== 2100Wh 432 konion MAKITA cells project == 16 june 2008

[Doctorbass]

I have answer for you ! :wink:

http://endless-sphere.com/forums/viewtopic.php?f=14&t=4357

Doc

 

[Dunhill_BKK]

How will you go about charging this huge pack?

Are you sure that no balancing is required? Does that mean we can charge a whole pack at one time with no worries?

I'm still a bit confused about charging packs in general and am still looking at various BMS systems. However this no balancing seems to be a winner for me.

What do you reckon?

 

[Dunhill_BKK]

What's up Doc?

I'm assuming you've been far too busy in the lab to post your progress, but I'm still interested in these batteries and your claim that balancing is not required. Can you elucidate further yet?

I'm looking to build an E-bike and these cells seem to have some very good qualities.

Cheers from Down Under,

 

[Doctorbass]

What's up Doc?

I'm assuming you've been far too busy in the lab to post your progress, but I'm still interested in these batteries and your claim that balancing is not required. Can you elucidate further yet?

I'm looking to build an E-bike and these cells seem to have some very good qualities.

Cheers from Down Under,

====== UPDATE 16 june 2008 =====

Yesterday i finished assembling the cells for the third pack.
i decided to keep the 6s 18p configuration for each pack.

Now i have 3 of those. the last one is close to be finished. for the pack 3 and 4 , theyr parallel 18p cells group are glued together with polyurethane adhesive. i hope this will ameliorate the strengh. I had no problem with the pack 1 and 2 but i want just to make sure...

Eachone give me 25V (22.2V nom) and 23Ah so i will be able to use 2, 3 or 4 in serie to acheive 50, 75 or 100V, or to put the pack in (2s-2p) or (4s 1p).

I also have a pair of AWG 14 wire for each 1s 18p groupe for charging up to 15A with mu diy multi DC-DC charger

That will give me a real number of 432 cells total of 5Wh each for a total of: 2.160kWh with a low voltage cut to 3.0V per cell. they can go to 2.5V, but i think they can loose life cycles.


that will represent a total of 40lbs for a total bike weight of 120 lbs with 200km + range at 35kph or 75km with hill climbing and fast mean speed of 60kph+ (35Wh/km)

Doc

 

[VRdublove]

Any new news on this pack? I have all my Makita drill packs disassembled and all the paired cells removed and resoldered. Now its just time to wire up the pack, but I wanted to make sure that yours turned out ok first.

As for charging, I have two 36V, 12ah 8p10s, connected in series for 36V and 24Ah. Would two Megapower 960 SR's work? I'd like to do the DC-DC thing, but I am fairly intimidated by the in depth project since I am new to electronics. Thanks!

 

[Doctorbass]

Any new news on this pack? I have all my Makita drill packs disassembled and all the paired cells removed and resoldered. Now its just time to wire up the pack, but I wanted to make sure that yours turned out ok first.

As for charging, I have two 36V, 12ah 8p10s, connected in series for 36V and 24Ah. Would two Megapower 960 SR's work? I'd like to do the DC-DC thing, but I am fairly intimidated by the in depth project since I am new to electronics. Thanks!

Welcome here VRdublove!

All my 3 assembled pack work very fine!! i did'nt finished the last one to complete the 4 total pack.

I have to say that i'm impressed to see how much range they give to my ebike!! WOW i praticaly never succed to empty them.. from now 1524Wh is a very good range and give me a great ride.

All pack stay well balanced without any balancer... +/-20mV max from one parallel group to another.

They also stay pretty cold!! i've never been able to warm them! even if i charge or HARD discharge them!!
at 23Ah 18p.. the sag voltage is minimal !

While i working on my DC-DC advanced charger, and that i can't use it from now, i use my POWER TEN 0-100V 0-10A power supply that i set to 75V and 10A. so it cahrge at 750W and the pack charge completly in 2h15 minutes when the battery is empty but like i said, it's rare from now.. i usually take 12 to 16Ah and it take 1h45 to fully charge.

i simply put all 3 pack in serie and then it's ok.. no cells overcharge.. no problem!

BUT all my 18p group haver the same Ah and internal resistance. i carefully measured all the cells and matched them with precise values.

You can for sure use two megapower cahrger with their balancer if you prefer.. but first, you would need to check if you can connect their output in serie.. so check if the 12V + and - input are completly isolated from the output + and - too when the charger is operating!

A great advice..

isolate all parallel group of cells from each other with non conductor material such as fiberglass, PCB without cooper or kapton,or the original white plastic separator of the makita pack cause the green plastic is too thiny and would not be safe if the pack could vibrate or absorb large mecanical shock... these cells are more powerfull than you can immagine!!.. so always make it safe!!

Doc

 

[shinyballs]

Doc, what do you use for your LVC? I can't seem to tell if it's already built-in in the cell, which is the case in its bms.

