PINNED - Lithium battery conversion/info

[UnicornBurner]

After looking into your links, I believe you are concerned about the banana plugs we soldered to the end of our cable that plug into the PL8.

We are not charging anything yet, just getting comfortable with the ZXD and PL8 prior to doing the initial charge as per your recommendation.

It appears you recommend, aka we “must” get 4mm insulated banana plugs and replace what you see in the pic.

Would this be a good example of the type you suggest? https://www.amazon.com/Insulated-Straig ... YJJ81?th=1

We will buy them from a reputable source, I just want to be sure we are on the right path and not the melting path.

Thanks!

[Burgerman]

Yes, same.

Until they are fitted be very careful that the bare ends do not get pulled out of the charger and allowed to touch. Thousands of amps will try to flow. And that would be bad.

Are all cells fully charged before assembly?
Are all joints soldered? Crimping alone is not good. Even if it seems OK today its likely to cause future balance problems.
What PL8 profile are you using to charge?

Initial charge will take longer to balance. Minutes if all cells are already at 100%. If not it may take literally days... And the full cells dont like that. Details especially initially, matter.

For e.g if cells are not very balanced and it is taking some time, better to drop charge voltage to 3.525Vpc while it gets there. Then do a top up INITIAL charge at 3.650V per cell. And then charge at 3.550V per cell from then on.

Termination current should be around 1/500th of C initially. Then after everything is balanced it should be adjusted until a full charge termination happens about 15 to 30 mins after balance ends.

[Burgerman]

The PL8 software is pretty much essential esp at the beginning.

Heres the latest PC software, and this includes the newest 3.5 and 3.6 firmware that you will need if its lower. Its also includes the driver for the FUIM3.

http://www.wheelchairdriver.com/doomed/PL8.zip

[shirley_hkg]

Your charge cables are pretty overkill. 10 awg wire are good enough.

Inter-connect 8awg.

[UnicornBurner]

Thanks for the advice on the wire size.

My husband decided to go with the #8 flexible battery cable because our charging cable is 14 feet long and he was concerned about using #10 with that long length. We need to be able to charge when on travel with our motor home/caravan and need the longer length cable.

What do you think?

[UnicornBurner]

Burgerman,

We are ordering the insulated banana connectors today and will be super careful as you suggest until they arrive, thanks.

No, we did not fully charge the batteries before assembly.

Yes, all joints are soldered.

No, we do not have a PL8 profile for charging at the moment. My husband is reading through the PL8 manual to gain a better understanding. He does understand the power supply. Shirley shared a similar recipe for initial charge as you recommend and we will follow it. Is the “PL8 profile” the “recipe” you are sharing with the initial and subsequent charging specs?

Also, could you tell us what “terminating voltage of 1/500th of C” means?

And thank you for the zip for the PL8. Our only challenge is locating an FUIM3. Can’t find one?

[shirley_hkg]

Termination current should be around 1/500th of C initially. Then after everything is balanced it should be adjusted until a full charge termination happens about 15 to 30 mins after balance ends.

C is the capacity of battery. You are using EVE-105 cells, so C is 105.

105/500 = 0.21 ie 210mA.

BM suggests to set termination current @210mA.

A few cycles later, adjust this value , so that PL8 stops within 15--30 minutes, after ALL CELLS BALANCED.

You could only do this by comparing the graphs of the charge process. That's why I emphasized the importance of getting one FUIM3 at least. Can't graph without it.


I loaded one of BM's presets to all PL8 I sold. I couldn't test it, otherwise.

[Burgerman]

No, we did not fully charge the batteries before assembly.

Then it will either take hours to days to balance up initially. Or you need to charge one cell at a time with a simple single cell profile, and a crocadile clip simple connection to one cell at once. No balance wires needed and no need to disconnect anything. BEFORE initial charge.

Why? Because is a cell has say 5Ah difference to the rest it will take 5 hours at 1000mA balance current to balance it up. If theres 30Ah difference it will take 30h to balance. Easy enough to do all 8 one at a time to get all 8 full initially. Initial charge always needs some time to balance properly even if all cells are nominally 100% initially.

