Club 80-90 Forums

JonB wrote:Do you guys keep or remove split charge relays when installing solar? My VSR needs replacing and would also look to uprate all the cables. Just wondering if nowight be a good time to go solar.

Voltage sensing relay and solar controllers don’t like each other generally , as the solar lifts the battery voltage and the VSR can’t tell the difference between that and the alternator lifting the voltage so just joins the two batteries together and makes the solar controller charge both at once with no conditioning . I suppose if you have a cheap PWM controller that is only for a single battery that would still work but if your controller is dual battery the vsr will cause problems
I kept my split charge system ( which is a alternator triggered 100amp relay rather than a VSR )but I built it with a kill switch so I can turn it off when it’s not needed , and I only switch it on when travelling in the dark if need be


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Hmm great point about night driving. So arguably both systems have useful scenarios, just a methid to isolate to stop them competing.

Isolate solar when driving
Isolate vsr when parked up

Was looking to use a Cyrix Ct which I beleive could be switched on the ground wire.

Will go with the original plan to update the vsr and then spend a little more time looking at solar.

You don’t need to isolate the solar when it’s dark , it won’t do anything !
Like I said I wouldn’t entertain a VSR , a simple alternator triggered relay is far superior - don’t fall foul if the urban myth that split charge systems don’t charge the second ( leisure) battery until the main battery is charged ( or part charged to 80% as I read with mirth the other day) it’s simply just not true , they just join the two batteries together as soon as the alternator raises the voltage to the switch point , no matter how charged either battery is .


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That 80% charge is most probably a reference to the smart alternators used with stop start engines nowadays where the starter battery is only charged to 80% for regenerative braking systems - someone got confused most likely. That is why a VSR/alternator switched relay cannot be used on them and you have use a B2B charger.

Mocki wrote:You don’t need to isolate the solar when it’s dark , it won’t do anything !

Ha ha no sorry my train of thought had moved on. A switch on the vsr to get over the initial issue mentioned, then an switch on the solar just for the ability to isolate if a need arose.

You're right though relay wired to the alternator is the easiest approach.

I installed a inline switch on the feed from my solar panel before the controller , so I can stop the power before it gets to the controller , but that is so I can switch off the solar charging when I want to use my HF radios because the MPPT controller I have sends out horrendous static noise all the way through the HF bands and up to the lower vhf frequencies.

Hi guys. hoping to put solar on the side elevating pop I have have. This is proving a really useful thread.

Was going to go with this set up before realising it won't fit where I want it on the roof:

https://www.photonicuniverse.com/en/cat ... -kit-.html" onclick="window.open(this.href);return false;

They do others that do fit but drop from 160w to 100w. Is this too low? What is the lowest I should consider if I want to run a 12v fridge etc off it? Cheers!

I wouldn’t pay that much for that kit , mainly because it’s a PWM controller and not a MPPT , so you will not be getting the most out of your panel , which you will need with one of those power thirsty compressor fridges , but also because the panel is over priced for a 100w

I fitted https://rover.ebay.com/rover/0/0/0?mpre ... 2724265811" onclick="window.open(this.href);return false;
Mppt controller because it is a dual battery one , so the main battery gets charge too , although it does have a nasty sporadic radio signal on the Hf and lower vhf bands if you are a radio ham

Thanks for the heads up Mocki, gives me something to think about! Thanks also for the recommendations.

mariner wrote:Hi guys. hoping to put solar on the side elevating pop I have have. This is proving a really useful thread.

Was going to go with this set up before realising it won't fit where I want it on the roof:

https://www.photonicuniverse.com/en/cat ... -kit-.html" onclick="window.open(this.href);return false;

They do others that do fit but drop from 160w to 100w. Is this too low? What is the lowest I should consider if I want to run a 12v fridge etc off it? Cheers!

I bought mine from here 3/4yrs ago. Really happy with it.


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Mocki wrote:

garry247 wrote:

Will need to see what size will fit


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Same roof as mine , so easily fit a 150w semiflexible on there

chewbacca wrote:I use this controller. Fitted it and never looked back. Tops up the starting battery, bulk of the charge into the leisure batts.

https://www.photonicuniverse.com/en/cat ... input.html" onclick="window.open(this.href);return false;

Yes I shortlisted that controller , but in the end paid a tad more for this one because of the Bluetooth

Hi Mocki. Hope this isn't a stupid question but can I just ask what the extra benefits of the bluetooth are? Deciding between the Voltronic and the one you recommended. Going to pair it with a 120w semi-flexible. Cheers.

honestly , the blue tooth just means you can acess and change the settings to fine tune for your circumstances ( dull weather or part shading ect) and you can monitor whats happening without needing to buy and install a screen . i rarely look at mine unless i need to change settings as i already have a volt meter for each battery so i can see what the state is ....

the main reason i went for the one i did is because its dual battery ,( but if you only want to charge one battery it auto detects that too) the others were only single battery .

Can i ask is it ok to directly bond with silkaflex or some other glue a semi flexible monocrystalline panel to the roof on my elavating top, does there need to be an air gap so it doesn't overheat ???

the short answer is , if its a cheap one without the ally heatsink back i dont know!
if it is a ally backed one , mine has been on 5 years and hasnt had any issue with over heating .
i suspect that is more a excuse dreamed up by people who bought the wrong panels .....
i wouldnt buy the cheap ones that are backed with fibre

Ok thanks Mocki, having not purchased one before what sort of price range am I looking at for a panel £150 perhaps ???