Porsche Enthusiasts Club Forum

Finally got around to buying one of these to prevent the battery on the 928 running down.

The instructions are fairly minimal but it says positive connection to positive terminal on battery and negative connection to car body.

Apologies for being ignorant but why doesn't the negative go to the negative terminal on the battery?

PaulPSB wrote:Finally got around to buying one of these to prevent the battery on the 928 running down.

The instructions are fairly minimal but it says positive connection to positive terminal on battery and negative connection to car body.

Apologies for being ignorant but why doesn't the negative go to the negative terminal on the battery?

Hi PAUL

Yes you are correct. it makes no matter whether you connect it to the negative terminal OR a good earth on the body as both are the same circuit...personally i would connect to negative on the battery as you are assured of a good earth there...

OR....connect it to the jump start terminal under the bonnet and any engine earth...if its easier...


All the best Brett

Thanks Brett - I couldn't see any difference either.

i cut the croc clips off mine and hard-wired it to the battery using a tamiya remote control battery charger type two pin connector, no issues over the past 4 years or so

Please make sure you have a fuse locally to the battery. Having told people time after time to do it & not doing it myself Went to to the SELNK meet the other week. Paul & I smelt burning electrics & after squealing to a halt in the pub car park, found the lead to the solar panel smouldering & melting

tr7v8 wrote:Please make sure you have a fuse locally to the battery. Having told people time after time to do it & not doing it myself Went to to the SELNK meet the other week. Paul & I smelt burning electrics & after squealing to a halt in the pub car park, found the lead to the solar panel smouldering & melting

mine has inline fuse between charger and two pin connector

PaulPSB wrote:Finally got around to buying one of these to prevent the battery on the 928 running down.

The instructions are fairly minimal but it says positive connection to positive terminal on battery and negative connection to car body.

Apologies for being ignorant but why doesn't the negative go to the negative terminal on the battery?

It's a safety thing Paul. When you complete the connection (if charger already plugged in) then there can be a spark.

The battery can vent hydrogen, so sparks in vicinity are not healthy!

Thanks folks

Can anyone recommend a good battery charger for keeping the battery good when the car is not being used, on motorcycles I use an Optimate but I haven't checked if it's suitable for larger battery's that you have on a car.

928GTSM wrote: Can anyone recommend a good battery charger for keeping the battery good when the car is not being used, on motorcycles I use an Optimate but I haven't checked if it's suitable for larger battery's that you have on a car.

It will be fine on a car. If you have a Lidl supermarket locally their version is actually a C Tek copy but much cheaper.

I have an Optimate I use for my motorbike and I have used it to recover the battery on my cars plenty of time with no problems but it does take time, however it will keep the battery charged over time.