Solar .... how big do I need to be??? (1 Viewer)

[MattR]

I don't have much roof space on our PVC but would like to consider solar power to top up our battery. I appreciate that the bigger the panel, the more energy that can be captured but what would be the minimum size panel to make solar worthwhile and what kind of costs would the supply and installation be for DIY?

 

[funflair]

It might depend how much battery you have and what your power usage is, saying that you can’t really have too much as it just means that you will have enough even on bad days, if you could fit two panels 80 or 100 watts that would be good. You should get panels at £1 per watt and the another £100 to £150 for controller and bits and bobs.

Martin

 

[Minxy]

The words: string, how long, and a bit of ... come to mind!

We've only got a 60w semi-flexible on ours which I fitted myself, I had to buy the panel, a waterproof gland for the roof, and a connector to plug it into our Schaudt system ... overall it should have cost about £200 I recon but I got the panel itself for £40 so that reduced the cost quite a bit! the panel has been more than sufficient for our needs, even Feb/March in France and Spain on aires/parking (no EHU).

How big a panel will depend very much on your needs but if I was starting from scratch I'd probably go for 100w minimum.

If you want a semi-flexible the benefit of these is that you don't need the mountings/fixing brackets but the panels themselves tend to be a bit more expensive.

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[Minxy]

Oh, nearly forgot, first think to sort out is a larger battery bank - a 2nd leisure battery should be your first investment.

 

[Lenny HB]

Agree with Mel if you only have one battery fit a second one before considering solar.
For solar I would say min of 80 watts that will probably kept you going from May until September, to extend the season you really need 200-300 watts.

 

[Stealaway]

I would measure whats gaps you have and source the panels to fit. Any size will help and when you have determined the panels sizes you can fit you'll be able to spec the rest.

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[MattR]

I would measure whats gaps you have and source the panels to fit. Any size will help and when you have determined the panels sizes you can fit you'll be able to spec the rest.

Am aiming to do that but while I am up there, I will have a better idea of what size panel I would try and fit in.

 

[MattR]

Oh, nearly forgot, first think to sort out is a larger battery bank - a 2nd leisure battery should be your first investment.

Our issue is storage space for the second battery and trying to remember what I was advised about overloading the charging / distribution unit if using two batteries. We have a German made blue charging / distribution unit (I can't recall the manufacturer's name. It is probably as old as the 20 year old PVC) and have heard that such units are designed to only charge one battery; adding a second one would over-load it / reduce the life expectancy of it. Have I remembered this advice correctly?

 

[Lenny HB]

Sounds like an Elektroblock, you are only likely to overload load it with more than one battery if you are constantly charging the batteries from fairly flat. With solar topping up the batteries you are unlikely to be in that situation. I have 3 batteries but have not upgraded the charger as 90% of my charging is by solar.

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[MyrtleGuru]

We have a 120 Watt panel feeding two 100Ah leisure batteries and have never run out of power. However we do run everything as 12v for efficiency i.e. no inverter: we have 12v power supplies for everything (laptop, TV, sound system, shaver, etc.) and all lighting is LED. Then again we rarely stay in one place more than 3 to 4 days, so the alternator does its business too in keeping us charged up. And, like most, fridge/heating/hot water can run on gas of course. Unlike some big rigs there is no microwave, washing machine and the other trappings of static life!

 

[MattR]

We have a 120 Watt panel feeding two 100Ah leisure batteries and have never run out of power. However we do run everything as 12v for efficiency i.e. no inverter: we have 12v power supplies for everything (laptop, TV, sound system, shaver, etc.) and all lighting is LED. Then again we rarely stay in one place more than 3 to 4 days, so the alternator does its business too in keeping us charged up. And, like most, fridge/heating/hot water can run on gas of course. Unlike some big rigs there is no microwave, washing machine and the other trappings of static life!

