PINNED - Lithium battery conversion/info

[Burgerman]

I like your nails...

You see those thin wires? I melt those! Got a set here all melted and burned. Really safe these powerchair manufacturers!

[expresso]

The inner case again - the divider if you notice has velcro - at the end to the rear frame - thats the part i am going to try to not happen - if i can get a new divider cut to size - i will make it shorter - before the frame and have it wider to lay on the edges for support - will give me a little room on top that way - not enough for my liking but enough to make it smoother to slide the battery tray in and out with out hitting it on top -

and Yes - they look old when new - and make it harder than it has to be - your proved that a long time ago with your chairs - which are the best that i seen - in craftsmanship and easy to make - use and service - sucks - but this is what i have to deal with - i think i can tidy this inner case better when i do this - Divider is the first item to get done correct - and then the wiring on the sides - that would leave the battery tray free - easy to move in and out -

[expresso]

haha - thats my friend helper - and those thin wires are 10 Gauge and i put them there - my direct charging cables - fused - charge at 20amps - dont have any problem with them - now if you use 40amp - then different story -

if i do the chair pack - i will use the 8AWG wire - and the charging cable - i have to follow the one you made for charging and balance etc, - but if i am not mistaken - isnt the charge cable you made and use 12 AWG wire ? the one with all the balance wires are etc, - the wires on the PL8 Charger isnt that 10 AWG and handle 40 amp ?

[expresso]

The cardboard i cut out to make a divider and see if it fits - which it did and make it wider to use the edges to lean on and keep it there stable - wont need the velcro in the rear to hold it which dosnt work coming loose anyway the velcro -

if you notice the front part that holds the divider - the two screws - the divider is screwed to that part - under it - which kinda angles it down in the case more - so i just reversed it - screwed the divider on the top part - it helped a bit - but then the other part is in the case in its place - it did help some so i will leave it that way for now -

[Burgerman]

Cant you just space the top higher by 5mm with washers?

Make a box EXACTLY 174mm x 240mm x 240mm and just test. And adapt till it fits!

[expresso]

I am not able to tell if the Black Connector is a PP75 or what every it is - as long as the Grey SB50 i have fit - thats fine with me - i wont really know that till i make a cable set one day hopefully - with 8 AWG wire - but yeah the factory wiring is not as thick as you would think - the inner wires going to the Control box behind the batteries - those wires are thicker - and the Main Black connector seems much thicker also - the thinner wires are the ones connecting both the batteries together - with the RED connector - they seem more flexible also - maybe silicon or rubber casing makes it so -

[Burgerman]

Yes - they look old when new - and make it harder than it has to be - your proved that a long time ago with your chairs - which are the best that i seen - in craftsmanship and easy to make - use and service - sucks - but this is what i have to deal with - i think i can tidy this inner case better when i do this - Divider is the first item to get done correct - and then the wiring on the sides - that would leave the battery tray free - easy to move in and out -

I started by throwing every part into a big pile, and using only the bits that were actually needed. And then did everything in the most simple way with as few parts as possible. Most of the powerchair was a mass of brackets, clips, covers, junk of some kind... I lost around 100lb of unneeded overweight badly finished crap.

[expresso]

Cant you just space the top higher by 5mm with washers?

Make a box EXACTLY 174mm x 240mm x 240mm and just test. And adapt till it fits!

it cant fit higher - i have the tilt seat lift and control box for it on top of the divider - and than those items are in a box small box to cover them between the divider - the way i did it was widen it a bit so it leans on edges and stays there -
its still screwed to the item in the front which screws in front of the control box -

i measured it needs to be about 13 1/2 inches wide at most and 13 inches at least to make it lay on the edge -

