Engine battery not charging off mains

Strollerbird

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Any help or advice gratefully received.
When we put our motorhome in storage we would occasionally plug it in to charge both the leisure and the motor battery. On the last couple of occasions we have found the leisure battery fully charged but the engine battery dead.
Where do I start to look to solve this?
 
Do as i did, connect a heavy battery cable through a 200amp relay and a dash switch, also handy for a jump start if you forgot to turn lights of.
Or as many do a rhine wire fused at both batteries, just pull the fuse when using the van.
Also is it the van charger which most are junk, best fit a smart charger of around 10amps or more, this with above wire will charge the lot and cycle to desulfer and maintain them.
12v 20a charger.png
bat ch a.png
bat ch b.png
numax duel.png
 
I do hope Phil's got this issue covered in his new book because this issue and three way fridges not working on gas has been done to death.🥱

Are you saying that the starter battery used to get maintained when on EHU but now it doesn't?

If so are you taking about the same van?

Can you post a picture of your electrical control panel, that'll help massively.
 
MERL said:
I do hope Phil's got this issue covered in his new book because this issue and three way fridges not working on gas has been done to death.🥱

Are you saying that the starter battery used to get maintained when on EHU but now it doesn't?

If so are you taking about the same van?

Can you post a picture of your electrical control panel, that'll help massively.
Click to expand...
IMG_3650.jpeg
 
According to the manual and what you've reported it would appear that something has gone wrong in the EBL unit and it's no longer supplying a charge to the starter battery. It's possible that there is a blade fuse that's blown but oddly there's no 12V fuse data in those comprehensive instructions. Pull each fuse one at a time and check them preferably with a multimeter, you may get lucky. If the fuses are OK then maybe the simplest fix would be to fit another form.of battery maintainer which wires between the leisure and starter batteries. This would of course keep your starter battery maintained while on hook up but also If you have solar then this secondary maintainer would give you the benefit of keeping the starter battery topped up from the solar that's feeding the leisure battery too, something that the EBL doesn't do.
Cheapest way is a simple fuse between the two battery positives, search Clive Mott battery maintainer.
Ablemail AMT12 can apparently be set to very low voltage drop so the starter battery is kept at a high enough voltage to prevent sulphation, cheaper alternatives (vanbits etc) aren't quite as good in this respect.
The best unit of all in this respect is the DIY design which I posted a while ago on here, it works better than any commercial unit and parts cost about £10-15. You will have to build it yourself though.
Thread 'High performance DIY Battery maintainer.' https://wildcamping.co.uk/threads/high-performance-diy-battery-maintainer.100567/
 
MERL said:
According to the manual and what you've reported it would appear that something has gone wrong in the EBL unit and it's no longer supplying a charge to the starter battery. It's possible that there is a blade fuse that's blown but oddly there's no 12V fuse data in those comprehensive instructions. Pull each fuse one at a time and check them preferably with a multimeter, you may get lucky. If the fuses are OK then maybe the simplest fix would be to fit another form.of battery maintainer which wires between the leisure and starter batteries. This would of course keep your starter battery maintained while on hook up but also If you have solar then this secondary maintainer would give you the benefit of keeping the starter battery topped up from the solar that's feeding the leisure battery too, something that the EBL doesn't do.
Cheapest way is a simple fuse between the two battery positives, search Clive Mott battery maintainer.
Ablemail AMT12 can apparently be set to very low voltage drop so the starter battery is kept at a high enough voltage to prevent sulphation, cheaper alternatives (vanbits etc) aren't quite as good in this respect.
The best unit of all in this respect is the DIY design which I posted a while ago on here, it works better than any commercial unit and parts cost about £10-15. You will have to build it yourself though.
Thread 'High performance DIY Battery maintainer.' https://wildcamping.co.uk/threads/high-performance-diy-battery-maintainer.100567/
Click to expand...
Which Merlin has installed on mine and a couple of other vans, Perfick, no EHU all winter with only 170w of solar to 100ah LA battery.
 
Pudsey Bear said:
Which Merlin has installed on mine and a couple of other vans, Perfick, no EHU all winter with only 170w of solar to 100ah LA battery.
Click to expand...
Double that mite be a better option for more than one overnight, esp in winter mths.
Fact is a 100ah lead acid is in fact about have that usable, you require 2 one hundreds to get 100ah
 
Strollerbird said:
On the last couple of occasions we have found the leisure battery fully charged but the engine battery dead.
Click to expand...

More questions for you to answer before we can get into diagnosis. Sorry about this but there are many unknowns and variables that could be relavent.

1) Do you have solar ?
1.1 Is the van parked outside or under cover?
1.2 Which batteries does the solar charge?

2) Do you have confirmation that the 230v was reaching the MoHo. e.g. an indicator on the control panel

3) Have you checked the 230v Fuses haven't tripped? Even if they look correct it is worth tripping and resetting them all

4) How do you know the leisure battery is fully charged ?

5) How do you know the engine battery is dead ?

6) Do you have an alarm?

7) How long has the MoHo been unused?

8) Do you have B2B ?
 
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