Dead battery

[aporschefan]

last time I drove the car, I had to charge the battery and then took the car for a 30-40 min drive.

Sadly since then, it's been many months and I haven't had a chance to even think about the car let alone go out in it.

Just to get the boot to open I had to release the hatch from the inside. I tried charging the car and no joy. The car with the good battery has been running for a bit now and there is absolutely nothing when I turn the key on the 944. Any suggestions???

The current battery in the 944 is a couple of years old at most and is a Bosch (hsb096) s5.

eta: the car is booked in with JMG in a couple of weeks time so I wanted to run her as much as possible between now and then.

 

[bmnelsc]

When you let a battery discharge completely it will likely develop a buildup on the internal plates in the battery. At this point it may not accept a charge from a low rate charger. If you have a battery tender type charger with desulphation mode you should try that. Otherwise take the battery to a service center that can properly charge and test the battery. It might be a goner from being completely drained.

 

[Monkeythree]

^^^^ what he said. Deep discharge leads to sulphation and only overcharging has a chance of breaking down the sulphates and bring the battery "back to life". With a relatively new battery, chances of recovery are reasonable. With yours being a couple of years old already, I would presume it dead. Buy a new one.

 

[aporschefan]

thanks guys. So if I have to buy a new battery, whats the best option? Dont mind paying a little more to get a superior product and save weight. (Provided its not super expensive)

Probably best to buy a trickle charger as well. Any suggestions?

 

[Monkeythree]

The "best" option is the one with the highest cold cranking amps and highest capacity that is available in the 944 box size. (I don't actually know what is the highest performance available on the market right now). That option won't be compatible with less weight though because more battery performance means more lead inside.

I wouldn't bother with a trickle charger. If you are going to be leaving the car unused for any length of time, just pop the earth lead off the negative terminal to relieve the battery of any drain from the car. The self discharge rate of disconnected batteries is very low and a new one will still be healthy after 6 months of inactivity if it doesn't having anything draining it.

 

[Shark]

ORIGINAL: Monkeythree

I wouldn't bother with a trickle charger. If you are going to be leaving the car unused for any length of time, just pop the earth lead off the negative terminal to relieve the battery of any drain from the car. The self discharge rate of disconnected batteries is very low and a new one will still be healthy after 6 months of inactivity if it doesn't having anything draining it.

That! (above)

 

[geoff Ives]

As the previous 2 posts.
I have a battery isolator fitted to the earth on my car and disconnect the battery with it every time I put the car away. It take 2 seconds and the same to reconnect the only downside is that the clock will stop. The upside is that it is also an anti theft device as to look at it it looks the same connected or disconnected.

 

[Ex Skyline]

ORIGINAL: geoff ives

As the previous 2 posts.
I have a battery isolator fitted to the earth on my car and disconnect the battery with it every time I put the car away. It take 2 seconds and the same to reconnect the only downside is that the clock will stop. The upside is that it is also an anti theft device as to look at it it looks the same connected or disconnected.

Me too Geoff [8D]!

 

[T3rra]

Would this effect the ecu? Hadn't drove mine or turned it over in a few weeks, now tucked up in a garage. My drain is low still had power for lights and that but didn't jump to life. Suspect it my imboilser kicking in if voltage is less 11.8. Will start with a jump or even battery charger plugged in. Will turn right off the bat.

Been thinking off getting a battery cut off switch

Battery wise I brought a new battery recently, bosch 5 star from eBay about £80 normally £130 wouldn't worry to much about weight get the largest that will fit

Think I got s5007 type height about right could go longer but wouldn't go higher