DS300 CBE

[Dahuws]

Hi can someone give me some advice please, I have the DS300 fitted to my motorhome, the B2+ wires are connected as described in the manual, the issue I have is the leisure batteries are drawing charge from the starter battery even when the ignition is off. I only want the leisure batteries to be charged when the ignition is on and the engine is running. Thanks

 

[trevskoda]

Put a breaker switch and relay between them so when stopped flick it to of.

 

[merl]

The CBE unit should work in the way you say you want it to.
You don't say if you've just installed it and it's not working correctly or if it's been working correctly previously and has now developed an issue so post this info along with the installation diagram, it will help massively.
Probably a faulty split charge relay but the background info is helpful.

 

[Okta]

The DS300 should send a 2A charge to the engine battery but only when on EHU and getting a mains charge.

 

[number14]

My pvc has factory fit CBE kit throughout. From the brief description you give, it does seem like the split relay function within the DS is faulty. User manuals describing all the connections are available online and, if you are competent with a DVM, you could open it up and have a look. Make sure there is no mains hook up first though!
Alternatively, just buy a new one for around £80. Probably cheaper than a professional repair outfit.

 

[Dahuws]

The CBE unit should work in the way you say you want it to.
You don't say if you've just installed it and it's not working correctly or if it's been working correctly previously and has now developed an issue so post this info along with the installation diagram, it will help massively.
Probably a faulty split charge relay but the background info is helpful.

Hi, thanks for your reply, its a new unit replacing a similar one, DS304SR which fried the fridge fuse, the connections are the same. The other one didn’t work correctly either, I had to install a split relay.

 

[Dahuws]

My pvc has factory fit CBE kit throughout. From the brief description you give, it does seem like the split relay function within the DS is faulty. User manuals describing all the connections are available online and, if you are competent with a DVM, you could open it up and have a look. Make sure there is no mains hook up first though!
Alternatively, just buy a new one for around £80. Probably cheaper than a professional repair outfit.

Hi, thanks for your reply, this is a new unit, replacing a similar one, all constructions are the same which have been confirmed with the installation manual.

 

[Okta]

If the old one didn’t work correctly either I would be looking for a wiring fault or modification that is creating a path between the 2 batteries. Also could be worth checking that the D+ signal is a pure one, not something that is getting activated or back fed from another source.

 

[merl]

Well you have several options.
Replace again.
Get a man in to take a look.
Diagnose and fix it yourself.
If you feel competent with a multimeter and possibly a soldering iron then there's enough knowledge here to guide you through but if not then you're really limited to options 1 and 2.
As Otka has mentioned, you could be making the same wiring error with both boards but then again both boards could easily be suffering from the same common fault but unless you have the confidence and equipment to start poking around you're working blind.
The split charge relays take a lot of current as do the PCB tracks supplying them, this is where I'd be investigating and then, if the culprit, looking into fitting a better relay 'off board'. Not hard if you have know what you're doing.
Just a thought, you haven't got the leisure battery and cab battery inputs transposed have you? Schoolboy errors do happen
Merl

 

[QFour]

Remove the split charge relay and see what happens. We have the same unit and it charges the vehicle battery but only when it's switched on.