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Posted: 6/18/2014 9:53:18 PM EDT
Hi guise

Here's my problem:

I have 8 solar panels with an output of 3v @ 25mAh. They run like this [+ -] and are about the size of a credit card. I want to wire them like this:

2 panels in series then paralleled with another two sets in series which are then paralleled into the other two sets which should be 6v and 100mAh. How do I do this most efficiently? Will this be enough power to charge a USB battery bank like a RavPower 14000mAh? I'll send a AFG2 to whomever helps me solve this and some other questions (like where and what kind of diode goes between that and the battery bank). Thank you in advance based electrical engineers
Link Posted: 6/18/2014 9:58:03 PM EDT
get a solar charge controller so you don't mess up your batteries.

make sure you hook it up right

if you got one already, what model?
Link Posted: 6/18/2014 10:02:19 PM EDT
[Last Edit: 6/18/2014 10:04:05 PM EDT by WilliamGray]
I would wire two sets of 4 in series, then parallel those two sets to give you 50mAh@12 volts.
I would feed that to a cheap battery charge controller and use it to charge a gel cell battery.
Later you can add more 12volt panels.
12 volts will be a lot more useful than 6 volts.
Link Posted: 6/18/2014 10:34:22 PM EDT
Except I'm pretty sure I'd need more panels since you need like 13.7v to charge a 12v and the 5v RaVpower bank is way more useful in this case and more efficient since I'm using 5v and not wanting to step 12v down to 5v.
Link Posted: 6/18/2014 10:35:20 PM EDT
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Originally Posted By RED_5:
get a solar charge controller so you don't mess up your batteries.

make sure you hook it up right

if you got one already, what model?
View Quote

... a RavPower should have an autodisconnect built in so a charge controller isn't needed, just a diode to prevent discharge back into the panels.
Link Posted: 6/18/2014 10:36:07 PM EDT
[Last Edit: 6/18/2014 10:36:19 PM EDT by WilliamGray]
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Originally Posted By NSFJojo:
Except I'm pretty sure I'd need more panels since you need like 13.7v to charge a 12v and the 5v RaVpower bank is way more useful in this case and more efficient since I'm using 5v and not wanting to step 12v down to 5v.
View Quote


My 12 volt panels put out roughly 17 volts in direct sunlight.
Thats where the charge controller comes in.
Link Posted: 6/18/2014 10:44:08 PM EDT
  • Operating Voltage: 3.00
  • Wattage: .066
  • Current: 22 mA
  • Typ Voc: 4.1V
  • Typ Isc: 30mA
  • Typ Output @ AM 1.5: 25mA @ 3V
Link Posted: 6/18/2014 10:47:23 PM EDT

Wait, don't go anywhere OP, I'll be right back...


Link Posted: 6/18/2014 10:49:25 PM EDT
[Last Edit: 6/18/2014 10:49:54 PM EDT by NSFJojo]
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Originally Posted By ScooterInVegas:

Wait, don't go anywhere OP, I'll be right back...


View Quote


Lol.

Link Posted: 6/18/2014 10:57:30 PM EDT
[Last Edit: 6/18/2014 11:23:51 PM EDT by ScooterInVegas]

My bad. I was looking up info for something else.


Link Posted: 6/18/2014 10:57:36 PM EDT

Link Posted: 6/18/2014 10:59:41 PM EDT
[Last Edit: 6/18/2014 11:05:41 PM EDT by NSFJojo]
Discussion ForumsJump to Quoted PostQuote History

Yeh, I get the difference. Those are pretty. Now do a bigger one with 2 sets of 2 serial in parallel. and make it efficient to wire up since I have to do all the connection point soldering. Can you answer if that's enough to power the battery bank?

I want to start this project but the logic is escaping me.

Ideally the panels being place in such a way that the least amount of wire is used to make the connections

If I have to up the amount of the prize just IM me your price to be paid in PMAGS or something.
Link Posted: 6/18/2014 11:05:45 PM EDT


you would have to recalculate the figures for the smaller panels for this one
Link Posted: 6/18/2014 11:14:13 PM EDT
[Last Edit: 6/18/2014 11:15:56 PM EDT by Devilman13xx]
this will give you double the voltage of the panels and 4x the amps



so it should be the 6v 100mAh your looking for


then you can mount it all in a setup like this

Link Posted: 6/18/2014 11:15:25 PM EDT
[Last Edit: 6/18/2014 11:19:00 PM EDT by ScooterInVegas]

My paint skills ROCKS!!



Oh shit. I just realized I doubled the ah. I'm too tied. Worked all day in the sun on 4hr sleep and my brain is fryed. Gots to get to bed. Sorry op.


