PINNED - Lithium battery conversion/info

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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 26 Mar 2022, 00:15

Burgerman wrote:The amount of voltage drop depends on the cable resistance and the current. Presumably volts are 28.80V.

So how many amps? At 0 amps, there will be zero voltage drop.


I have just one cell connected charging to 3.6v at 40amps the line resistance is 6mo 3ft long total length the cell voltage on the balance lead display is 3.3v the charging lead display shows 3.6v. I think the 0.3v difference is the icharger compensating for 0.3v voltage drop. I wanted to make sure that isn't alot. Yea when the amps are 0 the voltage from the balance lead and charging lead display the same voltage. Only shows a 0.3v difference at 40amps

I'm about to put the pack together. 2 weeks ago I charged 7 of the cells to 3.6v. I wasn't able to charge the 8th cell until today will I need to charge the other 7 cells to 3.6v again before putting the pack together?
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 26 Mar 2022, 01:59

Dont know what your charger measures or does but thats ok volt drop.

The charger should balance them up. But you can top all 8 up too if you prefer.
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 26 Mar 2022, 13:53

Burgerman wrote:Dont know what your charger measures or does but thats ok volt drop.

The charger should balance them up. But you can top all 8 up too if you prefer.


Thanks bm
These charge leads are much better this time. It did cc until the cell reached the set voltage then cv until the amps drop to 1%. It charged much faster.

Now when I put the pack together we will see how it does charging an discharging the whole pack once put together.

I'm feeling good about it. But if for some reason I can't get it working correctly with the full pack maybe I'll pack the ICharger up real good an ship it you bm to play around with :lol:
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 26 Mar 2022, 17:26

It will be fine!
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 26 Mar 2022, 20:26

Burgerman wrote:It will be fine!


:thumbup:
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 30 Mar 2022, 14:52

What do you guys think is 4ft total length to long for balance cables 16awg?
I could possibly go 3ft but it's going to be tough getting the charger close enough. 4ft would be ideal I just don't want to make balancing take a excessive amount of time.
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Re: PINNED - Lithium battery conversion/info

Postby shirley_hkg » 30 Mar 2022, 16:17


Mine is 8 feet long .
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 31 Mar 2022, 13:56

battery guage.PNG
im changing some of the battery gauge setting for Linx to accommodate lithium. I took a screen shot of the originial settings an i listed below what i plan to change an the voltage im changing them to. What do you guys think do i have these setting correct do i need to change anymore? I put a question mark on the ones i wasnt sure what to change them to

High batt rollback start 29v
Batt gauge minimum 24v
Batt gauge maximum 28.8v
Batt gauge low voltage warning 24v
Batt gauge high voltage warning 29v
Cut off voltage ?
Batt gauge final charging threshold 28.8
Batt gauge charging detect threshold ?
Batt gauge minimum charging threshold ?
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 31 Mar 2022, 14:33

High batt rollback start 29v

What does this actually do?
A lead battery is charged at (not "to") 28.2 Gel or 29.4 AGM Max. After charge it falls from this in a curve hat starts fast and gradually slows to 12.85V. So not sure how setting this helps anything?
Lithiu ion phosphate should reach 28.8V peak while charging. Then almost imediately drop to around 3.4 something per cell. So again, what is it for?
Additionally, If I do a fast turn in place or wheelie, the lead battery drops to 24.xxV in an instant or less depending on impedance. And then recover fast to around 25v and then climb over time for the next couple of hours. I can actually get it to hit 18 volts whie fully charged.

Batt gauge minimum 24v


Is that under load, ignoring this, or while I do the above? And for how long?

Batt gauge maximum 28.8v

This is for the display. So your guage will always read around 90 to 95% full when fully charged around 10 mins after disconnecting the battery charger?

Batt gauge low voltage warning 24v

I can make it voltage actually read 18V by repeatedly wheelying or even a rapid turn in place when FULL.
Watch vid. Note that the NOW voltage is the large number. The 3 lower smaller number are peak values. High, average, low.
This is because of internal battery resistance.
Note that this has just come off an overnight charge. I dropped it to 18.X Volts - lowest figure really easly. Download to desktop before playing.
https://www.wheelchairdriver.com/gopro/voltdrop.mp4

And so all the figures you choose above are meaningless. They are there because somewhere there exists a programmer that doesent understand ohms law or batteries wrote some "exact" code! The more nonsense they add the better or more clever they feel.


Batt gauge high voltage warning 29v

This will go off if you spike the voltage upwards by slamming in reverse to slow down due to regenerative braking. So whats it for?

Cut off voltage ?


What do you want this for? Look at the vid above. Does it cut of instantly, or average over time, does it only take a reading when stick is central? All these things determine whare is at al this should be set and again we dont know. And its just down to a programmer that hasnt a clue.

