Solar panel help new to this

[dave1976]

Hi,

Just bought my very first motorhome and want to make sure that i don't make a mistake and put my 4 kids safety at risk. I really don't have a clue and been trying to learn about all this solar panels and what size cables to use and things like breaker switches, Circuit Breaker Fuse and plus what's the safest Leisure Battery to get as i've read some horror stories about batteries that explode, fires and gases coming from them etc so want to make sure nothing like that happens.

Last year i wasn't really thinking and jumped the gun and bought these items below but am not too sure if they are safe or not as the cable doesn't seem too thick as the black cable that connects to the solar panels has a thin black & red wire inside like you get in a plug that goes into the PWM controller plus also the black & red wire that goes to the battery also seems very thin. As i know nothing about all this cable sizing and batteries etc i was hoping someone would please tell me if i have the right setup and the safest battery to buy and maybe a diagram or youtube video, that would be so helpful to me and my family. Thanks

The things i bought, Solar panels and 2 batteries.

200w Solar Panel Kit 12V/24V PWM controller battery charging cables brackets K4 | eBay

Solar Panels & Kits. Solar Kit Contents 2 x 100w Poly solar panel. Male Male Female & Female Female Male connectors. 100 Watt Solar Panel - (with 1m Cable & Solar Connector Plugs). Suitable for 12V or 24V systems, auto detecting & auto switching.

www.ebay.co.uk

12V 120AH SuperBatt DT120 Starting Auxiliary Deep Cycle Leisure & Marine Battery | eBay

Part Number: DT120. SuperBatt SILVER 9000 [Super Excellence]. SuperBatt leisure batteries are manufactured to the very highest of standards, but to get the very best performance, and longevity out of your batteries it is well worth following a simple care and maintenance program.

www.ebay.co.uk

 

[Stealaway]

It all looks OK to me.
A circuit breaker switch in the positive line from the panels

<Broken link removed>

And one of these

4pc Solar Panel Mounting Brackets Corner Mounts Campervan Motorhome Caravan for sale online | eBay

Find many great new & used options and get the best deals for 4pc Solar Panel Mounting Brackets Corner Mounts Campervan Motorhome Caravan at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

 

[Phill D]

Hi welcome.
Looks OK. make sure the battery is secured and vented.

 

[Tombola]

I had the exact same batteries, worked fine.
One thing I would say is if you can get an MPPT solar controller instead of the pwm, you will get better charge rates from the solar.

 

[dave1976]

Hi, Thanks for the replies. I will look into buying a MPPT solar controller as the one i got with it looks really cheap. What amp size breaker switch would do for the 200w panels? would 80A be too much? also would i need one between the controller and batteries? Thanks again

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[Stealaway]

The panels will only need a 20a breaker. I've never felt the need for a appt controller, so much more expensive for only a small gain at low light.

 

[Raul]

If you want to fuse the panels to the controller correct, that would be 6a per panel in parallel. Each panel protected by its own fuse, or 12a for both in parallel. No more. If you look at the back of the panel, the short circuit current is just under 6a. A 4mm2 ( cross section) from panels to controller.
From controller to battery you will need 15A max fuse with 6mm2 minimum cross section.
Ditch that controller as soon as you can. It does not do a 3 stage charging, and you will loose allot of water out of the batteries ( excessive gassing), that you can not replace.

 

[GeoffnDee]

When you fit this solar system it is important that you make sure that you fit the battery connections to the solar controller before connecting the solar panel (or switching on the breaker) as the controller needs to know it is dealing with a 12v system and set its self accordingly.

 

[dave1976]

That's great, any recomendations on cable gauge as some places are saying 10 gauge or 8 gauge from panels to controller as i would like to replace that thin one with a thicker separate red & black cable. As i said the cable between the controller and the batteries seems very thin as if it's 12 gauge so would that be enough to cope with the power coming from the panels/controller etc to the batteries?

 

[dave1976]

If you want to fuse the panels to the controller correct, that would be 6a per panel in parallel. Each panel protected by its own fuse, or 12a for both in parallel. No more. If you look at the back of the panel, the short circuit current is just under 6a. A 4mm2 ( cross section) from panels to controller.
From controller to battery you will need 15A max fuse with 6mm2 minimum cross section.
Ditch that controller as soon as you can. It does not do a 3 stage charging, and you will loose allot of water out of the batteries ( excessive gassing), that you can not replace.

Thanks for the info, can you recommend a good 3 stage charging controller? Thanks

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[dave1976]

I have attached the layout that i found that looks pretty easy to do with 2 panels but just wanted to make sure i use the right cable size and amps so i don't get it wrong.

 

[Stealaway]

That's great, any recomendations on cable gauge as some places are saying 10 gauge or 8 gauge from panels to controller as i would like to replace that thin one with a thicker separate red & black cable. As i said the cable between the controller and the batteries seems very thin as if it's 12 gauge so would that be enough to cope with the power coming from the panels/controller etc to the batteries?

It's likely that the controller connection will only take 4mm cables, maybe 6mm. There's no reason for any bigger given the maximum output of the panels.

 

[Revolvor]

If you are getting a new Solar Controller, consider getting one with a Dual output, to also trickle charge the engine battery. Alternatively, get a Battery Master, which will supply a small charge to the engine battery, from the leisure battery.

 

[Raul]

That's great, any recomendations on cable gauge as some places are saying 10 gauge or 8 gauge from panels to controller as i would like to replace that thin one with a thicker separate red & black cable. As i said the cable between the controller and the batteries seems very thin as if it's 12 gauge so would that be enough to cope with the power coming from the panels/controller etc to the batteries?

A victron 75/15 or 100/20 both good for your panels the wire gauge I mentioned in my previous reply: in mm2 cross section. In UK we don’t use American wire gauge, just simple mm2 cross section.

 

[autorouter]

Are there any leisure batteries fitted already? Will these two new ones replace one or two existing ones?

There are two factors that determine the thickness of the wires - safety and voltage drop. From the safety point of view, the wires in the kit are quite adequate. However with solar wiring you want to waste as little power as possible along the wiring, Thicker wires will reduce the voltage drop, and improve the efficiency. That's why it was suggested to use 4mm2 for the panel wiring and 6mm2 for the battery wiring.

If the battery wires get short-circuited, a current of hundreds if not thousands of amps will flow, and heat up the wires possibly causing a fire. That's why it's vital you wire in a fuse very near the battery in the positive wire, As in your diagram.

If the solar panels get short-circuited, you'll hardly notice. They will struggle to produce 12A in total. So a fuse isn't really necessary. However some method of disconnecting the panels is a good idea. An easily removable fuse, or a circuit breaker works well for this purpose.

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[ED O'DARAC]

What make is your motorhome? If German, and you have a Blue EBL Schaudt Elektroblok, just use the Schaudt LR1218 regulator and it just plugs in and charges each battery. Very simple and safe.