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Switching Relays
Scuzzle - 30/5/13 at 04:33 PM

Just a quick question-

Does the terminal on a switching relay that connects to the battery have a slight constant drain on the battery. Just asking because I've only recently fitted uprated wattage headlight bulbs and spotlights and given each one it's own switching relay and now the battery seems to be draining quickly.
When working on the car I only have the accessory switch on just so I can listen to the radio and the power has dropped right down in 3 days of working 5 hr days on the car, not a lightweight battery either 74 AH 600 CCA.

Has anyone any idea on why this should be, it's not as if I've had the lighting on, just the radio, but the battery deffo does not seem to be holding it's charge as well since I've fitted the relays.

Smoking Frog - 30/5/13 at 05:03 PM

If they are wired correctly, no. Drain would only happen if the relay coil is energised. This is where the switch is wired in, so normally the relay coil is not energised.

Scuzzle - 30/5/13 at 05:38 PM

They are wired as they should be, the battery drain just seemed to occur around about the same time the relays were fitted which is what has made me suspect them.

britishtrident - 30/5/13 at 05:51 PM

Modern batteries are so easy to damage if left without regular charging it could well be a battery issue.

disconnect the battery and give it a long low rate charge before doing anything else.

Chris_Xtreme - 31/5/13 at 08:47 AM

You'll also be surprised how much the radio can use...

I'd do the test from fresh charge, nothing on see how you go, if it does drain, do the same having removed your new relays to prove it is not them..

On mine the previous owner didn't put the alternator exciter wire on the ignition controll and it drew 3 amps non stop. Would kill the battery overnight.

Scuzzle - 31/5/13 at 11:56 AM

Could be, I've already had to replace one battery last year as inactivity and the cold winter killed it, this winter I removed the battery and took it into the house but it's possibly not what it should be.
The car never gets used enough to keep the battery healthy, when it's left in the car I remove both terminals and fit one of those solar battery maintainers but it still seems to lose charge quickly.

loggyboy - 31/5/13 at 01:21 PM

Disconnect the relays and see if it holds its charge for a few days.

britishtrident - 31/5/13 at 06:34 PM

quote:
Originally posted by Scuzzle
Could be, I've already had to replace one battery last year as inactivity and the cold winter killed it, this winter I removed the battery and took it into the house but it's possibly not what it should be.
The car never gets used enough to keep the battery healthy, when it's left in the car I remove both terminals and fit one of those solar battery maintainers but it still seems to lose charge quickly.


Disconnected starting with a full charge it should hold charge for months, standard manufacturers instruction for batteries in storage is charge once a month -- my guess is it could already be foobarred.
Always make sure a battery is charged to full capacity before storing, each discharge reduces the charge the battery will hold when recharged. The longer the battery lies with a low charge the more damage is done.

I foobarred a tintop 65ah battery this year by leaving it connected for 2 months. it started out fully charged but the few milliamps the ecus and alarm take in sleep mode slowly but surely killed it, two weeks charging and it still hasn't taken any charge.

Scuzzle - 31/5/13 at 06:37 PM

It's possible I've shortened the battery's charging capacity as I'm always leaving it for weeks on end. I might need to buy another one and really take car to keep it fully charged at all times.