Powering stuff from a car battery - Page 2

Dr. Z · 13-05-2009, 20:02

Sadly even the biggest ASDAs here have a teeny tiny motor section so the must be nothing like the US Wal-Marts.

Darrin · 14-05-2009, 05:22

Man, I wish shipping charges from here weren't so crappy. I can get a damned good jumpstart pack for around $20...

Nutcase · 14-05-2009, 07:36

This is rip off britain, don't you know?

mejinks · 14-05-2009, 23:46

What does it say on the top of your car battery? There should be a label with the CCA and amp hours rating.

I bought a cheapie inverter from Maplins and it has a low voltage alarm which allows me to use it and it still starts the car perfectly. If you are only charging cameras phones and such, you will only need a 600w one at worst (you may get away with a 300w one)

If you don't mind splashing out a bit, then you could always get a leisure battery from a camping shop and use this with a split charger when your engine is running. All you need for a split charger is a large (200amps) relay, a switch, some 4awg wire (enough to run from your battery to your boot if thats where you want to charge your battery) a diode and some bell wire.

Alternatively, you could buy a cheapy battery from somewhere like eurocarparts and use that instead of your vehicle battery.

Saying all that, have you looked at getting 12v adaptors for all of this kit? It would be less of a strain on the battery than using an inverter.

Toby · 22-05-2009, 19:42

Sorry, forgot about this thread.

Will check the rating on the battery when I get a chance. Do have 12v adapters for some stuff plus my phone has a dedicated cradle in the car for charging but it's things like lappies that I don't have 12v chargers for.

Are they worth getting? How much more efficient is it than using an invertor?

Mark · 22-05-2009, 19:46

Worth getting? Depends how much you need to use it.

More efficient? Most definitely. You'll be doing DC->AC->DC instead of DC all the way. The AC->DC conversion is usually fairly efficient, but unless inverters have got a whole lot more efficient in recent years, the DC->AC most definitely isn't.

Darrin · 24-05-2009, 00:18

Yeah, my 800W (120V) inverter has a peak rating of 1200W, which is 100A at 12V. Only problem is, when I drew 750W off of it, I was pegging a 90A ammeter. So not so terribly efficient. Only about 65%.

13-05-2009, 20:02	#11
Dr. Z I'm going for a scuttle... Join Date: Jul 2006 Posts: 2,021	Sadly even the biggest ASDAs here have a teeny tiny motor section so the must be nothing like the US Wal-Marts. __________________

14-05-2009, 05:22	#12
Darrin Dirteh Kitteh Join Date: Jan 2007 Location: Hiding out in Mormon Country Posts: 1,629	Man, I wish shipping charges from here weren't so crappy. I can get a damned good jumpstart pack for around $20... __________________ A bullet may have your name on it, but shrapnel is addressed "to whom it may concern".

22-05-2009, 19:42	#15
Toby Absinthe Join Date: Aug 2007 Posts: 1,023	Sorry, forgot about this thread. Will check the rating on the battery when I get a chance. Do have 12v adapters for some stuff plus my phone has a dedicated cradle in the car for charging but it's things like lappies that I don't have 12v chargers for. Are they worth getting? How much more efficient is it than using an invertor? __________________

24-05-2009, 00:18	#17
Darrin Dirteh Kitteh Join Date: Jan 2007 Location: Hiding out in Mormon Country Posts: 1,629	Yeah, my 800W (120V) inverter has a peak rating of 1200W, which is 100A at 12V. Only problem is, when I drew 750W off of it, I was pegging a 90A ammeter. So not so terribly efficient. Only about 65%. __________________ A bullet may have your name on it, but shrapnel is addressed "to whom it may concern".

14-05-2009, 07:36	#13
Nutcase Moonshine Join Date: Dec 2006 Location: Chelmsford, innit! Posts: 3,979	This is rip off britain, don't you know?

22-05-2009, 19:46	#16
Mark Screaming Orgasm Join Date: Jul 2006 Location: Newbury Posts: 15,194	Worth getting? Depends how much you need to use it. More efficient? Most definitely. You'll be doing DC->AC->DC instead of DC all the way. The AC->DC conversion is usually fairly efficient, but unless inverters have got a whole lot more efficient in recent years, the DC->AC most definitely isn't.