Market for battery packs

[tomv]

The situation with batteries for e-bikes is truly bizare. It's pretty much impossible to buy anything ready to use except SLA. e-bikes.ca stopped selling their Nimh batteries. FalconEv does sell them, but at more than 100% markup for Nimh, and what looks like more than 150% markup for LiMn.

So after some digging on the interenet here's what I find:
- Laptop/camera makers pay arround $0.30 per Wh for their battery packs. Can't find source now.
- Chinese companies will quote something like $0.60 for e-bike specific battery pack that's pretty much ready to use. Shipping from china. Example: Thundersky.
- There are no US/Canadian distributors that will stock batteries. Some will ship chinese stuff and charge 3X. Example: FalconEV. This is 500% more than the likely possible wholesale price.
- Batteryspace and all-battery seem to be chinese companies also selling cells at 3X markup, and have US stock, but not assembled packs.

The only explanation I can think of is that there's no market whatsoever for ebikes or batteries.

Anybody have any ideas for the total market size for ebikes?
Some anecdotes:
- Wavecrest labs made a few thousand TidalForce bikes before going bust
- Segway made a 23,500 units up till 2006 (known because of their recall of every single unit). Is this the best selling EV ever?
- Giant is the only major manufacturer offering e-bike for sale that I know of. They have only one model (used to have 3).
- Schwinn makes e-bikes, but not for sale in US (liability?)

 

[mvadventure]

From personal research as to the size of the bike market I've discovered it's a lot bigger that I previously thought yet not big enough to make a significant impact on even the bicycle market. I know that's not the answer you are looking for but let me explain a little.

A friend looking for a replacement business spent the last six weeks touring S FL and W FL looking for a "virgin" tourist spot to rent ebikes. He told me every viable location already had someone there, primarily in rentals. Last I heard from him he was in Pensacola, FL headed for AL and MI to the casino areas.

Unfortunately he doesn't know a SLA from a Energizer so he was useless when it came to giving information back but I believe most of the rentals will be SLA simply because of the price factor. He did see a LOT of Mongoose's in the rental fleets. Those he can recognize.

When I explore, in my mind only, the ebike market for batteries I look at the three primary forums and find lack of knowledge and confusion is the primary potential customers face.

At the moment it's easy to buy SLA's. There are several ebike web sites selling them, any battery supply store will get them for you with NO shipping charges and the more adventurous can find old UPS batteries that will work. They have one main thing going for them, they are cheap.

None of the N batteries or the L batteries meet any of those attributes. Confusion is rampant, prices are high and availability is nonexistent. It's easy to give up and buy more SLA's. To even think of LiFePo4 batteries as an impulse buy is simply silly.

There are a lot of the Endless-sphere members who live up north where the ebike season is very limited yet they are the most die hard and dedicated on the forum. It's the same way with boating really, I guess when you only have a few months to go outside you want to make the most of them.

So, I believe someone can either go to China or use a representative and find a reliable source for LiPo, import a container load, buy a business license and liability insurance, hire a technician to install BM Systems and custom make battery packs. Coupled with a good, reliable charger, a great web site and innovative marketing I really believe the next container load will be ordered within weeks. That's how much market I think is there! Availability and price will determine the market. As soon as little Susy has a 60 or 100 mile range on her bike then little Tommy will want the same thing and if Tommy can have one shipped within 48 hours he might very well make an IMPULSE buy which is what sells stuff.

Power, reliability, warranty and price ar the issues to get the market. A vendor with a supply here in the US can ship all over, the key is supply. Right now NO ONE has any, every body orders from China when they have cash in hand and that my friend is a sorry ass way to do business.

Oh well, another rant.

Mike

 

[xyster]

Thankfully, building one's own pack from individual cells or powertool packs is not hard, though may take weeks of dedicated effort.

 

[BiGH]

Thankfully, building one's own pack from individual cells or powertool packs is not hard, though may take weeks of dedicated effort.

thats right- it depends how crazy you are with the plans. I'm planning my chargers to go into a rack mountable case, just so that i can keep it all nice and neat!