 

[VRdublove]

Thanks Doc! I was trying to find the Power Ten power supply that you are talking about and all I can find is this $900 monster: http://www.accusrc.com/ccp4781-programmable-voltage---current-source---sink---0--228-228.htm

Where did you buy yours and how much did you pay for it? Thanks!

 

[Doctorbass]

Thanks Doc! I was trying to find the Power Ten power supply that you are talking about and all I can find is this $900 monster: http://www.accusrc.com/ccp4781-programmable-voltage---current-source---sink---0--228-228.htm

Where did you buy yours and how much did you pay for it? Thanks!

EBAY!

check thisone: http://cgi.ebay.ca/POWER-TEN-4500D-...ryZ58288QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

0-250V 10A very similar to mine but mine is only 1U (2 inch thick)

i paid it 100$.. it was supposed to be broken... and it was only the voltage sensint wire on teh rear panel that was missing...
lol...

a 2000$ value!

this one seems interesting for use below 40V... http://cgi.ebay.com/Sorensen-DCR-40...ryZ58288QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Doc

 

[ZapPat]

Hi doc,

Nice project, re-using old cells even if it means a bit of work and making a great big 2kW pack! I'm just about to order a ping pack made with his new and good sounding cells... my first LiFePO4! I'm even trying to get extra cells for testing, I'll let you know if I manage to get them. :wink:

I was wondering how you can get 10Wh per kilometer on flat, with no pedaling, at 35km/h? It seems to me more like at least 15Wh/km or so, no?

Pat

 

[Doctorbass]

Hi doc,

Nice project, re-using old cells even if it means a bit of work and making a great big 2kW pack! I'm just about to order a ping pack made with his new and good sounding cells... my first LiFePO4! I'm even trying to get extra cells for testing, I'll let you know if I manage to get them. :wink:

I was wondering how you can get 10Wh per kilometer on flat, with no pedaling, at 35km/h? It seems to me more like at least 15Wh/km or so, no?

Pat

It's possible when doing long distance and with minimal satrt and stop that normally draw many Wh.

like gas car consumpotion on highway and in city trafic...


Doc

 

[VRdublove]

Doc,

I have a Megapower 960 SR on the way in the mail. All 91 of my paired konions are fully charged to 4.2V. <<Talk about time consuming!!! My pack will be 54V fully charged and 22 ah. (13s/8p). How do you recommend I arrange the pack since I don't have access to the software that you used. Should I just make sure that all cells wired in parallel are as close in capacity as possible, or resistance? It could be a puzzle.

 

[Doctorbass]

Doc,

I have a Megapower 960 SR on the way in the mail. All 91 of my paired konions are fully charged to 4.2V. <<Talk about time consuming!!! My pack will be 54V fully charged and 22 ah. (13s/8p). How do you recommend I arrange the pack since I don't have access to the software that you used. Should I just make sure that all cells wired in parallel are as close in capacity as possible, or resistance? It could be a puzzle.

That's a great idea for having a 960sr! that will garanty you to get the best cells matching!

The idea is to get the SAME capacity for every 1s 8p subgroup. The closer capacity you will assemble them the most balanced will be your pack!

Ideally i would suggest you to mod your 960 charger for the "4 wire sensing" like i shown in one of my post here to alsi get the best accuracy for the internal resistance measurement.

ideally both of the capacity(C) and internal resistance (RI) are important. every subgroup should ideally be close to every other fr these two parameter.

the RI need to be calculated exactly like parallel resistor for your subgroup and the capacity like parallel cell...

The best would be for you to find in the internet a version of MAthlab and i could send you theprogram that operate with mathlab for optimysing your battery pack.

The acuracy and constancy of your cell measurement are also important and may take time.... cause ideally they should be measures at all the same temperature for finding their parameter when using the 960SR. so a room with a stable temperature would be great. Cause cells capacity vary with their temperature... Try to ventilate them with a fan pointing on them when measuring their capacity.

(dont forget that in the makita battery they are paired in parallel.. so you can consider these parallel pair like ONE CELL !!! that divide tyhe testig time by two!)

Here are the parameter that i follow for every cell test :

-------------------------------------------------------------------------------------------------
Parameter to sustain a constant absolute capacity value when measurement to match the packpack

-charge for 2each p cell group: 5.00A

-discharge current set to : 5.00A
-discharge trickle current stop: 0.10A
-discharge voltage LVC stop: 3.00V

-write on the cell: internal resistance, capacity and cell number like this on every 2p1s cell:

cell 1 3024 31

(where 31 is the RI, 3024 is the capacity and 1 is the cell number)

ex:
cell no : 1
capactié : 3024
res int : 31

Dont forget to charge them at 5.00A few hours after discharging
so when assembling your cells THEY MUST HAVE BEEN CHARGED ALL !!!

After that assemble your pack and try to follow the assembling idea that i shown in some picture on that foruim by searching for the tread about Konion !

