Member Contributer DannoXYZ Posted November 27, 2020 Member Contributer Share Posted November 27, 2020 A lot of people are over-building their packs with higher-capacity than necessary due to comparing to outdated CCA-ratings of lead-acid batteries. First, some background on CCA: CCA - cold-cranking amps is rating of lead-acid batteries to deal with loss of power as temperatures decrease. At -10 degrees, a lead-acid battery will have only 25% of its CCA rating. So V8 needing 150-amps cranking current at low-temps, requires 4x150=600CCA battery. Just in case it's ever needed to be started in cold-weather. Since I lived in Santa Barbara for so many years, I never needed cold-weather starting. So I just used a motorcycle battery in my V8 5.0 Mustang convertible for ages (until I sold POS car). However, more accurate numbers would be to measure actual starting-current needed by engine: 130-150a = V8 +5.0L auto-engine 70-90a = typically I4 auto-engine 50-70a = V4 moto engine 30-40a = 250cc twin moto engine 20a = 125cc moto engine Note that starters "suck" power from battery when cranking, I=V/R. Starter circuit will only suck as much power as determined by windings in starter and load imposed by engine. Bigger batteries with higher CCA doesn't force more power through starting-circuit. It just gives more potential in colder weather. Or lets you crank engine for 30-minutes instead of 5. So single 4-series pack of 26650 cells with 120a 10-sec burst output is more than enough. Link to comment Share on other sites More sharing options...
Member Contributer Gebruiker Posted November 28, 2020 Member Contributer Share Posted November 28, 2020 17 hours ago, DannoXYZ said: how to build your own (you actually only need 4-cell series pack): The bits are semi-cheap on EBay. But with my limited tech abilities, here's my next question...Can I just buy this at Costco for 50 bucks, cut off the alligator clips, and install it as my battery? Will it work? Will it charge? Will it set the bike on fire? (Costco has a terrific return policy. They might even give me back my $50 if it explodes...) Link to comment Share on other sites More sharing options...
Member Contributer DannoXYZ Posted November 28, 2020 Member Contributer Share Posted November 28, 2020 sure that'd work. You can test it before modifying by just removing battery and use the alligator clips to attach to harness battery cables. Be sure to keep them separated and insulated from each other. You'd do something like this: Link to comment Share on other sites More sharing options...
Member Contributer Gebruiker Posted November 30, 2020 Member Contributer Share Posted November 30, 2020 On 11/28/2020 at 10:49 AM, DannoXYZ said: sure that'd work. This would be a great improvement! I don't actually need a new battery just now, but Christmas is coming and a jump starter might be a terrific gift from me, for me. And then, when I do need a new battery for the VFR... 🤔 Link to comment Share on other sites More sharing options...
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