12v Solar Power in my camper

[AshleyDC]

Hi,

I've been racking my brains for weeks over this and getting help from everywhere I can, the attached image is what I've come up with. Could someone take a look and see if there are any faults/issues or generally unsafe areas please?

Many thanks,

Ash.

PS. I've been told i may need to add a diode so the panels don't drain some of the battery over night.

Van Circuit New.jpg
Van Circuit New.jpg

[ButchDeal]

you don't need fuses between the two modules and the charge controller (solar regulator)
I don't see how you could possibly get by with a 10A fuse in front of a 2kw inverter. It should be closer to 200a but I would say that using a 2kw inverter on 12V it foolish. 1kw is a bit big for 12V.
Further 25mm is too small of a wire for a 2kw inverter
your inverter needs its own dedicated wires to the battery bank and should have fuses at the battery post.

[Sunking]

First whoever told you need a diode should be ignored as they have no clue.

OK there is a lot wrong, just about everything you did is dangerous. Who decided to use a 10 amp fuse, on small wire, to run a 2000 watt 12 Inverter volt. It takes a 200 amp fuse, cable the size of your wrist, connected to a 800 pound battery, and a 1500 watt panel you do not have.

No one can really help you as it appears to be a joke.Nothing you have is workable, and ever worse very unsafe. If I were there in the camper, I would want the door left open so I can get out quickly in the event of a fire. No way would I lay my head down for rest in that camper unless the battery and panels are disconnected from everything. .

Other than minor details it is a perfect death trap.

Try something safe like this

[ButchDeal]

if you have two 12V modules in series the PV circuit will be 24V
MPPT CC will cut it down to 12V on the battery side.

if you want to use a different gauge wire for the fuses than for the inverter then you will have to fuse them differently at the battery.

And yes running a 1.3kw oven as well as air conditioning from the 12V battery bank is ridiculous.


> correct me if i wrong but 2000w divided by 230v equals 8.69A

YEs this is very wrong. that is the amps on the AC side on the DC side you are 12V and 2000W ( a ridiculous ) 167amps

[AshleyDC]

Hi ButchDeal,

Thanks for the comments, what do you mean by:

> if you want to use a different gauge wire for the fuses than for the inverter then you will have to fuse them differently at the battery.

Let me try and simplify all this.

2x 150w 12v 12.5A panels in parallel = 25A current at 12v. connected to 30A charge controller with 7AWG cable.

from charge controller to batteries 7AWG wire with 30A fuse.

If i knock the oven on the head, get a 1000w inverter to run aircon, laptop and speakers, 1000w divided by 12 = 83A so I'd need 2AWG cable with 90A fuse for the inverter.

from battery to the 12v fuse box a 7AWG cable with a 30A fuse.

Is this sounding closer to where i need to be?

Thanks.

[ButchDeal]

if it is an MPPT CC then you should not hook them up in parallel. hook them up in serial and the two of them will be more like 30V.

I see you are still dreaming of running air conditioning from 12V...

[Sunking]

Ashley you have a lot wrong

True 300 watts / 12 volts = 25 amps. But if you are talking about current from the panels is dead wrong. The panels are not 12 volts, more like 18 volts. 300 / 18 = 16.67 amps.. From the Controller to battery depends on what kind of controller you are using. If it is PWM which I suspect it is, the same 16.67 amps. or 200 watts. If you used a MPPT Controller, then you get 25 amps or 300 watts.

Again true 2000 watts / 230 volts = 8.7 volts, but who gives a crap, that is not what your batteries are drawing. Your poor little 12 volt battery is not really capable of supplying 2000 watts. From the battery that 2000 watt inverter draws more like 2200 watts / 12 volt = 183 amps or a cable the size of your wrist. At 2000 watt Inverter you should be running 24 or 48 volt battery.

[AshleyDC]

Its a PWM, so for 2x 150w panels I'd need a 20A PWM CC, 12AWG cable to regulator, 12 AWG to 2x parallel 150Ah batterys with 20A fuse. At this point please tell me nothing is blowing up or burning down...

Now from the battery to the 1000w pure sine inverter a 2AWG cable with a 90A fuse. and to the 12v fuse box a 7AWG cable with a 30A fuse.

Am I any closer to surviving a night in this van??

Thanks again for your help guys, I'd hate to be trying to help me out.

I still calculate that this aicon can operate on this system: http://www.coolmycamper.com/specification/

[Sunking]

OK the 20 Amp controller is just fine. 12 AWG is safe between Panels and Controllers, but unless your cable run is very short of 5-feet One-Way or less will incur excessive voltage drop on a 12 volt system. Until you can tell me what the distance is it will likely take 10 AWG or larger. No fuse is needed or required between panels and controller. Save your coins.

OK 2 AWG can have up to a 150 Amp fuse without any fuss. 90 is just fine. Only issue you might have and it is a stretch, is blowing the 90 amp fuse. Depending on the efficiency of the Inverter, if you pushed it to a full 1000 watts might over load the fuse and operate. If it happens no problem, replace it with a 100 Amp, you are good up to 150 amps with 2 AWG.

No issues with the 7 AWG except I have never seen any. in the US. Lots of 6 and 8, but not 7. We do not use the odd numbers. Anyway good up to 80 amps on 7 AWG if that is what you have.

[AshleyDC]

May I ask where you find these Amp ratings for each cable? Maybe the table im looking at is wrong, as it says 2AWG Cable can only handle up to around 100A and that 7AWG (or 8AWG) can only take up to about 34A.

Cheers!

[AshleyDC]

Brilliant! Finally getting somewhere thanks to you guys.

Another issue is I want to be able to charge the battery bank from the starter battery using a VSR, from what I understand the VSR detects the change in voltage when the starter battery is full and then allows the leisure batteries to start charging. What I don't understand and would love to know is how to know what amperage is flowing from the starter battery to the leisure batteries when charging, to be able to work out the cable size and fuse sizes. The starter battery is a 12v 110Ah 680A, and the leisure batteries 2x 150Ah.

Thanks again!