PINNED - Lithium battery conversion/info

[shirley_hkg]

87.5 Ah recorded @ 3.00V termination; … for a TDX backup chair.

Pretty small at today's standard.


Costed @73% that of a new pair of MK gel .

[ICEUK]

Alot of sweat and toil has gone into my lithium pack, i am pleased with result. I will start charging tomorrow,

[Burgerman]

I am seeing a lot of very battered looking crimps. I do hope they are soldered... Or there may be trouble ahead...

[ICEUK]

Yep all soldered, will charge pack tomorrow so hopefully resistance will be kk

[swalker]

You have short, straight cables between the cells.

It would be better if those were longer and curved a bit. That would allow for some movement without stressing the posts or connectors.

Other than that, it looks good. It must be exciting to be at this point!

Steve

[ICEUK]

I am going to discharge my pack to 3volts per cell, thats ok? Then do a full charge, can see how balanced pack is and resistance.

[Burgerman]

No FIRST fully charge, and allow the charger to completely balance the pack. Twice or 3x. Then do a discharge check. And that will show if all cells have similar capacity.

[ICEUK]

Here is a ss of the pl8 when finished, i will charge pack a few times.

[ICEUK]

What should i discharge the pack too? 3volts?

[shirley_hkg]

3.00V

When done , lower termination current to 180 ma for recharge.

[Burgerman]

Looking better.

[daunjan]

Hey there has anyone tried these? RELiON Lithium Iron Phosphate batteries (LiFePO4)... Can buy here instock looking for quick easy set for friend...They have 2-3yr warranty

https://relionbattery.com/technology/why-choose-lithium

Thnxx...

[Irving]

Hey there has anyone tried these? RELiON Lithium Iron Phosphate batteries (LiFePO4)... Can buy here instock looking for quick easy set for friend...They have 2-3yr warranty

https://relionbattery.com/technology/why-choose-lithium

Thnxx...

Complete waste of time & money... $1700 for two 75Ah bricks (RB75, G24 size) with included Battery Murdering System that you don't need or want. You can fit 180 - 200Ah in the same space DIY for about 2/3 the cost and a little effort.

[ICEUK]

A couple of pictures showing resistance and the pack charging up, it looks ok?

[Burgerman]

So far. Screen shots area bit literal! And hard to see though.

[ICEUK]

No problem BM, I will get the files uploaded to website showing a full cycle.

[terry2]

No problem BM, I will get the files uploaded to website showing a full cycle.

In windows, just make the program full screen. To take a picture just press the "prt sc" button.
Then load it in to paint then post it here.

[ICEUK]

If i charge my lithium pack all cell voltages are 3.595 then it stops but if i continue to watch the voltages one cell in particular loses more voltage than all the rest, is this a weak cell?

[Burgerman]

Depends on your definition of weaK.

Some cells will have a greater self discharge level. So if all charged equally that cell will drop in voltage faster. But voltage isnt capacity.
Some cells may have a greater capacity that other cells. Those become empty first. Or if unbalanced are full first.

But also, some cells are LAST to be charged full. While the rest are sat and soaked at the full voltage. This last cell as less time sat full. So discharge by 5 or 10 Ah, and recherge. Do this half a dozen times and that lower cell may vanish. Alternatively charge all full. And then charge ONLY THAT ONE, to 3.625V for a while. Then discharge, and recharge.

Also it matters how fast it discharges. And do you have any graphs, or screenshots?

[ICEUK]

Hi bm, thx for reply. Just doing a charge on pack then i can post the graphs, my tablet decided to retire a few days ago so now i can get the file uploaded with new laptop.

[ICEUK]

Here is a charge file, i think it looks ok?

I added .txt. To file extension so i could upload ot

[Irving]

Here is a charge file, i think it looks ok?

I added .txt. To file extension so i could upload ot

Looks OK to me, you added just a few Ah to bring all cells to balance...

[ICEUK]

Thx for having a look, i just done 10miles in the chair and returned 35ah, never have i been able to do 10miles with lead bricks.

[swalker]

Welcome to the world of long wheelchair rides!

Steve

[Burgerman]

Thx for having a look, i just done 10miles in the chair and returned 35ah, never have i been able to do 10miles with lead bricks.

What size cells?

176? So you should get 176 div by 35 = 5 x that 10 miles. Thats 50 miles to empty. Thats much worse than many of us. Pump your tyres up!

[expresso]

Thx for having a look, i just done 10miles in the chair and returned 35ah, never have i been able to do 10miles with lead bricks.

you could do about 4x that - looks like your used 105ah Cells ? 200ah - 210ah pack ?

[ICEUK]

Yes 210ah pack, 40miles really world is plenty for me.

[Burgerman]

I think that you will/should get a lot more than 40 if you were to try. If not then the motors must be pretty tired. What chair is it? You are using more Ah per mile than most people do. Similar to a chair with 4 motors.

[ICEUK]

My salsa is brand new but i got 8mph motors fitted and all electric, lift, tilt, recline, footplates, im a 100kg.

[Burgerman]

8MPH will reduce range a lot, esp if you do a lot of shuffling aroud indoors. And the heavier you are the worse it gets. But I think you will get more miles per Ah next time.