Jump Start Li Battery Pack.

[alexanderfoti]

The packs:


The top is a 6.6 AH 4S pack, the bottom is a 10AH 3S pack.

 

[leonrsa]

Interestingly, the instructions state that no attempt should be made to start a vehicle if the indicator is below 30%, which corresponds to 11.1V at the battery, or the total nominal cell voltage (3 × 3.7V)

Take note of the fact that Li-Ion are considered 'empty' at 3.3v, so 30% translates to roughly 3.4 v/cell, or 10.2V

Hence the little indicator is deliberately pessimistic AND the instructions are specific about how high the charge should be according to the indicator.

As it should be, as the indicator should indicate 'empty' at 9.9v.

When these batteries are discharged below 3v they are promptly destroyed, which is why there is protection circuitry included in the battery banks to prevent it from happening during use, as the batteries can combust under heavy load and too low voltage.

 

[Paul Goff]

And an update!

I have carried out a fairly controlled discharge on my "20"AH Sauoki jump starter pack, while monitoring pack voltage and discharge current.

The reality is that my 20AH Li battery, when discharged via the jump start leads is all out at 9AH or even a bit less!

So there it is, by any sort of sensible measure, the actual capacity is a great deal lower than stated "on the box", and the little charge state indicator is pretty close to correct.

The only rider to my conclusion is that I discharged at 3 amps, PERHAPS a discharge at a typical starting current, corrected for such a high rate of discharge, would produce a higher perceived capacity, but I have my doubts ;-)

Goffy.

 

[alexanderfoti]

The only rider to my conclusion is that I discharged at 3 amps, PERHAPS a discharge at a typical starting current, corrected for such a high rate of discharge, would produce a higher perceived capacity, but I have my doubts ;-)

Goffy.

That is not that surprising given most of them.

on nearly all batteries, more discharge current = lower effective capacity. Many batteries spec sheets will show 1c,10c ratings etc.

This is due to internal resistance going up with current draw! I would thing you would see even less capacity at a much higher current draw.

 

[kid-jensen]

If it is still under guarantee, I would try starting a cold engine with it....If it doesn't start the engine a couple of times, throw it back at the supplier.

You need to be sure it's 100% working now, at the side of a road in the snow is not a good time to find out it isn't .

 

[Taffy7hfa]

Halfords Advanced Lithium Jump Starter - Up to 3L
The Halfords Advanced Lithium Jump Starter - Up to 3L is small in size but high in power: the mini jump starter can start a 12V vehicle up to 3L. The jump starter uses lithium technology, and is a fraction of the size of a traditional lead acid power pack, but with no compromise of power.

It is easy to use, store and recharge: it can fit in your glove box and is ready for when you need it. With battery failure being one of the top reasons to call out breakdown services in the UK, this is an ideal way to avoid being stranded.

Simple to use: just connect and press to jump start. LED indicators show the charge level of the jump starter. The jump starter comes with Safe Connect clamps, for extra safety assurance. The Safe Connect clamps protect you if the clamps are connected to the wrong poles, and ensure that the voltage passing from the jump starter to the car is at the right level. It also has a USB port, so you can charge a phone or tablet, and LED torch, ideal for emergencies. Comes with USB charging cable, so it can be easily recharged in the car or at home.


Please Note: Product and packaging may vary slightly.

Halfords Advanced Lithium Jump Starter - Up to 3L Extra Info

• Compact, high power lithium jump starter for 12V vehicles up to 3L
• Small enough to store in the glovebox – ready for an emergency
• Easy to use, with clear LED indicators
• Safe Connect clamps ensure safe jump starting
• USB socket for charging phones, tablets and other devices
• Built-in LED torch for emergencies
• USB charging cable included
• This unit is designed to jump start a vehicle with a healthy but partially depleted battery. For safety reasons it will not jump start a vehicle with a battery where the voltage has dropped below 3V

Bought one of these last month a tad salty @ £85, feels like a quality bit of kit though,& started the Alto no problem, battery was very flat, not sure if it would work on the ML, hopefully I wont need it

 

[kid-jensen]

Looks pretty good, but normally the "up to 3 Litres" figure refers to petrol engines....

 

[Crispian]

I have a floureon version I bought around 4 years ago now,it started my neighbour's completely dead BMW 330i with no problem and also started my E350 (cdi) last year that failed to turn over due to a very weak battery.

I always have one in the boot, for the sake of £40 it could save a lot of grief.

 

[Blobcat]

I have a floureon version I bought around 4 years ago now,it started my neighbour's completely dead BMW 330i with no problem and also started my E350 (cdi) last year that failed to turn over due to a very weak battery.

I always have one in the boot, for the sake of £40 it could save a lot of grief.

As long as your metal key will open the boot...

 

[Crispian]

As long as your metal key will open the boot...

Very true.....