If you need a single cell charge profile that doesent need balance wiring and you probably do, then I can upload a profile for that. But again you need the CCS software and the FUIM3 to load it and any other profiles you want to add or use. Its pretty much an essential to see on screen whats going on, to change charge settings and to load profiles and update firmware. So you need to find one new or used. I have never charged a chair without controlling everything via a laptop yet. I do when at a flying site for hobby stuff only. And I dont really like it, it feels "naked"... And like you are not in control.

The reason you need my profiles and not the ones they come with for everything is that I have some access that you dont. And there are a lot of settings that are hidden that are changed so that he bigger packs are able to be set correctly without errors tripping you up or unable to set certain things correctly like timeout or voltage and cell limits. Its all super safety nazi as stock that is a pain in the ass.

This applies to all chemistries but esp to lead and lifepo4. And esp large packs. And all the default cellpro profiles are really set up as rediculous super safe for hobby lipo type firecracker packs.

[fishinjunky]

Cable is done. Charging time! Fingers crossed.

looking good and organized well done .

did you put a fuse in your charging cable on the battery side? it may not be as important if you use the safe banana plugs but m not sure. What do you think BM?

wont be long before you tell your hubby '' im ready for 230ah"

[fishinjunky]

No, we did not fully charge the batteries before assembly.

Then it will either take hours to days to balance up initially. Or you need to charge one cell at a time with a simple single cell profile, and a crocadile clip simple connection to one cell at once. No balance wires needed and no need to disconnect anything. BEFORE initial charge.

Why? Because is a cell has say 5Ah difference to the rest it will take 5 hours at 1000mA balance current to balance it up. If theres 30Ah difference it will take 30h to balance. Easy enough to do all 8 one at a time to get all 8 full initially. Initial charge always needs some time to balance properly even if all cells are nominally 100% initially.

If you need a single cell charge profile that doesent need balance wiring and you probably do, then I can upload a profile for that. But again you need the CCS software and the FUIM3 to load it and any other profiles you want to add or use. Its pretty much an essential to see on screen whats going on, to change charge settings and to load profiles and update firmware. So you need to find one new or used. I have never charged a chair without controlling everything via a laptop yet. I do when at a flying site for hobby stuff only. And I dont really like it, it feels "naked"... And like you are not in control.

The reason you need my profiles and not the ones they come with for everything is that I have some access that you dont. And there are a lot of settings that are hidden that are changed so that he bigger packs are able to be set correctly without errors tripping you up or unable to set certain things correctly like timeout or voltage and cell limits. Its all super safety nazi as stock that is a pain in the ass.

This applies to all chemistries but esp to lead and lifepo4. And esp large packs. And all the default cellpro profiles are really set up as rediculous super safe for hobby lipo type firecracker packs.

i agree. pc software with graphs are essential to us to be able to know whats happening with the pack an to diagnose any problems. Im using a iCharger its the second option behind the better pl8. The icharger pc software is not as good as the pl8 software but is ok. Im able to read the graphs moniter an log the charge data an control it from my pc.

[fishinjunky]

Progress!
We made our first pack and are working on the cord end that will plug into the PL8. Thank you to you all for the helpful information and to Shirley for his assistance with the PL8s ZXDs and EVERYTHING else.

whats type an size fuse did you use in the power cable and what type of fuse holder?
thank you. I like the small fuse holder. May use a fuse holder on my next pack.

[Burgerman]

Fuse near battery set to say 40A or 50A is a good plan. Because if anything crushes the charge cable or something shorts out the charger end, it will then blow and save the cable melting and burning...

Even with the safe connectors.

Yes having 100Ah in place of 80Ah lead is OK. But because you will be discharging them at an intermittent rate that can reach 200A plus now and again its not nice to the lithium. Lead doesent much care. Lithium does. So when using a small lithium pack it must really be a high C rate one like the olde Headway cells. Because otherwise this will shorten the life of those 100Ah ells. Tis is effectively cut in half with a pack double the Ah. So now its not an issue.

And because they are "only" 100Ah you will be discharging them much deeper on a daily basis than a 200+Ah cell twice the size. More in fact.
And if you leave say 20Ah in reserve (to get a good service life) and be sure you dont run them too low in error (you need to get home) then you really only have 80Ah to play with. Thats not too bad. Since you only get a usable 50Ah from lead. But its not a huge improvement, just 30Ah more that us useful to you. Thats noticible. But its nowhere near the 400% plus rangevand safe reserve the 230Ah cells would give you.

