Lidl and Aldi 'jump start' packs.

Notice both of these have Lithium car jump start packs on offer over the next few days.

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Lidl 8000 mA.hr £34.99

ULTIMATE SPEED Portable Jump Starter with Powerbank1 £34.99

8000 mA.hr 2-in-1 jump starter for cars and powerful power bank for smartphones, tablets etc With the latest Li-Ion technology and powerful 8000mAh LiFePO4 battery Particularly long lifespan with high cycle stability and up to 90% usable battery capacity Protected against reverse polarity, short circuit and overload Direct start without lengthy recharging with a high current pulse (approx. 200A/12V) With 2 USB ports,1 micro-USB port and integrated LED torch Includes charger, jump leads and micro-USB charging cable

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Aldi 7,500 mAh £49.99

Powerful and easy to use, this Lithium Car Jump Starter makes it easy for you to get your car started. Its compact size also means it's easy to keep it to hand in case of emergency. Contents

1 x 12V battery connector leads 1 x 12V charging plug 1 x 12V USB charging cable User manual Features Suitable for any petrol engines up to 3L and diesel engines up to 2L 2.4 amp USB socket for charging Includes charging plug, connector leads and user manual Safety feature included to protect against short circuiting 2.1 amp output socket for charging phones, tablets Recharges from 12V vehicle socket or USB

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Wonder which is better?

Reply to
Dave Plowman (News)
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On my Jet 14" BS, you just take the nut off and then the wheel comes right off. No wheel puller is required. IIRC, the nut is reverse thread.

Reply to
Lowell Holmes

In message , "Dave Plowman (News)" writes

I wouldn't trust anything supplying loads of amps - but specced in units of mA or mAh (presumably units intended to impress the gullible).

Reply to
Ian Jackson

On 23/11/2016 23:12, Ian Jackson wrote: I wouldn't trust anything supplying loads of amps - but specced in units

I don't see it as a problem when:

a. mAh is a (if not the) common metric for a portable "powerbanks" for charging mobile phones, tablets etc;

b. high current for a few seconds is often enough to help start a car so just a few hundreds of mAh may well suffice.

Reply to
Robin

What the hell's the point in saying 'thousnds of mA'?. It's just 10-^3x10^3. Also, if a cell is rated at 2500mAh I expect it to be within +-10mAh under real-world use; if it's 2.5Ah I'd accept +-100mAh. Precision exceeding accuracy yet again.

Reply to
PeterC

To me the specs on the Lidls one look better but I can't see how it recharges? Is it USB the same? If so it may take a long time also ....?15 cheaper

Reply to
Whittler Kev

They are designed to deliver hundreds of amps for a few seconds. mAh just tends to be the units normally quoted for (physically) small batteries.

Reply to
newshound

Presumably 8 amp hour battery? Minuscule compared to the normal car batteries. I wonder what the maximum discharge rate is without melting something? Unreliable sources suggest that a starter motor requires between 100 and

250 Amps.

Hmmm....8 Amps for an hour would be 480 Amps for a minute? So potentially

240 Amps for a minute to discharge to 50%. Or cranking a big starter motor for half a minute?

Then again this doesn't feel right. Looking up the battery for my Volvo

850 it is 73 Ah with a cold crank Amps rating of 680. This seems orders of magnitude greater than the Aldidl kit.

Cheers

Dave R

Reply to
David

Er...... Yes. That's why it's plain daft to quote big-battery specs in tiny units!

Reply to
Ian Jackson

Unless things have changed since I were a lad, until recently most car batteries have been around 40Ah.

The Ah rate isn't simply the product of current x time. It normally falls at higher currents. 8Ah could be 1A for 8h, but at 8A it might only last half an hour.

That's a biggun! I once had a 70Ah battery in my 1953 Ford Prefect - but that was 6V, not 12. It was, of course, similar in size to a 35Ah 12V battery.

I have always assumed that these jump start things work by first putting some charge into the flat battery - and then the no-longer-flat battery does most of the cranking work.

Reply to
Ian Jackson

Does it matter, if you know how do divide by 1000? One of mine is 8000 mAh, which tells me it eight times the capacity of my phone.

Reply to
newshound

My little Annke 8000 mAh battery is labelled starting current 180A, peak current 300A. So I probably wouldn't try to start a Volvo 850 with it, especially under cold conditions. But I suspect it would be fine for my little 1.3 Suzuki Carry three cylinder at ordinary temperatures.

All you need is a little common sense. If it won't crank at all when connected firmly, stop immediately. If it cranks at a reasonably speed but hasn't started in about three seconds, stop to let the battery cool down before trying again. I think some of them have some internal protection. I expect the Aldi-Lidl stuff comes with good instructions.

Reply to
newshound

Well I have had reasonably experienced in the certainly high tens of amps with lithium batteries in my time as model plane designer. IN general lithiums can just about be discharged at 30 times the hourly rate, if designed for that. So 8Ah would give you 240A for 2 minutes.

Certainly enough to start a car that *just* has a flat battery.

Reply to
The Natural Philosopher

No, as I said in the previous post LIPO of up to 30C discharge rates (2 minutes to flat) are now commonplace. And 'cold cranking amps' represents the worst that battery will do ...in reality cold amps its probably no more than 300.

You CAN overdrive lithium a bit, it wont make them last long, but I have seen model planes up to 5 times over current before the battery went up in flames.

Reply to
The Natural Philosopher

Its always been that way for LIPO.

because they started out as 800mAh etc etc

These super capacity batteries are relatively new..coming out of the hand tool market I would guess. And the model market which has always been used as a test area for new battery types.

Reply to
The Natural Philosopher

Can you buty anything these days that does not have a USB socket:-)?

The battery on my van (parked up ATM) got a good old 4A trickle charge last week from a clapped out charger.

Reply to
ARW

The one I bought last week says in the instructions that if the car hasn't fired in four seconds, stop cranking and let the battery pack rest for a minute before trying again. The instructions also say that it's suitable for petrol cars of up to 5 litre and diesel cars up to 3 litre.

Reply to
Munch

replying to The Natural Philosopher, Terry wrote: your lead acid car battery sags it's voltage drastically when the starter is running and upset the fuel pump. Lipo Jump starters like model airplane batteries don't sag at high currents and probably give more volts for a minute or so to help the engine management system to provide petrol ??

Reply to
Terry

replying to Dave Plowman (News), dave wrote: i know this is a pretty old thread but it might pop up on a search for someone like it did for me, trying to find one of these gadgets for my sister. I have the lidl ultimate speed booster pack, have had it for a couple of years now and only had to charge it less often than ive had to use it, the battery stays fully charged for months. its started a 2.2 diesel van no bother, and numerous fault finding starts on her car without losing a bar on the battery gauge. it was so easy to use she wants one now hence me looking. the actual starting is done by a little box (a capacitor?) with the croc clips built in that you plug into the side and charge up. it takes about 3 seconds, lets you know when its ready and wont work if you've connected it wrong, as I said, very easy to use. theres a bright torch built in too. charges quickly from the mains and can be charged in the car after use but I don't know how long that would take.

Reply to
dave

Reply to
kevindonegan719

and you've re-posted a 2 and a half year old post because?

Reply to
TOJ

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