Battery jump start packs ....how is it working..magic?

I've got one, Amazing bit of kit, 1000A peak current, and according to the blurb will start an 8 litre diesel 40 times, and only needs charging every 3 months. I'm not sure I quite believe that, however it spins up a 2.5l Land Rover diesel engine in the dead of winter with a totally flat battery like you would not believe.

It's great on a boat, the croc clips disconnect for storage so there's no chance of a short. Built in it has 2 torches and a strobe, 2 USB ports (so it's perfect for charging phones) and a female cigarette lighter connection, so when I blow the dingy up I just plug the electric pump straight into it instead of faffing around with wires trailing all over the boat.

It was a bit more expensive, around £80 IIRC, but one of the best bits of kit I own.
 
I have a car with a high-compression 1.7 litre 4-cylinder engine fitted with a 16Ah gel battery - it's more than adequate unless you need to crank it for very long periods (in which case it ain't gonna start anyway).
 
Iain C said:
I've got one, Amazing bit of kit, 1000A peak current, and according to the blurb will start an 8 litre diesel 40 times, and only needs charging every 3 months. I'm not sure I quite believe that, however it spins up a 2.5l Land Rover diesel engine in the dead of winter with a totally flat battery like you would not believe.

It's great on a boat, the croc clips disconnect for storage so there's no chance of a short. Built in it has 2 torches and a strobe, 2 USB ports (so it's perfect for charging phones) and a female cigarette lighter connection, so when I blow the dingy up I just plug the electric pump straight into it instead of faffing around with wires trailing all over the boat.

It was a bit more expensive, around £80 IIRC, but one of the best bits of kit I own.
Click to expand...

Nice to have a recommendation. Would you please post a link to the specific one you have. Thanks.

Www.solocoastalsailing.co.uk
 
Plum said:
Nice to have a recommendation. Would you please post a link to the specific one you have. Thanks.

Www.solocoastalsailing.co.uk
Click to expand...

Here you go. Most of the reviews are 5 stars. I must admit I'm thinking "user error" on the one star reviews, and "can't actually use a computer" for the person who thinks it's great and has given one star!

It's a seriously brilliant bit of kit in my book and I am usually very fussy and skeptical.

https://www.amazon.co.uk/TACKLIFE-T...07C7T4LBT/ref=cm_cr_arp_d_product_top?ie=UTF8
 
Thanks for replies. I am not electrickery wise but I know this is lithium polymer battery. In sturdy foam case. Even if croc clips touch safety thing stops bang. Saw identical one start a duff battery ( would not even turn over) a 2.5 litre diesel - took 4 attempts at 2 seconds per go on the key.
BUT can someone tell my thick brain again what sort of amp capacity I could get from it at 12 volts if I use it as a sort of leisure battery? Coz my sums are wrong as pointed out.
Cheers
 
ltcom said:
Thanks for replies. I am not electrickery wise but I know this is lithium polymer battery. In sturdy foam case. Even if croc clips touch safety thing stops bang. Saw identical one start a duff battery ( would not even turn over) a 2.5 litre diesel - took 4 attempts at 2 seconds per go on the key.
BUT can someone tell my thick brain again what sort of amp capacity I could get from it at 12 volts if I use it as a sort of leisure battery? Coz my sums are wrong as pointed out.
Cheers
Click to expand...

The specs are not clear in the amazon listing.
It says 20,000mAh implying 20Ah.
Then it says 64wH implying 5.3Ah. at 12V.
There is a lot of gibber in the descriptions of these things, they are often spec'd in terms of the lead acid battery they are equivalent to.
It says you can pump up 'at least two tyres using it to run a compressor. To me that implies about 10A for under 20 minutes unless you've got a fergusson tractor?
I thin kthese things are great as boost packs, with a bit of portable battery pack as a bonus, to run a phone or some other small use, or a short burst of medium current like inflating a dinghy. I think they are really not a house battery.
 
Daydream believer said:
Must be short of decent kit :ambivalence:
Click to expand...

Hmmmm...a bit of kit that goes in the bottom of my sailing bag that will blow up my dinghy, light my way aboard the big boat, start her up if she's got dead batteries and charge up my phone in one small package...nah, can't see the attraction in that at all.
 
lw395 said:
I thin kthese things are great as boost packs, with a bit of portable battery pack as a bonus, to run a phone or some other small use, or a short burst of medium current like inflating a dinghy. I think they are really not a house battery.
Click to expand...