 

[bobmcree]

36v LiFePo4 pack 20 Ah $2000 including bms/charger/shipping shipped from china

these guys have what looks like the best lightweight pack in terms of cost per cycle if one is willing to spend that kind of money. buying a123 cells in dewalt packs for $100 you would need 10 packs then you need a bms and charger, so the price is really not that hard to accept.

they were advertising single packs shipped from china at the prices on this page with sept delivery buy now it has moved to october. their raptor trike is cool if you want a tractor with an easy chair attached to cruise around the trailer park at 15 mph.

http://www.lifebatt.com/LiFeBATT%20Web_4.html

 

[BiGH]

36v LiFePo4 pack 20 Ah $2000 including bms/charger/shipping shipped from china

these guys have what looks like the best lightweight pack in terms of cost per cycle if one is willing to spend that kind of money. buying a123 cells in dewalt packs for $100 you would need 10 packs then you need a bms and charger, so the price is really not that hard to accept.

they were advertising single packs shipped from china at the prices on this page with sept delivery buy now it has moved to october. their raptor trike is cool if you want a tractor with an easy chair attached to cruise around the trailer park at 15 mph.

http://www.lifebatt.com/LiFeBATT%20Web_4.html

that seems very expensive - $2k I just ordered 2x 36v 12ah batteries from brett (solar bbq) for under $1100AUD (including chargers)

 

[bobmcree]

"that seems very expensive - $2k I just ordered 2x 36v 12ah batteries from brett (solar bbq) for under $1100AUD (including chargers)"

if you can get 36v 24 Ah of LiFePo4 with a good bms and chargers and a multi year warranty that can be expected to deliver 2000+ cycles for under $900 US then why are we paying over $1000 for that many a123 cells in dewalt packs and troubling ourselves to take them apart and rebuild them?

i don't know anything about the batteries you ordered, but something does not sound right here... are his packs li-poly or li-ion? is there a link?

 

[xyster]

Even if the price were the same, considering the significant 'investment', I'd choose to tear apart LiFePO4 or LiMn powertool packs. I don't have reason to have much faith in ebike packs yet, no matter their purported specs. The portable powertool market is far more mature, and I know more precisely what I'm buying.
Small powertool cells sometimes fail too. But replacing single small cells is cheaper and easier than trying to get a pack of large ebike cells serviced. And small cells can be built into uniquely-shaped modular packs that drape over the frame for easy removal or interior access.

 

[bobmcree]

i too am tearing apart the power tool packs. the A123 nanotechnology is unrivaled even by the best chinese LiFePo4 which is what the boomerbents packs are supposed to be. i merely pointed them out as one option for folks who are not inclined to build their own system, and to illustrate that such products are starting to become available.

the $1100 Au / $900 US packs brett white (solarbbq) is selling are Li-Poly. this is the type of battery that catches fire. theirs may be the best Li-Poly around, but they still have the potential to fail catastrophically....LiFePo4 batteries are MUCH safer, and the A123 appear to be the safest of them all so far.

Li-Poly batteries people are using in ebikes are delivering just several hundred cycles, from what several users have told me. this makes them much more expensive in terms of cost per cycle than the newer technology that should deliver thousands of cycles.

 

[Ypedal]

Batteries... well..

I think Mike is right.

There IS a market out there for high-end battery packs, but things change so quickly out there in high tech batteries that it's hard to stock any amount of packs as:

1- By the time you unload a container load, the next batch is not the same.. and you don't want to buy a container of un-tested packs

2- Limited shelf life, no one wants to sell/buy packs that have been sitting on a pallet for 18 months... :lol: ( LiFe may change that.. have not been able to get a solid answer on Life shelf life ? )

High-maintenance packs are not going to sell well with the masses.. all possible ( or as much as possible ) avenues for disaster have to be taken into account. . . . . can't fault the stupid or the un-unitiated..

Power tool packs, an option .. yes.. practicle it's not.. I think very few people will know/want/should do this.. dangerous on many levels.

 

[BiGH]

http://users.bigpond.com/solarbbq/lithiums1.htm

i ordered them as LiFEPO4 cells, if they're not iron phosphate they'll be going back.

not cobalt oxide or LiPoly or anything else.

yes there is some risk here as they're untested. I'm also going to be running Dewalt packs (most likely) unless these test really well.

