Konion Makita LiMn battery care and feeding by Doctorbass

[jerrysimon]

Yes thanks for the fast reply doc, I think I realised my error almost as soon as I posted

I have been using A123, 2.3Ah cells but thought I might give these a shot too. My A123 packs are made up in 2 * 6s1p packs i.e. 39.6v, 2.3Ah.

I will try and get some faulty MAKITA 18V LI-ION batteries off ebay as they seem quite cheap. Am I correct in thinking that to get a simlar pack the same as my A123 pack I have above, I would need 10s2p of these cells (giving me a slightly less voltage of 37v but slightly more capacity at 3.0Ah than the A123s) and maybe make them up in 2 * 5s2p packs for easy balancing though I am hopefull like the A123s they won't need it much ?

I reckon that would mean I need at least three faulty drill packs to take account of a few faulty cells ?

Finally I assume I would charge them on Turnigy charger/balancer on Lipo settings not LiFeP04. Also I assume I can't bulk charge them with a 36v SLA charger like I do with my 12s1p A123 pack ?


PS Just found the post below so I need to trawl through that!

http://endless-sphere.com/forums/viewtopic.php?f=14&t=7569&hilit=Konion+Makita+LiMn+battery


Regards

Jerry

 

[999zip999]

Nebriancent I see you have a 21ah pack what do you charge to and what is your cutoff voltage and what is your ah on the C.A. ? If you tested range

 

[nebriancent]

i am charging at 4 amp on my balancing charger up to 4.2 per cell(only balance charged once and they seem to stay were you put them)
most i have pulled out of the pack was 18ah at 2c discharge 60km range wide open on hilly terrain (BC Canada is like all hills)
i have set my ca to 36v lvc (37.5v ca is out... and thats under load)
i have no bms
my ca at around 18ah discharge is just starting to current limit
resting voltage is still close to 40v after said discharge
can still get up to 40kmh after 18ah gone
did a few 4.1 test charges then a 4.2 right afterwards and found the capacity difference to be less the 10% (batteries took 1.5-2.0ah ontop of 4.1v charge)
built my friend a pack using better solder wire and connections and his range is a bit better (less heat in connections and wiring and by less i mean almost none like 1-5 deg above ambient)

ca and charger agree on ah used within 50-100mah (1ah=1000mha)

end result is totally win and about 20 lbs

within the next couple of weeks i am going to rework my pack from 14p to 16p (had a few more extra cells then i accounted for)

for the rough pre balance b4 soldering together the parallel groups together i just charged each cell group to 4.2v then to 4.2v after the group was complete
then after i made a 4s14p sub pack i balance charged it (took awhile like 9 hrs)
i am about 10 cycles in and notice no real performance degradation near freezing temperatures as a posed to above 10 deg c

after reworking my pack i plan to continue charging to 4.1v as a posed to 4.2 as the cycle life will improve quite a bit as i understand

 

[nebriancent]

haven't ever used the full 21ah but it dose look like it is their if i did need it
and i picked 12s as it would be easy to convert a 48v meanwell to bulk charge on the go (just the r33 mod)

 

[999zip999]

Shouldn't your c.a. be set to 38v or 3.2v per cell ? 26v sounds low dangerous ?

 

[Doctorbass]

To preserve the cells life and avoid unbalance them i would recommand using 3.5V min per cells as i do with all my konion battery.

If you have a little difference in capacity between the higher capacity paralel group and the lower capacity group, the lower one might overdischarge and damage permanantly.

I agree, 3.5V is pretty conservative, but it will leave juust enough capacity i your battery to keep the cells balanced.

Doc

 

[999zip999]

My lvc is 53v or 3.5v per cell on a 15s and charge to 62.2v or 4.14v and cells high as 4.139v at 5a. ( range ) I'm thinking of going 84v and buying a 900w kingpan 60v12a can I charge my 55v18ah battery with this charger till I get more cells for 84v battery ?

 

[nebriancent]

Shouldn't your c.a. be set to 38v or 3.2v per cell ? 26v sounds low dangerous ?

36v
and my ca reads lower as i have a limiting resistor on my ignition section of my controller to protect the switch from in surge current of the caps in that section

 

[nebriancent]

26v was a typo
36v seen by the ca due to my limiting resistor is closer to 37.5v
the lvc on the ca engages from 37.5 under load
resting is still over 41v
sorry for my miscomunication

 

[amberwolf]

Is your CA a DP or SA model?

Either way, it should be seeing the actual voltage at the controller, regardless of whether you have a precharge resistor.

