Cafe Racer Forum banner

Antigravity 4cell on CB450?

1292 Views 7 Replies 5 Participants Last post by  3364
I’m trying to decide between the antigravity 4cell and the 8cell. I have a 73 CB450 and I want to use the electric start for it. Will the 4 be enough? I’d prefer the 4 over the 8 due to the size.
1 - 2 of 8 Posts
The number of cells is probably the least of your worries. What sort of regulator did you convert it over to?

If you're still running the stock charging system, a lithium battery is a bad idea. Modern battery tech does not play well with old school charging systems. Even with a modern regulator, some battery companies claim their lithium batteries should not be used on old school bikes because of the variation in the charging voltage, even if it is under the maximum allowed. And many modern aftermarket regulators specifically say they aren't to be used with lithium batteries.

At the very least you need a MOSFET regulator. The re-start antigravity batteries apparently have a BMS built in but even that isn't a fail safe. I don't know which batteries they have are 4 cell and which are 8 cell but if you're looking at the micro-start stuff with no BMS you're rolling the dice. You can kill it by running it down too far, or by putting too many volts into it. For a lithium battery, the max charging voltage is somewhere around 14.9. Does your regulator always keep the voltage below that at all rpm? Are you sure? Is there any stray drain on your bike that will run the battery down as it sits? Get it wrong and the battery is shot. No recharging. It's done. Buy a new one.

From the anti-gravity site:

The good news is, Anti-Gravity uses lithium iron which isn't as prone to flaming up as lithium ion batteries are. So if you overhcharge one, you'll likely only get some impressive arcing and really nasty smoke as it melts. It probably won't actually start burning.

IMHO a battery with no built in BMS doesn't belong in a bike. I say that as someone who's melted one down that HAD a BMS, but when you completely lose the regulator things get crazy. This took over 60 volts to melt down but a '91 Ducati has no problems doing that when things fail. With no BMS, 16 volts could eventually lead to this.

I'm running a lithium battery in an older bike that probably shouldn't be using one. I'm also running a MOSFET regulator and a volt meter. IMHO you need both of those, along with a battery that has a built in BMS to run a lithium battry in on old bike. And even then it's not "best practice".

If you must use a lithium battery;
Get a modern regulator
Install a volt meter
Don't use a battery with no built in BMS
Don't bitch when it still goes wrong.

Rough guess is you'll have about $350 into putting the first lithium battery in there. Try to cut corners and you'll have about $500 into it with the second one. Or you'll save money and find room for an AGM the second time around. Ya might want to find room for an AGM now and avoid all the costs/time of the lithium...

And what makes me think any of this can happen??? (NSFW language)

To answer your original question (sort of), buy the smallest Re-start version they have. It should turn it over fine. If it doesn't, cowboy up and use the kickstart.
See less See more
  • Like
Reactions: 1
I got the ricks motor sports reg/rec that goes to about 14.2. I just wanted to know if the 4cell is strong enough to start my 450.
Well in that case you're about five steps ahead of most newbs who post here.

I have no idea what the "4 cell" battery is. But like I said, if it doesn't have built in BMS it's a bad idea.

EDIT: I just googled it, the 4 cell looks like a previous model, I don't see it on the Anti-Gravity website but do see it at Revzilla (though it's sold out)

I think it's still available as a "Small Case" battery through Anti-Gravity, but it doesn't have BMS. It should be big enough to turn the engine over but with no BMS you're using it at your own risk.

Put it somewhere it won't take other things out if it melts down. The smoke is NASTY and you will never get the stench out of seat foam. And the arcing will ruin any paint/plastic in the general vicinity.
1 - 2 of 8 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.