Ultimatly the a123 cells are the best, but i'm willing to give other sources a go for the greater good of everyone - ie more information. If they fail after 200 cycles then thats the way it happened, its STILL one more gas guzzling car not doing my commute to work - so saving money there. I only need to get 120 cycles out of the pack to break even!

 

[xyster]

http://users.bigpond.com/solarbbq/lithiums1.htm

i ordered them as LiFEPO4 cells, if they're not iron phosphate they'll be going back.

not cobalt oxide or LiPoly or anything else.

yes there is some risk here as they're untested. I'm also going to be running Dewalt packs (most likely) unless these test really well.

Ultimatly the a123 cells are the best, but i'm willing to give other sources a go for the greater good of everyone - ie more information. ...

Way to take one for the team.

Charge the pack fully, drain it just a little -- for a couple minutes or so -- and then probe the individual cell's voltage. If > 3.7v, then it's lithium cobalt or lithium manganese, not LiFePO4. Except in very cold weather, LiFePO4 should be charged to 3.6v/cell max. But because the chemistry is quite tolerant of overcharge, they could charge to 4.2v/cell if the charger and BMS is a regular lithium charger and BMS instead of a LiFePO4 charger and BMS. In such a case, the voltage will quickly settle to 3.6v/cell when the pack is drained just a little, or allowed to sit around for awhile.

 

[BiGH]

http://users.bigpond.com/solarbbq/lithiums1.htm

i ordered them as LiFEPO4 cells, if they're not iron phosphate they'll be going back.

not cobalt oxide or LiPoly or anything else.

yes there is some risk here as they're untested. I'm also going to be running Dewalt packs (most likely) unless these test really well.

Ultimatly the a123 cells are the best, but i'm willing to give other sources a go for the greater good of everyone - ie more information. ...

Way to take one for the team.

Charge the pack fully, drain it just a little -- for a couple minutes or so -- and then probe the individual cell's voltage. If > 3.7v, then it's lithium cobalt or lithium manganese, not LiFePO4. Except in very cold weather, LiFePO4 should be charged to 3.6v/cell max. But because the chemistry is quite tolerant of overcharge, they could charge to 4.2v/cell if the charger and BMS is a regular lithium charger and BMS instead of a LiFePO4 charger and BMS. In such a case, the voltage will quickly settle to 3.6v/cell when the pack is drained just a little, or allowed to sit around for awhile.

Thanks Xy,

yes i think its important to get as much real world testing information out there as possible. I'm writing a help file at the moment about ebikes - might see if i could possibly spin it into e-bikes for dumbies or something

I honestly just want cheap affordable high speed bikes to be out there for the masses to use! so sick of cars sitting in traffic- it makes my blood boil.

 

[fechter]

Thanks Xy,

yes i think its important to get as much real world testing information out there as possible. I'm writing a help file at the moment about ebikes - might see if i could possibly spin it into e-bikes for dumbies or something

You could post something in the EV Basics section. Newbies (and even experienced people) need as much information as possible on these new-fangled things.

 

[bobmcree]

"i ordered them as LiFEPO4 cells, if they're not iron phosphate they'll be going back."

save your money on non-refundable shipping and cancel the order now. it clearly says on his site they are li-poly and not lifepo4.

if he is selling iron phosphate for that price sign me up...

there is all the difference in the world. the more expensive batteries cost twice as much and should last 5x as long.

 

[CGameProgrammer]

I am wrestling with the pack-source question myself. I'm a newbie and won't even attempt creating a BMS, so I'd need cells that can keep acceptably balanced if not overly discharged, but simply charging a battery pack is another issue I do not know how to solve.

And while the developer's kit for A123 seems pretty interesting (six pre-tabbed cells plus instructions), it's $2.42 per Wh ($18.33 per cell) which is very expensive, and you still have to assemble it, get a charger, etc.

 

[xyster]

I am wrestling with the pack-source question myself. I'm a newbie and won't even attempt creating a BMS, so I'd need cells that can keep acceptably balanced if not overly discharged, but simply charging a battery pack is another issue I do not know how to solve.