Precharge resistors should be bypassed as soon as you engage the actual power switch for the controller. (not the "ignition" switch for the controller, which never has any real current flow thru it anyway, but the main power to it the controller that the motor itself is bieng powered from).

If you have your precharge resistor in series with the only power to the CA/controller, and the CA is monitoring the actual power to the controller, then the power to the controller is all flowing thru the precharge resistor and that resistor is going to get very hot while the controller is powering the motor.

 

[jerrysimon]

Wow I am learning so much about batteries on Endless Phere trawling through this part of the forum

Anyway as already stated I have been using a light 1.0kg A123 pack on my ebike (a small portable folder with a light 180W assist motor, which draws about 5amps/10 amps max) made up in a 12s1p (2 * 6s1p) config for the last two years and 500 charge cycles. Recently I lost two cells in each of the 6s1p packs I have connected in series. I only balanced them (using a cheap RC charger/balancer for 6s) at the beginning when I built them and after that just bulk charged them with a 36V, 1.6A SLA charger. My commute is 10.5 miles round trip and uses 60% charge on the way to work (about 1.3Ah) and the other 40% (about 1.0Ah)on the way home i.e. the battery is flat when I get home if I don't charge it at work. I often didn't charge it at work so it died just as I got home and this together with rarely checking or balancing probably meant I abused it pretty bad

For the cost of the cells, £60, I still think I did well. Having read much more here I now know that I need to balance them say every couple of months and always charge at work (60%) through the discharge, to make them last longer.

Anyway back on topic, I have also been thinking about trying some of these Konion cells as well and initially thought I would build a 10s2p pack in two 5s2p packs for easy balancing (if it is needed at all). This would give me a 37V, 3.0Ah pack which would discharge 80% if I did not charge at work. However the penny dropped and I thought I could actually build a 10s3p pack which would give me a 37V, 4.5Ah pack and probably not weigh a lot more (total about 1.6kg) than my 12s1p, A123 pack. It would then have the added advantage of not needing to be charged at work

Reading up on Li-Ion charging I understand my exisiting A123 SLA bulk chargers would not be any use and I would need a new bulk charger as the these cells should not be float charged i.e CC and CV only. Would this charger be ok for bulk charging

http://www.batteryspace.com/smartcharger10afor37vli-ionpolymerrechargeablebatterypack.aspx

I am in the UK and assume if I wanted to buy it here then this one would be ok too ?

http://www.ebay.co.uk/itm/37v-2a-ELECTRIC-BICYCLE-Li-ion-SMART-BATTERY-CHARGER-/140488660251?pt=UK_SportGoods_CyclAcces_RL&hash=item20b5c6d51b

Thankyou for your advise in advance.

Regards

Jerry

 

[theRealFury]

The output on the ebay charger is listed as 2amps at 37v. This will not be enough to charge your pack as you would need a 42+v output to fully charge the cells.

on the battery pack config i would definately go with more capacity. 4.5AH sounds good but if you can afford it i would probably say 6AH is even better, only usinig 50% or less will masively increase the lifespan of your battery pack. 6AH should only be about 5lbs which is still a super light battery.

 

[jerrysimon]

Thanks for your prompt reply..

The output on the ebay charger is listed as 2amps at 37v. This will not be enough to charge your pack as you would need a 42+v output to fully charge the cells.

Like the charger listed on the batteryspace web site I think the one listed on ebay refers to the pack voltage it is charging i.e. a 10s Li-Ion pack, rather than the actual charger output. What I want to confirm is that do I need a different specific Li-Ion charger rather than use my existing SLA ones. My current ones use an equal charging voltage of 44.5v, followed by a floating charge of 41.5 volts when charging my 12s A123 cells. I did actually measure the output voltage of one them when it was switched on and idle the other day just to see just to see what it was. It measured 41.5v. Maybe that increases to 44.5v when the battery is attached for charging ? I need to measure it again when it is actually charging I guess.

It would of course be nice to use the same bulk chargers that I already have for my 12s A123 packs, but I assume if at any time the output increased to 44.5v then that would not be good for the 10s Konian cells ?

on the battery pack config i would definately go with more capacity. 4.5AH sounds good but if you can afford it i would probably say 6AH is even better, only usinig 50% or less will masively increase the lifespan of your battery pack. 6AH should only be about 5lbs which is still a super light battery.

As always its a balancing act. From what I have read you are right about them lasting longer if I only use 50% of charge on my journey. The reason I want to keep the pack as light as possible is because I carry the bike and bag into work or on trains/buses in multi modal commuting sometimes. Hence a 10s3p is a compromise as it is.

Bike weighs under 13kg and bag with current A123, 12s1p 3 kgs.