Also because the 100Ah is so much lighter then chair stability may be a real issue.

With 230Ah, which does fit. You get much more than you expect. Why? That usable 50Ah from lead means you have 4x the range, while still leaving 30Ah in safe reserve! And because average daily discharge is going to be far less then you can expect say 10,000 cycles. Instead of say 2000 with a smaller pack. Even more if you charge it say twice a week because with that sort of range thats all thats required. Maybe less. So those thousands of cycles are really thousands of weeks! The battery will be discarded or used for solar storage or something else long before it ever dies.

[Burgerman]

Another reliable safe source of 230Ah cells here. A and B grade but tested and direct from manufacturer. https://www.fogstar.co.uk/collections/l ... ll-grade-b

[UnicornBurner]

Thank you BM for your observation about our ability to use 230ah batteries. We did not think they would fit, but low and behold the EVE 230ah do fit in our Jazzy/Quantum Q6 chair. And yes FJ, I did quickly ask my hubby to upgrade to 230ah.

Luckily the EVE 105ah did not go to waste, we were able to install them in a chair our friends use that takes U1 batteries. So if anyone out there uses the little chairs that take U1 batteries, the EVE 105ah will fit. You will need to make two packs of 4 EVE’s and an extended cable to connect them. It’s a tight fit, but a great lifep04 solution for small chairs.

Thanks you again to you all for your support and excellent observations.

[UnicornBurner]

Hi All,

Our next question is about what to do after initial charge. After we have balanced all cells and completed initial charge, do you have a PL8 formula for 105ah and 230ah packs to charge on an ongoing basis? I assume this is a different formula than the initial charge?

We did receive a FUIM3 clone yesterday, thank you Shirley! We do not have the software yet, but I believe there are links provided elsewhere here if I search.

It was suggested to keep the the PL8 at 10amps for the initial charge. Can we “turn it up” for regular charging for ongoing charging?

It was suggested to charge to 3.53v for initial charge. Can we go to 3.6v ongoing?

I realize there is discussion about this in the thread, but I am struggling with the “search” function in order to find it, so any recap on this is appreciated.

[Burgerman]

OK lots of bad info there.

If you have a PL8 then you will need the software.
https://www.wheelchairdriver.com/doomed/PL8.zip

Make sure you use firmware 3.5 or 3.6. Its all inside the PC software.


And you will need some of my "secret" profiles. Thers a bunch of parameters in them that are not visible or changable in the normal PL8 software. So I will post these soon.

OK.
1. Initial charge should be to 3.65V on an individual cell basis before assembly. Or at least by using croc clips to each of the 8 cells one at a time afterwards. And this should be at around 30A or 35A on a cell as large as the 230Ah ones. Thats a LOW rate! After they each reach 3.65V, and sit there for 30 mins, stop charge and move to the next cell. Rinse and repeat.

Now connect up as an 8S pack, and use the PL8 to discharge around 10 Ah or more. Preferably 20 or 30.

Then you need to charge at the same 30A (up to 40 if you want, thats still quite low on a big cell like 230Ah). You CAN charge at 10A, but if the battery is low then that will take a full day, 24+ hours inc balance. Which is crazy. As it is a 40A charge is still only one sixth of a C or very low. 6 hour charge from empty. A 30A charge is usually OK as it manages this overnight.

And the charge voltage should be either 3.550V per cell. Or 3.600V per cell.
All the other parameters, such as balance settings, and termination settings are preset in my profiles. But the termination current will be wrong. Every pack varies.

You need to adjust that terminaion current up or down untill it hits CV and then sits there at the CV voltage for approx 30 mins. You do this over the next 5 or 10 charges in use.

[Burgerman]

OK here are 4 presets.

2 are for SINGLE CELLS and do not connect balance wires. Termination current may need fine tuned but should be OK. 2 hour CV limit.

2 are for charging 8s packs. And again, as above. No CV time limit as at least on initial few charges we want time for balance to work. It ca take a long time.

[UnicornBurner]

Thank you BM, your post makes very good sense and is easy to follow.

