Battery charging using an inverter

[snarfy]

As my Griff has no access to electricity when it is parked I cannot leave a charger or conditioner connected. However , I have a spare battery, I have a charger/conditioner, so if I bought a power inverter would it make sense to plug the whole shebang together and keep my griff's battery topped up ?
Does anyone know if the current draw would result in a dead slave battery in a day or two or if the thing could run for a reasonable time.. ie a couple of weeks ? I'd then recharge the slave battery and plug it back in and hey presto...no dead griff battery.
Anyone any ideas as an inverter (cheapish) is about 50 quid and if it doesn't work..........

[danny hoffman]

I suggest you drive your car more often!

Seriously though your idea does sound like it would work, but a bit if a PITA. Have you though about one of those solar powered battery conditioners?

[snarfy]

Yeah I know...must get out more. Been too busy lately and just haven't managed to drive much. Very rarely let down but then I've always had the spare battery to jump start. Just would like to keep the battery in good nick really.
Car lives under a cover so solar power is a no no, although I have got one of those solar panel thingies.

[wedg1e]

Inverters are still fairly inefficient and waste a lot of energy as heat. So I doubt you would get a couple of weeks.


Ian

[Mikej]

why not just use the spare battery to jump start the car if the main battery is flat ???. It would recharge quit quickly when the engine is running.

Mike.

[simpo one]

My phrase is 'smashing up a boat to make a raft'! You'd be going from 12V to 240 V and back to 12V again - with losses at each step as mentioned. I agree with MikeJ - just use the spare battery to jump it, then cart it into the house and recharge it when needed. You can also get a special jump-start pack which contains a battery, leads etc all in one shiny package.

If the car is in daylight, you can get solar-powered battery conditioners. But if it's in the dark and with no power, I think the spare battery routine is the best answer.

[richard sails]

snarfy said:

Yeah I know...must get out more. Been too busy lately and just haven't managed to drive much. Very rarely let down but then I've always had the spare battery to jump start. Just would like to keep the battery in good nick really. Car lives under a cover so solar power is a no no, although I have got one of those solar panel thingies.

Can you get a longer wire and put the solar charger on the roof of the building out of site of everything but the sun??

[chimburt]

you could, but as the others say, inefficient.
if you really want to go down that route then get yourself a hefty diode and just connect the battery terminals together, using the diode ( facing correct way ) in the positive lead. probably worth sticking a fuse in there as well.
this would keep the primary battery topped up off the secondary, and the diode would prevent current going the other way ( ie out of the primary into the secondary if there is a slight imbalance, or the secondary is flat )

[joust]

Inverter -> Charger is a very poor solution with large losses. Why not just buy a purpose made unit for the same cost...

e.g. www.halfords.com/shop/item.asp?id=714832 (there are many around the £40-50 mark)

J

[snarfy]

Thanks for all the replies guys. Having replaced the original battery for a new one recently I really don't want to run the battery down and jump start. I'm also aware of the sledgehammer/nut thing with an inverter which I know will not be that efficient but was kinda clutching at straws.

Looks like I'll just connect the two batteries together when the car is sitting there with the diode thingy from chimbert.

Ta. Now lets see if I can fry the electrics......