Link Posted: 6/18/2014 11:16:27 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ScooterInVegas:

My paint skills ROCKS!!



http://i258.photobucket.com/albums/hh259/scooterinvegas/1234_zps821f8d2f.png
View Quote


But your math skills suck.
Link Posted: 6/18/2014 11:22:26 PM EDT
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Originally Posted By WilliamGray:


But your math skills suck.
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Originally Posted By WilliamGray:
Originally Posted By ScooterInVegas:

My paint skills ROCKS!!



http://i258.photobucket.com/albums/hh259/scooterinvegas/1234_zps821f8d2f.png


But your math skills suck.

Not my math. I was just talking to a friend about his 6.0 ford and realized that I'm so tired that my brain is not working right... I doubled both V and A on one series jump.. Im going to bed guys..


Link Posted: 6/18/2014 11:55:46 PM EDT
So what is the right numbers for that diagram? 6v 100mAh?
Link Posted: 6/19/2014 8:09:03 AM EDT
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Originally Posted By NSFJojo:
So what is the right numbers for that diagram? 6v 100mAh?
View Quote

if the panels are 3v 25mAh, yes. 6v 100mAh
Link Posted: 6/19/2014 11:12:48 AM EDT
Originally Posted By NSFJojo:
I have 8 solar panels with an output of 3v @ 25mAh. They run like this [+ -] and are about the size of a credit card. I want to wire them like this:

2 panels in series then paralleled with another two sets in series which are then paralleled into the other two sets which should be 6v and 100mAh. How do I do this most efficiently? Will this be enough power to charge a USB battery bank like a RavPower 14000mAh? I'll send a AFG2 to whomever helps me solve this and some other questions (like where and what kind of diode goes between that and the battery bank). Thank you in advance based electrical engineers
View Quote



mAh is correct for a battery but not a solar panel. It's just plain milliamps. No hours. mAh is total capacity, and mA is the rate.
Link Posted: 6/19/2014 11:16:18 AM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ILoveGauge:



mAh is correct for a battery but not a solar panel. It's just plain milliamps. No hours. mAh is total capacity, and mA is the rate.
View Quote View All Quotes
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Originally Posted By ILoveGauge:
Originally Posted By NSFJojo:
I have 8 solar panels with an output of 3v @ 25mAh. They run like this [+ -] and are about the size of a credit card. I want to wire them like this:

2 panels in series then paralleled with another two sets in series which are then paralleled into the other two sets which should be 6v and 100mAh. How do I do this most efficiently? Will this be enough power to charge a USB battery bank like a RavPower 14000mAh? I'll send a AFG2 to whomever helps me solve this and some other questions (like where and what kind of diode goes between that and the battery bank). Thank you in advance based electrical engineers



mAh is correct for a battery but not a solar panel. It's just plain milliamps. No hours. mAh is total capacity, and mA is the rate.

Blessed based engineering Nazis. Now I'm correct in assuming if something is 14k mAh it would take 140 hours of charging at 100ma to restore the power? Would I be better off buying 2x more 100ma/6v strips and pushing them into parallel with the smaller farm to make 300ma?
Link Posted: 6/19/2014 11:43:29 AM EDT
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Originally Posted By NSFJojo:
Blessed based engineering Nazis.
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Originally Posted By NSFJojo:
Blessed based engineering Nazis.


Amperes macht frei!



Now I'm correct in assuming if something is 14k mAh it would take 140 hours of charging at 100ma to restore the power?


In a perfect world, yes. But you never get 100% efficiency, So figure 20% more for heat losses.

Are you sure it's not a 1.4k mAh (1.4 Ah) battery? 14Ah is a pretty big battery. Like a motorcycle lead acid battery. If you can fit it in your pocket, it's probably 1.4Ah.

Devilman13xx has the wiring and math correct.

Also, anything longer than a 20 hour rate is considered a trickle charge, and with the 1.4Ah it would take the better part of a week to charge the battery. At 140 hours you probably would never charge the battery due to sunlight time and internal discharging.



Would I be better off buying 2x more 100ma/6v strips and pushing them into parallel with the smaller farm to make 300ma?



