I have just purchased an Anker 20,100 power bank. I also have a compact jump starter that has a 13,600 mAh capacity.
I assume that the Anker would charge more devices than the jump starter. Is there a greater voltage output from the jump starter so that it will start a car with a depleted battery? I would have thought that the jump starter would have a greater mAh capacity than than normal power banks we use to charge our iPads.
Would someone help me understand?
Thanks, Jerry
Isnt it amps?
car needs a lot for a short time at 12-13V
powerbanks give 1-2A at 5V for a long time
There was a BLFer who jumpstarted his car with a bunch of 18650 ells in series
Yes, it is amps, and I guess that we could not get the amps from our normal power banks.
Thanks, Jerry
They use different cells:
-The powerbank uses 18650 cells all in parallel, most likely 6x 3,350mAh = 20,000mAh
-The jumpstarter uses high discharge LiPo, 3x in series for 11.1V nominal, 12.6V fully charged
18650 cells are safer, but they have very limited output current, generally less than 3C.
LiPo cells on the other hand, have lower internal resistance, and can put out much higher current, some can reach up to 100C.
They work differently:
-The regular powerbank has a boost circuit to convert the 3.7V into 5V output.
-The jumpstarter has a buck circuit to convert the ~12V into 5V, and additionally an direct output from the LiPo batteries, this is what allows it to “start” the car. Your 13,600mAh jumpstarter should have 3x 4,500mAh LiPo cells in series, and if rated at 40C they should provide 180A continuos, and probably 3 times that much in burst.
The reason why jumpstarters are more expensive is because they come with a protection circuit that triggers in case of reversed connection to the car battery or short, otherwise it would explode. They also require integrating a balancing charger because the cells are in series.
Keep in mind that these jumpstarters doesn’t actually start the car, they just aid your existing car battery to crank the starter motor, they won’t work on a fully dead car battery. Regular flooded car batteries are rather old tech and they usually won’t provide enough crank amps at <60% capacity, this is why better options exists nowadays such as SLA deep cycle AGM or GEL.
I have a RavPower 14,000mAh jumpstarter rated 600A, and fully charged it was able to quickly start my 2.4L 4I engine 3 times. After the 3rd attemp I needed to leave it connected much longer, the powerbank still had plenty of capacity, but it was the car battery which was discharged.
I hope this answers your question. 
Just a note on needing existing car batteries….to test mine since the car battery was fine, I disconnected it. It started a 1.5L Honda engine with no Pb battery involved at all. Then it did it again. And again. Then I stopped trying.
That is not a large engine and I could tell it had to work a bit. It generally does start pretty easily. If it needed a lot of cranking I doubt it would have worked.
In theory some of the car starters could use 18650 cells. Cells like thr vtc4 are 30 amps. Even enough 20 amps cells wouldn’t be a very big package. And don’t usually need even 600 amps to JumpStart. It would be interesting to see a teardown of several different models to see 18650 vs lipo pouches.
Hi will34,
Thanks a lot for your detailed an clear explanation. Just what I was looking for.
Thanks to All for the help. Each post adds to my understanding.
Best regards,
Jerry