compact starter batteries

[ditchcrawler]

I use a 1/2/both with the Red Flash on 1 and as posted above charge it on 1 for 10 minutes then turn to 2 for the domestics.

The electrician who fitted my Sterling Alternator Management System set the output to 14.4v which suits the Red Flash AGM and the Sealed Marine Batteries I have as domestics (2no 113a/h)
It has all worked faultlessly for 7 seasons so far.

 

[Plevier]

Right, I think that's what they told me too. It's jogged my memory . The problem wasn't that the bulk charging rates were so different, but that once it was fully charged (very quickly), the starter battery would prefer to be held at float voltage. However, as long as the house bank still needed topping up, the voltage in the system would remain at bulk levels, to the detriment of the starter battery.

Maybe it's one of those things where the manufacturer is concerned about ideal treatment, but in practice the effects of less-than-ideal are not too bad?

Pete

That is indeed a potential problem and the results can be serious rather than not too bad in drastically shortening the life of the Red Flash (or similar) starter battery.
The Red Flash is happy pretty well indefinitely at normal alternator voltage of ca 14V. If that's all you have, no need to disconnect it and certainly if you only give it 10 minutes you will be running it less than fully charged. You would have to run 24/7 to do any harm.
However if you have a boost charging system, whether it is shore power or alternator driven, if it boosts for long periods to get discharged house batteries up while the starter is already fully charged or close to it, you will lose irreplaceable water from the starter battery. Even a slight water loss from an AGM will reduce capacity and high rate performance.
How serious it is depends on the voltage and duration. If your boost is around 14.4V you'll get away with it for a long time, maybe years of use. If you have a really aggressive one giving over 15V I would suggest you disconnect the AGM battery whenever that is in use for more than a short time.
(On rare occasions you may want to do a high voltage equalising charge for a few hours deliberately to some AGMs but that should never be necessary with a Red Flash starter battery unless it's been abused and left flat for ages.)

 

[micha571]

I have an Odyssey PC625 for starting my Bukh DV10. Very light (just 6 kg) and starts the engine without any problems.

 

[charles_reed]

Right, I think that's what they told me too. It's jogged my memory . The problem wasn't that the bulk charging rates were so different, but that once it was fully charged (very quickly), the starter battery would prefer to be held at float voltage. However, as long as the house bank still needed topping up, the voltage in the system would remain at bulk levels, to the detriment of the starter battery.

Maybe it's one of those things where the manufacturer is concerned about ideal treatment, but in practice the effects of less-than-ideal are not too bad?

Pete

Sounds like further support for the hypothesis that one should fit individual chargers for each bank/type of battery.

 

[syvictoria]

We too are thinking about buying one of these compact types. Is anyone using one with a Beta 25?

 

[Tranona]

We too are thinking about buying one of these compact types. Is anyone using one with a Beta 25?

The type of engine is largely irrelevant as the cranking amps required are much the same on all small diesels. A 28 or 37 ah capacity will do the job, but make sure it is only used for starting.