Konion Makita LiMn battery care and feeding by Doctorbass

[999zip999]

No worries I just have a kingpan 300w charger that charges fast enough. But to think of a 37a charger is wild. The wires in my house would melt first.

 

[Doctorbass]

im just over 2300 km and 90 or so charge cycles on my pack and i have noticed no real decrease in capacity
i burst at up to 5c and my continuous now is about .75-2c depending on terrain so they do seem to hold up pretty well

i had to replace 2 paralleled strings due to my own mistake of overdoing the c rating in -15c weather and not checking the balance but the rest of the cells are within 20mv after 90 cycles with no balancing

i suggest from my small amount of exp with these cells to check the balance once every 4-5 cycles and if you notice your voltage looking a little low during your run check it then and there

side question to doc
i have done a shunt mod via a voltage divider to the current sensing circuit on a 12 fet infinion running 4110s
im getting peak amperage registered on the ca at 107.8 amp
im not sure what the phaze current multiplication is on these controllers or if its dependent on the motor its feeding

is this sustainable on a 9c 8x8 aka 2808 or am i risking popping my fets? if i need to tone it down it shouldn't be a problem as i have a 22 turn pot on the one side of the vd circuit

107A peak battery current should not be a problem for a 12 fets 4110, but ensure it is assembled in the extreme way ( beefed bus bar, etc...)

Doc

 

[andrew.box]

I'm pretty sure I know the answer to this unfortunately, but if these sit at 0V for long periods of time they're likely to be toast, ya? I have a colleague at work who has two Bionx packs (the 40.7V 11s version off a Trek ride+ bike) that have been discharged for a long time, as in several months or more. I've offered to look into rebuilding them for him, but I imaging it's probably not worth spending too much time trying to cycle or re-condition any of the old cells, correct?

So far, I've slow charged the pack using 300 mA CC until the voltage was ~28V (started at 1.6V for the whole pack), then plugged them into the OEM charger. They appear to be charging but it looks like they're charging way too fast to have much capacity left.

The Bionx BMS (if you can call it that, it doesn't appear to monitor cell level or sub-pack level voltages, just total pack voltage) must draw a lot of quiescent current, I've read a few posts on the web describing others with Bionx packs that have gotten to 0V rather quickly.

 

[amberwolf]

If they appear to charge fast, most likely they have high internal resistance. Do they also get hot, or warm? (might nto be able to tell that till you discharge test them)

 

[andrew.box]

They don't get warm. And in fact, the voltage started coming up much more slowly once the pack got up to ~40V and they charged long enough that they may have taken a full 6AH or so (I believe it's a 3p pack). Perhaps it warrants doing a few cycles after all and seeing how they hold up. Just need to cut into the pack to get access to smaller groups of cells so I can cycle them with the accucel 6.

I'll report what I find, it may be helpful to other Bionx owners in a similar situaition.

 

[999zip999]

Do you have access to the parelle strings to monitor or charge.

 

[andrew.box]

Need to cut into the shrink wrap to get access to the paralleled sets of cells. I may start it today.

 

[andrew.box]

Forgot to update how things went with this. The way the pack was put together, it was series first, then parallel so cycling groups of <6S cells on the hobby charger would have been a hassle, so I just slow charged the whole pack in NiMH mode (200mA) until it got to ~24V (as high as the accucel 6 will go before the open circuit alarm triggers), then switched them to the OEM charger. They seemed to take a full charge judging by how long it took before the charger kicked off, so next I cycled them using a 200W incandescent bulb as a load (draws ~1A at 42V) and a timer to estimate capacity. They seem to have close to the rated capacity and were holding voltage for several days, so I buttoned them back up and brought them back to my colleague. I don't think he's tried them on the bike yet but hopefully they'll work OK. Even if he gets a few months out of them it's better than nothing. Those Bionx packs are expensive.

I'm surprised sitting at close to 0V for so long didn't kill the cells, it certainly killed my lipo pack but they must be a different chemistry.

