solar pannels

[The Rock]

I have beem offered a solar pannell at a really good price, but I don't understand the specification,......Peak power output (V)=17....Max Power currant (A)=1.16....Short Circut Current (A)=1.27...... Could somebody tell me if this might be ok for my motorhome. Kind regards The Rock

[Ocsid]

At a current of only 1.16Amps this means that its potentially only capable of a maximum of 19.7Watts with an efficient controller and haze free conditions.

This is too small to do much good, and most times it will fall far short of this; though you could take the view everything helps.

 

For the UK buying less than 45/55 Watts is IMO wasting funds and the more sensible target I feel is buying about 85 Watts. However of course all this depends on what power you consume and your motoring/stay time off EHU pattern. The 17 Volts output is what you would expect for charging our 12 volt batteries.

[Clive]

Agree, 80 watt plus.

C.

 

[Guest Tracker]

Depends what you want it to do and how much it costs?

 

If you want it to help your leisure battery last longer off site, it won't help - you need a much bigger panel with regulator!

 

If you want it to help keep the battery charged when standing out of use it may help, but I would still prefer to use a regulator to prevent any risk of overcharging and boiling the battery in the scorching heat of an English summer!

[Clive]

And ALWAYS through a regulator.

C.

[AndyB]

I bought a 12 watt panel from Maplins for £50.

 

The idea is to use it to keep the 85AH leisure battery topped up for 3 days

whilst at the "Rewind" Festival in Henley Upon Thames in August, where there are no hook ups at the site.

 

We'll only be using the electrics for igniting gas fridge, water heater and oven and a bit of light at night, taps, but no telly/music etc.

 

I'll put the panel out of the way on the roof.

 

The vast majority of the time there will be minimal electrical use.

 

Any thoughts on if this panel will be up to job for this purpose ?

[Guest Tracker]

I would have thought that for the minimal use you suggest - apart from heating water? - the 85ah battery would easily survive three days use if fully charged when you start and as long it is not failing.

 

A 12 watt = 1 amp solar panel ought to be just about capable of maintaining the battery when the van is idle.

 

Most vans seems to have a small discharge rate of about 100 to 250 ma, but lets say 200 ma which over 24 hours is about 4.8 ah so you would need at least 5 hours full charge in direct overhead sunlight at 1 amp or, more likely, maybe 10 hours of UK sorta sunlight/daylight at .5 amp so it might struggle in the winter.

 

If you fit the panel to the roof don't forget to keep it clean and use the right sealant, preferably with sealed junction box sealed to the roof, where the cable comes through the roof.

[AndyB]

Tracker,

 

Cheers for the advice, won't be using the electric to heat the water, just igniting the truma water heater as, when and if needed

 

The plan is literaly to plonk the panel on the roof through the large roof light at the back. I'll be making some pads to protect the roof.

 

I may invest in a proper system later on during the year.

 

Andy

[Guest Tracker]

Fair enough Andy - seems like a good idea to me - just remember to put a note on the steering wheel so you don't drive off with it on the roof!

 

And heres another freebie tip - we have a little dangly sign that hangs on the wheel via a 'Terry' sprung tool clip to remind me to put the TV aerial down before moving off - oh yes - and lock and switch the fridge - and shut the loo door - and close the skylight(s) - luckily the step is automatic!