Battery Building Competition

[kfong]

Thanks Marty! Just for grins I put the smart switch on my scooter.
http://www.endless-sphere.com/forums/viewtopic.php?f=12&t=12031
I don’t use this much but keep it around for my nieces and nephew. Its bare bones so it’s the first real test of the smart switch. Using the same single A123 pack and a LVD at 28 volts. I pulled 1986mA from the pack. Lots of stop and go and I stayed relatively close since I only had flip flops on. No problem with the smart switch turning off on me. Near the end I could tell that the pack was getting low so I didn’t drift far from the house. Making the last turn to go back it cut off. I had to push it back from 3 houses, put the pack on the charger and as you can see I used most of the pack up without the problems normally associated with LVD that just cut off with no intelligence.

I'm really happy with the way this smart switch works and I will be putting it on all my ebikes and battery projects. Now I won’t need to take them apart for winter storage.

Also, thanks for getting my ass moving so I could come up with this new product. I doubt that I would of done anything with it for at least a year and now wonder why I didn't have it to use a year ago!

 

[John in CR]

Congrats KFong,

You really do have to match these cells in some fashion. In last batch I got from Marty, nearly half were dead, and only about 25% of the 4s strings showed reasonable capacity to go in one of my bike packs. Capacity is a useful estimate of cycles used, so it ends up with a rough age match too, but cycles used isn't really important anyway. 50 hard cycles is like hundreds of easy cycles. It's not like the cells have some kind of switch that makes them go bad after X cycles.

Push my packs too hard??? I've deep discharged them only a handful of times in a over a year and a half. My typical DOD is less than 50% and I charge to only 4.04V/cell. My daily rider is 18p20s and I add more for long rides. eg My range extender for tomorrow's ride is another 16p20s, because I'll be running all over town (40-50mi) with no long stops for opportunity charging.

To fit a nice pack, build the pack so the cells stand up. Then Marty uses a couple of washers and a strip of rubber to lift the deck if necessary for a nice snug fit in the battery compartment. The extra capacity is going to be needed, since the Marty cells are generally more worn that warranty returns that Doc sells, because Doc doesn't sell any with > 100 cycles or very low voltage (except 0.0V which indicates a blown fuse and often all good cells).

John

 

[grindz145]

Ladies and gentleman, I am pleased to announce the winners of the Battery Building Competition.

First place goes to KFONG. Kfong please email me a ship to address and I will ship batteries to you. Think it would be best if I also buy this charger - [Tenergy Intelligent 3.5A Charger for 29.6V 8S Li-ion / Li-Polymer Battery Pack] and have it shipped to you so you can test scooter battery with the charger that I will be using.

Second place goes to JOHN in CR. John if I am able to get any more Makita battery packs, I will contact you first before I sell them in the For Sale section of this forum. Please get your debit / credit card or PayPal account all loaded up with $.

Third place goes to GRINDZ145. Grindz since you live right down the road from me, I would like to invite you to come to Buffalo. Will buy you a dinner in a nice restaurant. Bring family and friends if you like.

Thanks to everyone else for sharing your knowledge.

You're going with the charger I spec'ed out and I only get 3rd! haha. Congrats Kfong! I hope you'll post some pictures of the build

 

[kfong]

Thanks Guys. The yield is a lot less than I had hoped for. Hopefully his new batch of cells are in better shape. I know Doc is the one to get them from, but his last batch gets snapped up faster than I can catch wind of. Yes I will be verifying the capacity of each pack with the 1010b and will do the matching like I did with my BMC build. Sounds like you don't push your packs to full discharge on a regular basis. That should keep them healthy. On my BMC I watch what I take out and put back in, it's been very consistent, this is a good indication of cell health, but Marty won’t have that luxury. With the smart switch I’m pretty sure he won’t need to worry much other than being too far away when the pack goes empty.

Marty’s new pack arraignment, putting them on end might be an option as well. Up to Marty how he wants them. He wants max capacity, so now it’s 13.5ahrs.

Yes, I will be posting like I do with all my ebike projects. With the new packs, more cool projects will be coming. The RC build this winter should be fun, going with a nice Kona Cowan for the build that I recently acquired. Built like a tank and made for jumping. Put some power to that baby and take it to the local jumping trail that was built a year ago and now we are having some fun

Congrats KFong,

You really do have to match these cells in some fashion. In last batch I got from Marty, nearly half were dead, and only about 25% of the 4s strings showed reasonable capacity to go in one of my bike packs. Capacity is a useful estimate of cycles used, so it ends up with a rough age match too, but cycles used isn't really important anyway. 50 hard cycles is like hundreds of easy cycles. It's not like the cells have some kind of switch that makes them go bad after X cycles.

