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Discussion Starter · #1 ·
Recently the 4 year old battery on my bird would not start my bike and I came to find that AAA will not jump start a motorcycle, but they will tow it instead :-(

So I waited and waited for a tow and a guy in the store offered to jump me and I cancelled the tow.

That said, I'm thinking about getting a small jump starter to stow in the "trunk" of my Corbin smuggler saddle for the bike only as I have a large one I keep in my truck for just such an occasion. Does anyone here have a small jump starter that they had luck with?
 

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Hi Gnappi,

Have a read through this thread

Covers:
a) cheap mini powerbanks capable of jump starting BBs
b) more expensive top quality versions
c) bike batteries with "built in" jump start button (albeit these bats are expensive)

I personally have a) and c) and have had success with both.

Rgds Mallow1
 

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As an aside I've even seen how to jump start using a fist full of AA batteries in an emergency. That's possible but much less advised (you connect sufficient AAs in series, attach to flat battery, leave for long enough to "trickle charge", disconnect then start… so not a true "jump start" more an emergency charge boost. If you try to jump start with AAs you'd prob fail and may set them on fire).
 

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You can bump start the bike reasonably easy. If someone is about just get them to push you. If there's a bit of an incline sit on and scoot it along before dumping the clutch.
 

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I have had an Anti-Gravity MicroStart for several years. Have not used it much, but when I have, it has worked well. Spun over my brothers Duramax diesel in sub zero weather.
Best thing about it is that it will maintain its charged status for several months if not used. Prevents finding it dead when needed.
 

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Discussion Starter · #6 ·
I decided that I have so many 18650 batteries here to make my own to fit the smuggler. At the very least I know it will work :) It will take some time to source some of the parts I need but after it's built I'll post it here.
 

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I decided that I have so many 18650 batteries here to make my own to fit the smuggler.
This chap did one for his car from 18650/ AA batteries. He at least shows his maths though the form figure of his device could be compressed a lot.
Plus the device is a charge booster not a true jump starter (unlike the devices in my link).

Would love to see your project once built. I love such diy projects!
 

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He at least shows his maths…
So for a flat battery how much energy (watt hrs) do we need in it to provide say a cold cranking amperage (CCA) of 400A for 3 secs at 12V?
Energy(Wh) = Amps(A) x Volts(V) x Time(h)

So noting that there are 3600 secs in 1 hr gives:
Energy = 400 x 12 x 3/3600
= 4Wh

That's his calc for a 1.8 L small/ medium car engine. For our BBs I'd say 250 x 14 x 3/3600 = 2.9Wh. So say an energy need of 3-4 Wh is in the right ball park with voltage north of 12v and ideally south of 15v.

An average AA is 1.5V so 9 in series is 13.5v… which looks perfect.

An indicative capacity of an AA is 2500mAh or 2.5Ah so 9 of them in series gives (9x1.5v) = 13.5v:
Energy = 2.5 x 13.5 = 33.75Wh

So there is about 10timed the energy needed. So if the flat and tge AAs were connected, the AAs can act as a charger for the flat battery. The video shows tgat 30 mins ought to he sufficient to transfer enough energy from the AAs to the flat to get it to start a BB. I wouldn't be on a hurry however to try to "jump start" from such a diy array of AAs, only "recharge" over time.
 

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The upside of a. through c. in my earlier post is that all three can provide an instant "jump start".
 
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