Batt gauge final charging threshold 28.8
Batt gauge charging detect threshold ?
Batt gauge minimum charging threshold ?


These things are a way to allow the system to better guess what stage the battery is in. All pretty meaningless really. Esp as lithium behaves diferently to lead... So these things wont help you uch or at all. Quite the contrary. They dont much help on lead either! This nonsense is why battery gauges are useless.
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 31 Mar 2022, 14:44

Burgerman wrote:]High batt rollback start 29v

What does this actually do?
A lead battery is charged at (not "to") 28.2 Gel or 29.4 AGM Max. After charge it falls from this in a curve hat starts fast and gradually slows to 12.85V. So not sure how setting this helps anything?
Lithiu ion phosphate should reach 28.8V peak while charging. Then almost imediately drop to around 3.4 something per cell. So again, what is it for?
Additionally, If I do a fast turn in place or wheelie, the lead battery drops to 24.xxV in an instant or less depending on impedance. And then recover fast to around 25v and then climb over time for the next couple of hours. I can actually get it to hit 18 volts whie fully charged.

Batt gauge minimum 24v


Is that under load, ignoring this, or while I do the above? And for how long?

Batt gauge maximum 28.8v

This is for the display. So your guage will always read around 90 to 95% full when fully charged around 10 mins after disconnecting the battery charger?

Batt gauge low voltage warning 24v

I can make it voltage actually read 18V by repeatedly wheelying or even a rapid turn in place when FULL.
Watch vid. Note that the NOW voltage is the large number. The 3 lower smaller number are peak values. High, average, low.
This is because of internal battery resistance.
Note that this has just come off an overnight charge. I dropped it to 18.X Volts - lowest figure really easly. Download to desktop before playing.
https://www.wheelchairdriver.com/gopro/voltdrop.mp4

And so all the figures you choose above are meaningless. They are there because somewhere there exists a programmer that doesent understand ohms law or batteries wrote some "exact" code! The more nonsense they add the better or more clever they feel.


Batt gauge high voltage warning 29v

This will go off if you spike the voltage upwards by slamming in reverse to slow down due to regenerative braking. So whats it for?

Cut off voltage ?


What do you want this for? Look at the vid above. Does it cut of instantly, or average over time, does it only take a reading when stick is central? All these things determine whare is at al this should be set and again we dont know. And its just down to a programmer that hasnt a clue.

Batt gauge final charging threshold 28.8
Batt gauge charging detect threshold ?
Batt gauge minimum charging threshold ?


These things are a way to allow the system to better guess what stage the battery is in. All pretty meaningless really. Esp as lithium behaves diferently to lead... So these things wont help you uch or at all. Quite the contrary. They dont much help on lead either! This nonsense is why battery gauges are useless.


thanks bm,
thats what i thought, im just going to leave them as is i just want to avoid any error codes. But if i get any error codes ill make adjustments if needed. I wont be going by the battery gauge anyway i stopped going by it after listening to you guys that they are useless an missleading. Im going to go by millage averages and AH going back in.
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 19 Apr 2022, 13:36

I'm working on getting some backups and was wondering what you guys prioritize for having backups for first.

Backups
1. Charger
2. Power supply
3. Balance leads / charge cables / fuses / psu ac power çable
4 bus cables
5. Ring terminals

Do you guys have backups on hand for this stuff ?
Can you guys add anything else the I should have a backup of?

I feel vulnerable with only 1 of these items
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 19 Apr 2022, 14:30

Do you guys have backups on hand for this stuff ?

Yes. And
computers, software, medicines, continence supplies, bed motors, 5 powerchairs, 3 compllete sets of r-net systems, spare wh motors, drills, taps, bolts, bearings, tyres, chargers, power supplys, 5 years worth of frozen foods, cans, water, fuel, 3 generators, DC to AC inverters, solar, backup batteries, propane, diesel, petrol, 3 phones, 3 different internet connection methods, house paid for, savings, and eerything possible future proofed. You?
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 19 Apr 2022, 14:44

Burgerman wrote:
Do you guys have backups on hand for this stuff ?

Yes. And
computers, software, medicines, continence supplies, bed motors, 5 powerchairs, 3 compllete sets of r-net systems, spare w/c motors, drills, taps, bolts, bearings, tyres, chargers, power supplys, 5 years worth of frozen foods, cans, water, fuel, 3 generators, DC to AC inverters, solar, backup batteries, propane, diesel, petrol, 3 phones, 3 different internet connection methods, house paid for, savings, and everything possible future proofed. You?


