Jump-starter as a battery charger?

I do not have a battery charger but I do have a jump-starter battery pack - do you think it may harmful to leave it connected to the battery and also leave pack connected to the mains to continue the charge or will I head to the shops tomorrow and buy a custom-charger? Just wondering whether or not it would work even if it was safe. I'd just like to get a little juice into it to turn the starter. Advice very welcome thanks

Why not start the Landy with the jumper pack and take the Landy for a long run?

Frenchdame said:

I do not have a battery charger but I do have a jump-starter battery pack - do you think it may harmful to leave it connected to the battery and also leave pack connected to the mains to continue the charge or will I head to the shops tomorrow and buy a custom-charger? Just wondering whether or not it would work even if it was safe. I'd just like to get a little juice into it to turn the starter. Advice very welcome thanks

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don’t know if it’s any use , but have u seen the CTEK battery chargers, can leave them plugged in all the time to keep ur battery topped up , then just unplug them before u start the vehicle

i bought this one, there around £70

https://www.ctek.com/products/vehicle/mxs-5-0

Al2O3 said:

Why not start the Landy with the jumper pack and take the Landy for a long run?

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Sorry, it's not for my landy, it's for a mates Merc cdi van a few miles away on a farm. I should have said. It's been out in the open for a month in the snow and frost and it's dead. His battery is only twelve months old so I'm hoping a good few hours on charge might turn it over.

gstuart said:

don’t know if it’s any use , but have u seen the CTEK battery chargers, can leave them plugged in all the time to keep ur battery topped up , then just unplug them before u start the vehicle

i bought this one, there around £70

https://www.ctek.com/products/vehicle/mxs-5-0

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That looks a fair bit of kit.

All another 12 volt battery will do is to equalise the voltage on each battery over time as one discharges into the other, that is if one battery is below 12 volts and the other is 12 volts, they will both end up at a value somewhere between the low battery voltage and 12 volts of the other one.
In order to charge a 12 volt battery you'll need something in excess of 13.8 volts.
If I were you I'd just go with the advice from the others and use your jump starter pack to do just that, start the vehicle and let the alternator do its proper job.