 

[docnjoj]

I had good luck also after my 6 parallel Fatpacks with Konion cells were drained close to 0 volts by my leaving my controller on for a few days. They charged right up using the Bosch charger and showed about 10-11 AH on a D/C test. This was about 2 years ago and they are still working fine on my wifes trike.
otherDoc

 

[gestalt]

all my cells are sorted and about to be balanced, so I need a charger and I'm trying to figure out the best combination of affordable, powerfull and expediant. I'm also shopping for a friend who is building the same setup so I figured that since I have two of these 24v 25a power supplies http://www.ebay.com/itm/D-C-POWER-SUPPLY-MODULAR-24-VDC-25AMPS-OUTPUT/260292051822 I might be able to feed two hyperion 1420 chargers to charge our 12s packs.

am I off base here?

 

[Doctorbass]

For those who want a very efficient and powerfull solution to balance their pack or cells during or after the construction here is one cheap that is EXCELLENT:

the BC168:


A 8A balancing charger!! Yes it does Balance at 8A !!!


http://endless-sphere.com/forums/viewtopic.php?f=31&t=41107&hilit=bc168

Doc

 

[whereswally606]

Doc I have two BC168's that I broke, you wanna fix them? I was charging (by mistake the top half of a 12s battery and the bottom half of the 12s battery at the same time) i forgot to remove my series jumper wire

 

[whereswally606]

Edited message above to include details.

 

[mistercrash]

I have something like 2500 km done on the 74V pack I made more than a year ago. I rode all winter and I had to replace a couple cells in the Spring. They don't like to work too hard when it's very cold out. This year I insulated the pack and put two battery warmers around it. I tried warming the pack a few times, the battery warmers work great plus the battery seems to be very happy at between 35 and 40 degrees Celsius. At that temperature, I get the most torque and speed and the voltage drops much less on hard starts.

It's a love/hate thing for me with these cells. They do work really well but what a PITA to put together.

 

[1KW]

bout to get some of these...I understanding the initial charging, soldering of parallel groups, and then to series them together. But how to charge once its all connected, and do YOU have to have balance wire connections with these? Or a simple + and - for charge/discharge?

 

[Doctorbass]

But how to charge once its all connected,

You need a charger that have the voltage of the number os serie groups x 4.15V or 4.20V ( 4.2 is only for occasional balancing and 4.15 is for regular charge)

The max cahrge current is 1.5 time the capacity of your pack

and do YOU have to have balance wire connections with these?

Preferably you should. it's easyer to check the balance state or to rebalance if required.

Or a simple + and - for charge/discharge?

NO

 

[1KW]

What would be an easy higher voltage series setup? Would 16s be easy to charge than 18s, since you could break it down into technically 2 8s packs and use 2 charges for each half? Or if i do 18s, use one of of those 4 port 6s chargers, and can charge it all at once.

I have a basic idea of how to do it, seems simple honestly. Just taking time to charge every cell individually to 4.1 is the killer, then soldering parellel links.

Then the only question i really have is attaching balance wires, discharge, and charge wires.

Hard to find anything online with these last bits.

 

[mrzed]

Also about to start my first battery build using toolpacks, and I echo all the questions above. I get how to wire up the parallel groups and then series them (though I could use a real photo showing the different options on current sharing high versus low amps compared). I am missing something on wiring balance leads properly though.

I'm also curious the relative merits of different levels of RC balance chargers, for example, if I don't care about charging speed much, am I just as well with a $50 charger rather than something like the Bc168 referenced above at about double the price.

 

[999zip999]

Tell us about the battery size and Volt - ah - and amp demand of controller and the answer is easy. Maybe total needed too. Yes all answer's a must.,

 

[mrzed]

Looking to do 12-14s/8-9p depending on how harvesting the packs goes. I have a 20a and a 40a controller, and will use either with a 9c2808 rear.

 

[Doctorbass]

I recall all info about Konion battery building are here guys :wink:

: http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=28285&hilit=makita+building

Doc

 

[molybdenum]

Needing a powerful ebike but not finding a suitable battery for a reasonable price, I looked into DIY batteries. Fortunately, Endless-sphere is an incredible repository of information; thus, I embarked on endeavor to build a 17s10p triangle pack for my first ebike build.