14 1/4 inch deep - which is shorter than what it is now - so this way it wont reach under the rear frame of the chair - the way it is now - its taking space away

and if i can find something thinner also but strong enough to not bend or buckle etc, - that would be even better - now finding something and if hardware store will make the cuts and size i need etc, - in the past only one place i knew was very helpful with things like that and they are no longer open - the others are ACE and Homedepot - which are not helpful at all - and seem to ask to many questions as to why this or that - if i ask them to cut this etc, etc, - they want to know what i am doing and why etc, etc, - whats the difference - can you make the cut or not - anyway that ends up with not getting it done - most of the times -

its not the same as it used to be where you had stores willing to help - they just want to sell you what they have and thats it - nothing custom to do - but i can give it a shot and see what i can get done -

in doing this - if it works out with a new divider the way i vision it - then i feel much better with the space - but still not good enough to use the 72 Cells - i feel i have a better chance of success and options if i do what Scollard suggested with the 56 Cells - because even with the 56 Cells - i would have 5 mm space left on top - if i did my math correctly - and maybe more if i get the divider done my way now - in the end - i should be able to slide that in and out easily with 56 Cell Pack -

now if for some reason it dosnt work as planned - i can then use 48 Cells and have room for sure that way - so i have a back up option this way - i will shoot for the 56 Cells - and settle for the 48 if something else gets in my way -

sound good ?

[expresso]

yeah i agreed - from seeing it - its a mess - and that would be great doing it that way - thats not a option for me at least not now - not this chair and not with the helpers i have - they are great but not that great

the only way i can something like that is - on a chair thats not brand new - i just got that chair - if i do this and they take it in for service - will be fun explaining what i did and why and how bad they did it - i shouldnt have issue with my Vendor - they know how i am already - but if anything goes wrong - Sunrise or Motion Concepts - may try to Pin that on me for touching it - its all bullshit - we know that - they find some reason to make it my fault - so i hope nothing goes wrong if i do this after -

i would need someone like you BM or Scollard - Flagman etc, someone who knows much more than me and able to do it - i need that kind of person to do it with me for me - here etc, - or else - this is about the best i can expect to do -
and to be honest - not that bad if i can get this done - my main goal was just extra range - power - etc, - the ADD on was all i was going to try -

taking so long to get started - now i got more and more thinking of the whole chair - and feeling like its a much more doable job - i am starting to see how it can really get done - i know its alot of work - i have to think about it - i need the PL8 for sure and then hope i can make a charge balance cable like you did to make it work - thats also scary -

how do you charge a single cell with the PL 8 ? i know i have to charge them all first - one at a time and store them - i will start another section for the PL8 questions soon -

[Burgerman]

Yopu go through the settings, and use a LiFePO4 preset, and choose 1 cell. 3.600V, manual choose a termination current of say 150mA, Charge at 5A. Then go through all the other settings that limit time etc . Its actually easy. I can send you a preset... You load it in, press go.

[expresso]

Yopu go through the settings, and use a LiFePO4 preset, and choose 1 cell. 3.600V, manual choose a termination current of say 150mA, Charge at 5A. Then go through all the other settings that limit time etc . Its actually easy. I can send you a preset... You load it in, press go.

Yes you can send it to me - that would be great - should i start another section for this - the PL8 etc, - or just post to this one about it ? i will have questions for sure - the PSU is one of them - this is one that seems good for the PL 8 -

http://www.hobbypartz.com/26p-efuel-60a.html - i really want one that has the on and off switch - i feel safer that way - dont have to unplug it all the time etc, and others would be using it here so - i like to have it plugged in on the power strip - with the charger etc, all together on a little table near the chair once done and charge that way - one of those little snack tables - wooden kind - thats how i will have to do it -

what other PSU do you think would be good with the PL 8 - with the On and off switch - with this stuff - you would connect everything first to power - then turn on the PSU first or the PL 8 - is there a way to power this stuff on with out damage to it or the chair cable when charging -

what would the proper safe steps to take - in order lets say - - also the Charger i would have to make a cable to connect to the banana on the PSU to the Charger for power to the charger ? these Banana plugs used - are they the same ones used in the Audio industry for Amps and Speakers ?

like these

http://www.amazon.com/Sewell-Silverback ... lugs&psc=1

[Scollard]

Yopu go through the settings, and use a LiFePO4 preset, and choose 1 cell. 3.600V, manual choose a termination current of say 150mA, Charge at 5A. Then go through all the other settings that limit time etc . Its actually easy. I can send you a preset... You load it in, press go.

