I need help w this wiring of solar panels

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[ARCHIVED THREAD] - I need help w this wiring of solar panels

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

Posted: 6/18/2014 9:58:03 PM EDT

[#1]

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?

Posted: 6/18/2014 10:02:19 PM EDT

[#2]

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.

Posted: 6/18/2014 10:34:22 PM EDT

[#3]

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.

Posted: 6/18/2014 10:35:20 PM EDT

[#4]

Quote History

Quoted:

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.

Posted: 6/18/2014 10:36:07 PM EDT

[#5]

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Quoted:
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.

Posted: 6/18/2014 10:44:08 PM EDT

[#6]

Operating Voltage: 3.00

Wattage: .066

Current: 22 mA

Typ Voc: 4.1V

Typ Isc: 30mA

Typ Output @ AM 1.5: 25mA @ 3V

Posted: 6/18/2014 10:47:23 PM EDT

[#7]

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

Posted: 6/18/2014 10:49:25 PM EDT

[#8]

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Quoted:

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

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Lol.

http://www.amazon.com/15000mAh-Portable-Ultra-High-External-lightning/dp/B00D5VAYRU/ref=pd_sim_cps_10?ie=UTF8&refRID=07T7M2TD3K3CQ5Z0QSJW

Use the panels to charge this.

Posted: 6/18/2014 10:57:30 PM EDT

[#9]

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

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

[#10]

Posted: 6/18/2014 10:59:41 PM EDT

[#11]

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http://cdn.instructables.com/FFP/XOOR/D4LEV1BET46/FFPXOORD4LEV1BET46.MEDIUM.jpg

http://cdn.instructables.com/F3C/J65L/GVYEV1BET3M/F3CJ65LGVYEV1BET3M.LARGE.jpg

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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.

Posted: 6/18/2014 11:05:45 PM EDT

[#12]

you would have to recalculate the figures for the smaller panels for this one

Posted: 6/18/2014 11:14:13 PM EDT

[#13]

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

Posted: 6/18/2014 11:15:25 PM EDT

[#14]

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.

Posted: 6/18/2014 11:16:27 PM EDT

[#15]

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My paint skills ROCKS!!

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

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But your math skills suck.

Posted: 6/18/2014 11:22:26 PM EDT

[#16]

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But your math skills suck.

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Quoted:

Quoted:

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..

Posted: 6/18/2014 11:55:46 PM EDT

[#17]

So what is the right numbers for that diagram? 6v 100mAh?

Posted: 6/19/2014 8:09:03 AM EDT

[#18]

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So what is the right numbers for that diagram? 6v 100mAh?

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if the panels are 3v 25mAh, yes. 6v 100mAh

Posted: 6/19/2014 11:12:48 AM EDT

[#19]

Quoted:
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.

Posted: 6/19/2014 11:16:18 AM EDT

[#20]

Quote History

Quoted:
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.

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Quoted:

Quoted:

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?

Posted: 6/19/2014 11:43:29 AM EDT

[#21]

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Blessed based engineering Nazis.

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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.

Posted: 6/19/2014 1:27:00 PM EDT

[#22]

Also what is the running load on the system? If there is say a 50mA load charging will be half as fast

Posted: 6/19/2014 5:06:00 PM EDT

[#23]

Quote History

Quoted:

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

Quote History

Quoted:

Quoted:
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..

Posted: 6/19/2014 6:24:10 PM EDT

[#24]

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

Posted: 6/19/2014 6:36:59 PM EDT

[#25]

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.

Posted: 6/19/2014 6:38:37 PM EDT

[#26]

I helped my uncle install his solar panels. We wired them backwards and they became giant flat lights shining into the sky....

Posted: 6/19/2014 7:18:44 PM EDT

[#27]

Quote History

Quoted:

... 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

Quote History

Quoted:

Quoted:
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".

Quoted:

Quoted:
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.