72V 100A 60Ah 4.3kWh 10s24p 200lbs.....

[miked826]

No need to ask, it's 280A continuous rated multiplied by 74v nominal to make 20.7 kW discharge capable. HOWEVER, I would be hesitant to do that with the cells packed so tightly together with no method of heat removal.

Agreed. No doubt about that. What kind of BMS would you need to keep all those batteries in check voltage wise?

I was trying to skirt the whole BMS thing on my Turnigy's cause I know that is gonna be costly, but not near as costly as having a battery pack go up in flames for whatever reason. LOL

 

[miked826]

Jayls5 whatever you finally come up with will work for me cause our systems are closely matched. You know more than I do cause these LiPo's are new to me. I know I need a proper HK charger/balancer/discharger with a separate power supply, cause what I'm doing, with what I got, just ain't gonna do.

 

[Jayls5]

Yeah, I'll cover more details when I'm finalizing stuff. I am going to fireproof my case to give me added time to escape in the event of thermal runaway.

Anyways, I found one of my abused cells to drain... and the balancer seems to be doing things correctly so far:

 

[miked826]

Yeah, I'll cover more details when I'm finalizing stuff. I am going to fireproof my case to give me added time to escape in the event of thermal runaway.

Anyways, I found one of my abused cells to drain... and the balancer seems to be doing things correctly so far:

If that's what you call abuse, then you would probably call the cops on me to haul me away if you saw my battery readings. LOL

 

[Jayls5]

If that's what you call abuse, then you would probably call the cops on me to haul me away if you saw my battery readings. LOL

Just snapped another picture. One cell has now matched the other bottom cell and is no longer being discharged like before. Seems it's working exactly as it should. The last 2 are still being drained to meet the others:

I don't know what to tell ya man. I jump started cars with this one. What on earth did you do with yours?

 

[miked826]

Just snapped another picture. One cell has now matched the other bottom cell and is no longer being discharged like before. Seems it's working exactly as it should. The last 2 are still being drained to meet the others:

I don't know what to tell ya man. I jump started cars with this one. What on earth did you do with yours?

I never got a chance to do squat with mine but let it sit, unmonitored for about a month or so. I have two 37v batteries. One of them holds up much better than the other as far as letting it sit neglected for long periods of time.

I have not been able to charge every cell to 100% ever since because I can't level all the cells evenly using the crap passive balancers that I have.

 

[biknut]

No need to ask, it's 280A continuous rated multiplied by 74v nominal to make 20.7 kW discharge capable. HOWEVER, I would be hesitant to do that with the cells packed so tightly together with no method of heat removal.

Thanks Jay. I was wondering that myself. His bike is limited to about 100A. High speed cruising will see about 55A. Normal cruising at about 30 to 40 mph is around 30-45A.

Does that seem reasonable for this type of battery pack considering dependability, and lifespan?

Mike, he's using a BMS that monitors 14, 20 cell packs.

 

[miked826]

Thanks Jay. I was wondering that myself. His bike is limited to about 100A. High speed cruising will see about 55A. Normal cruising at about 30 to 40 mph is around 30-45A.

Does that seem reasonable for this type of battery pack considering dependability, and lifespan?

Mike, he's using a BMS that monitors 14, 20 cell packs.

100A is pretty dang good for any battery pack for an electric bicycle and should do good in limiting excessive heat. Could probably be set to double the amp release that the Bomber currently comes with and those batteries can be custom designed to fit any space cavity. Most prebuilt battery packs from China don't even come close to that kind of power release.

Your Bomber would take off like it was shot out a cannon at 100A. LOL

 

[biknut]

100A is pretty dang good for any battery pack for an electric bicycle and should do good in limiting excessive heat. Could probably be set to double the amp release that the Bomber currently comes with and those batteries can be custom designed to fit any space cavity. Most prebuilt battery packs from China don't even come close to that kind of power release.

Your Bomber would take off like it was shot out a cannon at 100A. LOL

Just like Jay said, the owner calculates 280 amp continuous, and 420 amp burst. His Bomber runs 60 mph plus.

He's replaced his controller, and cycle computer with an Adaptto. I really don't care about running the kind of power he has, my stock power already is way enough to get me in trouble. All I want is the ah. He said I can just slap this kind of battery in my bike with no changes to my controller. That's what I'm talking about.

https://www.youtube.com/watch?v=IvzJxmwVMv0

 

[Dan]

oh man. that was cool, BN.

 

[biknut]

Just like all bikes it's always about compromise, and it's no different with battery's. I ask about the differences with his battery, and the stock battery. He charges his pack to 84v, but the stock battery charges to 87.6 v. On the surface it looks like the stock battery is stronger, but he explained to me it's not. It had to do with the chemistry of the battery's.

LiFeP04 (LFP) vs Lithium Manganese Cobalt (LMO),

On the plus side the LFP has decent power density, and long life, and fairly low internal resistance.

The weakness is even though it charges to 87.6v hot off the charger, as soon as you put a load to it, the voltage drops almost instantly to about 80v. Because of the internal resistance, when you whack the throttle the voltage sag is about 10v.

The LMO in comparison has greater power density, and less internal resistance. The trade off is less cycle life.

Hot off the charger the LMO doesn't drop blow 84v for about 10 km, and then settles to about 80v. Sag under full load is a lot less. about 2, or 3v, instead of 10, so acceleration is better in comparison.

I'm not really planning to change any of my limit settings, I'm mainly only interested in the greater ah capacity, but a little better acceleration won't hurt anything either.

