Elektroblock EBL99 starter battery Drain, Burstner 681 2004

[baff57]

Good morning all, i am new on here and a new motorhome owner with a few problems a slowly learning the systems and how they work.
I have noticed my starter battery has a parasitic drain dragging the battery down in 48 hours.
I have traced this down to the Rectifier /Charger EBL99 which when i isolate the 12v system with the switch on EBL99 the drain goes away.
I also notice that i can not see any charging on the Leisure side but strong charging when i introduce mains voltage on the starter battery.

Looking at the circuit diagram i see the start battery should not be connected to be able to drain unless the engine is running (feed from alternator), i see that relay FRC3A controls this function as must be stuck on?
I am trying to avoid high cost as units £600 to buy and £130 to repair but relay is readily available at approx. £5 and easy to replace.
What i want to ask has anyone had similar problem, am i barking up the wrong tree?
I have not started the work yet just reading online, cant see how the unit switches the charge output from EBL99 to both batteries unless the same relay does this by having two positions 1/ charging both batteries or 2/ Just charging leisure battery when starter is isolated.
I have a 300w solar charging the leisure and starter so the leisure side is nearly always 100% charged so possibly the fault could be just the starter battery isolation, just never noticed any charging voltage increase when on mains.

Any experience would be very appreciative.

 

[autorouter]

There are two paths from the starter battery to the EBL. One is as you say, a thick wire from a terminal at the back of the EBL, through the 50A fuse next to the starter battery. The other is through a thinner wire on Pin1 of Block2 on the front of the EBL. It comes from the starter battery via a 20A fuse located near the starter battery next to the 50A fuse.

I think the first thing to do is to pull those fuses one at a time and see which one stops the drain. I can't see any path to drain the starter battery if there is no fault, so I think you're right about a relay probably stuck on.

If the 20A stops the drain, then it's one of the two fridge relays. If the 50A stops the drain then it may be as you say the relay labelled 'Battery cutoff relay' in the diagram, usually called the split charge relay.

 

[autorouter]

I have not started the work yet just reading online, cant see how the unit switches the charge output from EBL99 to both batteries unless the same relay does this by having two positions 1/ charging both batteries or 2/ Just charging leisure battery when starter is isolated.

The mains charger automatically comes on whenever the mains hookup is connected. There is a 20A fuse labelled 'Internes Lademodul' (Internal Charge Module) to cut its output to both batteries. There is a bit of circuitry that produces a trickle charge for the starter battery from the main charger feed, and this is controlled by a relay. This relay switches on automatically when the mains charger is on, and should go off when the hookup is disconnected and the mains charger goes off.

 

[Lenny HB]

The EBL should only charge the starter battery at 2 amp and the leisure battery at up to 18 amps.

The switch on the EBL only isolates the leisure battery, also best not to use that switch they are know for failing and not turning back on.

Sounds to me that you starter and leisure battery connectiona to the EBL maybe crossed.