Good luck VRdublove

 

[VRdublove]

Doctorbass,

Thanks for all the help. Now that I have the Megapower on my hands, I need to figure out what battery specs to put in under the BATTERY NAME menu. The LiFe preset values are for a 3.3V cell. The LiPo preset values are for a 3.7V cell. Here are the specs that it asks for:

Batt type: Life or LiPo?
1. Batt Volt.
2. Capacity
3. Chg curr.
4. Dchg curr.
5. Dchg volt
6. Cut temp
7. Max cap.


Thanks!

 

[Doctorbass]

Doctorbass,

Thanks for all the help. Now that I have the Megapower on my hands, I need to figure out what battery specs to put in under the BATTERY NAME menu. The LiFe preset values are for a 3.3V cell. The LiPo preset values are for a 3.7V cell. Here are the specs that it asks for:

Batt type: Life or LiPo?
1. Batt Volt.
2. Capacity
3. Chg curr.
4. Dchg curr.
5. Dchg volt
6. Cut temp
7. Max cap.


Thanks!

1. Batt Volt. 3.7V (max 4.2 when full)..
Set the charger on Lipo mode.. that's 3.7V per 1s

2. Capacity:
set it to 3000mAh because each cell a re paired in parallel and they usually have around 1500mAh each

3. Chg curr.
Set the current to 5A. each cell will take around 2.5A. when charging, that should take around 45 to 55min for full charge


4. Dchg curr.
Set it to 5A (max rate availlable)

5. Dchg volt
Set it to 3.0V.. never under this value!

6. Cut temp
I dont use that cause they usually keep temp under 40 Celsius.. but you can use the temp sensor and set it to 40-45 C

7. Max cap.
Set it ti 120%.. so if one pair of cell have more than 3000mAh your charge or discharge process will not be affected

Stop the charging process to 0.05A manually if it does not activate.. avoid keeping this trickle charge too much time cause on long period it could affect the cell life.. Li-ion dont like trickle charge (about keeping the low current after charge process is ended...it's not very good)


Here is the result i got with few of my used konion:

and the spec of those!

 

[VRdublove]

Thanks for the quick response! I'm discharging now. Can this charger discharge 2 batteries at the same time? (1 on each port?) Or discharge one while it is charging another?

 

[Doctorbass]

Thanks for the quick response! I'm discharging now. Can this charger discharge 2 batteries at the same time? (1 on each port?) Or discharge one while it is charging another?

The second port is an aux output ONLY made to recharge the remote control battery of RC car like ni-ca

I dont use it.

When you talk about battery, do you mean cell or battery? about charging 2 of them at the same time?
Cells are paired in the battery pack so i recommand to keep them paired.. they have the same age and history.. so they are perfectly matched already (usually a 18V 3Ah have 5 pair of cell in serie.

I know that it is better and faster to charge the last discharged one while you discahrge the next .. but from my side i use another charger or power supply limited to 5A to recharge every cell that have been tested(discharged).

It is IMPORTANT that when tou have finish this step of testing them, when it's time to assemble them in serie/parallel cells, that every cell are charged equally.. DONT parallel a discharged a cell with a charged one!!! that would destroy or reduce the life of that cell.. because the current that goesfrom the charged one to the discharged one would be to high.. 40-60-80A sometimes!!!.. that happened to me.. they become very hot (the discharged one)
A cell like this should never be cahrged to more than 2.5A.. (5A for a parallel paired cell)

Doc

 

[VRdublove]

Yep I mean paired cells. That is how I am discharging them, the 3 Ah paired cells. thanks again

 

[karma]

doc i found a makita service center that will save me packs. i was wondering how manny cells i would need for X2 32v at 5ah or 10ah.? :wink:

432?


cheers

 

[Doctorbass]

doc i found a makita service center that will save me packs. i was wondering how manny cells i would need for X2 32v at 5ah or 10ah.? :wink:

432?


cheers

You need 640Wh energy or 20Ah at 32V .. and each cells give you 5Wh max

that's 128cells.. and each makita packs have usually 8 good cells inside..

that's 16 packs... but you will need to get around 30 packs to get 18 working.

:wink:

 

[karma]

30 no problem ill dig for em dumster dive time

thanks

 

[steveo]

30 no problem ill dig for em dumster dive time

thanks

they recycle!

 

[karma]

yes there keeping them in a large plastic dumster. i was just kidding about jumping in. im sure all i need to do is reach for em :wink:

 

[karma]

doc looks like makita has made some changes to there packs. the thermal fuse is gone all there is for heat is a probe in the top case.
and there not using glue anymore to hold the cells together it a solid piece of white plastic. removing two cells together may prove difficult.

 

[pwbset]

I definitely encountered two different 18v LXT packs also... one with the little klickion-thinghy and one without. Never did see a pack with cells glued together though the 1.5ah 1p slim packs have a black rubbery cell holder that can be difficult to remove the cells from without also tearing the green casing. The white plastic cell holders in the 3ah are super easy to (carefully) slice through with an exacto blade so you can dremel apart and exacto into 1s2p chunks if you want. There are plenty of pictures in this thread showing the 1s2p if you look carefully.