12 replies to this topic

[Uncaged]

I'm having a few problems with battery drain when the mini isn't being used and have bought a dis-car-nect after seeing suggestions on this forum...

My question is about which battery terminal I should attach it to? Live or Earth? Will this make any difference/cause any problems?

I plan on attaching it directly to the battery in the boot. Any help is much appreciated...


Stubbon little '95 Sprite (SPi).

Edited by Uncaged, 29 June 2011 - 12:13 PM.

[Ethel]

It can only be a work around and not a solution, whatever the fault is it'll still be present and it would be better to track it down, it could get worse.

Where you put the isolator won't matter, but if it attaches to the battery post, be aware that they are different diameters to discourage you from fitting the battery the wrong way round.

[Burnard]

dis-car-nects need to be fitted to the EARTH terminal.

[dklawson]

dis-car-nects need to be fitted to the EARTH terminal.

While I tend to agree, FIA certified disconnects break the "hot" lead, not earth.

The OP asked if there would be any problems. The answer is highly dependant on your car. If you have a clock, it will stop. If you have a stereo with presets, it will loose them. If your car is late enough to have an ECU, there may be problems, others more familiiar with the late model cars would have to tell you.

[Uncaged]

"Where you put the isolator won't matter, but if it attaches to the battery post, be aware that they are different diameters to discourage you from fitting the battery the wrong way round."

Thankyou Ethel & Burnard: I didn't know that, I'll check the post size and aim for the 'EARTH', earth will certainly be easier to access.

I'm trying to find the electrical fault but its taking time, I've even removed the stereo as I thought that could be the issue...

Dklawson - I don't have a clock or stereo at the moment: down to bare bones so pretty safe there, It's a '95 Sprite (SPi) & so does have an ECU, When the battery has been out of the car I haven't had any problems so I'm assuming/hope it wont cause it to fail.

Many thanks...

Edited by Uncaged, 29 June 2011 - 01:50 PM.

[mike.]

I've got mine fitted to the earth terminal on mine.

The dis-car-nect also comes with a small 10 amp bypass wire as well which is enough to keep your clock running and radio presets.

[dklawson]

The dis-car-nect also comes with a small 10 amp bypass wire as well which is enough to keep your clock running and radio presets.

Yes... but the OP is saying that he is installing this device to address a current drain that is making his battery go flat.

If you use the 10 Amp fuse to support clock and radio presets, you also allow sufficient current flow to let the battery go flat. Therefore, in this instance you cannot use the bypass and if you have a clock or radio with presets, those settings will be lost.

[xrocketengineer]

You guys are right, there can be battery drain caused by the ECU. The easiest way to start looking into that is to charge the battery and let car sit and cool down overnight. In the morning everything should feel cool to the touch. If the relay pack feels warm to the touch a relay is active causing the drain. In my case it was the main relay that was being kept active by the ECU. Disconnecting momentarily either of the connectors of the relay pack would reset the failure. Starting the engine would set the failure and it would not reset until a connector was disconnected or the battery died. The battery would die in two or three days. The problem was corrected with remanufactured ECU from ATP.
Now, the car can sit with no use for over three weeks and starts right up, it is doing better than my 2008 Nissan Titan.

Hope that helps,
Ivan

Edited by xrocketengineer, 29 June 2011 - 04:42 PM.

[Uncaged]

The dis-car-nect also comes with a small 10 amp bypass wire as well which is enough to keep your clock running and radio presets.

Yes... but the OP is saying that he is installing this device to address a current drain that is making his battery go flat.

If you use the 10 Amp fuse to support clock and radio presets, you also allow sufficient current flow to let the battery go flat. Therefore, in this instance you cannot use the bypass and if you have a clock or radio with presets, those settings will be lost.

I've fitted it to the 'Earth' last night (without the bypass wire) & it's a snug fit to the terminal, 'Ethel' was right the ring terminal of the positive would have been too large for a good connection!

[Uncaged]

You guys are right, there can be battery drain caused by the ECU. The easiest way to start looking into that is to charge the battery and let car sit and cool down overnight. In the morning everything should feel cool to the touch. If the relay pack feels warm to the touch a relay is active causing the drain. In my case it was the main relay that was being kept active by the ECU. Disconnecting momentarily either of the connectors of the relay pack would reset the failure. Starting the engine would set the failure and it would not reset until a connector was disconnected or the battery died. The battery would die in two or three days. The problem was corrected with remanufactured ECU from ATP.
Now, the car can sit with no use for over three weeks and starts right up, it is doing better than my 2008 Nissan Titan.

Hope that helps,
Ivan

Very helpful, I'll check the relay! If you don't mind me asking are remanufactured ECU's expensive? Would it be an easy job to change?

Many thanks,

Martin

[xrocketengineer]

Very helpful, I'll check the relay! If you don't mind me asking are remanufactured ECU's expensive? Would it be an easy job to change?

Many thanks,

Martin

It was expensive because of the shipping back and forth between the UK and the USA. The actual repair was £120. The removal and installation of the ECU is easy, about three small bolts, one (or two connectors) and the MAP vacuum line. Here is the whole story:
http://www.theminifo...x...=119357&hl=

Before checking the relay, make sure to have run the engine and leave everything plugged in and battery connected before letting the car sit overnight.

Ivan

[SolarB]

If you can't find the fault using xrocketengineers advice try the following.

Put an ammeter inline on the battery. Positive or negative cable, it doesn't matter which. A cheap multimeter will do and if you don't have one it's well worth the investment.
Remove all fuses. At this point the ammeter should obviously read 0 amps.
Replace fuses one at a time and note ammeter display as you do this. When you replace the fuse on the problem circuit you'll see the amount of current the fault takes. This is, of course, assuming the fault is constantly present. If it's not constantly present you'll have to start replicating the way you use the car to trigger the fault.

You can also use the ammeter while removing relays and de-mating connectors. With a little work you should be able to trace the problem.

[Uncaged]

If you can't find the fault using xrocketengineers advice try the following.

Put an ammeter inline on the battery. Positive or negative cable, it doesn't matter which. A cheap multimeter will do and if you don't have one it's well worth the investment.
Remove all fuses. At this point the ammeter should obviously read 0 amps.
Replace fuses one at a time and note ammeter display as you do this. When you replace the fuse on the problem circuit you'll see the amount of current the fault takes. This is, of course, assuming the fault is constantly present. If it's not constantly present you'll have to start replicating the way you use the car to trigger the fault.

You can also use the ammeter while removing relays and de-mating connectors. With a little work you should be able to trace the problem.

I've finaly got round to doing this and I've found two fuses are causing the drain 7 & 10, possibly the anti-theft alarm? I'm not quite sure where to go from here...

Do you think that would be the ECU?