Using a Jump pack as an auxiliary battery & Charger

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ontheplane

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Have recently bought a decent jump pack and am looking to use it for cars.

However I had a thought, rather than have two batteries on a smaller boat (rib / sportsboat etc) has anyone used one of these jump units aboard.

I see the advantages twofold -

1) Whilst out hooning about then anchoring up, no chance of flattening both batteries

2) At night when moored in marina, just attach jump pack to other battery, plug it in, and presto - both batteries charged....


I consider this plan so simple it must be flawed - so has anyone tried it?
 
Yes, I always had one aboard that I kept at home fully charged, and took with me every time. Any issues with the only boat battery, it jump started the engine instantly
 
rafiki_ said:
I don't think the booster pack will charge your battery, it will only give a high instant starting power.
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A big one will charge the battery: I had a problem with my last merc (3.2 diesel), the boost pack couldn't turn the engine over on its own but if I left it half an hour it would start. According to the documentation you can charge it from a car 12v socket - or (and this is bit that I was sceptical about) it will charge the car battery through the same socket.
 
WhiteMischief said:
A big one will charge the battery: I had a problem with my last merc (3.2 diesel), the boost pack couldn't turn the engine over on its own but if I left it half an hour it would start. According to the documentation you can charge it from a car 12v socket - or (and this is bit that I was sceptical about) it will charge the car battery through the same socket.
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Thanks, interesting.
 
Maybe a techy can help here.

I sometimes have a problem with a car thats left unused for periods - you know the immomilizer and little flashing lights everywhere causes huge drain and it will not start if left for over two weeks - cannot use a trickle charger unfortunately.

So I have to connect a charger and give it several hours as another car (with big battery too) will not turn the flat car over using jump leads.

Would a mains rechargeable Jump start pack under discussion here work in this case?
 
The jump pack is a plastic box containing a battery and a charger, maybe a lamp and a 12v socket, nothing more.

It will do exactly the same job of charging your battery as a spare battery and some jump leads would do. If the booster battery is charged more than the car battery, it'll balance out, no more.

The bigger/better ones just have bigger/better batteries in them. The el cheapo Chinese ones aren't worth buying, work OK ish for a while, don't last five minutes.

A good quality one, fully charged, is a very useful tool to have on board, especially on a small boat with only one battery.
 
Thanks Paul

Even when the fully charged jumping battery is connected and the donors engine revved up to put some amps in the sick car just goes tick tick tick tick....will not turn it over.

Should I simply leave both connected for 5 mins and then try the sick car once they have balanced to over 12v?
 
mjf said:
Thanks Paul

Even when the fully charged jumping battery is connected and the donors engine revved up to put some amps in the sick car just goes tick tick tick tick....will not turn it over.

Should I simply leave both connected for 5 mins and then try the sick car once they have balanced to over 12v?
Click to expand...

In that case, the boost pack wouldn't start it straight away either. What might work for you is to connect the jump leads, then pull the earth lead off of the car battery. That way you won't have the flat battery soaking all the power up. Could do the same with the boost pack, or leave it connected for a while.

What car is it ?
 
mjf said:
Thanks Paul

Even when the fully charged jumping battery is connected and the donors engine revved up to put some amps in the sick car just goes tick tick tick tick....will not turn it over.

Should I simply leave both connected for 5 mins and then try the sick car once they have balanced to over 12v?
Click to expand...

this is similar to what I had, I just left it connected for about 20 mins and it was ok. I could start with a jump from another car but it took a good 10 mins if it was really flat.

You have to be quite disciplined though, if I tried before the 20 mins it just killed it and would have to wait again. the halfords one you can use as trickle charger too. I sold the car in the end BTW, merc never got to the bottom of it.
 
Back to the OP though - would these units also be able to be used as a charger if plugged into a shorepower overnight?

I have a camping shorepower lead with a RCD and circuit breakers in - fully self contained, just plug the unit in, connect to main battery, and bingo? Or not bingo?
 
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