What size panel for max 20A? (1 Viewer)

[ShaKen]

I’m going to install a panel (some panels) on my Chausson and use the prefitted wires which I believe are 4sqmm.

On my existing distribution/fuse box the circuit is protected by a 20A fuse.

Now of course I could run new wiring to the regulator, but that looks like an extremely difficult task on my van.

Thus I’m looking for a solution that gives a max of 18A or so at peak.

The question is, do I simply look for a panel that has a max output of 18A (or less) or should it be that the controller has a max output of 18A or less??

Any thoughts welcome!

 

[funflair]

You should be safely inside at 240 watts so 2x120,

Martin

 

[SuperMike]

We have 400w on the roof and only on super sunny days will you see 18A or more. Theoretically a 100w panel will push out 8A at best, but in the real world 5A is normal, because of the suns angle to the panel etc.

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[The Wino]

I keep thinking about getting solar on our Chausson but apparently if ou use the prewired systam it only charges the battery when the control panel is on. Might be worth checking. Also why do you want the max possible solar ? the reaso I've never got around to it is we have never got near a flat hab battery and its still going fine after 5 1/2 years!!

 

[funflair]

We have 400w on the roof and only on super sunny days will you see 18A or more. Theoretically a 100w panel will push out 8A at best, but in the real world 5A is normal, because of the suns angle to the panel etc.

We have 320 and mppt regulators and see over 20 amps with good sun and of course demand from the batteries.

Martin

 

[Jev88]

Use solar , controller and route straight to the leisure battery and ignore your existing connection?

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[Lenny HB]

I keep thinking about getting solar on our Chausson but apparently if ou use the prewired systam it only charges the battery when the control panel is on. Might be worth checking. Also why do you want the max possible solar ? the reaso I've never got around to it is we have never got near a flat hab battery and its still going fine after 5 1/2 years!!

Built in solar are regulators are often only PWM far better to fit a decent MPPT regulator like a Votronic.

 

[ShaKen]

I keep thinking about getting solar on our Chausson but apparently if ou use the prewired systam it only charges the battery when the control panel is on. Might be worth checking. Also why do you want the max possible solar ? the reaso I've never got around to it is we have never got near a flat hab battery and its still going fine after 5 1/2 years!!

From my understanding of the circuit (and circuit diagram), you could fit the feed from the Regulator to either side of the relay that is switched by the control panel - ie. connect the regulator feed to bypass the relay but still connected to the correct 4sqmm wire.

 

[Reallyretired]

I often get 20+A from my 380w panels sur le continent in the summer.
Getting just 2.8A today , heavy overcast but MH is in storage so not using much. 30A mppt controller but not using any built in wiring which seems a bit thin so didn't want to use it.

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[The Wino]

Built in solar are regulators are often only PWM far better to fit a decent MPPT regulator like a Votronic.

Not sure on that as the panels have got a lot cheaper I wonder which is the best spend bigger panel and PWM or smaller and MPPT

 

[autorouter]

Not sure on that as the panels have got a lot cheaper I wonder which is the best spend bigger panel and PWM or smaller and MPPT

Bigger panel or more panels is definitely a cost-effective option. But sometimes that's not possible because of space or weight. If you're restricted on panel size, then monocrystalline panels with MPPT gives the most power in the smallest space.

 

[autorouter]

The question is, do I simply look for a panel that has a max output of 18A (or less) or should it be that the controller has a max output of 18A or less??

The usual rule of thumb is that a panel will never supply more than 90% of its rated power output, assuming you do not venture into the Tropics. I presume the 20A fuse is on the solar regulator output to the battery. 20 amps at 12 volts is 240 watts. That is your 90%, so 100% would be 240/0.9 = 267 watts.

So any panel less than 267 watts will be OK.

Alternatively, as you say you could find a regulator that has a maximum output of 20 amps. That will automatically limit the output to 20 amps. You can connect more panels to this, and the controller will be quite happy, it will simply waste any power above 20 amps. The advantage of this is, you will reach the 20A limit earlier in the day, and keep it going later in the day, so there is some benefit in doing this.

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