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Getting charge to a second battery????

Posted: Mon Sep 20, 2004 10:33 pm
by Screwy
guys,

I have just put a winch in, and need a second battery for the job.
My question is, The winch cables go straight to the battery terminals, how do i get charge to this battery withour spending money on a duel battery setup???

Do all i have to do is, run a positive Lead from the battery over to the other bateries positive? or the the alternator?

I dont need control of this battery, nor do i need it to run anything apart from the winch, just want it to get charge.
any help appreciated.

cheers,

screwy

Posted: Tue Sep 21, 2004 12:33 am
by Woop
Running a cable between batteries will work, but if one battery goes flat, it will flatten the other battery if they are connected together all the time.. The best way is to use either a high current relay--more than 30A or a Solenoid. Either connect the solenoid to a switch so you can activate/unactivate it or connect it to an ignition source so when you switch the car off, the solenoid will de-activate, thus isolating the batterys. Connecting it to the Alternators's no good as its still connected to the main battery. The reason you need to use a high current relay or solenoid is that if the second battery is very flat--say after winching, a high current will flow when you join the 2 batterys together until the flat one charges up. This may burn out a low current relay.

Nick

Posted: Tue Sep 21, 2004 7:47 am
by Screwy
thanks nick will will look into it, in the last system i had i ran a cable between the batteries and it was fine, but ill re think, may chuck a cheap duel kit in there to keep me safe:)

screwy

Posted: Tue Sep 21, 2004 8:21 am
by chimpboy
Woop wrote:Running a cable between batteries will work, but if one battery goes flat, it will flatten the other battery if they are connected together all the time.. The best way is to use either a high current relay--more than 30A or a Solenoid. Either connect the solenoid to a switch so you can activate/unactivate it or connect it to an ignition source so when you switch the car off, the solenoid will de-activate, thus isolating the batterys. Connecting it to the Alternators's no good as its still connected to the main battery. The reason you need to use a high current relay or solenoid is that if the second battery is very flat--say after winching, a high current will flow when you join the 2 batterys together until the flat one charges up. This may burn out a low current relay.


My old man can supply a unit that will do this automatically using a high current voltage sensitive relay. It's a wire-in-and-forget-it option.

See my sig line below.

Jason

Posted: Tue Sep 21, 2004 9:40 am
by fightara
chimpboy wrote:
Woop wrote:Running a cable between batteries will work, but if one battery goes flat, it will flatten the other battery if they are connected together all the time.. The best way is to use either a high current relay--more than 30A or a Solenoid. Either connect the solenoid to a switch so you can activate/unactivate it or connect it to an ignition source so when you switch the car off, the solenoid will de-activate, thus isolating the batterys. Connecting it to the Alternators's no good as its still connected to the main battery. The reason you need to use a high current relay or solenoid is that if the second battery is very flat--say after winching, a high current will flow when you join the 2 batterys together until the flat one charges up. This may burn out a low current relay.


My old man can supply a unit that will do this automatically using a high current voltage sensitive relay. It's a wire-in-and-forget-it option.

See my sig line below.

Jason


I'll second that this works well and is v. easy to install. From my point-of-view I probably could have done it myself, but for the time saved it was easily worth the small outlay.

battery

Posted: Tue Sep 21, 2004 6:29 pm
by ratboy
if u want to get out cheap but not to nasty have a look at jaycar dual battery system a kit u make for $ 50 easy and u dont have to worry about
a manel switch :twisted: :twisted:

Posted: Tue Sep 21, 2004 9:41 pm
by Big Red Toy
for what your doing screwy, just link em, you only really need to worry about separating them if you are running fridges etc overnight, or accesorie's when the car isn't running, which in a comp car isn't a big deal, just another thing that COULD go wrong in mud etc
:D

Posted: Wed Sep 22, 2004 1:13 am
by pongo
If you really want to get out of it cheap,buy a starter solonoid from a very early ford.they were seperate to the starter motor and will handle heaps of current.Just wire it to the ign , acc or put in a manual switch(could be a 3 way switch man-auto-off).should be about 10 buks from the wreckers.

Posted: Wed Sep 22, 2004 7:46 pm
by Screwy
Ive ended up buying a Marine switch, and in theory it will work really well and will be simple to be install, only downside it that its ugly :x
But ill live with that :D
Thank TOM!

screwy

Posted: Thu Sep 23, 2004 7:35 pm
by Not For Highway Use
When installing a winch with two batteries the best way is to join the batteries in the winches soleniod box. eg Where the positive feed is connected in the winches soleniod box add a second cable to the Aux battery. You can still run your Marine swith but it doubles the cable supply to the winch. Ever noticed the power cables to winches get hot? When I connected up my winch this way i could actually see an increase in line speed. If you want more details just ask? I am setting up duel soleniod boxes to run my new Warn 6hp on a High Mount. Note: only use clean heavy duty terminals. I melted the top off a battery with OE terminals.