Adding extra solar panels

Aug 17, 2019
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Advice needed my 2022 bailey caravan is fitted with a truma 100w solar panel i'v changed my battery over from lead acid to lithium 110amp battery we do 90% off grid caravaning all year round and was thinking of adding another 200w panel to the roof so in total 300w on the roof is it an easy upgrade just conecting the two panels into just one and then down to my 30amp solar regulator thankyou for any advice
 
Oct 19, 2023
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I have limited experience with solar, but from an electrical perspective ......
300W at 12V works out at 25 Amps. Your controller is rated at 30A so that would be OK. I had a quick Google and your battery should be OK charging at 25 Amps (check the manufacturers specification to confirm). My only concern would be the size of the cable from the existing panel to the controller, and from the controller to the battery. It would have been designed to carry 8.3 Amps and may not be capable of carrying 25 Amps without overheating.
 
Jun 16, 2020
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You will need more professional advice, but I am sure it will work fine when you have the answers. I believe it is both possible to wire in parallel or in series and there are pro’s and cons which also depends on the type of controller. And how the panels mix. I did the same in 2016, but cannot remember the details.

If you are to buy your new panels from a specialist you may well get some good advice thrown in fot free.

When I installed my panels, I used semi flexible ones glued down. Which saved a fair bit of weight.

John
 
Oct 11, 2023
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Advice needed my 2022 bailey caravan is fitted with a truma 100w solar panel i'v changed my battery over from lead acid to lithium 110amp battery we do 90% off grid caravaning all year round and was thinking of adding another 200w panel to the roof so in total 300w on the roof is it an easy upgrade just conecting the two panels into just one and then down to my 30amp solar regulator thankyou for any advice
You need a 100 watt panel to match your existing 100 watt panel, you will see no advantage by fitting a 200 watt panel to a 100 watt panel, you will only see 200 watts. Wire your panels up in series with a Victron MPPT solar controller 75/15.

Or alternatively disconnect your existing 100 watt panel and fit 2 x 130 watt flexible solar panels in series with a Victron MPPT 100/20 controller
 
Aug 17, 2019
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You need a 100 watt panel to match your existing 100 watt panel, you will see no advantage by fitting a 200 watt panel to a 100 watt panel, you will only see 200 watts. Wire your panels up in series with a Victron MPPT solar controller 75/15.

Or alternatively disconnect your existing 100 watt panel and fit 2 x 130 watt flexible solar panels in series with a Victron MPPT 100/20 controller
Thankyou for all the advice i have a truma MPPT solar controller fitted i'd have thought that would have been fine and now thinking of just going with like you say have just 2 100w panels .
What do i have to buy to connect the 2 panels into just 1 from my truma one fitted from new
 
Oct 11, 2023
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You can buy a male to female cable and connector online probably from your solar panel supplier, ditch the truma controller it pants, wire up your panels in series to a Victron controller (I always add a fuse), I connected my Victron directly the habitation battery (I always add a fuse)

I have 2 x 80 watt solar panels via Victron bluetooth 75/15 solar controller.
 
Aug 17, 2019
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You can buy a male to female cable and connector online probably from your solar panel supplier, ditch the truma controller it pants, wire up your panels in series to a Victron controller (I always add a fuse), I connected my Victron directly the habitation battery (I always add a fuse)

I have 2 x 80 watt solar panels via Victron bluetooth 75/15 solar controller.
Thanks for the advice but would the 75/15 victron controler be safe for 2 100w panels just looked on amazon and can get a 75/20 for £65 would that be better and are they ok to use with lithium 110amp batterys i have'nt got the other panel as yet so would only be useing the 100w panel for now

And what wrong with the truma controller ??
 
Aug 17, 2019
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100/20 bluetooth will be fine don't forget to adjust your setting for lithium, I added a Victron battery sense to monitor the temperatures, don't charge a lithium below zero degrees C
My lithium battery has built in heater plates so chargeing in low temp is not a problem
Is it easy to change the settings to lithium as getting on a bit and all this tech stuff just goes over my head and would the 75/15 controller be ok when i upgrade to two 100w panels as i dont want to buy one the have to change ltr thankyou again for the advice
 
Jun 16, 2020
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When I linked my panels 8 years ago, I was informed that I could. Mine were well mismatched, one being 100 watt, the other 18. But I followed the advice given at the time and my system worked with an Epever controller, BT and WiFi.

I cannot exactly remember how I did it, so will not attempt to advise. But some googling will say it can be done, though not to be advised.

I feel that this is an expert area.

John
 

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