Leisure battery question.

[lakeside]

I use my Berlingo in micro camping mode for hiking and do not always drive again before the next days walk so I wondered about depleting the leisure battery.
The leisure battery is fitted in the boot area of my Berlingo; it was professionally fitted. I use a cigarette lighter extension lead from it which it more convenient to use to fuel my small kettle or recharge my phone. If I remove these items from the extension cable but do not remove the cable from the battery i.e the red light is still showing is fuel still being taken from the battery? To unplug the cable easily means inconveniently going outside and into the boot. I am thinking not, I guess a bit for the red light, but someone with more electrical knowledge than me (not difficult) would have the definitive answer.

[Tree]

Fit an isolator switch on the live cable

[Tree]

https://www.furneauxriddall.com/cgi-bin/...l#SID=1009 one like this - this is how we isolate batteries on a boat

[Gravity]

Question is - Where do you locate the isolator switch?
If it's fitted close to the battery, which is best practice, then you still have to go to the boot to turn it off.

[GraemeT]

I'd just suggest checking the leisure battery voltage for a couple of nights ideally when you are at home. 2 or 3 with the gubbins connected then 2 or 3 with the negative terminal removed. That should give you an idea of how much the voltage drop is across a normal evening and then the difference with just the battery sitting by itself.

A leisure battery is designed to recover from a deep discharge and I would have thought that a single LED is not going to kill it overnight. We run a 110 Ah one in our caravan and there are a couple of permanently wired 'thingies' in there with LED display (including a handy voltmeter) and over an entire weekend we see no appreciable voltage drop.

[lakeside]

Thank you for the information.

[Gadgetman]

Is that, a 12V extension lead with a built-in LED?
Unless there's some really weird electronics in there, I'd expect it to draw 20 - 50mA.
This means it would take 20 - 50 hours to drain 1AH off of the battery.
Even at the horrid rate of 100mA, it would take a MONTH to deplete a typical 60AH leisure battery that's fully charged.

[Gravity]

If it's wired with the correct type of relay (see my Camper thread) it will be connected in parallel with the normal starter battery but will not be used by the car electrical systems - ie. it will not assist the car battery when you start the engine, for instance.

The alternator will charge both batteries as needed while you are driving, so - unless you have had a big drain (and a cooler is a big drain) - the leisure battery will just get a trickle charge.

So the only drain on the leisure battery would be the leisure items that you use while you are stationary with the engine off, such as additional lighting, cooler or frig, plus any leisure sockets for moblle, tablet, tv, etc.

It shouldn't take much driving to keep it topped up, but even if it's drained heavily to within an inch of it's life, it should recover easily - being a deep cycle unit.

As for a red led light showing, just ignore it. I often leave my cars unused for weeks with a couple of led light blinking (alarm etc) with no ill effects.

[dumdum]

Fit an isolator switch on the live cable

It makes no odds in reality, but it’s often easier to put it in the earth to the chassis, that isolates the entire battery system from the vehicle and can be better in the event of a short circuit somewhere as it stops everything dead!

You could cut the feed from the positive to a fuse box or similar but if the cable down the van shorts out it won’t help as even if the items are off you’d still want it to charge, so the live cable would need to link not through the switch so you’d be reliant on the feed...

So many ways to do this, with all sorts of positives and negatives to various solutions... but most important is fit a fuse at both ends of the cable as close to the batteries as humanly possible!... linking batteries together!!

Oh and make sure the fuses either end are at least the rating of the alternator as in theory it will throw that amount of current one way, so for example 120A alt, 2x120a fuses would do

[Marshbeak]

In my opinion I would take the car to a professional workshop.