Push my packs too hard??? I've deep discharged them only a handful of times in a over a year and a half. My typical DOD is less than 50% and I charge to only 4.04V/cell. My daily rider is 18p20s and I add more for long rides. eg My range extender for tomorrow's ride is another 16p20s, because I'll be running all over town (40-50mi) with no long stops for opportunity charging.

To fit a nice pack, build the pack so the cells stand up. Then Marty uses a couple of washers and a strip of rubber to lift the deck if necessary for a nice snug fit in the battery compartment. The extra capacity is going to be needed, since the Marty cells are generally more worn that warranty returns that Doc sells, because Doc doesn't sell any with > 100 cycles or very low voltage (except 0.0V which indicates a blown fuse and often all good cells).

John

 

[marty]

Kfong,
Boxes are packed. Labels are printed. Will ship with USPS, 5 - Large Flat Rate boxes.
31 small packs fit in one Large Flat Rate box.
21 large packs fit in one Large Flat Rate box.

Here is packing list:
31 - 1.5Ah
31 - 1.5Ah
21 - 3.0Ah BLUE
21 - 3.0Ah WHITE
21 - 3.0Ah WHITE
Total packs is 125 because of the way they fit in the boxes.
Note that some 3.0Ah packs have BLUE printing and some have WHITE printing. Not sure which is older?

Have fun with batteries!

 

[kfong]

Thanks Marty

 

[marty]

MAKSTAR Battery Checker detects the number of charges, and diagnoses the condition of MAKSTAR Ni-MH/ Li-ion batteries. This equipment reads the history of the battery from the built-in CPU, finds how the operator treated the battery, and gives the right advice to MAXIMIZE THE LIFE OF THE BATTERY.

* It can be also used for simple-checking conventional Makita batteries, using the adapter which is included with the Battery Checker.
* PC is not included in the set.
* Battery Checker works with Makita Makstar charger DC24SA, DC24SC and a PC.

http://www.makita.biz/product/li-ion/index.html

 

[kfong]

That would be nice to have, I emailed DocBass and he said he doesn't have it or any info on the protocol.

MAKSTAR Battery Checker detects the number of charges, and diagnoses the condition of MAKSTAR Ni-MH/ Li-ion batteries. This equipment reads the history of the battery from the built-in CPU, finds how the operator treated the battery, and gives the right advice to MAXIMIZE THE LIFE OF THE BATTERY.

* It can be also used for simple-checking conventional Makita batteries, using the adapter which is included with the Battery Checker.
* PC is not included in the set.
* Battery Checker works with Makita Makstar charger DC24SA, DC24SC and a PC.

http://www.makita.biz/product/li-ion/index.html

 

[kfong]

I got the batteries. FYI guys don't send them by air, one of the packages opened up. The post office held the 5 packages; luckily it made its way to my local post office. I was following it on the tracking number and figured I better check. They did not deliver it to my house because it was considered hazardous material. They ended up giving it to me, maybe because I showed up, what else were they going to do with them but dispose of it? They certainly won’t be air mailing it back. Anyways they are sending a letter out to both of us, but I don't know the details.

You can see the one on top and bottom had been resealed.

 

[kfong]

Lots of batteries, time to sort them.

The batteries are grouped in lots, anything 3volts or under are in the very left, most of these were near zero. These are considered trash. The next group is 5-9volts, this is usually a couple of cells you can harvest but it wouldn’t be worth it for ebikes. Useful for electronic projects though. The next group of cell is 10-12 volts, these need to be cycled and tested, and can be more than 2 cells bad. The last group in boxes is the ones that made the grade, 13volts or higher. These usually have 1-2 cells bad, and are usually the very first of the string of cells. Removing the bad cells usually gives you a nice 8 cell brick to work with and on some of these all 10 cells are good. Overall I’m happy with the yield. There should be plenty left over for my own projects.

Now for the tedious part of testing the cells and cycling them, not to mention cleaning off the tape insulation, that never seems to come off as one piece. This testing is going to take a while.

I was surprised to see one pack with AAA cells, not sure what that was all about. It would be funny to think that someone tried to replace the pack with these. Also some of these packs were extremely grungy, even for closed up packs, they have seen some hard use.

