MD2 B CCA

[Saddletramp]

Time for a new engine starting battery. I have had an 85 amp hr leisure battery but want to change to starting battery and need to kow the cold cranking amps. My local motor factor has quoted around £50- £65 depending on CCA. Cheers

 

[VicS]

The owners manual merely states a maximum capacity of 60Ah, as does the workshop manual. Neither give a CCA figure the starter motor.

Owners manual

I do not know why Volvo quote a maximum capacity but they always do!

 

[Saddletramp]

If I ask for a battery that would start say a diesel land rover do you think that would be sufficient?

 

[VicS]

About Landrovers I know nothing but the MD2B is a tiny thing compared with a Landrover engine and I'd expect what is essentially a commercial vehicle to have a pretty big battery anyway.

Maybe one of the marine battery suppliers will have an application guide on their website.

Had a look but still no indication of CCA for the later 2010/2040 range of engines.

 

[Saddletramp]

Cheers Vic, I will take my old battery along. It will be down to price in the end.

 

[bedouin]

I have successfully hand-cranked a Landrover engine, a feat I have never managed with my MD2B. So I would surmise that the MD2B takes a bit more grunt. The difference of course is the massive flywheel on the MD2B.

 

[VicS]

I think the hand starter is geared up so that the crankshaft speed is twice that of the starting handle. That'll make it difficult. Presumably a Landrover starting handle is straight onto the crankshaft.

 

[roly_voya]

The CCA on the M2B is almost irrelevant as the starter motor only 1/2hp (370w) which is 30a @12v. When measuring with a max reading ammeter I used to get about 90a max for the surge on startup but only for a few seconds. If you ever find a problem getting it turning (ie when very cold) just use the valve lifters. This relates to the belt drive, if its been 'updated' with a geared starter you need to find the power for the starter but the standard upgrade was to a 1hp motor so still only about 60a but sure could be around 180a so just getting into the area of minimun CCA. The max batt size for the dynastart modle was 45a otherwise the generator side was in danger of burning out. With the alternator fitted depends on the alternator.

 

[VicS]

[ QUOTE ]
The CCA on the M2B is almost irrelevant [ QUOTE ]
That may be some interesting arithmetic but I for some reason things don't work out quite like that.

As an example take the fact that the starter motor on my car is rated at 810W (or 1.1 hp) output but the currents given in the w/shop manual are 30-50amps at 11.5volts unloaded, 185-220amps at 9volts loaded and 400-490ampss at 7volts locked.

If you apply your logic, 810 watts at 12 volts would be only 67.5amps but the above figures show that the CCA is in fact in the range 185-220amps.

I suspect the answer to the discrepancy lies with the word "output " to describe the stater motor

On that basis I would suggest that for a starter motor rated at 1 hp the battery should be rated at around 200 CCA.

Unless it is only fitted with a Dynastarter.

 

[Saddletramp]

I have an alternator and geared flywheel. Other than that I am getting out of my depth.

What I need to know is the minimum cca, which the consensus seem sto about 200 cca. Also is there a maximum, ie a bigger battery would cause damage to the starter or alternator.

As a guide I have just looked up tractor batterys, they are around 900 cca

I would prefer not to have the minimum as the engine is slow to start in cold weather or when not used for a while.

Thanks for the replies.

Just for info I have managed to start it by hand from cold once or twice, when warm it starts by easily.

 

[VicS]

[ QUOTE ]
I have an alternator and geared flywheel

[/ QUOTE ] Ok then you do not have a Dynastarter. (That's a combined dynamo and starter motor which would have a belt drive only)

Since there is no guidance on CCA in the manual any suggestions would be purely person opinions.

I don't know why Volvo state a maximum capacity but if you take that at face value any 60Ah starter battery should be adequate and probably well in excess of 200CCA. Purely for starting you do not ned a capacity anywhere near 60Ah.

I could just understand perhaps if a maximum CCA was quoted but even my hypothesis on why the CCA rating might be limited is a bit thin on supporting facts.