EC 325 not working batteries dangerously low

We had a similar problem with a different power supply controller in our 3 year old caravan last year and I had to fit a new unit. I have searched for problems with the Sergent EC 325 on the internet and the first entry was about one in a autotrail Cheyenne! Indications in that and other entries suggest there have been problems with this unit. 

Suggest you do a search as I did.

Sounds more like you battery has had it.

peedee

The user and all related content has been Deleted User

agree with Peedee. 

not only that, a totally knackered battery will cause any charger issues as it tries (in vain) to resuscitate it...

it may be that the charger is knacked too.

a couple of tests...

find true state of leisure battery....disconnect everything from it, let it rest for an hour or two and measure with a voltmeter....anything less than 12v is bad...

test that charger and solar panel are doing their jobs re charging...pull fuse on solar panel input (to remove the effect of that) and turn on EHU/charger..use voltmeter to check that a raised charge (of around 14+v is present....check leisure battery and vehicle battery.

disconnect EHU (will turn off mains charger) and reconnect fuse in solar panel....repeat voltmeter reading for charge being applied to leisure and vehicle batteries by the SP. Again should be 14v+.

the results of the above will tell you 

a) if the leisure battery is dead

b) if the EHU/charger is charging both sets of batteries

c) if the SP is doing as above.

If checking the voltage output on a solar panel at this time of year, I would suggest parking on a very steep south facing hill if you want to see an output above 14v. Mine our just about managing 13.6v parked on the level as the sun is so low in the sky

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56 degrees north, less than an hour to sunset, it's raining, and my panel is doing 13.6 volts.  Some do - some don't.

To identify the Op's problem, it would be simplest to swap out the battery for another one to prove the charger unit is the trouble.

A battery at 8.7 volts is definitely scrap.

It may be the batteries are gone and if you’re not careful, could take the charger out. I haven’t used them so can’t recommend, but there’s a lot of useful information on this site about chargers, charging and the different types of battery. They have a section on your charger unit and solar panels;

http://www.aandncaravanservices.co.uk/sargent.php

Good luck