Electrics Question; Solar Maintainer

[Dippy]

Hi all

My other car is a bit of a toy and often sits unused in the garage. Had to buy a new Battery for it recently (it was 6 yrs old, not bad), 80Ah. Thought about a maintainer, everyone recommends CTEK, but as I'm in a sunny country I wondered about a solar one.

I found this one which looks great. My only issue is, if I leave this connected for a month during a very sunny August as is very likely when I leave for hols, is there any chance it would boil the Battery? As there is no mention of any regulator. I'd put the solar panel in the south facing garage window so it would get plenty of charge.

http://www.amazon.co.uk/Ring-Automotive-RSP240-Solar-Maintainer/dp/B003M9FRH2

I'm sure there's a simple equation involving W, v, A and time but I don't know it :(

Thanks for your thoughts :)

[FROSTYBALLS]

There is also this one - http://www.amazon.co.uk/gp/product/B009MPA7JS/ref=s9_simh_gw_p263_d0_i5?pf_rd_m=A3P5ROKL5A1OLE&pf_rd_s=center-2&pf_rd_r=1RS1PCJNWZBMK9F5039K&pf_rd_t=101&pf_rd_p=430153987&pf_rd_i=468294#productDetails - where the description says it will not overcharge the Battery.

[Dippy]

Ooh, many thanks!

Forgot to say, I actually phoned Ring's technical line to ask about the first one. His answer was only very slightly longer than "It shouldn't" which might well be right but I didn't find it very reassuring!

I see in another 4W charger on Amazon they say "We recommend using with a Battery size of 30Ah or greater. If using with a lower capacity batter then a 4A charge controller will be required." Again implies there will be no problem - but I would like to be reassured by some calculations! I have horrible visions of an exploding garage and then the insurance not paying out as I was "negligent" :(

[Uncle_P]

Maplin do a 13w solar briefcase with all connections and a charge controller for an out £50. It's worth having a look at maplin.co.uk as they have all sorts of solar goodies.