Quick daft question!

[WESTY66]

I have 100w solar panel on roof the blk/red wire from it goes into a control box and has two outlets, one for the hab, one for the cab batts, if I add another solar panel do I just put we panel wires into the same input with the two wires from the first solar panel or do I have to buy a bigger/different controller? Does that make sense??
Thanks Ady

 

[pappajohn]

Basicly, Depends how many watts the second panel is and how many amps the controller can cope with.

 

[WESTY66]

Thanks PJ I was thinking 100w, I’ll look at controller tomorrow? I just want more off grid capability, I have 2x110 leisure batts?

 

[WESTY66]

pappajohn this is my controller, being relatively new to all things motorhome I haven’t got a clue what the specs are for this, is this what they call a mppt?

 

[WESTY66]

pappajohn this is my controller, being relatively new to all things motorhome I haven’t got a clue what the specs are for this, is this what they call a mppt?

It would help if I’d actually uploaded the picture?‍

there you go PJ

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[autorouter]

STI do at least two controllers, a 10A and 20A. Looking at pictures on their website, the label is identical on both. Is there another label/marking to show the model type? STCC10 or STCC20 for example.

The 10A version is OK for up to 150 watts of panel, the 20A will take up to 300 watts.

If you put panels of 200 watts into the 10A controller, you will not get more than 10A output. The controller will limit the output to 10A. Apart from that, it should be fine. You will waste power in the middle of the sunniest days, but will get up to 10A faster in the mornings, and delay the drop below 10A in the evenings. So you will still get some benefit.

 

[WESTY66]

STI do at least two controllers, a 10A and 20A. Looking at pictures on their website, the label is identical on both. Is there another label/marking to show the model type? STCC10 or STCC20 for example.

The 10A version is OK for up to 150 watts of panel, the 20A will take up to 300 watts.

If you put panels of 200 watts into the 10A controller, you will not get more than 10A output. The controller will limit the output to 10A. Apart from that, it should be fine. You will waste power in the middle of the sunniest days, but will get up to 10A faster in the mornings, and delay the drop below 10A in the evenings. So you will still get some benefit.

Thanks I’ll check for more labels, of it’s STCC20 can I just put new blk/red into the input with the existing solar panel?

 

[autorouter]

Thanks I’ll check for more labels, of it’s STCC20 can I just put new blk/red into the input with the existing solar panel?

Yes that's one way to do it. Alternatively, if you have MC4 connectors on the solar panels, you can use MC4 branch connectors to connect into the existing wire, saves running a new wire through the roof etc. MC4 connectors are weatherproof.

MC4 Solar Branch Connectors (Pair)

MC4 T-Branch or Y connectors are for use with strings of panels where the maximum voltage for your inverter has been met and you require a second string to add wattage. Use it to connect 2 x 12v panels in parallel to keep a 12v output. Double O rings for secure protection. MC4 Solar Branch...

www.sunstore.co.uk

what the specs are for this, is this what they call a mppt?

It's a PWM type, not MPPT.

 

[cossie303]

If you unscrew it from where it is mounted it will tell you on the back if it is a 10A or a 20A