Dometic charger DIP switch settings for Exide gel batteries

[Pablo19]

I'm starting a new thread as it's a different question to my last one even if it is connected!

I have eventually decided and bought a couple of Exide ES900 gel batteries after receiving recommendations on here and elsewhere. I managed to buy 2 just taken out of a brand new Carthago having a lithium upgrade so a bit of a bargain! My question relates to the charging and I'm keen to set this up properly this time becausen I'm sure the settings were not right for the Banner AGM that is coming out. I have read up on connecting in parallel and that's straightforward although it will be challenging due to the weight of the batteries and the lack of space they are going into.

The Dometic MCA1225 charger has a manual explaining the settings but to an electrical simpleton like me I don't really understand them!
The battery blurb states a required charge of 4.1-4.4v and that's fine. the charger DIP settings list the various options but they seem to contradict eachother, see link below, page 24. It talks of switchover, retention and constant voltage and it's not clear to me what the setting should be. Can any of you knowledgable folk assist please? Also, do I need to vent a gel battery? If so can I just cut into the existing vent and add a T section to link the second battery?

Thanks!

Page 24

 

[autorouter]

When charging, the charger steps through three stages (phases), called bulk, absorption and float, denoted by I, Uo and U.

For the absorption voltage you have a choice of 14.4V and 14.7V, and for a gel battery you want 14.4V. The 14.7V is more suitable for an AGM.

For the float voltage, you have a choice of 13.5V and 13.8V, and for a gel battery you want 13.5V. The 13.8V is more suitable for an AGM.

The other settings like Power Supply Mode are for example to run the charger as a power supply to run your habitation circuits, without any battery installed. You could imagine that a permanently sited caravan with a permanent hookup supply might find a battery unnecessary. Many chargers won't function without a battery connected, but this one will.

So to be clear, I think the best settings for gel are S1, S2 and S3 set to ON, ON, OFF.

For the venting, yes, the arrangement you describe will be fine. Gel batteries are sealed, with a pressure release valve in case of faults. In normal use they don't vent any gas, but best to provide a vent for if there's a fault in the battery or the charger.

 

[daveandsan]

I think you will find there are no vent pipes on the exide gel batteries.

 

[Pablo19]

When charging, the charger steps through three stages (phases), called bulk, absorption and float, denoted by I, Uo and U.

For the absorption voltage you have a choice of 14.4V and 14.7V, and for a gel battery you want 14.4V. The 14.7V is more suitable for an AGM.

For the float voltage, you have a choice of 13.5V and 13.8V, and for a gel battery you want 13.5V. The 13.8V is more suitable for an AGM.

The other settings like Power Supply Mode are for example to run the charger as a power supply to run your habitation circuits, without any battery installed. You could imagine that a permanently sited caravan with a permanent hookup supply might find a battery unnecessary. Many chargers won't function without a battery connected, but this one will.

So to be clear, I think the best settings for gel are S1, S2 and S3 set to ON, ON, OFF.

For the venting, yes, the arrangement you describe will be fine. Gel batteries are sealed, with a pressure release valve in case of faults. In normal use they don't vent any gas, but best to provide a vent for if there's a fault in the battery or the charger.

Thanks autorouter, that's really useful and a great explanation. What about S4 though? This is the one that activates sleep mode but I'm not sure what that means! I would imagine that should be set to off as well?

 

[Pablo19]

I think you will find there are no vent pipes on the exide gel batteries.

Thanks, I won't bother buying anything until after they are delivered and will check but the images I can find online seem to suggest you are right.

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