Jump starts - affecting the good battery?

Cartman78

Hi all,

This should probably come with an official "Stupid Question Alert" but here goes....

I've been off sick from work lately so one of our cars (a 01 Polo) has been basically sitting in the driveway for the last week. Tried to start it during the frosty weather but no joy so had to jump start it off our other car (a 04 Fiesta) left it running for 10-15 mins and took it for a quick spin around the estate etc.

Anyway had to do this 3 or 4 times during the past few days, and then this morning (no frost) we had trouble starting the Fiesta. It eventually started but wondering now if the jump starts have had some affect to it's battery??????

cheers cm

corktina

did you run the Fiesta whilst jumping? Ideally this should be done at around 2000 rpm to ensure that the battery is kept charged.

For a start I'd get the Polo battery tested, it shouldn't go flat in a week.
Was the Fiesta engine running for all these jumpstarts? If so you should get the Fiesta battery tested too, it may just be coincidense that it has failed in and around the same time.

Cartman78

Thanks for the replies

During the jump start - the Fiesta engine is only running for about half a minute (ie. the time it takes me to hop into the other car and get it going).

Should I leave it on longer, or run it at higher RPM?

BrianD3

If the Fiesta has been used for short journeys and several jump starts then that may well have shortened the life of the battey. If it is the original battery in the Fiesta then 7 years is a fairly good innings from that battery anyway.

biko

As long as it's running it should be fine imo.
Both batteries could be nearing their twilight years, one is just getting weaker quicker.
How old are they?
The cold weather will affect batteries more than you think so if in doubt, just change the battery/ies.

biko

biko wrote: »

so if in doubt, just change the battery/ies.

If in doubt get them tested, don't change them for the sake of it

Cartman78

Ok...how much does the average battery cost?

biko

I forget, money doesn't grow on trees any more

Cartman78, ask in a few factors. Batteries are usually between 70 and 100 depending on brand etc.
The factors take the old battery back for recycling.

rcdk1

Is it possible to test a battery with a multimeter? If so, how? "My friend" bought a cheap (€10) multimeter in Lidl/Aldi in spite of the fact he has no idea how to use it.

biko

biko wrote: »

I forget, money doesn't grow on trees any more

Also it may be something draining the battery so a battery test is essential in my view.

rcdk1 wrote: »

Is it possible to test a battery with a multimeter? If so, how? "My friend" bought a cheap (€10) multimeter in Lidl/Aldi in spite of the fact he has no idea how to use it.

Should get over 14V with the engine running I think.

mustang68

rcdk1 wrote: »

Is it possible to test a battery with a multimeter? If so, how? "My friend" bought a cheap (€10) multimeter in Lidl/Aldi in spite of the fact he has no idea how to use it.

There is a bit of voodoo involved, a battery may show a good output voltage, but is unable to maintain it under load, so you need a professional tester (puts a load across the battery) to be sure, but...

If the multimeter (with the engine off) shows:
13.4 volts battery is fully changed (but see above)
12 volts or less is dead, needs charging

As for length of a batteries life, expect one year, five would be unusual.

rcdk1

mustang68 wrote: »

As for length of a batteries life, expect one year, five would be unusual.

Is that not very short?

mickdw

mustang68 wrote: »

As for length of a batteries life, expect one year, five would be unusual.

One year? What are ya talking about. A battery with be guaranteed for at least 2 and I would be looking for 3 years as a minimum, all else being well.

mustang68

mustang68 wrote: »

As for length of a batteries life, expect one year, five would be unusual.

Five would be normal really, one would be extremely unusual.

biko

I think Halfords give a few years warranty on their batts but beware