Building an EV motorcycle. Batteries: Need opinions.

[TurnNBurn]

Originally Posted by Ryland

I haven't searched for issues with Alltrax controllers but when I read about EV's I see that there are people who have 1000's of miles on them with Alltrax, then I have people walk up to me and start going off on how their Kelly controller failed and meet people who's Kelly controller looks like someone took a cutting torch to it and see the other damage it caused and I look around for people who are HAPPY with the Kelly controller and I fail to find the happy EV builders other then a few people who have way over sized Kelly controllers on E-bikes... way over sized on a bicycle, not hard to do.

But that is why EValbums is nice, you sort by part brand and you see everyone who has it and you see how it performs and you see their notes about issues.

Yeah, I use EValbums a lot as a reference. I do find it hard to find a kelly controller on there. That's why I chose Alltrax. It was the most popular.

I've got an ad up in the classifieds now for the motor. I'll be downgrading to the ME1003 an keeping the Alltrax 7245. Do you know if there's an way to squeeze more than 72V out of a motor rated at only 72V? I've seen people take the 96v rated ME0913 and get more out of it.

[Ryland]

Search by Controller Brands

[TurnNBurn]

I have a question now regarding speed and the ME1003 motor.

Endless-sphere.com • View topic - The "Juice Cafe" Racer. From start to Ton up!

Regarding that link the guy used an Alltrax 450 controller and a ME1003 motor, the same motor I'm going with now. He achieved 100+ MPH. I was told 72V motors (depending on gearing) would max out around 75-85 MPH. How would he be able to achieve 100+ mph?

[Ryland]

Originally Posted by TurnNBurn

Regarding that link the guy used an Alltrax 450 controller and a ME1003 motor, the same motor I'm going with now. He achieved 100+ MPH. I was told 72V motors (depending on gearing) would max out around 75-85 MPH. How would he be able to achieve 100+ mph?

It's hard to say, but Lithium batteries operate in a narrower voltage range then lead acid, a 72v lead acid battery pack could be over 90v when you pull it off the charger.

In terms of 12v batteries their voltage can range from 15.5v under an equalize charge and stay at that voltage for a few minutes dropping down to about 15v until you put a load on them, under high load that voltage can drop down as low as 10v.
So the 72v speed controller is designed to handle that peek voltage, but lead acid also sags a great deal under load, it could sag down to 60v under high load, a 72v lithium battery pack that just came off the charger should only be around 79v or even a little less, so a higher voltage lithium pack that is at 90v off the charger it will sag under load to around 82v and the 72v 450amp Alltrax should handle that just fine and allow the motor to put out around 49hp for two minutes (controller rated 450amps for two minutes) at that point you're going full speed and you could bypass the speed controller with a contactor that closes at full throttle.

So if you had lead acid batteries and an Alltrax 7245 controller your motor would put out a peek of 36hp because of voltage sag compared to that 49hp that the lithium batteries could pump out of that same motor.
You were asking why lithium batteries might be better then lead acid before, right?

[TurnNBurn]

Originally Posted by Ryland

You were asking why lithium batteries might be better then lead acid before, right?

Yup! I think I'm going with lithium batteries. I may go with those earlier mentioned prismatic cells. 20ah, though. I was hoping for at least 40ah.

[Ryland]

Originally Posted by TurnNBurn

Yup! I think I'm going with lithium batteries. I may go with those earlier mentioned prismatic cells. 20ah, though. I was hoping for at least 40ah.

Make sure that they can handle the discharge rate you are going to give them, I almost bought some 20ah cells then realized that they could only handle a 100amp discharge and at crusing speed my motorcycle draws 120 amps and can draw up to 300+ amps, that is why I like my current batteries so much, they can handle 1,000 amp discharge for a short time and a sustained 300amps, so many times above what a motorcycle would draw.

[3-Wheeler]

Originally Posted by TurnNBurn

....I'm down to 3 battery choices: Lead-acid, LiFePO4, and LiPo.

On endless sphere everyone (literally EVERYONE) pointed me away from lead acid....

I'm not a battery expert!

I have an Insight NMH battery pack that I am current testing sticks for discharge and capacity, along with self discharge. So I like NMH cells.

However I have been reading in Wards Auto World that *some* of the major manufacturers in considering *going backwards* to hybrid Lead-Acid-Super-Capacitor batteries.

Why?

Lithium battery cost is still way high, AND there are issues with ambient temperature sensitivity with NMH and Lithium chemistries. Mine lost 40% capacity last year due to my foolishness of daily trickle charging and use in high Wisconsin summer heat. Lesson learned!

*Lowly* lead acid seems to be making a comeback.

Jim.

[TurnNBurn]

Originally Posted by 3-Wheeler

I'm not a battery expert!

I have an Insight NMH battery pack that I am current testing sticks for discharge and capacity, along with self discharge. So I like NMH cells.

However I have been reading in Wards Auto World that *some* of the major manufacturers in considering *going backwards* to hybrid Lead-Acid-Super-Capacitor batteries.

Why?

Lithium battery cost is still way high, AND there are issues with ambient temperature sensitivity with NMH and Lithium chemistries. Mine lost 40% capacity last year due to my foolishness of daily trickle charging and use in high Wisconsin summer heat. Lesson learned!

*Lowly* lead acid seems to be making a comeback.

Jim.

Lead-Acid Battery Gets Second Look | Suppliers content from WardsAuto

[Ryland]

Originally Posted by 3-Wheeler

However I have been reading in Wards Auto World that *some* of the major manufacturers in considering *going backwards* to hybrid Lead-Acid-Super-Capacitor batteries.

Lead acid batteries may be something that some manufacturers are looking at improving, but I don't know of any that are looking at using off the shelf lead acid batteries in vehicles, the lead acid batteries that any of us can buy right now are a poor choice for a vehicle that you want to take highway speeds.

NmH batteries also seem to be a decent choice fore hybrids because they handle short quick discharges and recharging ok, but people who have tried to stack up hybrid packs to power an all electric vehicle seem to have them fall short, one of our EV club members who refurbishes hybrid battery packs has tried putting them in his electric car from time to time and said that they give poor performance under sustained driving.

[TurnNBurn]

I have a question regarding Lipo. If I can get. a few packs together that are 45000mah and 3.3 volts AME combine them into a pack (groups of 4) to make a 12 volt pack, would that be a significant replacement for a single 12v lead acid battery?