stupid question - batteries

[Anadinolin]

Hi guys n gals

I have a silly question about batteries, i dont know if there needs to be a difference, or if you can use the same batteries

My diesel escort is having trouble starting, i have 9V on the glow plugs, new plugs and relay....my only other thought would be the battery...its got written on it "12V 50mAH" is that for a petrol car, not a diesel?

what do i actually need for a diesel battery? (this is my first diesel older than 3 years)

cheers guys

[Rustee]

I don't know the answer for a Escort diesel but suggest if no other response you might pop in to Halfords and check their look up lists by the batteries and it will tell you what one suits the various Escorts made.

[Marty Dolomite]

You need to look at the CCA = Cold cranking Amps, it is the Ampage that give the ommph to start a car but having low Voltage certainly doesn't help, the AH number is just the Amphour which says how quickly a new battery will drain itself with the lights left on.
You say you have 9V on the glow plugs what V is the battery showing when stationary?
Diesels take a lot more to start than a petrol car so the battery does need to be more powerful.
Does the yelloow coil (glowplug) light show up on the dash and do you let it go out before starting the car?

[Marty Dolomite]

Originally Posted by Rustee

I don't know the answer for a Escort diesel but suggest if no other response you might pop in to Halfords and check their look up lists by the batteries and it will tell you what one suits the various Escorts made.

Or go to another car accesory shop and get the correct battery at half the price.

[Anadinolin]

Originally Posted by Marty Dolomite

You need to look at the CCA = Cold cranking Amps, it is the Ampage that give the ommph to start a car but having low Voltage certainly doesn't help.
You say you have 9V on the glow plugs what V is the battery showing when stationary?
Diesels take a lot more to start than a petrol car so the battery does need to be more powerful.
Does the yelloow coil (glowplug) light show up on the dash and do you let it go out before starting the car?

the battery when on stanstill is measuring 12V accross the terminals, negative to engine case is 0.2ohms - the glowplug sign does go out after a few seconds, but still a pig to start the thing - ill have a look for anything saying about cold cranking, thanks

[Rustee]

Originally Posted by Marty Dolomite

Or go to another car accesory shop and get the correct battery at half the price.

I didn't mean to actually purchase one from that temple of doom just that you can get the info free from their look up charts.

[jetronic63]

Sounds a bit low for a diesel to me. A lot of the manufacturers have battery selectors on their websites so you can see what size they recommend (try Varta, Bosch etc).

[Anadinolin]

well suggested stewie, the sites say i need 70AH upwards

so my battery is a petrol battery....grr, wannabe traders get on my wick -_-

[Marty Dolomite]

Originally Posted by Anadinolin

well suggested stewie, the sites say i need 70AH upwards

so my battery is a petrol battery....grr, wannabe traders get on my wick -_-

No No No, its is not the AH fiqures that matters it is the CCA number.

AH= Amphour, how quickly the battery will go flat with the sidelights (or alarm) left on.

CCA = Cold cranking Amps, the amount or AMPAGE , i.e power the battery will give out when cranking the engine.

[Anadinolin]

Originally Posted by Marty Dolomite

No No No, its is not the AH fiqures that matters it is the CCA number.

AH= Amphour, how quickly the battery will go flat with the sidelights (or alarm) left on.

CCA = Cold cranking Amps, the amount or AMPAGE , i.e power the battery will give out when cranking the engine.

the ones that bosh etc are trying to sell me are 680CCA 70AH 12V

the one in the car is 50mAH with 12V i cant remember the CCA figure on it, i think it was 400, but will have to check after work