Yes you can send it to me - that would be great - should i start another section for this - the PL8 etc, - or just post to this one about it ? i will have questions for sure - the PSU is one of them - this is one that seems good for the PL 8 -

http://www.hobbypartz.com/26p-efuel-60a.html - i really want one that has the on and off switch - i feel safer that way - dont have to unplug it all the time etc, and others would be using it here so - i like to have it plugged in on the power strip - with the charger etc, all together on a little table near the chair once done and charge that way - one of those little snack tables - wooden kind - thats how i will have to do it -

what other PSU do you think would be good with the PL 8 - with the On and off switch - with this stuff - you would connect everything first to power - then turn on the PSU first or the PL 8 - is there a way to power this stuff on with out damage to it or the chair cable when charging -

what would the proper safe steps to take - in order lets say - - also the Charger i would have to make a cable to connect to the banana on the PSU to the Charger for power to the charger ? these Banana plugs used - are they the same ones used in the Audio industry for Amps and Speakers ?

like these

http://www.amazon.com/Sewell-Silverback ... lugs&psc=1

Don't spend that much money for a power supply. It's crazy. Get the one I linked to on eBay. If you want an on-off switch plug it into a surge protector with a on-off switch. You will save yourself $120. That's like 5 batteries.

[Scollard]

Scollard - My other half of the order is coming next week - Cells on Monday - maybe Tuesday - holiday Monday and the extra buss bars on Wed. next week - so maybe we can start next weekend - and just wait for BMS at the end -

i took more pictures last night - checked the chair - that divider - will post the pics later - its still tight for my liking - but i can try to replace the divider with thinner one - shorter and a little wider - that would hold itself on the sides not need the velcro which is keeping it lower - the inner box has clips on the sides which the wires should be in there - and they werent - have to fix that when i do it - - i just noticed it in the pictures - i have to have a divider - on top of divider there are the control box and more wiring for the seat lift and tilt etc, - and another box over it - - so the divider has to stay put - but i can try to have one made - if the hardware store around here has a sheet of plastic - thinner and strong - i can ask if they can cut it to my size - that would be better -

but even so - its a tight fit for my liking - i may still not do the 72 cells - i am leaning on the 15ah cells the way you suggested - 48 Cell pack and extra 8 on top - which i am not sure how they would stay put etc, but when i get there - you can explain that part - one step at a time first - i like the idea of having the options this way - 90ah pack - and 8 Cells on top, if i see it fits good for my liking - then i leave it with the 56 Cells - that way - and hopefully have the room to be able to pull the tray out and back with out having to force it like now - the tops of the posts rubbing on the divider - i dont want that -

the tray is exacte size of the space - so with or with out the tray - not much difference - i feel a little better now - once i get this ADD on pack done - maybe i feel even better to keep going -

And the Red Anderson i have on the battery pack in my chair - does not fit the Grey SB50 i have - its different - but the Black one which goes to the Chair Main power - that looks the same as my Grey - i think thats the same connector -
hopefully it can be confirmed once i post the picture -

I am ready to help. Once you get the add-on done you will see it's pretty easy.

For the full pack. I would stick with the 56 cell pack. It is nominally the same capacity as the 72 cell pack but will fit easily. We will also make it so you can move your add-on pack easily.

To answer your question as to what will keep the 8 cells on top from moving; the nine 8 AWG wires that will be needed to wire it to the 48 cell pack

[flagman1776]

I used a cheap switch surge strip & plugged the power supply into it. I just turn the switch on & off to start the power supply & thus the charger.
I could have picked up a switch for the power cord (to the power supply) as an alternative... but I would have had to carefully cut back the insulation & then cut the correct conductor. I had the strip & didn't have the switch... and my hands were good right then.

[expresso]

Ok i have to check again - i actually closed my ebay account - i got pissed off with them and a recent seller - - i have to reopen it now -

Scollard - do you still have that link - but it seems so big - very long - i am not sure i have room for that - but i will look over it again -

if you have the link again - i check it out -

about the 8 Cells on top of the pack - i need 9 wires 8 AWG each ? i cant vision that right now - but if you say so - i am all in - i am going to give it a shot with your help step by step - i can get it done -

as long as i get my chair divider fixed and wiring neatly placed out of the way - i hate have to work or have someone work for me in such tight area - makes it easier for things to go wrong - when theres more room - i feel better -

i am about to check my chair again divider - to see if i can raise it a bit -

[Scollard]

Ok i have to check again - i actually closed my ebay account - i got pissed off with them and a recent seller - - i have to reopen it now -

