Question everything electrical.

[Simonjdcooper]

There are two ways to charge a leisure battery from the alternator while the engine is running. The simpler way is to use a relay (an electrically operated switch) to directly connect the leisure battery to the starter battery when the engine is running, and disconnect it when the engine stops. That way the alternator charges both starter and leisure batteries, but they are separated when you are parked up. The relay is called a split charge relay.

Is there any way to know if I have this set up fitted from the photos on my OP? There's a complex box under the passenger seat on my MoHo (left hand driver Burstner)

The second method is to use a proper battery charger that takes whatever the alternator provides (12 to 15V, whatever), and processes it into exactly the voltage and amps the leisure battery needs. That is a bit better for ordinary leisure batteries and a standard alternator, and is essential for a smart alternator and/or lithium batteries. A charger like that is called a Battery-to-Battery (B2B) charger, or maybe a DC-DC charger or DC-DC Booster.

So i'll need that if and when we upgrade to Li.

The alternator sends out a signal when it is running and producing charge. This signal (called the D+ signal) is used to switch the split charge relay on and off, or switch the B2B on and off, when the engine starts and stops.

Thanks again for some straightforward info/advice.

 

[Simonjdcooper]

The pics I included show all the kit I could see. I've seen people commenting about chargers, how do I know what charger I have?
My Moho is a burstner coachbuilt. Where would I find the battery charger? Given there is solar and a little box with green lights on it (is that a b2b or a mppt?)

 

[Northernraider]

I wouldn't try running an inverter of any significant size unless via a Lithium LPo4 battery. Lead Acid just can't hack it.

That depends

My last van ,euramobil integra had 1100watt solar on the roof supplying 700ah of lead acid batteries , running a 2000watt inverter and domestic 240v fridge freezer plus all other electrics . It all worked fine .

40amp renogy b2b as a back up.

The fridge was obviously the biggest drain but it could manage 3/4 cloudy days fully offgrid , sunny days were endless .

 

[autorouter]

Is there any way to know if I have this set up fitted from the photos on my OP? There's a complex box under the passenger seat on my MoHo (left hand driver Burstner)

That will be the Schaudt EBL 99, in pic 7. Schaudt is now part of Lippert, and the manual for it is available here:

https://res.cloudinary.com/lci-cloudinary/image/upload/v1694803226/lippert-eu/support/power-on-board/pdf/anleitungen/911/9110419/911419_20100120_EBL99K_EBL99KOVP_BA_EN.pdf

There is a wiring diagram near the end.

As you say, it's complex, and you're right that the split charge relay is inside it. It also contains the mains charger module, and the fridge relay that sends 12V power to the fridge when the engine is running. The mains charger is a smart 3-stage 18A charger (the symbol IUoU on the front denotes this). It has a settings switch for Flooded/Sealed Lead-acid and Gel batteries, but doesn't have an AGM setting.

If you install lithium batteries you will need to install a B2B. You will also need to disable the split charge relay, which is quite easy with the EBL 99. If you were using mains hookup a lot, then a new lithium-compatible mains charger would be a good idea, but if you only rarely use hookup then the existing charger should more or less do the job.

In case you were wondering, there is a big 50A fuse near the starter battery, and a wire from there to the back of the EBL. There is also a big 50A fuse near the leisure battery, and a wire from there to the back of the EBL. The split charge relay connects these two wires together when the engine is running, so the alternator can charge the leisure battery while it is charging the starter battery.

 

[Simonjdcooper]

That will be the Schaudt EBL 99, in pic 7. Schaudt is now part of Lippert, and the manual for it is available here:

https://res.cloudinary.com/lci-cloudinary/image/upload/v1694803226/lippert-eu/support/power-on-board/pdf/anleitungen/911/9110419/911419_20100120_EBL99K_EBL99KOVP_BA_EN.pdf

There is a wiring diagram near the end.

As you say, it's complex, and you're right that the split charge relay is inside it. It also contains the mains charger module, and the fridge relay that sends 12V power to the fridge when the engine is running. The mains charger is a smart 3-stage 18A charger (the symbol IUoU on the front denotes this). It has a settings switch for Flooded/Sealed Lead-acid and Gel batteries, but doesn't have an AGM setting.

If you install lithium batteries you will need to install a B2B. You will also need to disable the split charge relay, which is quite easy with the EBL 99. If you were using mains hookup a lot, then a new lithium-compatible mains charger would be a good idea, but if you only rarely use hookup then the existing charger should more or less do the job.

In case you were wondering, there is a big 50A fuse near the starter battery, and a wire from there to the back of the EBL. There is also a big 50A fuse near the leisure battery, and a wire from there to the back of the EBL. The split charge relay connects these two wires together when the engine is running, so the alternator can charge the leisure battery while it is charging the starter battery.

Great, I understood some of that, so things are getting better. We dont use hook up a lot, just to keep things topped up when we are at home and not using it much.

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