13 replies to this topic

[yeti21586]

did a search and looked through 16pages of posts (i am sooo sick of the word battery now lol)

im thinking about fitting another battery to Vini as well as the standard one.

i was thinking about fitting a 12v motorbike.

the reason im thinking this is that i wont 7 extra spot/fog lights (dont ask why i just do lol) and also i like my music so am hainv a larger than normal sound system so i dont wont any of it affecting the running of the car, also would mean i could listen to music etc with out draining the main battery


can anyone think of anyreason why i cant/shouldnt do it and also how would i wire it all up so that it charges and works all the time etc


cheers

YetI

[bmcecosse]

Motor cycle battery will only last about 10 minutes!

[yeti21586]

how come?

[kalkat]

How are you intending fitting it?

If you simply wire it in parallel with the car battery, you'll end up with a whole raft of electrical issues.

I have big Cibies on my car and a Transit battery - it just fits in the battery box

[Bungle]

you want a split charge system

roofless asked this question a few days ago

[yeti21586]

what does bmcecosse mean by it will only last 10 mins>>??

oooh so is there a topic on the split charge thingy??


cheers guys

YetI

[bmcecosse]

Because it's small - it will be run flat in 10 minutes!! Easy enough to install - charge it through either a relay or more simply with a diode - just make sure it can handle the current.

[yeti21586]

not really sure im understanding you.

why would it run flat if its being charged etc via the alt like the main battery

[kalkat]

The thing with electricity is it is like water. Seems daft but in effect, it is always trying to find the easiest way downhill ie. to earth.

Because of this, the current draw of your car + accessories would come from the smaller battery (the 'bike one) then the draw would be from the car's main battery. However due to the smaller battery now being flat, the current draw would now be through that as a primary means to earth (effectively trying to re-charge) BUT due to the load the car presents................ well without working out a whole load of things, lets just say it's not a good idea.

A car battery is usually rated at something like 40 ampere hours or so (you could draw 1 amp for 40 hours) a motorcycle battery is only about 5 - 10 ampere hours.

Split charge systems usually work with two batteries of approxiamately the same size (powerwise) and alternate the charge as each battery requires.

It would be far easier to have one big battery (generally cheaper too as a decentt split charge system can cost £50 + ) and a decent size alternator which some cars already have.


Emma

[bmcecosse]

It will run flat when you stop - with the 'music' still on! If you are going to keep the engine running - don't worry about an extra battery!!

[yeti21586]

It will run flat when you stop - with the 'music' still on! If you are going to keep the engine running - don't worry about an extra battery!!

oh i understnad now lol

Edited by yeti21586, 12 May 2010 - 10:07 PM.

[mgb1978]

You can get a split-charge relay from most caravan or towbar places (and E-bay of course). Then you can run the extra spots/sound system from the second battery. The relay will allow the alternator to charge this battery when the engine is running.
When you switch off the ignition the relay switches off any connection between both batteries , so thet the second one can't draw current from the main one.
There are various types of system available-just google "split charge relay" to see what suits you (and your pocket).

just found this:
http://www.landyzone...stem-61268.html

plenty of info there

Edited by mgb1978, 13 May 2010 - 07:31 PM.

[Cooperman]

If you want to run loads of auxiliary lights, etc, do an electrical power calculation. Add the wattage of all electrical items which may be swithed on at the same time. Divide that number by 12 and that gives you the amperage drawn. You then need an alternator with above that figure. For example, my rally car runs 100W headlights and twin 130 w spotlights. add in the sidelights, brake lights, interior lights, trip computer, heater fan, auxiliary fan, etc, and I get a maximum current draw of c.700 watts. Now, 700 divided by 12 is almost 60 amps. So I have a 65 amp alternator which works fine. You can, for a price, get even more powerful alternators.
Also you can get a high amp-hour battery which will help some as well, but the key to it is the alternator.

[yeti21586]

ok cheers guys lots of very usefull info there


YetI