We have not charged the 230ah yet, just our 105ah. We will follow the recipe of individual charges, then top off, then discharge, then recharge as you suggest. We also only briefly played with the 105ah after initial charge. We will discharge and recharge as you recommend as well. The amps you suggest make so much more sense, we just misunderstood previously. Newbies you know.

Thank you also for the program and profiles. We will look into downloading all of that before charging.

And thank you to Shirley for sourcing and sending our supplies. They arrived yesterday in excellent condition!

We will keep you posted!

[Burgerman]

Steep learning curve. But once you get it and do it its easy.

Stock 55Ah lead bricks are only really good for 45 to 50Ah. Because of a thing called peukert. So you now have 5x that.
So if you got 20 miles per charge before, now you get 5x that.

So 230Ah if decent cells, will give you around 100 miles. Or charge 5x less frequently. Meaning they last 5x longer anyway. Its best to be somewhere in the middle. Discharge them about halfway and charge. If you plan a long day like say an airshow or something, lots of grass, hills, do a full charge before you go and never run out. Nobody really needs 100 miles range in a powerchair (even expresso) it just ensures that the batts get an easy life and so last decades. And you never get range anxiety.

[fishinjunky]

Thank you BM for your observation about our ability to use 230ah batteries. We did not think they would fit, but low and behold the EVE 230ah do fit in our Jazzy/Quantum Q6 chair. And yes FJ, I did quickly ask my hubby to upgrade to 230ah.

Luckily the EVE 105ah did not go to waste, we were able to install them in a chair our friends use that takes U1 batteries. So if anyone out there uses the little chairs that take U1 batteries, the EVE 105ah will fit. You will need to make two packs of 4 EVE’s and an extended cable to connect them. It’s a tight fit, but a great lifep04 solution for small chairs.

Thanks you again to you all for your support and excellent observations.

looks really good i like a really organized pack. Now you got me wanting to build another pack with 230ah cells mine is 200ah. But im going to wait until i get a new chair in 2 years.

how is charging with the PL8 and ZXD going?

[Burgerman]

200 or 230 is just a 15% bigger than you have. Or if you prefer yours is only 12 percent smaller...

I doubt you would be able o tell the difference in use. So dont stress it! Its the difference between 88 miles or 100 miles wwhich is both how shall we say, plenty!

[fishinjunky]

im discharging my 200ah pack at 5amps for storage. Below is the internal resistance for each cell. Are they high? should i be concerned about cell 2 an cell 6?
the pack is 1.5 years old.

cell 1 = 0.40 ir
cell 2 = 0.50 ir
cell 3 = 0.30 ir
cell 4 = 0.30 ir
cell 5 = 0.30 ir
cell 6 = 0.50 ir
cell 7 = 0.30 ir
cell 8 = 0.30 ir

[Burgerman]

They are as close as its practical to measure. That is a minute difference. A tiny bit of oxide or difference in metals on the termnals on the terminals or connectors makes 10x this much difference.

The only sensible way to measure cell resistance that is remotely accurate is by using a AC IMPEDANCE meter. Seperately on each cell. At the half charged (50%) point. These use 4 probes, 2 per terminal. They are accurate. You cant take an accurate DC resistance measurement that means anything by reading what a charger says. If it said one was 40mOhm, and the rest were 5, then you would start looking for a dirty or loose connector.

So dont take a lot of notice of it!

[fishinjunky]

They are as close as its practical to measure. That is a minute difference. A tiny bit of oxide or difference in metals on the termnals on the terminals or connectors makes 10x this much difference.

The only sensible way to measure cell resistance that is remotely accurate is by using a AC IMPEDANCE meter. Seperately on each cell. At the half charged (50%) point. These use 4 probes, 2 per terminal. They are accurate. You cant take an accurate DC resistance measurement that means anything by reading what a charger says. If it said one was 40mOhm, and the rest were 5, then you would start looking for a dirty or loose connector.

So dont take a lot of notice of it!

ok thanks for the reassurance BM as always.

im discharging my pack now. How many AH should I remove for storage an how often should I charge while in storage (with battery still connected to chair) ?