Agreed 100%.
 
lw395 said:
The specs are not clear in the amazon listing.
It says 20,000mAh implying 20Ah.
Then it says 64wH implying 5.3Ah. at 12V.
There is a lot of gibber in the descriptions of these things, they are often spec'd in terms of the lead acid battery they are equivalent to.
It says you can pump up 'at least two tyres using it to run a compressor. To me that implies about 10A for under 20 minutes unless you've got a fergusson tractor?
I thin kthese things are great as boost packs, with a bit of portable battery pack as a bonus, to run a phone or some other small use, or a short burst of medium current like inflating a dinghy. I think they are really not a house battery.
Click to expand...

Cheers. Understanding a bit better now.
 
I think the 20,000mAh is at 5v for usb charing and the like. At least that's how I believe my old one is specced.

Used a few times on the motorcycle, and on the neighbours car to good success.

Not used it on the boat engine, but have used it to run 12v systems on the boat, whilst I was I carrying out some battery maintenance.
 
Mikedefieslife said:
I think the 20,000mAh is at 5v for usb charing and the like. At least that's how I believe my old one is specced..
Click to expand...
Agreed - I was about say the same when I saw your reply.

All USB power banks seem to specc'd in mAh - in the absence of a voltage this makes little sense to me, but 5000mAh ones are advertised as being able to charge a mobile phone once or twice (depending on the phone).
 
I would have thought that the current needed to start an engine might depend a lot on the capacity of a single cylinder. So quoting total capacity of an engine might be misleading. ie a 500cc single cylinder diesel will take a lot of turning over ie overcoming compression compared to say a 1litre 4 cyl where each cylinder is only 250cc and the pressure of one cylinder might help to over come next compression.
Anyway OP has identified the battery as lithium in his power pack. Lithium batteries have a voltage drop characteristics more dramatic than lead acid which are in turn more dramatic than Nicad. So a cell will typically start at 4.1 volts and be considered discharged at about 3v. Hopefully your power pack has a controller for charge and discharge so that it should cut out if cell voltage falls too far. So yes use it for power supply for lights etc on the boat but don't be alarmed at volt drop. Typically for a "12v" battery they fit 3 cells in series which then stat at 12.3v but can fall to 9v in service.
good luck with the power pack ol'will
 
William_H said:
I would have thought that the current needed to start an engine might depend a lot on the capacity of a single cylinder. So quoting total capacity of an engine might be misleading. ie a 500cc single cylinder diesel will take a lot of turning over ie overcoming compression compared to say a 1litre 4 cyl where each cylinder is only 250cc and the pressure of one cylinder might help to over come next compression.
Anyway OP has identified the battery as lithium in his power pack. Lithium batteries have a voltage drop characteristics more dramatic than lead acid which are in turn more dramatic than Nicad. So a cell will typically start at 4.1 volts and be considered discharged at about 3v. Hopefully your power pack has a controller for charge and discharge so that it should cut out if cell voltage falls too far. So yes use it for power supply for lights etc on the boat but don't be alarmed at volt drop. Typically for a "12v" battery they fit 3 cells in series which then stat at 12.3v but can fall to 9v in service.
good luck with the power pack ol'will
Click to expand...

Mine has done very well with a Land Rover engine...2500cc 4 pot diesel so that's 625cc per cylinder, and a Porsche 2700cc petrol 6 pot at 450cc per cylinder. Both had absolutely stone dead batteries...the Porsche had a least one failed cell.
 
CLB said:
On mobo's I would say the average is somewhere around 3 litres, with plenty that are much larger.
Click to expand...

But some of boats with 'much larger' engines will have generators. Start that, and charge a battery for the main engine. Or twin engines, in which case there's not much excuse.
And some bigger engines might have decompressors, so not so hard to start with a weak battery?

But I think owning a jump pack is mostly going to be justified for use on multiple cars rather than your own boat?
 
CLB said:
On mobo's I would say the average is somewhere around 3 litres, with plenty that are much larger.
Click to expand...

I've just competed an engine room re-wire on a boat with two 6 litre diesels.

Each engine has it's own battery. Each engine can also be started from the other engines battery, or from the domestic bank.

If by some inconceivable circumstance all three banks were discharged and unable to start the engines the generator will power the battery charger.

Not really much need for a jump pack on a carefully planned installation.
 
You must log in or register to reply here.

Other threads that may be of interest

W
Battery suicide
Replies
17
Views
598
Refueler
Refueler
Y
The Seafarer 700 and NASA clipper sounders saga
Replies
10
Views
439
Dellquay13
Dellquay13

Share this page

Top