Scollard - do you still have that link - but it seems so big - very long - i am not sure i have room for that - but i will look over it again -

if you have the link again - i check it out -

about the 8 Cells on top of the pack - i need 9 wires 8 AWG each ? i cant vision that right now - but if you say so - i am all in - i am going to give it a shot with your help step by step - i can get it done -

as long as i get my chair divider fixed and wiring neatly placed out of the way - i hate have to work or have someone work for me in such tight area - makes it easier for things to go wrong - when theres more room - i feel better -

i am about to check my chair again divider - to see if i can raise it a bit -

Here is the link to the power supply:

http://r.ebay.com/BUDQPk

Four wires to connect the bottom of the pack and 5 wires to connect the top.

I just charged my next 20 cells today. I now have 40 charged. Next Thursday I'll charge the remaining cells then I can determine my groups of 7 cells that will self discharge at approximately the same rate. Next weekend I will probably start banging together my pack.

[Burgerman]

You realise you can charge 10 or 20 at a time in parallel, one big connection? I did it in groups of 10, with 2 chargers. So 20 at a time.
Only recharge needs to be individual.

I left my last ones for 6 weeks. Makes results very clear/accurate.
There are some neg numbers too, only because I initially charged to 3.600v and 50mA per cell, and removed 1000mAh. Then later topped up to 200mA termination ( I think from memory?)

Note, this isn't AS essential with a 1000mA balance circuit on a PL8, but I still thought it best after seeing the cell destroying mess BMS systems get into for days after storage trying to balance a pack with 10x less balance power and no ability to throttle the charger...

After 6 weeks there was up to 150mA DIFFERENCE. Not too bad, that would have taken about 3 hours to balance on a BMS. But that's only because I swapped out 2 worse cells that showed 560mAh and 275mah difference, and didn't use those. They would have taken 6 to 12 hours to balance by BMS. Or much worse. That means the other 7 sets continually going over voltage on/off for hours on end every time the BMS reconnects the full power charger. Early grave!

Code: Select all


CELL NO.  RETURNED MAH.  DIFFERENCE.
MIX  to correct

ONE
1  -            1038             38
3  -            1002             2
7  -            1019             19
57 -            1050             50
33 -            1017             17
21 -            1010             10
79 -            1016             16
9  -            990             -10
42 -            1041             41
23 -            1047             47
                               total 231
TWO
11 -            995             -5
34 -            1020             20
13 -            1019             19
14 -            1016             16
15 -            1020             20
16 -            1023             23
4  -             997             -3   
18 -            1008             8
19 -            1013             13
20 -            1120             120
                               total 231
THREE
2  -            1016             16
22 -            1012             12
24 -            1015             15
25 -            1007             7
72 -            1019             19
12 -            1011             11
28 -            1016             16
29 -            1016             16
30 -            1018             18
37 -            1102             102
                               total 232
FOUR TOP
31 -            1024             24
32 -            1004             4
26 -            1018             18
5  -            1024             24
35 -            1002             2
36 -            1019             19
27 -            1024             24
38 -            1071             71 
71 -            1019             19
49 -            1025             25
                               total 230


FIVE
41 -            1020             20
51 -            1005             5
43 -            1009             9
68 -            1027             27
45 -            1056             56
46 -            1019             19
47 -            979             -21
60 -            1012             12
40 -            1024             24
50 -            1080             80
                               total 231

SIX 
52 -            1059             59
53 -            1023             23
78 -            1027             27
44 -            1022             22
76 -            1018             18
58 -            1055             55
6  -            991             -9
48 -            1010             10
39 -            1003             3
59 -            1023             23
                               total 231

SEVEN TOP
75 -            1004             4
62 -            1002             2
63 -            1005             5
64 -            1003             3
66 -            1020             20
10 -            1104             4
67 -            1057             57
17 -            1034             34
69 -            1068             68
70 -            1034             34
                               total 231

65 -            1008             8
55 -            1022             22
73 -            1068             68
74 -            1046             46
61 -            1006             6
56 -            1020             20
77 -            1008             8             
54 -            1026             26
8  -            1020             20
80 -            1007             7                 
                               total 231

[Irving]

These look interesting

The battery tray on a Spectra Plus is 215w x 360l and there's 195mm height available at the rear of the tray when seat fully tilted back.