We normally survive for 3-4 days in one place with one leisure battery - around 90Ah suspect that it gets run down too much to help it last longer than about 3 years. We're wondering if solar would make enough difference to help reduce battery damage. However, when camping in Europe during the summer, we tend to park under trees for shade - we might not get enough sunshine on the panel to make any difference anyway.

 

[Stealaway]

However, when camping in Europe during the summer, we tend to park under trees for shade - we might not get enough sunshine on the panel to make any difference anyway.

You will have the choice though and our batteries are pretty much charged before we get out of bed!

I kept my solar panels completely separate from the Elektroblock by fitting a dual battery solar controller.

https://www.ebay.co.uk/itm/EPsolar-...m=162447816421&_trksid=p2045573.c100506.m3226

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[Just smiffy]

Following form your other thread I didn’t realise you only had one battery, another will instantly double your power requirements and two batteries working at half the output each will be better then one delivering all the power... if you get my drift.
Your already lasting 3-5 days off-grid so in theory you will double that by adding another battery.... however, it will take twice as long to charge them back up again whilst driving, (unless battery master fitted)

Fitting an other battery will be the cheapest option, to keep both batteries at optimum levels and if going off grid more, then fitting even a 100w panel will keep them topped up even if you park under a tree for a week. It benefit them no-end ...

You’ll get some good suggestions like you already have and as soon as you know what size you can get up there post it here and product reviews will come rolling in....

 

[MattR]

You will have the choice though and our batteries are pretty much charged before we get out of bed!

I kept my solar panels completely separate from the Elektroblock by fitting a dual battery solar controller.

https://www.ebay.co.uk/itm/EPsolar-10A-20A-Dual-Battery-Solar-Panel-Charge-Controller-12V-24V-Auto/162447816421?_trkparms=aid=555017&algo=PL.CASSINI&ao=1&asc=50926&meid=219932de709b4407b42dcf5874417e0d&pid=100506&rk=1&rkt=1&&itm=162447816421&_trksid=p2045573.c100506.m3226

I understand that it is the two battery strain on the Elektroblock when charging from 240v that is the issue.

 

[Guigsy]

Just to point out that in the UK (and even within the UK) that there's a big difference between seasons. Even a slightly dreary summer day will produce loads more energy than a cloudless sky in the early spring and late autumn. Going off-grid 3 seasons requires a barn-door of panel and an MPPT charger.

And you need to think about what uses the power. Definitely change to all LED lighting. Don't expect to watch a lot of TV. And with the limited roof space on a PVC, you can probably forget about running the fridge on electric.

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[Marty Gilly and Pup]

I’m about to put my SP on the roof this weekend. I’ve already doubled the batteries to 200ah and there’s an mppt regulator wotsit going in too.
My thinking has been like this:
If I can last a number of days without charging currently, then a panel (in my case, 150w) is going to extend that considerably. I’m not too bothered whether I can last forever without hookup, more that I can extend that time before doing the campsite hookup and dirty washing stop.

If I use 40ah per day and recover 20 on ave then in theory that’s 10 days eh?
If I use 40 and recover 30 that’s 20 days! This is assuming no movement charging too. I can always double the SP later and stay off grid till Putin voluntarily gives up The presidency if necessary! (That’s forever by the way)

 

[Ivory55]

For people with limited space etc is there any advantage having a bigger alternator fitted to th the van ? I am no mechanic that’s why I asked.

 

[funflair]

For people with limited space etc is there any advantage having a bigger alternator fitted to th the van ? I am no mechanic that’s why I asked.

I think the answer would be unless you have a massive battery bank the standard alternator will be fine but would charge your leisure batteries faster and better with the addition of a B2B charger.

Martin

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[Ivory55]

Just wondered as have seen larger alternators for sale as up grades

 

[TerryL]

I understand that it is the two battery strain on the Elektroblock when charging from 240v that is the issue.

It shouldn't be an issue, charging two batteries is no more strain than one. It'll just take a bit longer is all, the charger will only output what it is capable of.