Charging Jump Starter Pack

[RJH]

Would it be OK to charge on of these:

(jump starter/compressor/light/USB) by connecting the jump leads to a car battery charger, rather than use the supplied AC adapter?

[T i m]

I'd say 'yes', assuming it contains a 12V LA battery (it looks like it does) and the chare rate is kept low, (say around C/20 of 17.2Ah = ~1A).

What is the current output of the supplied charger OOI? As long as you are less-than or equal to that you should be fine.

As it's a maintenance-free (likely 'sealed') battery, I wouldn't charge it any higher than 5A or if you did, for too long (and keep an eye on the battery temperature (with your fingers) if you can get to it easily). Any sign of any real warmth, stop.

The only reservation re charging back though the output leads might be what constitutes the 'overload protection', but nothing any output indicator on the charger or your voltmeter wouldn't determine.

That's the sort of job an Optimate 2 was designed for (as it can be left on indefinitely). ;-)

Cheers, T i m

[Paul]

Charger = 15V @ 500mA for K640046

Product pictures. Vorne and Hinten.

[e-mail]

[e-mail]

Switch for jump-starter leads.

[e-mail]

Switch for compressor is not shown in detail. Noise warning sticker. 10 minute run limit.

[e-mail]

Note mains connector.

[e-mail]

Considering the battery could be a sealed lead acid with limited regeneration rate, and the battery is 12V @ 17.2Ah, that's probably a good rate. That's like a third of an automotive battery. It could be a sealed battery, not intended to leak hydrogen into the room (it still has to be vented for safety - like a vent that opens at 5 bar).

If connecting your own charger, I'd use a smart charger with charge current in the ballpark. Say, a 2A charger max. Don't use an old dumb charger (transformer plus selenium rectifier), because the current flow is rather uncontrolled.

Since you won't be running it all the way down, it will never take 34 hours to charge with the included adapter. Maybe 6 hours to top up, after a usage. The unit should really have undervoltage cutoff, to protect the battery. Since it has overcurrent protection, the protection device can be used for more than one function (like, a relay or contactor for heavy current).

Note that there is a switch to switch on the battery leads! The switch contacts are not rated at 150A, but some other contactor inside might be worked by the switch or something. This might present some issues for forcing charge in through the croc clips.

A battery that small is going to be limited on CCA. You won't be able to start a vehicle with that unit alone. The battery in the vehicle also has to help.

The larger Walter jump starter, has 240A max output. This unit, no spec is offered for the max output (overcurrent protect). Neither is there any mention of undervoltage cutoff. The USB SMPS for the phone charger, that should have an undervoltage cutoff, to avoid damaging the battery by draining to zero.

But since Walter offers no downloadable manual, we're forced to guess by looking at tiny pictures of the product. I don't buy products without a user manual, for this very reason, poor marketing materials online.

Paul

[alan_m]

There may also be some diodes in series to prevent "back" charging or to prevent accidental damage when a 12V unit is connected to 24V.

Albeit a lithium battery based unit, my battery booster has a diodes in the +ve lead.

[Dave Plowman (News]

They'd be some diodes to carry starter current. And the voltage drop through those is something you don't want when jump starting under extreme conditions.

[alan_m]

Big Clive video

[RJH]

Thanks - it is a LA sealed battery, and I've got one of those Lidl 'intelligent' chargers, which I'd guess is quite gentle.

>

[RJH]

That's actually the compressor switch. The jump leads are permanently live.

It was from Aldi so came with a UK plug/PSU. That's actually why I'm asking, in part. The insulation/wire going i to the PSU has broken down a little.

Yes, that's the battery. I had to open it up after I posted because the USB switch got stuck. Took complete disassembly to get to it - squirt of contact leaner and all's good.

I think it has pretensions of jump starting - but I've never needed it. I'll be using it as low rent leisure battery, just for things like phone charging, tyres, lights.

It did come with a manual. And there is one on that page I linked to. Amongst other things, it says 'charge monthly'. I think I've charged it 5 times in 5 years, and then only to top up. It's been barely used.

So, thanks, overall I think you're saying it should work.

FYI, the jump leads connect direct to the battery, nothing inline. Two smaller wires feed direct to the other gubbins from the battery. I suppose my concern is that the charger might push something unpleasant along those smaller wires. But quite what, if anything, is way beyond my pay grade . . .

[RJH]

Nothing I could see - the jump leads bolt directly onto the battery terminals.

[T i m]

<snip>

Well, ours has two rates (indicated by the symbol of a car or a motorbike) and so yes, the motorcyle setting could be considered better for that capacity / design of battery.

Yours could state on it the rate(s)?

Cheers, T i m

[Paul]

You might not want to have both chargers connected at the same time. That's the only case I can think of that might be an issue. If the external charger went to over 15V, there might be an issue this way.

15V 500mA --------- charger ----------- battery ------ <=== external charger PCB

Should be OK like this, with 15V input open-circuit. The charger PCB has to be able to "withstand" the potential offered by the battery. And that should (to be safe) be designed to cover up to 18V, when the charger PCB is open circuit on the left side. It's when the charger PCB has a power source connected on the left, there might be a failure case to worry about, moving current from right to left. The wall adapter might not like that particularly.

