Converting a bus into a tiny home. Help me solidify my wiring diagram!?

s0l4rn00b · Oct 9, 2019

We realized we have room for eight 100w panels. We already purchased six, just need to add two more. What are your thoughts? Any issues? Anything missing?

Solar Inverter we will be using - https://www.ebay.com/itm/110Vac-240...ery-charger-/131951259033?hash=item1eb8e86d99

FULL SIZE DIAGRAM -

https://imgur.com/a/qaZK3He

Vlad-Solacity · Oct 9, 2019

Hi there, most likely you would need to make 2 string of 4 panels as the charge controller input is usually limited to 150V. And in general, a combination of series and parallel connections is more solid. Add a 250A fuse on the positive terminal of the battery bank.

s0l4rn00b · Oct 9, 2019

Vlad-Solacity said:
Hi there, most likely you would need to make 2 string of 4 panels as the charge controller input is usually limited to 150V. And in general, a combination of series and parallel connections is more solid. Add a 250A fuse on the positive terminal of the battery bank.

Is there something I'm missing? wiring in series would give me 96v coming in, giving me over 50v to work with. Also, I have a 150A breaker switch on the positive and negative terminals of the battery. Is there a reason you think 250A is better?

Vlad-Solacity · Oct 9, 2019

Ok, I see your panels are 12V each, so then you are fine. However, if one panel is exposed to shade or brakes it will affect the whole string dropping down the power yield up 0. The size of the fuse depends on the largest load that is the inverter. The potential continuous current draw is 100Amp and usually an inverter supplies twice more for 30 seconds (not sure about this one though) and that is already 200A. Then 25% of the oversize factor comes to 250A fuse. Please note, the fuse should sit on the positive terminal of the battery bank thus protects all positive wires going through it.

s0l4rn00b · Oct 9, 2019

Vlad-Solacity said:
Ok, I see your panels are 12V each, so then you are fine. However, if one panel is exposed to shade or brakes it will affect the whole string dropping down the power yield up 0. The size of the fuse depends on the largest load that is the inverter. The potential continuous current draw is 100Amp and usually an inverter supplies twice more for 30 seconds (not sure about this one though) and that is already 200A. Then 25% of the oversize factor comes to 250A fuse. Please note, the fuse should sit on the positive terminal of the battery bank thus protects all positive wires going through it.

Good call on the power drop, that was definitely a concern. Would it be smarter to go with two arrays of 200ah at 48v, or four arrays at 100ah at 24v?

Also, the 250A fuse makes sense. I have one placed on pos and neg (not sure if needed or helps). I realize my battery setup is 200ah at 24v, correct?

I've updated my diagram to be 2 arrays of 200ah at 48v.

Also, is the 80amp fuse still good before the solar inverter? or does that now need changed?

https://imgur.com/a/hWyeyFe

PHoganDive · Oct 9, 2019

s0l4rn00b said:
Is there something I'm missing? wiring in series would give me 96v coming in, giving me over 50v to work with. Also, I have a 150A breaker switch on the positive and negative terminals of the battery. Is there a reason you think 250A is better?

You need to use the panels open circuit voltage when figuring the max voltage, which is probably closer to 20 volts per panel...that times 8 = 160 volts.

s0l4rn00b · Oct 9, 2019

PHoganDive said:
You need to use the panels open circuit voltage when figuring the max voltage, which is probably closer to 20 volts per panel...that times 8 = 160 volts.

That makes sense, I've adjusted here -

https://imgur.com/a/hWyeyFe

Vlad-Solacity · Oct 9, 2019

PHoganDive said:
You need to use the panels open circuit voltage when figuring the max voltage, which is probably closer to 20 volts per panel...that times 8 = 160 volts.

And most likely, the limit is 150V. Not a good idea to connect them in series.

PHoganDive · Oct 9, 2019

s0l4rn00b said:
That makes sense, I've adjusted here -

https://imgur.com/a/hWyeyFe

FYI, Either the positive or the negative wire from the charge controller will have to go to the jumper at the far end of the panels to work properly...and the end panels need to be positive to positive and negative to negative connected together (i.e.flip the bottom row of panels left to right).

Vlad-Solacity · Oct 9, 2019

You have a 24V 200Ah battery setup, that is fine as you have a 2400W 24V inverter/solar charger box unit. Locate the fuse just on the positive side. For the best design, add 15A DC breaker between the panels and the charge controller and 80A between the MPPT charge controller and the battery bank. Cheers

s0l4rn00b · Oct 9, 2019

PHoganDive said:
FYI, Either the positive or the negative wire from the charge controller will have to go to the jumper at the far end of the panels to work properly...and the end panels need to be positive to positive and negative to negative connected together (i.e.flip the bottom row of panels left to right).

Is this correct?

https://imgur.com/a/oV1xpXb

Converting a bus into a tiny home. Help me solidify my wiring diagram!?

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