Cheaper supplementary batteries?

[4bound]

I wonder if anyone had experimented with this sort of battery to supplement their ebike power. It claims to be a 12AH Lithium Ion battery for £70 which is dramatically less than an ebike battery. I am not sure how this works with different voltages - does this equate to just 4AH on a 36V battery?

There are two main issues I see.

1) is it really equivalent to an ebike 12AH battery? and
2) how could it be connected?
https://www.amazon.co.uk/ABOX-Starter-Portable-Lithium-ion-Protective/dp/B07DDBND4D/ref=sr_1_4?ie=UTF8&qid=1543606686&sr=8-4&keywords=lithium+car+battery+starter

 

[Nealh]

It's a 12v battery so only 3s, so won't do diddly on a bike. Likely to be 3 x12ah lipo pouch cells wired in series, whether each cell can deliver 1500a unlikely I would say.

I have a tiny 4ah 3s lipo which has a 65/130a rating and easily turned over my flat car battery (car not used very much <1k p.a.), following a 185mile journey the car battery has been fine and now use a small solar panel (with diode to prevent discharge) plugged in to lighter socket to keep the battery trickle charging.