Battery master and AGM/LA batteries

[SteveandSueJ]

Just changed MH. Veh battery is LA and Hab Is AGM. Going to fit my Battery Master but wondering as AGM charges and is full at higher voltages, is it safe for BM to trickle charge the LA battery which is full at a lesser voltage than AGM? Is the BM intelligent enough to stop charging the LA battery when full? May not have phrased it correctly but you guys know what I mean..!!!!! Appreciate your thoughts.... thx.

 

[bigtwin]

The battery master is unidirectional and operates on the basis of a voltage differential; if the starter battery drops below the differential delta a charge current will flow from the leisure battery.

The BM is a dumb device but physics means that no current will flow when the voltages equalises so your starter battery will not overcharge.

Ian

 

[eddie]

The simple answer is yes it will be fine, you’ll never really fully charge the engine battery anyway because of the quiescent drain on it

But when a battery is charged (full) you can’t force ‘more into it’ with the set up you described

 

[SteveandSueJ]

The simple answer is yes it will be fine, you’ll never really fully charge the engine battery anyway because of the quiescent drain on it

But when a battery is charged (full) you can’t force ‘more into it’ with the set up you described

Excellent guys, thank you...

 

[BCHOME]

What about the other way round.
Can I use a Battery Master if I have a LA Leisure battery and an AGM Vehicle battery?
Thanks

^{_{Subscribers  do not see these advertisements}}

 

[SteveandSueJ]

What about the other way round.
Can I use a Battery Master if I have a LA Leisure battery and an AGM Vehicle battery?

Well, I have been running a new lithium hab battery and a LA Veh battery for a trip across Spain, last 2 months and worked fine. But I am sure someone will come back if we are misusing the BM.

 

[BCHOME]

Well, I have been running a new lithium hab battery and a LA Veh battery for a trip across Spain, last 2 months and worked fine. But I am sure someone will come back if we are misusing the BM.

Thanks - I've seen a few threads where the vehicle is LA and the leisure is AGM or Lithium. So the Battery Master is charging from a potentially stronger battery to a LA battery. I've not seen this the other way round - the LA is charging (via BM) the AGM or Lithium.

As you say - hopefully someone will have a view on this

Maybe I need to start a new thread with this question......

 

[CAB96]

What about the other way round.
Can I use a Battery Master if I have a LA Leisure battery and an AGM Vehicle battery?
Thanks

Yes.

It is the voltage that's important.

If the Leisure is a certain amount higher than the vehicle, it will charge it. It doesn't matter what type they are.

 

[eddie]

What about the other way round.
Can I use a Battery Master if I have a LA Leisure battery and an AGM Vehicle battery?
Thanks

Yes

A better question is

Unless you have a B2B installed, your charging the AGM from the LA via a split charge really (SCR) which sounds fancy, but in practice is a pony old, quids worth of automotive relay, irrespective of if it’s hidden in a fancy metal box with Sterling or Elkotroblok printed on it!

A SCR simply connects the two batteries in parallel when the engine starts!

However, the industry had done it for years and got away with it!