[Burgerman]

I take about 1/3rd to 1/2 the Ah out of long term stored chairs. And if not using it for a week, I take about 10% out.

I do a full charge/balance every 2 months. Longer isnt a problem but they seem happier when used now and again. Stops them getting so much out of balance too. Its not critical.

[wheelie207]

I read about the BMS stuff but I found a site that sells group 24 lithium batteries I was looking at for my permobil F3 Corpus chair. Will the battery display show the correct power level with these batteries. Here is a link for the battery that I'm looking at and wondering if I'm making a good decision as I want better batteries that I get from my local wheelchair repair company. https://www.litime.com/products/litime- ... 0wh-energy

Harold Hartley
Phoenix, AZ 85022

[Burgerman]

I am so fed up with repeating the same thing every few weeks.
Will it work. It *might* work in some chairs depending on the controller fitted, and the programming of your chair. Heres the problem. If you drive like my grandma, are not very heavy, have a slow chair, or one programmed like a stock chair (sluggish and gutless) then even with a 120A control module fitted it may never pull more than the 100A limit that this battery is capable of. Note that if you exceed 100A draw, its BMS will chop of power completely and you stop dead. It then needs to be reset so you an continue.

If your chair is faster, is programmed to "go" and to turn with high turn acceleration, you are heavy, or you climb ramps, curbs or accelerate up a steep hill then your 120A R-net power module may demand up to 120A per channel. 240A total. If I fitted this to my own chair it will definitely cut out with monotonous regularity.

So the answer is that it depends.
I might add that lithium works much much better if a much larger Ah pack is used. To realise the actual advantages the lithium CAN provide then you need a fair bit more Ah. 100Ah is not much better than 80Ah lead. On this site we now use for e.g 8x 230Ah cells and this allows a lot of advantages over what you are looking at. Instead of getting a bit of extra range you get 5x the range. Around 100 miles, and around 2 decades of service life because of the light loads and the shallow discharges and infrequent charging needed.

1. They will fit in the same battery volume.
2. NO BMS! And at the same 1C discharge rate, instead of a 100A limit you have a 230A limit. In line with potential discharge load you chair can demand.
3. Your average daily discharge level will be far, far lower, giving a much much longer service life.
4. A hobby style charger does a much better job of charging, offers more control, charges much faster at 40 to 70A.
5. The average daily discharge rate will be less than half in C rate prolonging service life further.
6. FIVE TIME the range. A massive increase over swapping 80Ah lead for 100Ah lithium. Mostly because you need to leave some in reserve with lithium anyway.

So its up to you if you want to risk reliability issues (balance, cell death, shorter lifespan, cutting out under load etc for little gain in range) or not.
I know that a few here like nandol (deceased) tried this and it kept leaving him trapped needing rescue. So the battery supplier disconnected the BMS inside so that he didnt keep getting stuck. So there are much better ways to do this. The Dakota 120Ah lithiums at least have a much better higher current BMS. But all BMS can cause issues...

[Burgerman]

No the battery display will show full practically all the day, and may lose 1 or 2 lights rapidly right at the end just before the BMS chops of power...
These are no like lead. The battery capacity is almost impossible to determine between 95% and about 10% by voltage alone and a few joystick lights.

One of the further advantages of fitting a 230Ah setup is that with all that capacity you cannot discharge them completely in a day as you will wear out long before the battery. No gauge needed. And the hobby charger will tell you exactly how many Ah you return when charging.

I think the closest anyone got was our freind expresso in new york with 80 miles GPS on his phone and a sore bum.

[wheelie207]

From what you posted I think it's time I built a custom wheelchair like you did and order my own parts like you did. I spent most of my time outdoors and I usually can do the 20 miles I get from my chair. I could do more if my chair and battery would allow it. I think I'll follow the links to the parts you have on the web site. Also what are people using for chargers now to charge up the lithium power cells.
I just haven't been on here for a few years and need to catch up on the latest info.

[Burgerman]

I have 6x pl8 chargers. Those are no longer made. But shirley keeps on supplying them. I got another 2 recently!

And theres 2 complete with power supplies in the buy sell bit here right now...

Others are using the iChargers, but they dont have any sensible PC software and the way you set the termination current is a bit odd. But common on hobby chargers. So those are usable too.