Charging issue - mystery box

[ricp]

I have a 88 AutoHomes camper with a Subaru 2.5 fitted. This all works perfectly. It has 2 batteries fitted, one under each front seat. The leisure one also has some sort of charging relay fitted next to it (see photo bottom left), but I'm not convinced it is working as the leisure battery often goes flat. Also the 25A fuse in-line (green wire, red tape) with the starting battery often blows.

Can anyone identify this component or has a wiring diagram. Then I can ensure that it is correctly wired or removeing it and starting again.

Many thanks in advance.

[kevtherev]

You have tested the leisure battery to see if its not died I trust?
A dead battery will demand so much power it will blow fuses due to the high draw.

Charge it conventionally and leave it overnight to see if it loses voltage
And check you have no short draining it.

[California Dreamin]

As Kev says, you need to establish the condition of the battery by fully charging it conventionally for 16 - 20 hours (DIY charger)
Then do a simple volt check 'Before' & 'After' starting across the battery terminals. It should read 12.6 - 12.8 'Before' rising immediately to around 14 volts with the engine running.

Perhaps it might help if we had details off the relay...name/numbers etc.

Martin

[Walrus]

I've got one of those relays - I took it off because it seemed to drain one/both batteries very quickly (< week). I now use a trigger-wire (simple) relay.