:worship now that's what I'm talking about. I'm working on it. Thanks bm
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 19 Apr 2022, 18:25

I do that because to function, esp if disabled you *MUST* be prepared. Because I discvered long ago that you cannot rely on others. And that the unexpected happens. Shortages of supplys, wars, strikes, viruses, shipping issues, wars, stupid governments, stupid local authorities, unreliable banks (save gold, crypto, cash, etc). You literally never know where the next incompetant idiot, or problem will come from. But come they do, one after the other...
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 20 Apr 2022, 13:57

Burgerman wrote:I do that because to function, esp if disabled you *MUST* be prepared. Because I discvered long ago that you cannot rely on others. And that the unexpected happens. Shortages of supplys, wars, strikes, viruses, shipping issues, wars, stupid governments, stupid local authorities, unreliable banks (save gold, crypto, cash, etc). You literally never know where the next incompetant idiot, or problem will come from. But come they do, one after the other...


I read your post to mom an we are making a list. We have been working on getting backups for these things. Great advice!! I am still pretty new to my injury 12 years an learning from you guys with experience has been essential.
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 20 Apr 2022, 19:28

Youneed a list of all the things that could screw you up. Then figure out several solutions in advance.
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 21 Apr 2022, 12:50

Burgerman wrote:Youneed a list of all the things that could screw you up. Then figure out several solutions in advance.


Great idea we have two lists working on. I really do take the advice you guys give me seriously an I follow it :thumbup: This is something that should be drilled into every newly disabled persons head in the hospital an rehab.
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 22 Apr 2022, 13:01

I was curious is anyone placing fuses in their balance leads. If the balance leads are routed safely an female connectors used on the chair side. I'm not going to do this just wondering if anyone else is?
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 22 Apr 2022, 17:22

They are so thin that they will work AS a fuse if shorted out. However you can use what are called 3A polyfuse. Those are fitted to the commonly used balance boards us hobby people use when charging 3 or 4 packs in parallel. They are electronic auto resetting fuses. So anything over 3A and they open like a fuse. Disconnect the problem, and they reset automatically.

Is it worth it? As long as wires routed with care probably not.
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 23 Apr 2022, 02:15

Burgerman wrote:They are so thin that they will work AS a fuse if shorted out. However you can use what are called 3A polyfuse. Those are fitted to the commonly used balance boards us hobby people use when charging 3 or 4 packs in parallel. They are electronic auto resetting fuses. So anything over 3A and they open like a fuse. Disconnect the problem, and they reset automatically.

Is it worth it? As long as wires routed with care probably not.


Ok thanks bm,
I routed them carefully and they are all contained in the battery box.
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Re: PINNED - Lithium battery conversion/info

Postby Scooterman » 26 Apr 2022, 08:41

This is only the THIRD charge after I thought my 180Ah pack had gone terminal.

Scooter left outside all winter and voltage dropped to almost ZERO (around 4 volts for a 24 volt pack!).

It took some jiggery pokery to get pack to recover, thanks to WD.com forum members.

But it looks good now. The cells have probably sustained some damage, and I was resigned to having to buy new cells to build a new pack which I didn't fancy doing.
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 26 Apr 2022, 09:21

You were lucky.
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Re: PINNED - Lithium battery conversion/info

Postby shirley_hkg » 26 Apr 2022, 12:18


It's not about money. There were bunch of dedication to build a pack. Use it wisely with shallow discharge.
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Re: PINNED - Lithium battery conversion/info

Postby Scooterman » 28 Apr 2022, 06:16

Burgerman wrote:You were lucky.

You’re right there BM I was.
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Re: PINNED - Lithium battery conversion/info

Postby Scooterman » 28 Apr 2022, 06:16

:thumbup:
shirley_hkg wrote:
It's not about money. There were bunch of dedication to build a pack. Use it wisely with shallow discharge.
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 30 Apr 2022, 13:22

Has anyone done a 22nf battery swap to lifepo4? What's the most AH that will fit?
I have a 12 year old invacare mwd tdx sp that I just can't let go of mostly because of nostalgic reasons it was my first chair an I've taken good care of it but I only use it in winter an indoors or as a spare. I'm not a fan of mwd. I would like to fit it with lifepo4 mainly for longer service life an improved performance but the range will also be great if I need it. Also to be honest I'm missing the build process of my last lifepo4 build. What do you guys think?
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Re: PINNED - Lithium battery conversion/info

Postby Burgerman » 30 Apr 2022, 16:39

Start by measuring carefully.
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Re: PINNED - Lithium battery conversion/info

Postby shirley_hkg » 01 May 2022, 12:07


16 of these will add up to 144 Ah.
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 01 May 2022, 12:19

shirley_hkg wrote:
16 of these will add up to 144 Ah.


thanks ill check them out
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Re: PINNED - Lithium battery conversion/info

Postby fishinjunky » 01 May 2022, 13:20

shirley_hkg wrote:
16 of these will add up to 144 Ah.


with 16 cells would i make two 8s packs then connect the two 8s packs in parallel ?
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