100w Flexible Solar Panel

[Joker79]

I've wanted for sometime to fit a solar panel to my camper and increase my leisure battery power whilst off grid.

I have a Westfalia high top and I wasn't keen on the idea of fitting one of those rigid solar panels to the roof, so I opted to fit a 100w flexible solar panels, a 20w Solar Charge controller, 20w remote metre and 2x Tayna 100AH Leisure Batteries wired in Parallel under the driver & passenger seats (mines a diesel so starter battery is in the engine bay). I used heavy gauge 3 meters of 300 amp Battery cable to link the 2 batteries together, this is becuase I wanted to utise the space under the seats and not loose elsewhere in the van.



100W Flexible Solar Panel: £150

I used Sikaflex 252: £20 to securely mount the panel to the high top, the nice thing about flexible panels is they don't need any clearance like the rigid ones do.





20W Dual Battery Charge Controller & Remote Meter: £70

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6 meters of hi flex 300amp battery cable (3m mtrs Red & 3 mtrs Black) & battery terminal connectors: £100

Total cost of install about £350 and already saved a load on Electrical hook up.

On a sunny day with no cloud in summer I get up to 4 amp hours which keeps the batteries topped up.

[kevtherev]

Sweet

[scottbott]

the company my son works for in australia has a special offer on flexible solar panels,buy one get one free,I thought maybe get him to buy one for me and keep it until I go over next time then I checked the size and they were 5 metres long!,bit too long I reckon,pity as it would be two for about 150 quid

[MattBW]

I have similar setup, 80w panel and a 16A dual charge controller from maplin.
I find the flexible panel fits beautifully to the roof and gives amazing charge to both batteries.

Curious why you used 300amp cable, my 80w panel gives at most about 4 to 5 amps tops, I think I used 16a wire and a 5a fuse. Making me wonder if I should have used higher rated cable?

[Joker79]

I agree I 'm really pleased with the flexible panel and you can hardly see it, if I had enough room on the roof I'd put more on there.

From the charge controller I used 20amp cable, because may batteries are in parallel I have the the postive cable going to the battery under the drivers chair and the negative to the passenger one. So my dual controller is only charging one battery (its treating the 2 batts as 1 big one). I've not got round to running a cable from the charge controller to the starter battery in the engine bay.

The 300 amp battery cable was used to hook the two leisure batteries up in parallel which gives me a total of 200 ah. It runs through the floor of the battery tray next to the bit connects both wheels together and then back through the other battery floor.



This is the passenger chair battery and the red positive cable runs from the driver battery positive terminal, the black negative terminal is also connected to the drivers battery and earthed here.



Sorry this is a bit of a crap picture but the red and black cable run through here to the drivers side battery floor. I spent some time working out how best to this and did not want to have much voltage drop which is why I went for the biggest cable I could afford. I found this site really helpful when working our how best to link the batteries. http://www.smartgauge.co.uk/batt_con.html" onclick="window.open(this.href);return false;



Although I only have 2 batteries this image demonstrates my setup because if you only have 2 batteries, then simply linking them together and taking the main feeds from diagonally opposite corners cannot be improved upon.

[ghost123uk]

Aye, very nice setup there That panel installation looks SOooo neat

Though I can see why you were asked "why 300 Amp cable", as you would only ever need that if your input / output to the "battery" (ie, 2 x batteries = 1 big "battery") was huge. As your input is around 4 amps and your output is equal to whatever loads you have (lights, Propex, stereo, water pump, phone / laptop etc) which is likely less that 10 Amps max, and your initial charge from the split charge relay will be around 40 amps (and then only for a short time), then it does beg the question why spend all that dosh on 300 Amp cable.

Not saying you are in error by the way, you can never have "too much" capability, just curious

[Joker79]

Thanks Ghost

In all honesty I'm not sure what it should be exactly, because the cable distance between the 2 batteries is about 2 meters I felt I needed a beefy cable to allow for the additional resistance (Ohms). I wouldn't have felt comfortable knowing there's 12v and a shed load of amps flowing through a small cable connecting two 100ah leisure batteries under my ass. From what I've seen batteries in parallel are usually right next to each other and you could probably get away with a smaller cable although the ones I've seen are usually a decent size.

The 300 amp cable is only used to link the batteries together the feeds to the radio, change controller, fridge, eberspacher etc are all either factory standard or 20 to 30 amp cable feeds.

[ScienceBoy]

Great install mate!

If I've already got a battery control (albeit long in the tooth) can I just hook a solar panel straight in?

[HarryMann]

It is normal to connect high amp sources together in parallel using heavy busbars.

If one or more cell becomes dud or a mismatch occurs large currents can flow.

I think if they were next to each other with short but thick busbars it would have raised no comment. Ditto if you had ripped the cable out of a couple of scrappers for a few quid

Al (v-lux) has some incredible storage batteries in his Syncro and it might be worth seeing what rating he used for connecting them together?

Good topical subject by the way; seems quite a few are and many more will be going down this route

[Joker79]

Is it a Solar charger controller or a standard 240v control like a westy BBB or Zig unit? If not then you will need a solar charge controller, otherwise you might boil your batteries. My solar charge controller is in additional to and compliments the existing Westy BBB charger.

My solar charge controller regulates the charge from the panel, if the batteries are full it converts the surplus charge to heat (it has a heat sink on the back).

I found this diagram when researching really helpful when researching my install, and gives a good high level view how a solar setup fits in with an existing van setup.



Might be worth getting a Solar panel setup section in the Wiki?

[zzippyman]

Very tidy installation you've got there! If my high-top didn't have "styling" ridges along its length I'd have gone down the semi-flexible route too...

[HarryMann]

My connections between batteries are 35mm2 welding type cable terminated with M6 ends.

That is about 7mm dia cable if a quick mental calculation is right

[HarryMann]

Might be worth getting a Solar panel setup section in the Wiki?

That is a good idea Joker

[v-lux]

The actual copper part of my cable is probably around the 7mm diameter mark possibly slightly more. Externally the cable including its insulation its around 10-11mm. It's basically welding cable.
Good for 300A also if memory serves me right.
Definitely a good idea to be connecting batteries together with beefy cable, a lot of amps can be let loose by a large battery in the event of a short.
Also correct thinking in terms of voltage drop, bigger the better.

I have 150A fuses at strategic points too, just in case anything goes wrong.

[v-lux]

There's nothing really all that special about my batteries to be honest. They are just an unusual set up for one of our vans i guess.

I have 3 x 105ah telecommunications batteries linked up giving me a 315ah leisure/aux battery. The dimension of them are very different to a car style battery as they are designed to be fit into 2u racks. Roughly they are about 600m deep, 120mm wide and 200mm high.

So far i have not bothered installing any solar power as the returns for the outlay are minimal. I'm not knocking solar, just saying its not my preferred method. I opted for getting as much out of my alternator as possible as it provides a far higher charging rate.

For the record, my main consumers are my stereo, phone chargers, lighting, fridge (never turn this off), eberspacher, and laptop from inverter. This set up gives me give or take about 7days without needing to put anything extra into the batteries. I never let the battery bank run down lower than 12V if i can help it, certainly never ever any lower than 11.8V.

All my charging is provided by a Sterling power Alternator to battery charger when on the move. Or a Ctek M300 25A 240V charger if i get the option to plug into a hook up.

More importantly, reducing the consumers is the real answer to making your batteries work for you. Things like LED lighting, Compressor fridges go a long way to having a set up that will provide long lasting power.