Cab battery going dead.....

[Bart]

So atm our mh has been parked up at home for the last 2 months and the Cab battery has went to 11.4V twice.
It is fitted with 300w solar which feeds the habitation battery bank ( sun provided ofc ) which we ain't getting much of these days >>.
Then between the hab battery bank and the Cab battery there is a split charge relay so the cab battery should get a trickle charge once the Hab battery bank is charged, here is that split charger.
https://www.ebay.co.uk/p/Car-Batter...SB2-CBE-Accessories-Camper-Nautica/1679771620
here are some pics before the mh was connected to the EHU

and here are the readings after the EHU has been connected , note that the split charge relay is now lit up.

Is my setup working as it should and the cab battery has just went flat due to there being no sun >>solar power >> charge going into hab batteries >> then a charge going into the cab battery via the split charge relay ,,ONCE the habitation battery bank has reached a certain charge ( i would like to know this point if anyone knows it )
as once i connect the MH to the EHU and the onboard battery charge starts to charge the Hab battery bank , the split charge relay becomes active and starts to charge the Cab battery ok.

 

[Kybod]

Hi, i have just this week fitted one of the same split charge units this week. Although the paperwork is in the motorhome which is in storage, i do recollect that the charge was directed to the starter battery once the leisure battery was at or greater than 13.6 volts. Mike

 

[pappajohn]

The leisure battery voltage has to exceed 13.6v before the split charge switches on.
It continues to charge until the leisure battery voltage drops to 12.5v.
Your first pic shows 13.1v at the leisure battery which isn't enough to switch the unit on.
It must have recently dropped below 12.5v and switched off and hasn't got back to 13.6v on solar.
Once on hookup the voltage has increased and switched the split charge back on

 

[Bart]

Thanks i thought all was working ok , i just wanted to check incase the split charge relay had went caputt.

 

[pappajohn]

Maybe worth plugging in overnight every few weeks to be sure of charged batteries.

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[Bart]

Maybe worth plugging in overnight every few weeks to be sure of charged batteries.

yip looks like i will have to

 

[funflair]

We have the CBE CSB2 which as others have said needs at least 13.6v before it will switch, this does not always happen during winter sun so I added a VanBitz battery master which works on a voltage differential of about 0.65v so in you solar example @Bart it would have started charging about 2 amps to you starter battery when it hit 12.45v which is still a good voltage to start.

The two systems work OK together for me.

Martin

 

[Top Hat]

The leisure battery voltage has to exceed 13.6v before the split charge switches on.
It continues to charge until the leisure battery voltage drops to 12.5v.
Your first pic shows 13.1v at the leisure battery which isn't enough to switch the unit on.
It must have recently dropped below 12.5v and switched off and hasn't got back to 13.6v on solar.
Once on hookup the voltage has increased and switched the split charge back on

Does the battery master work on the same voltages

 

[TerryL]

How old is your engine battery? A trickle charge won't help a failing battery and going "flat" that quickly suggests the battery itself is on it's last legs - almost exact same symptoms I had couple of years ago, battery was seven years old so I just changed it. I don't like leaving things to chance.

Got the same solar/battery master set-up as OP and no probs since.

 

[pappajohn]

Does the battery master work on the same voltages

I believe the battery master works on the principle of voltage differential.
If there's 0.5v difference between the hab and cab batteries regardless of actual voltage the charger kicks in.

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