Its worth noting that you can actually discharge a lithium battery almost to zero percent and it will still have a good voltage and not damage it whereas a flooded/agm/gel battery is pretty much done at 50 percent or so discharge ... I learned this through using my mobility equipment , I imagine its the same for starter  batteries as well as  deep cycle ... In effect lithium a lithium of 6ah should be similar to a standard battery of 12ah... please correct me if i am wrong ... good luck

You have to be more specific when you say "Lithium". Do you mean Lithium Ion, Lithium Polymer or Lithium Iron Phosphate (LiFePO4)? I suspect you mean the latter, in which case I tend to agree that it will tolerate much lower discharge voltages than the other types mentioned. Btw, LiFePO4 is a type of Lithium Ion battery, but it's preferable to differentiate between the two types.

A123 (LiFePO4) cells are used in Dewalt cordless drills and they are known to tolerate deep discharge states.

Yes , I meant the LifePO4 batteries... As the batteries are made of smaller cells it would be possible to make a pack to fit the space available as well .. cheers

I have a Shorai LiFe and it's got 18ah. I can fail to start 10/20 times and it's still good to go after a little run time.

1.8Ah is a bit small for 500cc in my opinion. Mine is 3.8Ah and it works fine in warmish weather. I wouldn't want a smaller capacity battery.

Mind you, two of those 1.8Ah's, in parallel should work great.

Take care! Other type LiPo batteries will most likely be junked after over discharging. They'll swell up, with a chance of explosion.

That's good advice. LiPo (Lithium Polymer) cells are not safe for use in vehicles. LiFePO4 OTOH is quite safe, but I would still recommend using a BMS (battery management system) if making up your own battery pack.

My Shorai LiFe is rated 18ah.

Quote from: struckjm on February 14, 2021, 01:12:08 PM
My Shorai LiFe is rated 18ah.

Sorry for wrongly assuming 18Ah was a typo. That is not a small battery.

Then I don't understand why it should have problems starting a 500cc engine. Or maybe you mean if the engine doesn't start immediately, it has enough juice to try a few times. At 18Ah it should have. That's double the capacity of a stock GS500 battery.

Mine is only 3.8Ah - nearly 5 times smaller and it starts my GS500 with ease - every time.

i have a non running bike with a Shorai in it. A tribute to the duration: I can fail to start the bike (for other reasons) ten times in a row, and it's still at 13v.