Yes. Like beer, money, ammo, and pussy, more is always better.
Link Posted: 6/19/2014 1:27:00 PM EDT
Also what is the running load on the system? If there is say a 50mA load charging will be half as fast
Link Posted: 6/19/2014 5:06:00 PM EDT
[Last Edit: 6/19/2014 5:07:56 PM EDT by Cathan91]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By NSFJojo:

Blessed based engineering Nazis. Now I'm correct in assuming if something is 14k mAh it would take 140 hours of charging at 100ma to restore the power? Would I be better off buying 2x more 100ma/6v strips and pushing them into parallel with the smaller farm to make 300ma?
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By NSFJojo:
Originally Posted By ILoveGauge:
Originally Posted By NSFJojo:
I have 8 solar panels with an output of 3v @ 25mAh. They run like this [+ -] and are about the size of a credit card. I want to wire them like this:

2 panels in series then paralleled with another two sets in series which are then paralleled into the other two sets which should be 6v and 100mAh. How do I do this most efficiently? Will this be enough power to charge a USB battery bank like a RavPower 14000mAh? I'll send a AFG2 to whomever helps me solve this and some other questions (like where and what kind of diode goes between that and the battery bank). Thank you in advance based electrical engineers



mAh is correct for a battery but not a solar panel. It's just plain milliamps. No hours. mAh is total capacity, and mA is the rate.

Blessed based engineering Nazis. Now I'm correct in assuming if something is 14k mAh it would take 140 hours of charging at 100ma to restore the power? Would I be better off buying 2x more 100ma/6v strips and pushing them into parallel with the smaller farm to make 300ma?


100 mA to charge a 14 ah battery gives you a charging rate of 0.7%, not accounting for inefficiencies. Barely a trickle charge. So no, it's not enough power to charge that battery pack with that solar panel set up. 140 hours is best case scenario. Assuming 5 sun-hours per day, your 140 hours = 28 days.

If you want to charge in 2.8 days instead, add a zero to your solar capacity. If you want to charge in 0.28 days, add two zeroes.

I think your battery pack is Li-Ion. I'm not sure about Li-Ion batteries and what the charging rate should be for them. I only know 12V lead-acid. For a deep-cycle lead acid battery that you're regularly discharging, the general rule is a 10-13% charge rate. That would mean a ~40W panel for a 14 ah battery..
Link Posted: 6/19/2014 6:24:10 PM EDT
[Last Edit: 6/19/2014 6:31:08 PM EDT by Devilman13xx]
the only way to add panels and not up the volts but increase the mA I believe is going to require a charge controller. or go with a different panel with a higher mA rating.

if you only needed the 3v but 200 mA you could wire them like this



compounds the amps but retains the voltage
Link Posted: 6/19/2014 6:36:59 PM EDT
I just checked the specs on that ravpower battery.

It needs 1A input. so your going to need to get that output out of your panel array.
Link Posted: 6/19/2014 6:38:37 PM EDT
I helped my uncle install his solar panels. We wired them backwards and they became giant flat lights shining into the sky....
Link Posted: 6/19/2014 7:18:44 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By NSFJojo:

... a RavPower should have an autodisconnect built in so a charge controller isn't needed, just a diode to prevent discharge back into the panels.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By NSFJojo:
Originally Posted By RED_5:
get a solar charge controller so you don't mess up your batteries.

make sure you hook it up right

if you got one already, what model?

... a RavPower should have an autodisconnect built in so a charge controller isn't needed, just a diode to prevent discharge back into the panels.


No. You still need a charge controller. Photovoltaic cells have to be run at a certain load or else their efficiency drops by a huge percent. If you have a 100w panel that is putting out 100 watts, and you increase the load too much the output can fall to less than 1 watt despite no other changes in light exposure. More info here. Read the section called "How Your System Affects Panel Efficiency".


Originally Posted By ILoveGauge:
Originally Posted By NSFJojo:
I have 8 solar panels with an output of 3v @ 25mAh. They run like this [+ -] and are about the size of a credit card. I want to wire them like this:

2 panels in series then paralleled with another two sets in series which are then paralleled into the other two sets which should be 6v and 100mAh. How do I do this most efficiently? Will this be enough power to charge a USB battery bank like a RavPower 14000mAh? I'll send a AFG2 to whomever helps me solve this and some other questions (like where and what kind of diode goes between that and the battery bank). Thank you in advance based electrical engineers



mAh is correct for a battery but not a solar panel. It's just plain milliamps. No hours. mAh is total capacity, and mA is the rate.


Technically you could use mAh if you knew how long the panel would be in the sun at a given output over it's lifetime. Of course this is completely impractical for anything anyone would need to calculate.
Link Posted: 6/20/2014 12:50:46 AM EDT
So.... much... good... info....
Link Posted: 6/20/2014 2:52:23 PM EDT
[Last Edit: 6/20/2014 2:55:08 PM EDT by ILoveGauge]
If you want solar panel wiring ideas, just check out the roof of the mall. I'm sure you have keys...




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