I ordered 28 Makita packs from Doctorbass last May; of these, about 200 cells were between 3 and 4.2V; I lost another 8 due to self-discharge but only needed 170 cells to complete my 17s10p triangle battery. I have another 40 odd cells between 2.5 and 3V which I may use down the road as spares and for auxiliary packs for lights etc. The remainder below 2.5V were sent for recycling

Of the 28 Makita packs, three were of the new generation type; these were easy to open even with my primitive tools once I found the deeply recessed security screws in the inner plastic housing (I'm not sure what people were complaining about).

After charging and testing all the cells, I was able to build the pack in a triangular arrangement to fit an EM3EV triangle bag and it just squeezes into the smallish triangle of my Norco Sasquatch. With the weight in the triangle, the cornering is awesome and the bike feels strong and incredibly stable at high speeds.

All in all, I’m very pleased as the 71.5V (hot) 16Ah pack is far more powerful than most commercially available batteries, all for a total cost of $450 including charger, soldering supplies, wire and all shipping. My build flies along at 60+kph on an HS3540 even when approaching lvc. My DIY pack easily handles the 28 km hilly commute to and from work with 30-50% reserve depending on my riding I save about 30-40 minutes a day in commute time compared with the car or regular bike. Without these cells and self assembling a pack, I simply wouldn't have been able to have the battery I needed in a triangle mount.

After 200 km of riding, my CA reports an overall resistance of about 0.09 ohms (down from 0.15 when I first rode). The pack feels warm but not hot when I arrive. When I assembled the pack, I made sure each parallel group was balanced at around 4.15V each. The 17 parallel groups remain perfectly balanced within 0.01V

These cells are amazing!

 

[Doctorbass]

Needing a powerful ebike but not finding a suitable battery for a reasonable price, I looked into DIY batteries. Fortunately, Endless-sphere is an incredible repository of information; thus, I embarked on endeavor to build a 17s10p triangle pack for my first ebike build.

I ordered 28 Makita packs from Doctorbass last May; of these, about 200 cells were between 3 and 4.2V; I lost another 8 due to self-discharge but only needed 170 cells to complete my 17s10p triangle battery. I have another 40 odd cells between 2.5 and 3V which I may use down the road as spares and for auxiliary packs for lights etc. The remainder below 2.5V were sent for recycling

Of the 28 Makita packs, three were of the new generation type; these were easy to open even with my primitive tools once I found the deeply recessed security screws in the inner plastic housing (I'm not sure what people were complaining about).

After charging and testing all the cells, I was able to build the pack in a triangular arrangement to fit an EM3EV triangle bag and it just squeezes into the smallish triangle of my Norco Sasquatch. With the weight in the triangle, the cornering is awesome and the bike feels strong and incredibly stable at high speeds.

All in all, I’m very pleased as the 71.5V (hot) 16Ah pack is far more powerful than most commercially available batteries, all for a total cost of $450 including charger, soldering supplies, wire and all shipping. My build flies along at 60+kph on an HS3540 even when approaching lvc. My DIY pack easily handles the 28 km hilly commute to and from work with 30-50% reserve depending on my riding I save about 30-40 minutes a day in commute time compared with the car or regular bike.

After 200 km of riding, my CA reports an overall resistance of about 0.09 ohms (down from 0.15 when I first rode). The pack feels warm but not hot when I arrive and the 17 parallel groups have remained balanced

Excellent report !

Thanks molybdenum!

This remind me the first 4 big pack I built with 432 total of these cells in 2008 ! These cells perform really well for ebike application! and battery construction as well! easy to charge and safe and powerfull !

 

[litespeed]

I'm just starting my journey with these cells. I like everything about these. I have built many packs with emoli (V28 packs and Dewalt's a123 cells. I like the ease of building these type because with hot glue you can make any shape imaginable. I have broke open 30 packs and charging the pairs as I write this but it's going to take a while even with two really good R/C chargers. After I get them charged up ill just be waiting for my spot welder to arrive. Wish me luck!

Tom

 

[Doctorbass]

Nice work ! :wink:

With that equipment this become really easy !

Doc