Regards

Jerry

 

[nebriancent]

first off let me be very clear that this post is in no way meant as arrogant or to attack anyone(sometimes i come across that way)
and i very highly respect both aberwolf and the doc and their opinions

i don't have a pre-charge resistor
that's not at all what i am talking about
my ca is of the DP flavour
it pulls voltage off the ignition side of the controller
when i first started doing higher voltage tests on thins controller the switch built in would not handle the inrush current to the caps on the logic/ignition side of the controller at said higher voltages
i went through about 6 switches before finally figuring out what was going on as i too understand that by default the draw on the ignition side is verry verry low
once i wired a resistor in series with the switch the problems stopped and i didn't have to keep replacing my ignition switch (or bypassing it on the side of the road)
my ca voltage offset was not 100% properly calibrated from stock and until now i have pretty much ignored it
the current travelling through the resistor in-line with my ignition switch (not main voltage in) demands by ohms law a voltage drop
i am also drawing a additional 12-15w (depending on if my brake light is engaged or if its just my tail/headlight) through said switch and resistor bringing up the voltage offset a little bit more
voltages seen by the ca and what pack voltage truly is has been confirmed using 3 different multimeter of all different makes (not same brand or model)
so i not only had a typo in my first post about my set lvc but had also forgot to mention the voltage offset that i have calculated for

 

[jerrysimon]

Like the charger listed on the batteryspace web site I think the one listed on ebay refers to the pack voltage it is charging i.e. a 10s Li-Ion pack, rather than the actual charger output. What I want to confirm is that do I need a different specific Li-Ion charger rather than use my existing SLA ones. My current ones use an equal charging voltage of 44.5v, followed by a floating charge of 41.5 volts when charging my 12s A123 cells. I did actually measure the output voltage of one them when it was switched on and idle the other day just to see just to see what it was. It measured 41.5v. Maybe that increases to 44.5v when the battery is attached for charging ? I need to measure it again when it is actually charging I guess.

Ok answering my own post but hey. Last night I decided to monitor one of my bulk A123 battery charges with my Turnigy Watt meter to see what was going on. Interesting stuff 8)

For the majority of the charge the charger was outputing around 41v but then towards the end the charger went up to around 44v before the green charged light came on. The current started at around 1.4amps slowly reducing throughout the charge. So it seems this charger would be no good for bulk charging Konion cells, as I suspected.

Regards

Jerry

 

[amberwolf]

i don't have a pre-charge resistor
that's not at all what i am talking about

Ah; sorry. Somehow I interpreted it as being a precharge resistor, as that is usually what a limiting resistor in the current path is used for.

However, it sounds like that's all you really need for the situation you describe. That's precisely what a precharge resistor is intended to do: limit inrush current, by pre-charging the capacitors. Then the switch is thrown to short across the precharge resistor, allowing normal current flow and voltage levels, just as if the precharge resistor werent' there (because it is only needed at power up or battery connection).


What I would do in your situation is to put a momentary button switch that connects the precharge resistor in between battery power and the "ignition/keyswitch" input to the controller. Press and hold that button for whatever time you've calculated the resistor to charge up the caps most of the way, and then turn on your ignition switch, and then let go of the precharge button. It does add a slight bit of inconvenience to turning things on each time, but it totally eliminates the voltage drop you have, as well as reducing the size of the limiting resistor needed (since it only has to dissipate a higher amount of power for a second or two, most likely, instead of all the time the ignition switch is on).


Also, it's possible that part of the inrush current problem is caused not by charging caps, but instead by the dropping/divider resistors in the controller's low-voltage section input being too small for the higher voltage now being used. It's often necessary to increase those resistors (or rather, the first one) to a higher value and sometimes to a higher wattage resistor, in order to safely use the controller at the higher voltage. I have a Lyen 6FET controller that I have added a switch to that shorts out one paralleled resistor in that section to cause higher resistance for 72V operation, and leaves it in to make lower resistance for <60-72V operation. I have an 18FET controller from Methods that already had such a switch, installed by him, for the same purpose. There's some discussion about that in various "infineon / xie chang / ecrazyman" controller threads.


FWIW, for correcting the voltage reading of the CA without altering any other part of your setup, you could move the DP CA main power connection inside the controller so the + line hooks up to the battery point in the controller, rather than the "ignition/keyswitch" point. Of course, that would mean the CA would be powered on all the time the battery is hooked up, which you probably don't want.

 

[Doctorbass]

For the majority of the charge the charger was outputing around 41v but then towards the end the charger went up to around 44v before the green charged light came on. The current started at around 1.4amps slowly reducing throughout the charge. So it seems this charger would be no good for bulk charging Konion cells, as I suspected.

