p38 battery power

need to order a new battery but not sure what type to get as in cranking power voltage type of thing or will a standard diesel one do it any ideas please

Standard is 107 Amp 750 CCA but you can get slightly larger ones. I have a 115 Amp 900 CCA on mine.

cheers wammers

135Ah 1000CCA is the largest that will fit. I got mine from battery megastore on line £98 delivered, very happy with it after 2 years or so, others like Bix have not had a good experience with the same though.

Datatek said:

135Ah 1000CCA is the largest that will fit. I got mine from battery megastore on line £98 delivered, very happy with it after 2 years or so, others like Bix have not had a good experience with the same though.

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I also have had bad experience with one of these

ovalandrover said:

I also have had bad experience with one of these

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I did say "others". There are also several who have good experiences with them.

My battery megastore battery is approaching two years and I'm very happy with it so far.

My brother also got one, and his is still going strong.

ovalandrover said:

I also have had bad experience with one of these

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What actually happened, purely due to having too big an output or the brand?

P

F

Parisien said:

What actually happened, purely due to having too big an output or the brand?

P

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You can't have too big an output. Looks like Megastore had a bad batch.

Datatek said:

F

You can't have too big an output. Looks like Megastore had a bad batch.

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Surely too much juice would blow the starter motor?

TCubed said:

Surely too much juice would blow the starter motor?

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How do starters manage with the garage battery chargers like the one i have with a start switch that throws a 150 amps at them?

Datatek said:

F

You can't have too big an output. Looks like Megastore had a bad batch.

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So that led to what actually happening or not happening?

P

TCubed said:

Surely too much juice would blow the starter motor?

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Ohms law, V over R = I, so whatever the capacity of the battery, the voltage is the same, the resistance of the starter motor is the same, so the current draw will be the same. The higher capacity just means that the voltage/current can be better maintained and for longer

Datatek said:

Ohms law, V over R = I, so whatever the capacity of the battery, the voltage is the same, the resistance of the starter motor is the same, so the current draw will be the same. The higher capacity just means that the voltage/current can be better maintained and for longer

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Ah OK, I did know that but thought the resistance on a starter motor was just extremely low so it could take super high amperage, which was limited by the battery. I definitely noticed a faster crank speed when I fitted my bigger battery. Same went for my old boat engine

TCubed said:

Ah OK, I did know that but thought the resistance on a starter motor was just extremely low so it could take super high amperage, which was limited by the battery. I definitely noticed a faster crank speed when I fitted my bigger battery. Same went for my old boat engine

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That is because the battery voltage dropped less when cranking.

Datatek said:

That is because the battery voltage dropped less when cranking.

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Ah I see!
So when a car is jump started from a running engine with battery at ~14V does the starter run much faster?

Parisien said:

What actually happened, purely due to having too big an output or the brand?

P

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after about 6 months the voltge dropped to about 9 volts .
not uncommom for any battery that shorts a cell out.
I could not claim as i was travelling and in Sweden at the time and needed a battery urgently.
when it was new it turned the engine over well .

TCubed said:

Ah I see!
So when a car is jump started from a running engine with battery at ~14V does the starter run much faster?

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Generally no because of the voltage drop in the jump leads and connections.

Datatek said:

Generally no because of the voltage drop in the jump leads and connections.

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Oh so is that why you need to run the engine on the donor car to make up the deficit?

TCubed said:

Oh so is that why you need to run the engine on the donor car to make up the deficit?

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Not really, it just makes sure you are less likely to flatten the doner battery. It's quite possible to jump start a vehicle using a spare battery, I do it all the time, I keep a large tractor battery on trickle charge for just that purpose. It does tractors mostly and my digger cos I'm too mean to buy a new battery for it.