X--------- charger ----------- battery ------ <=== external charger PCB

If you were to use the product to start a car, the car alternator will be pushing current from right to left, just like the external charger will be. So they have to handle the case of the alternator putting say,

14.4V on the right.

Paul

[T i m]

<snip>

Ideal then (for you proposed solution).

So charge indicators (if there are any), the USB board or even the socket for the supplied charger etc.

Unlikely unless the battery is open circuit and a smart charger has a de-sulphation phase that might try to pulse the battery with higher volts etc. Otherwise, *any* charging of that battery is going to 'push whatever along those wires. ;-)

(As an aside ...) It still sounds wrong when people say that, although I understand it *also* covers knowledge about something, rather than the level of authority / responsibility over others. ;-)

Cheers, T i m

[Dave Plowman (News]

That's how I charge my Lidl jump start pack. One of the very first things I bought from Lidl perhaps 20 years ago. The compressor no longer works, and I've replaced the battery. ;-) But it did very well for the price - about half that of the Halfords equivalent.

[newshound]

IME these are pretty indifferent products, they don't contain much of a battery, and the compressors are feeble too. Being lead acid you do have to keep them charged regularly.

I have a couple of Lithium Ion car starters, and they are brilliant. The smallest is literally pocketable, about half the size of a standard paperback and will still fit in a jacket pocket with the leads and big croc clips. This is more than enough for a 1.3 petrol engine.

The larger is about 20x10x6cm and I am sure would do a large petrol or small diesel engine.

IME these hold their charge very well, I probably only check them once or twice a year.

The tyre pump that comes with my Honda is pretty good, and I have something like this for my 3500 van.

which has a great deal more "oomph" than the toy things that are sometimes on offer at petrol stations.

[T i m]

+1

I have one also and used it several times in succession (as an experiment) to start step-daughters Seat Ibiza when something (we think the inbuilt radio) was killing the battery every 3-4 days when it was left unused. You would literally *just* get a weak ignition light yet the lithium pack would allow it to start on the button.

I was asked to move the kitcar by some utility co and it hadn't moved for months. Whilst the battery was 'ok' and would still have started it had it fired up quickly, it didn't and so I just nipped in and got the lithium pack, hooked it up and it span the engine up long enough to get some petrol up and away it went. As you say, that hadn't been charged for months yet even after that (prolonged) starting, it was still showing a couple (out of it's 4) lights.

I have also a separate 12V pump that has also worked well for several (well 4 <g>) tyre complete re-inflations on the trot (after installing Punctureseal etc). Many cheaper things would have melted before that.

Like yours it allows you to set the desired pressure and switches itself off when it gets there (just as well as it is quite loud so I prefer to move away when it's running for any prolonged period). ;-(

I keep both that and the single mechanical foot pump in the car.

Cheers, T i m

[newshound]

I used to keep a spare inner tube and a short "bicycle" pump under the seat of my motorbike. I only ever had rear punctures. The one time I had a front tyre deflate when riding was when I was rescuing someone else's bike, and that turned out to be a faulty patch on the tube. I *never* patched front tyres after that.

[Dave Plowman (News]

Eh? Lead acid self discharge very slowly.

Interesting. The Lidl jump start pack I mentioned which has an 18 amp.hr gel battery has been used to start my 3.5 litre V8 Rover. Recently. The Li-Ion one I also have says up to 2 litres and this was certainly true, as it wouldn't even attempt to turn the engine.

I'd want to be certain, rather than sure. Check the specs for starting current, not so called peak. And the capacity of these Li-Ion packs (at a reasonable price) are much less than the equvalent lead acid types. Oddly, they all seem to quote in mA.hr. Wonder why that would be, since car related batteries are always amp.hr.

[T i m]

<snip>

I carried a spare wheel on my Lambretta. ;-)

I think the old BMW motorbikes came with (or was an option to come with) a cycle style pump up the main tube accessible from opening the saddle.

I don't have punctures any more (Punctureseal). ;-)

(often the way it seems, 'no good deed not going unpunished' etc... )

I have taken on many a second hand cycle and found that patches just peel off the tube, suggesting they were only stuck on with spit?

Luckily, most of my motorbikes ran tubeless tyres (as do my trailers now).

Cheers, T i m

[T i m]

But maybe they discharge quicker than lithium?

But those results don't seem to match the general experiences of others. I have at 2 'shells' of LA based 'booster packs' that used to contain ~17AH sealed LA batteries that were written off because the batteries died, often from lack-of-use and you could generally buy a complete new unit for less than the price of a replacement battery. I did re-battery one once then when that was found dead, never bothered again.

I've started daughters 1800 diesel Connect with my Lithium pack and it did so easily? That said, as long as it can spin over a couple of times at a reasonable rate it does seem to start fairly easily.

I'm not sure they are Li-Ion but Li-Poly?

I think it's because they have come from an environment (RC Models etc) where batteries were generally rated in mA. <shrug>

However, a pocket sized LiPo could have the same CCA as a LA battery

10x the size.

Cheers, T i m

[newshound]

Try leaving one for six months. Also, I bet most of these contain bargain basement batteries.