Regards

Jerry

Jerry, i'll take this occasion to repeat to all of you this:
Charging a cell to 4.4V WILL DESTROY IT ( no explosion or fire... but.. and you will permanantly increase the internal resistance so the voltage will sag and you'll have difficulty to pull the same current than before so by the same time the Low Voltage Cutoff will trip faster, giving you less Ah capacity.

Just a reminder.. if accidently you overcharge any lithium cell, you'll make irreversible damage to the cell.

The Makita Konion are very good cells, but like for all lithium cells, there is some rules to not bypass about the charging parameters.... 4.2V max.. best is 4.1V and best trade off is 4.15V to have prooven to give good results for Konion and also lipo.

When i accidently forgot my 432 konion cell pack charging to 4.5V per cell, the power was INCREDIBBLE !! but over the nexts cycles of discharge i had, i noticed a voltage sag that increased and my Low Voltage alarm leds have blinked sooner.

Please take care of your lithium cells.. than you'll appreciate them more time :wink:

Doc

 

[999zip999]

Jerry they are many cheap little 2a lifepo4 chargers but the end voltage is a little low 3.6v and for a konion pack 4.1v it would have to be adjustable. For a123 pack a lifepo4 charger does help.

 

[jerrysimon]

Thanks for the clarification.

The first Makita pack I got from ebay only output 3.35v on the main terminal so I new straight away I had purchased a dud

When I opened it up only one pair of cells was any good.

One thing it may be worth telling people before people buy these Makita packs is ask the seller to measure the output across the pack to get an idea of how many cells may be any good to salvage.

Regards

Jerry

 

[parabellum]

Just received my box with 29 packs. Fast considering my location, thanks Doc!

 

[Doctorbass]

One thing it may be worth telling people before people buy these Makita packs is ask the seller to measure the output across the pack to get an idea of how many cells may be any good to salvage.

Regards

Jerry

That's a detail over everything that MUST be verified with slavaged makita pack!!

What i ensure to every buyers is:

-ALL PACK HAVE UNDER 100cycles ( It's GARANTY because every pack are tested with the makita computerized tester made especially for this purpose)
( I just reject all the rest ( 101 cycles or more) and send them to battery recycling service.

- All pack are tested once i get them.. and than they standby for at least one weeks in my garage... than i test them again and keep the one that are 13 and above and that have not V droped

-I supply on the forum EVERY inf on these cells and for pack building.

-I personally perfectly know how to use them and can recommand the best way to make your pack. I work with them since 5 years now 8)


I rarely see ebay battery seller doing that...

Next time you guys get makita battery, ensure you at least have these info and care for the pack you buy :wink:

Doc

 

[jerrysimon]

Doc,

I would love to buy packs off you knowing that you have done all these checks first. However I live in the UK and after P&P, import duty and VAT it would not be worth it

I could of course buy new ones from Germany here.

http://www.cnc-modellsport.de/product_info.php?manufacturers_id=8&products_id=545

Ten of those would set me back 100 Euros, £85 or $133

Regards

Jerry

 

[parabellum]

Doc,

I would love to buy packs off you knowing that you have done all these checks first. However I live in the UK and after P&P, import duty and VAT it would not be worth it

I could of course buy new ones from Germany here.

http://www.cnc-modellsport.de/product_info.php?manufacturers_id=8&products_id=545

Ten of those would set me back 100 Euros, £85 or $133

Regards

Jerry

So what is the point? For price of 1 cell you could get ~ 9. You save 9x in negative.
I doubt that P&P, import duty and VAT would cost half of that.

 

[jerrysimon]

True. I don't know if the cells Doc provides are lose or in the packs ?

Guess I should pm him for details.

Regards

Jerry

 

[nebriancent]

FWIW, for correcting the voltage reading of the CA without altering any other part of your setup, you could move the DP CA main power connection inside the controller so the + line hooks up to the battery point in the controller, rather than the "ignition/keyswitch" point. Of course, that would mean the CA would be powered on all the time the battery is hooked up, which you probably don't want.

i thought about cracking open the controller again to correct this and my solution was to put the resistor on the load side of the switch and have the ca intercept power b4 the resistor but still off the switch

i guess the main reason i haven't done anything about it yet is i got a little tired of tearing down the controller for awhile (lazy) and it works fine for now as i realise the offset and my charger is reading ah put in within 5% (as in less then) what the ca reads spent and i do of course realise that by having the ca read voltage low it wont be a true wh spent (be a little bit higher the what is read)