The top row is the 3ahr pile

The bottom row is the 1.5 ahr pile, same cells just one row of 5.

 

[John in CR]

LOL, someone tried to fix their Makita pack with 1.5V alkaline cells. That or they pulled the good cells out and returned that crap. If so I hope they get caught despite the tempting idea.

 

[kfong]

Yeah, they weren't even wired. One of the cells still had a good 1.5 volts and the others were around 1.3 except for the one that had corroded. I assume they might have all have been good cells at one time but no attempt at wiring, what was he thinking? Too funny.

I found one pack with weird discoloration, that's when I realize it had been under water. I can see the rust. Some of the packs I want to wash my hands after touching them. I can't believe how much dirt can get inside a pack.

 

[John in CR]

I don't care to much about dirt or rust. The ones I worry about are those with some kind of powdery substance. Sure it's probably just dust from drywall/sheetrock, since I can see cordless drills as screwdrivers being a great tool, but you never know in what environment they are use...possibly around hazardous materials. I guess some of that chinese sheetrock would qualify. I open mine outside and keep a wisk broom handy to brush them off, and always a good hand washing afterward.

John

 

[kfong]

Yeah, I was thinking of the same thing after removing the cells from the packs all morning that I should have worn gloves, one of the batteries had a leak too that was oozing black stuff. Unusual since these cells remain relatively dry. Some were in water, so who knows what environment that had to be. I have a shop vac with a hepa filter that I use for my composites and stuff to clean the area, which gets messy after a few packs.

Initial testing of the ones in the boxes haven’t been so great as far as capacity goes, only around a 1000ma, this is still early on and only a few packs, but these are already omitted as being unfit. I still have lot of cells to be put through this. Unfortunately it’s a slow process since Doctorbass recommended the charge rate to 2amps a cell. With 2 cells in parallel 4amps still takes a bit of time to go thru. I would like to run 2-3 cycles on each to get a good feel for the capacity. Only one 1010b charger, I have others but like this one the best. I'll probably play around with the charge/discharge currents to shorten the test time, I'll see what Doc is doing with his setup. Doctorbass may end up being the best place to get these used cells since he gets them with less than 100 cycles. At this point the testing of the cells is what’s going to take the longest. I’ll probably get the other chargers working and maybe do the discharging separately as well.

Looks like it's 2.5amp max charge and discharge per cell for safe testing. So I can now bump it up to 5amps per 2P.

I don't care to much about dirt or rust. The ones I worry about are those with some kind of powdery substance. Sure it's probably just dust from drywall/sheetrock, since I can see cordless drills as screwdrivers being a great tool, but you never know in what environment they are use...possibly around hazardous materials. I guess some of that chinese sheetrock would qualify. I open mine outside and keep a wisk broom handy to brush them off, and always a good hand washing afterward.

John

 

[John in CR]

I don't have the fancy stuff, so I group them by 3s and 4s packs after removing the bad cells and setting unbalanced blocks aside, and charge them in one big parallel batch. Leave them connected for half a day to ensure same starting voltage per cell of all packs. Then I connect them in one series string, and discharge using however many light bulbs in series are called for. I discharge for what would be 60-70% DOD. Then I match the blocks together by ending voltage. That gives me relative capacity.

Sorry to hear the cells are mostly duds.

 

[kfong]

That would be ok, but relative capacity is still guessing. I’m seeing wide ranges in capacity from 1200 – 300 mA the packs built this way will only perform as good as the lowest capacity in the pack.

I also prefer to cycle them, the first time the cells have been dormant and the numbers between charge and discharge vary widely. The second and third time the discharge and charge number start getting very close to one another. I record the discharge capacity, that gives me a very good indication of the cells health and useful capacity. If the numbers are still wide apart I would mark it as a bad cell or cycle it again. Then only the ones that meet a certain capacity are considered useful. From those it’s easy to match the capacities together; this will insure that one cell won’t take the rest down when it runs out of juice too soon.

I don't have the fancy stuff, so I group them by 3s and 4s packs after removing the bad cells and setting unbalanced blocks aside, and charge them in one big parallel batch. Leave them connected for half a day to ensure same starting voltage per cell of all packs. Then I connect them in one series string, and discharge using however many light bulbs in series are called for. I discharge for what would be 60-70% DOD. Then I match the blocks together by ending voltage. That gives me relative capacity.

Sorry to hear the cells are mostly duds.