I think it'd be best in your case to buy either complete Dewalt/A123 or Milwaukee/Emoli powertool packs, and tap in power leads to each pack below the BMS, keeping the rest intact. Then use the corresponding charger to charge. This way, the BMS will balance the cells. However, you'll need an on-board voltmeter to know when the cells are depleted.

 

[BiGH]

Does the CycleAnaylist have the ability to do this ? (and cut the pack off automatically?)

 

[Doctorbass]

Yes, At 36v, if the cutoff voltage protection on the controller is 29V it's safe for the pack. I re-adjusted mine to 2.5V to get 10% more capacity without loosing considerable cycle life.

In my case, i will need to monitor each parallel group seperatly with voltmeter when runing at 66V (2s3p) or in another case, i will re-adjust the cutoff voltage to 50V and hope the two group have same capacity to match the 25 +25v discharge and not like 29 + 21....

cheap meter can be found at webtronic :
http://www.web-tronics.com/panelmeters.html

this one is interesting (very low current draw and small size)
http://www.web-tronics.com/ccminlcddigp.html

Doc

 

[CGameProgrammer]

I think it'd be best in your case to buy either complete Dewalt/A123 or Milwaukee/Emoli powertool packs, and tap in power leads to each pack below the BMS, keeping the rest intact. Then use the corresponding charger to charge. This way, the BMS will balance the cells. However, you'll need an on-board voltmeter to know when the cells are depleted.

Can you explain further? What do you mean "below the BMS"? And if I were to use DeWalt packs, I'd probably want like 10 in parallel. Do I have to worry about keeping these balanced if they're all going to be charged individually? I'm guessing not.

 

[xyster]

I think it'd be best in your case to buy either complete Dewalt/A123 or Milwaukee/Emoli powertool packs, and tap in power leads to each pack below the BMS, keeping the rest intact. Then use the corresponding charger to charge. This way, the BMS will balance the cells. However, you'll need an on-board voltmeter to know when the cells are depleted.

Can you explain further? What do you mean "below the BMS"? And if I were to use DeWalt packs, I'd probably want like 10 in parallel. Do I have to worry about keeping these balanced if they're all going to be charged individually? I'm guessing not.

See Magudaman's pics and build description below. By keeping the BMS intact, and using the stock charger the cells will be balanced with every charge (and maybe on discharge too depending on how the BMS works). 10 in parallel would provide very good range. People typically get about 3 miles of range per Dewalt pack going 20mph or so. You might also consider 5 in parallel and 2 in series for 66 volts 11 amp-hours. The range will be the same at the same speed because you'll still be using 10 packs, but you'll have twice the power on tap when you want it, and the potential of going twice as fast (which will obviously cause range to suffer, but you don't have to use the extra speed).

By tapping in power leads directly to the pack, you can run them in series without having to worry about frying the BMS -- which has I think a 15 amp fuse, so too few in parallel with a high amp controller can blow the fuses if the batteries aren't tapped directly.

http://visforvoltage.net/forum-topic/batteries-and-chargers/578-a123-developer-packs

I orginally posted this on the visforvoltage.com page but I feel it important enough to what you want to do. I too currently am running 4 dewalt batteries with 2 stock chargers. Here is a little write up them:

I finally did it: I spent 200 dollars and got 2 Dewalt 36 volt batteries and a charger. I received my package on Friday and have started to make the packs work for my application. I am hoping to eventually buy two more Dewalt batteries to have total of around 8.5 ah of capacity at 33 volts. The packs weighs 2.5 pounds according to a postal scale so my 8.5 ah pack is going to be 10 lbs and will definitely out range my current 21 lbs 10 ah lead acid pack. If you were to pull out the BMS and case with all the balancing probes you probably could shed off a half pound maybe more.

