooter]

Originally Posted By dread-pirate:
I'm probably being dense so let me see if I understand. These are used as couplings to quickly and easilly hook up 2 cables for what ever purpose?

Yes, they're quick-disconnect power plugs.



I'm not sure how this would relate to a car, maybe with stereos, CB's/HAM, audio equipment etc? I assume you are not putting them on the terminials or jump starting purposes?

In regards to this project, they are being used to securly and easilly hook the cables to the various parts of the inverter/charger/batteries? Right?

I have a quick-disconnect cable "permanently" attached to the Optima battery terminals. This goes to my Battery Tender Plus charger. I also have two sets of leads attached to the terminals that are terminated in Powerpoles. This allows me to use my VHF/UHF and HF rigs together. I bought the type of terminal connector that would normally have your regular batter cable connected. Of course I don't have the car's battery cable. The connectors simply gave me an easy way to attach leads to the battery terminals.

The vehicles have 12-ga leads connected to the battery terminals via ring connectors. These leads go through the firewall, under the carpet, and under the driver's seat where they're also terminated in Powerpoles.

All three of my radios (2 dual-band mobiles, 1 HF) have their power leads terminated in Powerpoles. I can take any radio to any vehicle or run any radio off my battery. It's all very quick and easy.



I'd be interested in seeing some large pictures of the unit and a step by step and safety precautions (I never knew there were dangers with working with these batteries).

I've been meaning to get some shots of my setup. My neck is killing me tonight and tomorrow's Father's Day so it might be next week before I have a chance. I'll try.
Link Posted: 6/16/2007 6:10:23 PM EDT

Originally Posted By TomJefferson:
Advice?

First and foremost, the major limitation of any generator in an emergency isn't the generator but the availability of fuel. How much you can keep on hand should heavily influence what size you buy. Tj


Read what TJ said, then reread it.

One of the primary reasons I went away from Gas to Propane (or NG if thats available).
Link Posted: 6/16/2007 6:12:58 PM EDT

Originally Posted By GySgtD:
It's been mentioned before, but is worth repeating:

After every significant "event" that I've been through (hurricane, etc.), it was so quiet in the neighborhood that you could hear a pin drop.

Running a generator under those circumstances draws a lot of attention. Not all of it welcomed.


Realy?

Diffrent here. We lost power for 10 days, winter storm. It knocked down my fence and 2 of my dogs got out. While driving around looking for them (no one shot them!) I bet 1 in 8 houses had gennys running, was a dam racket.

Dogs were found, they picked a comfy porch to cheill at till the home oeners got there and called me. LOL, slackers were only 1/2 mile from home.
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