Making a battery for a conventional motorcycle

[Spence /1/]

Alright so I want to get rid of my huge lead acid battery on my cycle and replace it with a new technology a123 battery pack. I was thinking of using 4 cells wired in series to give a 4S ~13.2v pack, The Ahr shouldn't matter as once its started it is self sustained. I'm not sure what amperage my starter draws,but I think a 120A pulse (10 sec) would start it no problem. I am also wondering how can I make a BMS for this? (I'm assuming all I really need to do for the BMS is regulate the voltage and make some way to charge and balance charge it?)

I basically want to make this battery pack, but using the a123's it will be even smaller and more dependable.

Link to sale site of similar pack: http://www.amazon.com/BALLISTIC-PERFORM ... +2+battery

Link to technical specifications of similar pack: http://www.partscanada.com/files/produc ... 0flyer.pdf

Thanks,
Spence

[SamTexas]

I'm not sure what amperage my starter draws,but I think a 120A pulse (10 sec) would start it no problem.

Depend on the size of your motorcycle engine. But 120A is plenty for a motorcycle. If you look at the main leads on your existing battery, you know those wires are too small to handle 120A.

Link to technical specifications of similar pack: http://www.partscanada.com/files/produc ... 0flyer.pdf

I'd love to get my hands on one of those so I can explore their BMS. I hope their BMSs are better than the junks we have in ebike batteries.

[frodus]

They don't have a built in BMS, they have a balance port and balance charger.

I use a Blinky Balancer for A123, works perfect and they're about $30 or so... but it's overkill since it's only 4-cells.

I'd suggest just forgetting about a BMS and just use a balancing charger once in a while... since you don't use the battery much (except for starting), it shouldn't really go out of balance quickly. Just get a decent balancing charger and be done. That's what 95% of the aftermarket lithium motorcycle battery manufacturers use (Ballistic is only one, there's other like Shorai).

[SamTexas]

Thanks frodus.

So no BMS. Do they have Low and High voltage cutoffs?

[frodus]

Reading the datasheet (hint hint), it does not mention LVC or HVC..... Larger traction packs, I'd say that'd be useful, but I don't really see the point. It's not a traction pack, it's just to start the engine. If it can't turn it over, it's dead, just like any other motorcycle battery..... charge it up and you're good.

It's JUST a battery in a purty case with high power terminals. That's it.

[SamTexas]

It's not that simple frodus. For auto/motorcycle application, HVC is very important. Alternators/generators highest voltage are not the same. They don't cause that much trouble with Lead-Acid battery because LA battery can tolerate overcharge very well. Lithium battery don't do that. Overcharging will significantly reduce life cyle and/or kill the battery.

[frodus]

I get what you're saying, Was thinking more LVC sorry..

Call Ballistic then.... find out for us.

[SamTexas]

No need to call them. They don't have HVC. The following are from their Instruction Manual (hint, hint):

Standard Charge: 2A @ 13.2-14.4V for approximately
45 minutes or until the battery registers 14.4V.

WARNINGS:
Do not charge a Ballistic Performance Component
Battery above 14.4 Volts. This could damage the
battery.

http://www.ballisticparts.com/downloads ... ctions.pdf

That's bad news. I have seen more than one cars with alternators generating 15V.

[frodus]

I know it was in the instruction sheet.... "call them" was my way of being sarcastic....

[Spence /1/]

So it is indeed feasible to make a a123 pack using 4 cells to start a 400cc 1980 yamaha XS400; with the only modification to the battery pack is a overcharge protector? (possibly a discharge protector just in case would be nice also) This pack should have enough juice to run the starter for 2.5min just to give you an idea of the dependability.

Also how would I make a port for this charger using the 4 Series port?; it uses a 5 pin wire.

http://www.amazon.com/Battery-Balance-C ... sbs_auto_2

[frodus]

You could make a clamping circuit for the rectifier.... so if it goes over 14.4V it gets clamped, or limited.

You can use a 4 pin port.... the negative (or positive) is the fifth wire.

And 120A for 2.5 minutes is ~5Ah.... and that'll be ~52C discharge. You'd get less than half the AH out of a 2.3Ah M1 cell if you ran at that high of a discharge. If you need 2.5minutes at 120A, then you're going to have to build a larger battery (think 4s3p).

[SamTexas]

So it is indeed feasible to make a a123 pack using 4 cells to start a 400cc 1980 yamaha XS400; with the only modification to the battery pack is a overcharge protector? (possibly a discharge protector just in case would be nice also) This pack should have enough juice to run the starter for 2.5min just to give you an idea of the dependability.

And 120A for 2.5 minutes is ~5Ah....

My educated guess is around 30A draw for that mid size motorcycle. 2.5min??? Not continuous, I hope. Starters are not designed to be run that long. If my bike doesn't start after 10 secs, I stop.

[Spence /1/]

I didn't mean continuous lol, I was just stating that a 4s 2.3ahr pack could do run the starter for around 2.5 min (at a 30-40A draw), that these a123's are ridiculously dependable, the 4s pack could never do 120A for 2.5min because it would overheat and explode..

[Spence /1/]

It looks like the rectifier on my bike is regulated to put out 12v constant, so all I really need to do is hook up a 4s pack and it will be good to go?


also im still confused about the balance charging method..

This is what and how ballistic uses to charge their pack:

http://www.youtube.com/watch?v=Hc9kcGI1 ... re=related

[SamTexas]

It looks like the rectifier on my bike is regulated to put out 12v constant, so all I really need to do is hook up a 4s pack and it will be good to go?

That's not possible unless your bike generator/alternator is broken. 12V is not enough to charge a 12V lead acid battery. Around 13.7V is usually the minimum. The generator/altenator voltage for motorcycles and cars usually vary with the engine rpm. The 12V you saw is probably at or around engine idle speed.

The only way to be sure is have a voltmeter installed so you can see the actual voltage under various conditions. That said, you are probably ok as most generators/alternators don't go over 14.4V. But again, you're the only one who can check and verify that.

also im still confused about the balance charging method..

What are you confused about?

[Spence /1/]

I figured out the balance charger; I wasn't sure how they were wired to the batteries, but now I got it.

Thanks for all the help, I will build this thing when I can order the batts from emissions free.

[marcexec]

Take a loo at my signatue for the link to my Headwaay SLI battery test - worked just fine.