Temporary Starter Battery Charging

[ElliesBoss]

Visited our moho today and it wouldn't start. We have solar charging the leisure battery. Can I connect the +ve terminals of the starter and leisure battery together with a jump lead for a few days to charge the starter battery.

 

[autorouter]

Yes that would work. A few minutes is all that is necessary, but leaving it for a few days would in theory do no harm, provided you disconnect it before starting the engine. However jump leads have no fuse protection. That is fine if you are watching all the time, ready to pull off the leads if anything goes wrong - for example the bonnet falls and cuts through the insulation.

A better way if you're leaving it overnight is a 'car-to-car charger', like this:

Amazon product ASIN B00FLVS48SAmazon product ASIN B00NVCRIH2
It's designed to connect batteries in two separate vehicles, but works equally well between leisure and starter battery in one vehicle. It has two cigarette-lighter plugs, so if you have permanently live sockets connected to the leisure battery and the starter battery, just plug it straight in. If not, you could buy/make an adapter with a cigarette-lighter socket and croc clips. Or just cut off the plug and fit croc clips, with an inline 10A fuse in the positive wire.

Amazon product ASIN B003SQ6U6Q
This device is basically a simple wire connection, but there's a current limiter that limits the amps to below 10A. That stops the huge amps surge that would otherwise happen when connecting with a simple wire like a jump lead.

Other brands are available. I don't know the brand of the one I've got, I've had it years.

 

[The Wino]

Yes that would work. A few minutes is all that is necessary, but leaving it for a few days would in theory do no harm, provided you disconnect it before starting the engine. However jump leads have no fuse protection. That is fine if you are watching all the time, ready to pull off the leads if anything goes wrong - for example the bonnet falls and cuts through the insulation.

A better way if you're leaving it overnight is a 'car-to-car charger', like this:
View attachment 388828
Amazon product ASIN B00FLVS48SAmazon product ASIN B00NVCRIH2
It's designed to connect batteries in two separate vehicles, but works equally well between leisure and starter battery in one vehicle. It has two cigarette-lighter plugs, so if you have permanently live sockets connected to the leisure battery and the starter battery, just plug it straight in. If not, you could buy/make an adapter with a cigarette-lighter socket and croc clips. Or just cut off the plug and fit croc clips, with an inline 10A fuse in the positive wire.
View attachment 388830
Amazon product ASIN B003SQ6U6Q
This device is basically a simple wire connection, but there's a current limiter that limits the amps to below 10A. That stops the huge amps surge that would otherwise happen when connecting with a simple wire like a jump lead.

Other brands are available. I don't know the brand of the one I've got, I've had it years.

Presumably you could leave one like that plugged in during storage your solar would then keep the starter battery charged up when you get a chance you could fit a battery master or similar.

 

[autorouter]

Presumably you could leave one like that plugged in during storage your solar would then keep the starter battery charged up when you get a chance you could fit a battery master or similar.

Yes, it's great to find the perfect solution for storage in lockdown - just after lockdown has ended

 

[ElliesBoss]

Thanks for your replies. Have just ordered a Battery Master but that will take a few days to arrive. I may go the jump lead route for a day or two as the leisure battery is behind the passenger seat and the starter battery is under passenger floor so not much risk of bonnet shutting on it! May just use some wire and jubilee clip it to battery posts. May even include a fuse. Perhaps a diode so current only flows one way. Nah, I'll use the jump lead?

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[Millcourt]

A better way if you're leaving it overnight is a 'car-to-car charger', like this:
View attachment 388828
...……...….I don't know the brand of the one I've got, I've had it years.

Can anyone confirm this works? The reason I ask is that on most modern vehicles the Cig-type sockets (other than the ones used for "domestic" purposes e.g. TV and powered from the leisure battery in a motorhome) are only "live" when the ignition is turned on.

 

[Richard n Ann]

Can anyone confirm this works? The reason I ask is that on most modern vehicles the Cig-type sockets (other than the ones used for "domestic" purposes e.g. TV and powered from the leisure battery in a motorhome) are only "live" when the ignition is turned on.

No it won't work on a Sevel type van as the two sockets go off with the ignition. When our leisure battery failed in Benidorm i bought some 1.5mm flex and did a similar job with that, (I actually disconnected the leisure battery) . Slightly different circumstances but worked for the way home.

 

[autorouter]

Can anyone confirm this works? The reason I ask is that on most modern vehicles the Cig-type sockets (other than the ones used for "domestic" purposes e.g. TV and powered from the leisure battery in a motorhome) are only "live" when the ignition is turned on.

Yes this will work, if you connect direct to the battery using a cigarette-lighter socket to croc clips adapter. Use one for each battery if the existing wired sockets are not permanently live.