I decided to go ahead and use the stock charger so that I can get the benefit of cell balancing hopefully keep the life of the batteries nice and long. Plus it a pretty fast charger bringing a battery to full in 1 hour (as tested). When I buy the two more batteries I going to get a second charger so I can refill my whole pack in 2 hours. The picture below is the charger and then :

So I am going to parallel all my packs so I had to by pass the BMS for my output to my scooter. All I did was solder directly to the two output tabs of the cells and left the BMS in. You can see below my okay solder job, but it doesn't warm up at all even at 15 amps.

The wire is 12 gauge Dean's "wet noodle" and then I put a 45 amp Powerpole connector on the end. I soldered the Powerpole on too:

So now I had the pack ready for high current so I did some testing. First I ran the pack though on my CBA. Below is the chart with a discharge rate of 3.5 amps down to 28.5 volts. It pretty amazingly flat right up the end around 2.1 ah. This was the first cycle and I'm not sure if it will improve over time. In addition I grabbed the pack almost immediately after it said it was done and I'm not sure if it continues to float in that other 200 ma. UPDATE: I just ran another cycle after it sat on the charger for a while and it put out another 120 mah. I’ll do another test in a month or so and post those up.

In addition to the CBA I also test the battery at higher currents with my Watts up. After removing 1.4 ah from the pack I exposed it to a 13 amp load and it still wasn’t dropping below 31 volts. For my purpose I need it to be above 30 volts to be usable since my controller shuts down at 30.4 volts. I have not exposed my pack to more than 15 amps but it seem to hold it voltage very well. During my test I was sucking almost 500 watts out of the pack but it should be able to handle more since Dewalt claims the drill can out put 750 watts peak. Finished pack photo:

UPDATE: well as you might have seen it has took me a while to get this posted to the forums and I couldn’t resist to try the scooter today. I don’t have my parallel setup wired so I did just a single pack. The results were as expected for a single pack. With a 30.4 amp load a fresh pack drooped down to 29.21 volt. This is a normal drop according to the cell spec sheets for 30 amps. But I was able to ride around and try it out at full speed. I notice the top speed loss but I’ll live with it, and it should only get faster as I add more paralleled packs. My scoot did shut down from low voltage. With 20 pounds removed from the scooter it was easy to get out of my garage. I keep you up to date when I get the paralleled stuff set up.

ADDITION SINCE ORIGINAL POST:

This is my completed pack inside the scooter. All four are paralleled together using powerpoles connectors and 12 gauge wire. They all run through my watt's up (which is way overloaded) then into the controller.

If you have any questions about the set up let me know.

 

[OneEye]

The intact BMS will only balance on charging. Whether you go through the spade connections that are 15A fused or tap the cells directly, you are bypassing all the smarts in the BMS for discharging. Generally speaking this is not a bad thing with the DeWalts, since you will need to work very hard to create a hazardous situation with them.

 

[bobmcree]

i have been playing with the a123 cells i harvested from dewalt packs, and they are awesome. i have tested each cell to deliver 2.2A @ 15A and tried overcharging them to 5v without a single failure.

these batteries are the way to go!!!!

i agree the bms is only useful for charging. i am building a constant current charger and bms that will bypass each cell at 3.7v. i found that you could get an extra 10% capacity out of the cells by charging them up to 4v but if it shortens the lifetime it will not be worth doing.

the simplest bms will be a 3.7v bypass on each cell and the CC current charger will cut off when all cells have reached the target voltage. for discharge i am relying on my drainbrain to tell me when i have used 80%

as i mentioned in the TF group which i left i will make my bms and charger designs open source if anybody wants to duplicate my efforts.

i'm off now for a ride on the cruzbike to take some movies...

 

[Doctorbass]

Hey Bob,

I'm interested about your bms plans. keep us informed!

from now, i will test each cells to balance each pack i built with same cells capacity using my mega power infinity 960sr charger. the best charger i found for A123 cells.

Doc

 

[CGameProgrammer]

I'm still not clear on why the BMS has to be bypassed. I thought that even with two packs in series, the voltage through each BMS would only be 36V. Is that incorrect? What about packs in parallel -- is that also a case in which the BMS would fail if not bypassed?

In any case, I'd be doing both. I'd want a 72V pack with at least 18 Ah... though I'd probably just do one 2s4p pack at first, and create a second identical pack later on that would be hooked up in parallel with the first.