Andrew Harper

Quick Battery question for my '96 RX7.

I have been suffering lately from very slow battery drainage.

If I fully charge the battery and then leave it overnight the battery has lost around a 1 to 1.3v which still makes the car start but the starter cranks very slowly.

I do have a certain amount of Hi-Fi in the car and I'm not sure if this is causing the problem.

I have a Optima Orange Top battery in the car and having spoken to the dealer I bought it from. It seems that maybe a yellow top may be more right for the system as it is now.

If anyone has any experience of things like this or can point me in the direction of a good forum then I would be grateful.

In Car system;

Pioneer Headunit
DSP Hideaway unit
Digital Radio Unit
Genesis Compact 4 Amp
Active 6.5" Bazooka Tube
Multichanger in the boot

Wondering if the Bazooka is draining more current than the system can handle as it is the last addition to the system?

ijneb

Something is staying on overnight. My friend wired his amp to a wire that was always on, and had the same problem. When you turn the car off, see if anything is still on.

Also- Didnt the 3rd Gens have a problem with the glove compartment light staying on overnight causing dead batterys?
I think i read that somewhere.
Ben

911GT2

Yeah, I agree, the battery shouldn't lose any power no matter what kind of stereo equipment you have in the car. Basically, turn the car off, and go piece by piece with a multimeter, and find the wire/wires thats drawing current with the car off. Then follow it back to it's source and put it somewhere that only has power when the car is on.

T88NosRx7

iTrader: (1)

have you done anything recently?

hyper7

i had the same problem but i found that simply adding some water to the battery then charging it fixed the problem. the glove compartment box light only comes on if the lights are on. so if it is parked with the lights off the glove box light cannot be on even with it open. you could also run a small light between the negative post and the negative wire, and if the light goes on then current is obviously flowing and draining your battery.

Andrew Harper

Thanks for the help,

Luckily both the Genesis and Bazooka Tube Amps have power lights so I am able to tell if they are on all the time.

I installed the system myself and was very thorough in making sure all earthing and cabling was good and clean and well thought out.

The last addition to the system was the Bazooka tube at the moment it shares it's earth point with the CD Changer, maybe I should try it with it's own earth?

Can using too long an earth lead from equipment cause problems?

hyper7

have any luck yet!

Andrew Harper

Thanks for the interest hyper7,

Ran some tests on the electrical system over the past couple of days and have found no obvious problems.

Nothing seems to be earthing itself.

To make matters even more puzzling fully charged the battery and took the voltage at 12.4V and then left it overnight connected to the car.

Next morning the voltage had dropped to 11.1V (as expected) and then on the next morning its dropped to 10.90, next morning 10.87. This morning its only dropped another .02 to 10.85.

This very small loss seems reasonable (alarms and so on). So I'm a little puzzled now as to whats causing the rapid (albeit 24 hr initial discharge).

T88NosRx7

iTrader: (1)

hmmm....I had battery problems and here was my pattern at the time. When car was on it was well above 14V, as soon as car was shut off it went to ~12V, then within the hour wit would be sitting at ~10.5V, and then the drain was minimal after that. It sounds like a battery problem, try changing the battery, that should solve the problem. Do you drive you car often?

Andrew Harper

No I haven't been able to use the car that much recently(I've only covered about 100m since January).

Maybe a Deep Cycle (Yellow Top) would be better?

Thinking about buying one of those Solar Trickle Chargers So I can leave it on the Dash.

Are these safe with Optima Batteries?

T88NosRx7

iTrader: (1)

yes, I currently have one hooked up to the car, if you don't use you car much that battery loses it charge capacity, thats why your battery is dead. Just get an optima battery and keep the trickly charger hooked up, then you'll never have to worry about battery problems again.

Andrew Harper

Thanks "T88NosRx7",

I've currently got the Orange Top Optima, but like you've said short journeys and infrequent use can play havoc!

T88NosRx7

iTrader: (1)

yeah, keep me informed. Like I said I had this problem before and a quick battery swap did the trick.

adam c

iTrader: (2)

There are other things that can drain your battery. Here are a couple that I found out about (the hard way)

1. The fan mod. If you run your fans, and don't turn off the switch, the switch will continue to be grounded, and drain your battery. This drain continues to happen after the fans shut off.

2. Aftermarket alarms. Many aftermarket alarm systems have a hood sensor. If you leave your hood up after driving the car, the sensor will try to send a signal to the alarm. This will drain your battery too.

If your system is working properly, you should NEVER have to charge it. Good luck finding your problem.