People in the know are paying less than $6.50 for these cells, so 280 cells x $6.50 = $1820 for 35 ah, which is about twice the size of the stock 18 ah battery which costs $2600 for the factory.

 

[Jayls5]

This is right as the balancer was finishing up. Only 1 cell left, and getting close to matching the rest that aren't being actively discharged:

MikeD, I think the inability to charge is the result of cells in your pack with uneven impedence and/or capacity. The crappy ones will charge first, and then the balancer tries to drain it as you continue charging the pack in series to finish up the other cells. You're right that these passive balancers don't drain fast enough, but neither does my nice 400w turnigy balance charger on my crappier abused batteries. By your own admission, yours are in even worse shape, so a better charger might not be the solution to your problem. I think your current LIPO batteries just aren't in the right shape to wire them into a bigger pack.

 

[Jayls5]

People in the know are paying less than $6.50 for these cells, so 280 cells x $6.50 = $1820 for 35 ah, which is about twice the size of the stock 18 ah battery which costs $2600 for the factory.

Well, let me tell you why I picked my 14.8v 5 AH LIPO packs. They're about $25 a pop after shipping. That's ~$875 for the exact same pack size, and their specs have been shown to be accurate. You just have to figure out how to arrange it and connect everything together. It already has balance wires on them and everything, unlike 18650 cells. The downside is they're more dangerous if you don't know what you're doing. I spent a little bit of money making a fireproof enclosure with ceramic insulation, but even after all of the drawbacks it's crazy cheap by comparison.

 

[Goat Herder]

You gotta do another home renovation. I wanna get your feed back on that controller! Buy it Bikenut!

Still think that's kinda quiet. Might wanna play me some orchestra music when running through town lol. Meh Ice cream truck tunes heh heh.

That bike was freak'in insane fast. I liked the hands off the bars at 85 KPH. Still have to make a video of my sack of dog food draped over my handle bars at 40 plus MPH lol.

 

[biknut]

Well, let me tell you why I picked my 14.8v 5 AH LIPO packs. They're about $25 a pop after shipping. That's ~$875 for the exact same pack size, and their specs have been shown to be accurate. You just have to figure out how to arrange it and connect everything together. It already has balance wires on them and everything, unlike 18650 cells. The downside is they're more dangerous if you don't know what you're doing. I spent a little bit of money making a fireproof enclosure with ceramic insulation, but even after all of the drawbacks it's crazy cheap by comparison.

I've looked at those battery's Jay. The problem for me is no matter how you slice it, the pack ends up being to big to fit in my frame. I figure about 20 ah is all I could get in there.

With 18650 35 ah is proven to fit, and that's just the 2500mah. LG also has 18650 3400mah which could allow up to 40 ah, but I don't know if the chemistry is the same, or as desirable.

 

[biknut]

You gotta do another home renovation. I wanna get your feed back on that controller! Buy it Bikenut!

Still think that's kinda quiet. Might wanna play me some orchestra music when running through town lol. Meh Ice cream truck tunes heh heh.

That bike was freak'in insane fast. I liked the hands off the bars at 85 KPH. Still have to make a video of my sack of dog food draped over my handle bars at 40 plus MPH lol.

Well his bike is the tits, but I'm telling you, my hinny is already hanging out just riding 50 mph on the streets. I pushing the envelope as it is lol. I guess someday I might get crazy, but hopefully I'll get too old first.

His controller is a super quiet, full sine wave, but heck, mine is pretty darn quiet too. I like his Adaptto computer though. He can monitor the 14 data lines on his bms through it. My CA won't do that. He can also monitor his motor temperature with it. It's really pretty slick. That stuff comes from Russia.

 

[Jayls5]

I've looked at those battery's Jay. The problem for me is no matter how you slice it, the pack ends up being to big to fit in my frame. I figure about 20 ah is all I could get in there.
.

Really? That's surprising.

The LIPO pack is 139mm x 44mm x 43mm. It's capacity/voltage is equivalent to 8 of those 18650's. It is larger, but I didn't think it was that much of a difference.

 

[biknut]

Really? That's surprising.

The LIPO pack is 139mm x 44mm x 43mm. It's capacity/voltage is equivalent to 8 of those 18650's. It is larger, but I didn't think it was that much of a difference.

My battery area in my frame is 14x6x4.5 The 4.5 could be stretched about 1/4"

To tell the truth I'm afraid of the lipo's. Even the non protected 18650 seem a lot safer, especially for my questionable experience/skill level.

 

[Jayls5]

Oh... touché. I didn't really think about inexperience combined with several killowatt hours of volatile energy between your legs. I'd probably opt for something else in your shoes as well. Mine's going to be conveniently behind me and protected.

 

[miked826]

This is right as the balancer was finishing up. Only 1 cell left, and getting close to matching the rest that aren't being actively discharged:

MikeD, I think the inability to charge is the result of cells in your pack with uneven impedence and/or capacity. The crappy ones will charge first, and then the balancer tries to drain it as you continue charging the pack in series to finish up the other cells. You're right that these passive balancers don't drain fast enough, but neither does my nice 400w turnigy balance charger on my crappier abused batteries. By your own admission, yours are in even worse shape, so a better charger might not be the solution to your problem. I think your current LIPO batteries just aren't in the right shape to wire them into a bigger pack.

There's no sense in going with more of these batteries when yours do the exact same thing for much less money. Is there an HK charger that exists that can actually isolate a single cell and charge it up or down? That is what I need.

Your eBay balancer is actually light years ahead of the 2 that I got at HK if you can believe that. LOL