Leisure battery tested at 6 Volts

[BongoBongo123]

So just been tinkering with the wires as some of the connections/crimps looked pretty shabby. So sanded them and cleaned/recrimped and checked all fuses. Check continuity where I could do.

The battery will not accept charge off vehicle, kaput ! Probably for being in a discharged state for months over winter at a guess.

So I am thinking the following possibilities:

1) All is sorted now I made the connections better.

2) The split relay (voltage sensing relay) is not working properly.

3) The battery died of its own accord/fault.

Starter battery is 12.6V so I assume ok for now. It has been sitting for 2 weeks without moving after a 360miles outting.

I have a leisure battery of the same type (quite well worn and not holding charge well for hobby activities) but certainly better than the completely dead one from the vehicle. I am thinking charge it as best as I can put it on the vehicle and measure volts before a long journey I am soon to do. And test volts at the other end and see what is measured.

In meantime is there a way I can check if the correct volts are coming out of the split relay ? At a guess I imagine I should read 12V or so coming out now (with engine running) as the main battery seems charged. I have a multimeter so can check those output terminals.

Just to add it has been previously working ok and the control panel gave the voltage as being fine 6months back. So it seems like a relatively recently developed issue. Now when I turn the camper electric unit on with the 6V battery as you might imagine it was all dim and hardly lit up and beeps were going off to let me know it was low volts.

Thanks

[BongoBongo123]

I forgot possibility 4

Ahhhhrrrggggggggg!

That is the second leisure battery the fridge has killed, no wonder our food stayed so cold for so long last journey. It has a really bad circular knob switch which is hard to know whether it is on or off. There is a click and yet I have no idea how it keeps getting switched on.

and

Kind of glad I only put £38.00 ones in the Bongo... the same fate would have happened if it was a £130.00 one I suspect. Gaffer taped over the switch.

[mikeonb4c]

It might be worth fitting a low voltage cut-off unit in the circuit as general protection against over discharging the LB.

[BongoBongo123]

I would have to work out where the wires are. It's a good long term suggestion.

Is a low voltage cut out a common "inline" thing to buy as a simple passive module ?

Thanks

[jimmo62]

Re checking the split charge relay....

Disconnect the split charge relay from the leisure battery. With the engine off, check the voltage at the output (the leisure battery side) - should be zero. Then turn the engine on and give it a rev - the output should then turn on and go to about 13.8 volts (depends on the output of your alternator) - the same as the main battery voltage.

When you turn the engine off the voltage should go back to zero

If that is all OK then the split charging should be fine

[cmm303]

Check inline fuses in wires from SB to split charge relay and from LB to the relay. Replace both if either blown. A drained LB can cause one or both to blow when the engine is on because the charging current is too high.

[mikeonb4c]

I would have to work out where the wires are. It's a good long term suggestion.

Is a low voltage cut out a common "inline" thing to buy as a simple passive module ?

Thanks

If Geoff doesn't read this and reply you could try pming him as he's top dog on all things electric.

[g8dhe]

Everything is being covered so no need to repeat

The low voltage cut-off's don't appear to be common in this country, plenty on offer in the States, Australia, South Africa. I added my own design, but its homemade on veroboard and added to my relay mount directly off the battery.

[BongoBongo123]

Thanks for the replies. Highly likely the fridge is the culprit. Fuses all seem ok to the eye and a couple checked with multi-meter. The crimps needed doing on a few connections as they were held on with a few strands loosely so hardly a good reliable set of connections. All better now.

Thanks for the split relay testing procedure.

I have another leisure battery that is better than the one that has had a battering (and seems not to take long to charge) but the +/- are the wrong way round for the Bongo to have the terminals facing forwards. I will check to see if that will fit/leads reach in reverse or not. I suspect the safety clamp would be in danger of shorting out the battery. I will have to see.

We actually do not use the fridge preferring to put lots of freezer blocks in it does us for a day or 2. It must just keep accidentally turned on. I have covered the switch up now.

Will look into one of those VSR's, I spotted a few on ebay. Thanks for suggestions.

[cmm303]

Perhaps remove the fuse supplying the fridge (assuming it doesn't feed anything else) as an interim fail safe?

[BongoBongo123]

All sorted for now with a 1/2 decent leisure battery (handy to have a few spares hanging about, gone of my hobby now for a while anyway). Cause the battery tray is a decent size and it is not too cramped up front (no engine) the wires reach despite terminals being reversed and all seems safe and secured. I added some layers of insulating tape to the retaining clamp bar to be sure. There is good clearance between the clamp and terminals.

Also a good idea cmm I will look into where the wiring goes.

[Jimbobvfr400]

Even better fit a separate switch for the fridge. Maybe then you could set the knob inside at the right level and pull it off so it doesn't get caught.