AGM Leisure Batteries

[Alkers]

I have been reading mixed reviews of AGM leisure batteries online so was wondering whether anyone has particular experience of them in the bongo?

I am happy generally that they are good batteries but my concern is about the bongo alternator not providing them with a high enough charge voltage and providing them with too high of a float voltage.

The first is easily enough overcome by charging on EHU but I'm wondering would long drives damage the battery if it was already charged.

Does anyone know what the bongo alternator outputs and how this is affected by a split charge setup?

[ade33]

My work-buddy's car has just killed his (expensive!) AGM battery in 9 months after it was fitted as a replacement for a 'traditional' battery. Euro Car Parts listed both types for his vehicle (a modern diesel), as there is a variant which has the stop/start function. The garage fitted the wrong type (the AGM) and the 'regular' charging system in his car has ruined it in a short period.

[g8dhe]

The Bongo alternators don't reduce the charging voltage downwards from 2.4 to 2.25 per cell when fully charged (as is the same with any standard vehicle alternator prior to stop/start technology) hence will have a tendency to overcharge an AGM battery on a long run.
Quite a good and simple explanation of alternators and the voltage regulation process here https://www.carparts.com/classroom/charging.htm

The Split Charge Relay system should not have any affect as such other than the batteries won't be matched and hence will both get the same charging regime imposed on them.

[Alkers]

The Bongo alternators don't reduce the charging voltage downwards from 2.4 to 2.25 per cell when fully charged (as is the same with any standard vehicle alternator prior to stop/start technology) hence will have a tendency to overcharge an AGM battery on a long run.

Yes, that's what I thought - in your experience would this rule out using AGM as a leisure battery in a bongo?

Thanks

[Alkers]

And are there any recommended (non AGM) batteries?

[mikeonb4c]

I've been very happy with Banner Energy Bull - i can actually JUST squeeze a 135ah one in mine. They're not a cheap option, but they are very good.

[g8dhe]

I'm always reluctant to recommend specific models or makes, for commodity items like these a lot more effort is put into the Marketing than what they put into the actual production of the device, with lots of claims shouting the largest numbers out of context, its impossible to get actual test data on such things as well.
For instance the AGM batteries, whilst capable of supplying high currents, they also have much thinner and less robust plates, which damage more quickly than the standard starter batteries which have greater separation between plates and hence are also thicker in order for them to support there own weight as opposed to being pressed together with the glass fibre sheets between them insulating them and relying on the complete assembly to hold the plates in position.
For my own use I accept a shorter life than is advertised and choose a cheaper battery, on the basis that the questionable longer life is offset by the cheaper product and accept that I will replace them every one to two years.

[Alkers]

I've been looking at the NCC verified batteries:
https://www.thencc.org.uk/downloads/Ver ... 0.2018.pdf

and it seems that all the Class A batteries are AGM batteries and so not suited for a lot of vehicle alternators.

The Elfa Elementenfabriek GLX-D looks very good with a tested 2,500 cycles and 110Ah but requires similar charging voltages as an AGM battery so suffers the same issue and is pricy.

I'm now leaning towards this:
https://advancedbatterysupplies.co.uk/p ... s-lx27-mf/

Which has been tested as NCC class C to 220 cycles which is about as good as I can find and not too bad of a price.