These packs are 210 x 260 x 6mm. Laid flat you can get 195/6 = 32 packs in which is 8S4P giving 24v @ 120Ah, chargable at <240A and <360A continuous discharge. More expensive than the Headway cells, but easier to assemble and better energy density.

What am I missing?

[Burgerman]

Missing? Nothing. They are ok but the same C rate as the larger prismatics and a bit less than Headway cells. Those are copies of the 20Ah A123 pouch cells used in cars. As long as you use plenty of them for high capacity they will be fine. But quality? Unknown so how can we know if they will be good in a few years or not swell up etc?

[Scollard]

You realise you can charge 10 or 20 at a time in parallel, one big connection? I did it in groups of 10, with 2 chargers. So 20 at a time.
Only recharge needs to be individual.

I am at my recharge step after 1 month of storage. I now have the self discharge numbers for 40 of my 58 cells.

[Burgerman]

Frustratingly slow isn't it. I had 82 to do. And 2 were markedly worse. So were not used.

They will get another job. I need a longer life pack for my auto mower... http://www.wheelchairdriver.com/gopro/fastmower.mp4

[Burgerman]

viewtopic.php?f=2&t=5380&start=160#p76313

[Burgerman]

For all those that want to know why you cant measure state of charge by measuring voltage...

This graph shows a powerchair pack being discharged for five and a half hours, at 4 Amps continuously on my PL8 hobby charger... So far.

Its already had a previous 10Ah removed, and during that time the voltage sat at 3.305 Volts exactly, across all cells. Now, another discharge session for a further 5.4 hours so far shows it is STILL at exactly 3.305V per cell. And showing no sign of dropping yet. Nor will it for another 5 hours at least. Then it may drop by 0.001V or not...

Voltage CANNOT tell you how charge a LiFePO4 call is.

[Irving]

Two of these turned up today, at just over £6 each inc P&P it seemed silly not to. Will get some Andersons put on them. They are the same as the Turnigy ones but branded G.T.Power, took 6 days from China.

[Burgerman]

I have a few. Some on solar panels, some on powerchairs. Very enlightening. You need an extended cable or two, so you can watch as you drive. If you put one on a motor cable you should see a massive Amp difference.

I use my clamp meter. Motor amps read 100 while the battery reads 40 at low/stall speed. On a hill its the other way around.

[Burgerman]

7.1 hours and still no change. 28Ah out (plus original 10Ah) and still no voltage change.

[shirley_hkg]

To avoid abusing the pack too much, therefore, I'd recommend a gentle push on your joystick, for the first 10 minutes of each recharge.

Wont be an issue. The resistance and peukert on lead will stop it mattering. The pack will just slowly top up the lead initially. There will not be a huge current flowing after the first few secs. Cables and connectors and peukert will add adequate resistance on initial connection, and in use under heavy load the Odyssey has LESS voltage drop than gel does. So less current will flow. But more will flow off load to recharge the lead afterwards.

Here are my observation on voltage drop on load of my chairs.
2 chairs are of same model, INVACARE. GB, weight 230Kg with user together.

Batteries are 200Ah @ 24V A123 20AH prismatic pouch cells (5C) ,
140AH @24V A123 26650 cylindrical cells (30C)

Voltage drop:
0.15V @ cruising
0.25V @ start up / going up ramp to pedestrian bridge
0.32V @ going up ramp with my wife of additional payload of 120 lb. (NEARLY 2 volts drop on a pair of 85AH Fullriver AGM.

Chair feels completely different on lithium.
BEWARE ! It's a ONE WAY TICKET.

[Burgerman]

If you only get 2 volt drop you are doing well.

[shirley_hkg]

Not quite sure. May be over 2 volts.

Just returned to lead for a week's trip to Bangkok last October.

[Burgerman]

I can get it down to 18V from 25v in about .5 of a meter!

http://www.wheelchairdriver.com/gopro/voltdrop.mp4 This is a fast meter with high sample rate. It is measuring highest, average, and lowest. Small figures at the bottom. Play it slow...

And on a long 2 hour 6.5mph drive it drops to about 20V on slight uphill sections. Lead is truly crap!