Anyone own a Rolson's 12V Jump Start with Air Compressor unit?

I'm using a charger from something of Panasonic's. Output 13.5V DC, 400 mA, 9.2 W with the +ve in the middle.

Hmm.. the candidate adapter I'm looking at is labelled EMC (model WJB-DC) and the output is 12V DC at 500ma.

It's unlikely to fully charge it. The nominal 12V of the sealed lead acid that's 99% sure to be inside it really needs 14V or so to charge it.

If you try and charge it with a 12V charger you'll find it doesn't last long at all.

But then again a lot of cheap chargers are unregulated - which means they put out a voltage that can vary a lot with load. You'd have to measure it in that case.

13-15V is what I'd look for, ideally 13.8-14.4.

Thanks for that. I'll keep looking.

Rather silly of me to have misplaced it :(

Mine is badged Tronic and came from Lidl at the vast cost of 20 quid a couple of years ago but probably from the same factory.

IMHO because they can also be charged off a car system they will have an internal regulator to prevent cooking the SLA battery. So a plain 12 volt DC supply will be fine. Mine is marked 12V 1000mA DC

Isn't it badged 'Rolson'?

You won't do any damage by trying it. The charging indicator light should go off when the battery's charged.

BTW be sure to charge it regularly. It appears these batteries don't last as long as car batteries.

The one I have is not a Rolson it is branded as Bigmaster but it has a

12v 17ah battery and the mains adaptor is a model HB-DC 12v 500 and rated at 12v 500ma. Hope that helps Trevor Smith

It should certainly be charged before storage if well discharged. But shouldn't need routine charging - SLA batteries have a very low self discharge rate.

Seems my Lidl cheapy was even more of a bargain with a 1 amp charger. ;-)

Your Rolson probably is this one:

This is a dead ringer to the "B Grade Portable Jump Starter & Air Compressor" from Maplin, and is almost identical to the one from Halfords: ?J10B21DAD (see the enlarged image) So, you might as well pop down to your local Maplin/Halfords and take a close look at its specifications and the mains adapter. If you need to buy the adapter, unfortunately Maplin don't sell this accessory separately (as in their answer to someone who also lost the charger and posted a similar question like yours in the Q&A!)

Isn't it amazing the price differential?

The one I have suggests a full charging at least once every six months.

I'd imagine a nominal 12v/400ma adaptor will probably give a bit more at low load as the battery nears charge.

Yup - mine looks identical to those except for the black case and cost

19.99. Somewhat of a bargain. It's been used to jump start cars about a dozen times and often for pumping up tyres.

Yep that would be the one.

Talk about taking the piss! I bought mine for around 22 quid at my local general store about a year ago :)

It is an extremely useful bit of kit. I've never needed to use it so far (touch wood) but it is nice to have it just in case.

Hi any one know how to get Rolson 12v jump start to start changing again from stone dead bin stood in a garage for over a year

Fit a new battery.

Tim

In message , snipped-for-privacy@gmail.com writes

I rather depends on why it's stone dead. For example, it could be that the plates have become sulphated, or possibly debris deposited below the plates is shorting them out.

I'm no expert, but maybe the quickest way of finding out if the battery might be recoverable would be to borrow an ordinary 'non-smart' charger, and see if the battery voltage shows signs of coming up. If the ammeter just sits there, pinned at maximum, it's likely that debris is shorting the plates. If there's little charging current, it's probably sulphated. Either way, there's little chance in getting the battery to recover.

Lead acid battery? Probably unsalvageable. You could try connecting it to a traditional "transformer/rectifier type charger for a while but I don't hold up much hope.