Author Topic: Smallest battery that will still turn starter?  (Read 2362 times)

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Offline Scott S

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Smallest battery that will still turn starter?
« on: January 22, 2014, 02:22:49 AM »
 I've been reading through a lot of the "cleaning up the triangle" threads. I finally found a titled frame for my next CB550 project and it's already been de-tabbed, so I guess I'll be going a little more custom than I originally planned.

 For a couple of reasons, I'd like to be able to keep the electric starter. I can mount the battery on the swing arm and, possibly, depending on size, under the seat/hump. The seat I have planned has a somewhat lower café hump that usual.

 I was talking to a friend about his kick only Harley, and he's running an 8 cell Ballistic. He says his friend with a 74 cu. in. Harley has the same battery and it works fine with the "electric thumb".

 Is there a battery that is small enough to hide and still run the starter?
'71 CB500 K0
'17 Triumph Street Scrambler
'81 Yamaha XS650

Offline dusterdude

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Re: Smallest battery that will still turn starter?
« Reply #1 on: January 22, 2014, 04:20:04 AM »
I would think a 9bs series battery would turn it over,i use one on my gl1100 wing and it works good


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1972 k1 750
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Offline flybox1

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Re: Smallest battery that will still turn starter?
« Reply #2 on: January 22, 2014, 07:04:46 AM »
Recent thread...these batteries are small and light compared to oem.

http://forums.sohc4.net/index.php?topic=133480.0
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

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Offline Scott S

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Re: Smallest battery that will still turn starter?
« Reply #3 on: January 22, 2014, 07:05:02 AM »
 Sweet. It's good to know there are options out there. I guess I still have to run a wire that's heavy enough to handle the amps. And hide the starter solenoid somewhere.
'71 CB500 K0
'17 Triumph Street Scrambler
'81 Yamaha XS650

Offline andrewk

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Re: Smallest battery that will still turn starter?
« Reply #4 on: January 22, 2014, 06:45:40 PM »
I've found the "4 cell" ballistic to be insufficient for electric start bikes, but no problems with kick only.  I think for best performance you want something about 12ah equivalent, if not 15.  The A2 Shorai mentioned above is one of the better candidates, I think.

Offline Garage_guy_chris

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Re: Smallest battery that will still turn starter?
« Reply #5 on: January 22, 2014, 09:38:18 PM »
If you can measure the starter draw with a DC clamp on ammeter while starting, that will give you a reference point on how many Cold Cranking Amps or CCA / Cranking/Amps CA are required and will let you size a battery accordingly.

Your CB550 uses the same 12ah 180cca battery my CB450 uses so this may help. I have a CB450 that i reduced the battery from a 12aH 180cca battery to a 7aH 110cca battery and if its cold (reduced capacity/more internal resistance in the engine) it doesnt have enough juice to crank it. Also with lead acid batteries, they loose capacity through use and wear so consider it wont last as long till it doesn't have the output to crank it over. I havent got more than 2 years out of a battery yet on my bike, Next im gonna have to try a shorai or something to get some extra capacity in a smaller package.
1971 Cb450 Cafe  (on the road)
1974 Cb750 Restomod (on the road)