Solar battery chargers

[Waspy1]

My wife's car (Rav4) is under used.

Sometimes when she goes to start it, the battery is flat.

We were recommended to buy a solar battery charger that feeds a trickle to the battery through the cigarette lighter when the car is parked.

The thing is, her car's cigarette lighter turns off when the ignition is turned off.

Will it still work? If not how can we get round this please? She doesn't fancy the crocodile clip solution.

[Ozzie Osmond]

Waspy1 said:

cigarette lighter turns off when the ignition is turned off. Will it still work?

No.

If a battery is going flat in less than, say, 3 weeks it's probably time for a new battery. It'll only get worse in the winter.

[Waspy1]

Thanks for your answer, but the car (and obviously the battery) is only (nearly) four years old.

I would expect a battery to last longer, and as I said before the car gets very little use and then mostly short trips.

A mechanic friend suggested the solar battery charger thing but I guess I would need to wire it in permanently? Would it need an on/off switch? Or can I make the fag lighter permanently live?

[Lanby]

You could wire it in permanently but why not get a CTEK XS800 or XS3600 charger, just plug it in and ok to leave on charge for weeks

www.ebay.co.uk/itm/CTEK-MULTI-XS-3600-12v-Battery-...

[RemainAllHoof]

Can you have a separate cigarette "port" to the battery that is permanently connected then plug in the solar charger as and when you need to? (Might be a stupid suggestion, mind.)

[IainZ]

Waspy1 said:

Thanks for your answer, but the car (and obviously the battery) is only (nearly) four years old.

I would expect a battery to last longer, and as I said before the car gets very little use and then mostly short trips.

A mechanic friend suggested the solar battery charger thing but I guess I would need to wire it in permanently? Would it need an on/off switch? Or can I make the fag lighter permanently live?

Based on the usage you describe I wouldn't necessarily expect it to last more than 4 or 5 years at all - its the worst possible pattern of usage for a battery. Batteries last longest when they are fully charged. Lots of short trips means it barely gets time to recover from starting the engine before you stop the thing.

I wouldn't try to mess with the existing lighter, but it would be very easy to buy a lighter socket off E-bay & send a single wire through to the battery for a permanent live feed & then find an earth somewhere nearby in the cabin. Whether solar chargers actually do any good is a different debate - but in theory something is better than nothing.

In the meantime, as has been said the existing battery is dying. So the other thing you can do is change the battery & look carefully at the specs of the battery you buy. Firstly it may be possible to buy a physically bigger battery than the one that's there (which will inevitably be stronger) & secondly you need to look at both the AH and CCA ratings of any battery you buy - bigger is better on both. You get what you pay for with batteries & speread over the lifetime of the thing an extra 20 quid to pay for a good battery is a cheap price to pay for getting rid of the angst a crap battery can cause you.

[Waspy1]

Thanks for the help. Perhaps a new battery, a solar charger plugged into an additional, live fag lighter and an occassional full charge will do it.

[anonymous-user]

I would in this case recommend a "Key off" current draw check! When you key-off, the electronic control modules don't immediately switch everything off (it's called "Keep alive" or "retained accessory power" mode). They should after a period of time (30s to over 20mins depending on conditions) turn off, leaving you with only a small (<1amp) draw on the battery. However, if you have a wiring or other fault (can be as simple as a door switch fault etc) they may fail to turn off. This can result in an excessively high current draw, easily flatenning the battery in 3 weeks!

If the problem persists, get the "key'd off" current draw checked by your friendly mechanic/garage !

[Ozzie Osmond]

Waspy1 said:

The car (and obviously the battery) is only four years old.

I would expect a battery to last longer ........ the car gets very little use and then mostly short trips.

In all honesty I think the "very occasional short trips" use cycle is bad for batteries and almost certainly has lead to the death of yours.

[Ozzie Osmond]

Yes, here's link

http://www.auto-facts.org/dead-car-battery.html

"There are many variables that will determine how long a car battery will last. Some of the things that will send it to an early grave are as follows.

"Many short trips can reduce the life of your automotive batteries. If your vehicle has an average run time of less than 20 minutes, your alternator will not have the opportunity to recharge it fully.

"Many starting cycles, coupled with short run times will leave your battery below the ideal charged specification for most of it’s shortened life."