PINNED - Lithium battery conversion/info

[Gnomatic]

I had my battery box on my wheelchair extended by 30mm, I'll get some pictures up when its finished printing

Looking forward to seeing your creation!

[ICEUK]

I had my battery box on my wheelchair extended by 30mm, I'll get some pictures up when its finished printing

Looking forward to seeing your creation!

Yea no problem, i will get some high res images uploaded when its fomplete, i printed one box as a prototype, i made the fompartments different sizes to see what works best, i have finshed final design and i'll starting printing tomorrow, it will take 4days for one box but it does look good.

[terry2]

Can you post pictures of your wiring please

Thanks

Thank you very much.

[ICEUK]

Here is a image of my 3d printed battery box

[Gnomatic]

That's awesome!!!

What are the outside dimensions of your box?

[expresso]

very nice perfect fit -

[ICEUK]

My dimensions are

179 wide, 234 length. 208 high

I had my battery compartment enlarged by 40mm

[Gnomatic]

I don't have that option with my chair, but I'm glad it was for you. Again, great job!

[wilsonintexas]

I lucked out and got hold of a power lab 8x2 2688w 2 channed battery work station.

What firmware updates do i need to check for and what settings do i need to adjust?

I plan on charging lead acid as well as lipo batteries.

[Burgerman]

You dont want that. It cant use my modded presets, will give issues...

[shirley_hkg]

Putting 8 X 230Ah cells into pair of original battery boxes of an INVACARE .

[shirley_hkg]

Just passed my threshold , still going .

[Burgerman]

220 Ah. Whats going on with cell 6? Has it been working out? This is why having a stupid bms that balances all the time would UNBALANCE your pack severely. Some do this and think they are doing a marvelous job!

[shirley_hkg]

It's the last hour shot I zoom in for details .

This is the first run , and #6 might have been kept at high volts longer than the others , during balancing.

[Burgerman]

On the first charge I make sure they all sit for at least 1 hour at 3.600V and sometimes then also 15 mins at 3.650V. So I know all really are fully saturated to start off with.

Then reduce everything to 3.550V for all subsequent charges with 15 to 30 mins at fully balanced condition. By setting termination current to achieve this.

[Burgerman]

Heres some LEAD and LITHIUM ION PHOSPHATE profiles that are for every size pack, and for AGM and GEL lead as a single set of user presets. 20 of them. Inc various sizes of single cell when building.

Modify these on LifePO4 packs by adjusting the TERMINATION CURRENT. So that they terminate around 15 to 30 mins after Cell balance is complete. I cant guess that well, as every pack seems different.
Once its all charging and balancing well, after a few cycles, you can reduce volts per cell to 3.550. Not less.

The single cell ones will end 15 mins after CV. On a timer.

Load file via from the top menu: FILE > RESTORE ALL USER PRESETS

[shirley_hkg]

Roger that .

[Fedor]

Hello!
Does anyone have any experience with the different grades of EVE 105ah cells?
In my country I can buy this new Grade A cell for $115 or Grade B for $55 and that is a big difference.
The seller claims that the Grade B ones he offers have the same capacity as the new ones and the life span is still good. What do you think?

[Burgerman]

I think he lies

B grade cells generally are failed cells. They maybe had too high humudity during manufacturer. They are inclined to swell up or "bulge" more easily. They have higher internal resistanve and more importantly higher or less consistent self discharge rates. So go out of balance rapidly.Especially if not charged daily. So you end up with maybe almost as much range as A grade perfect cells. And more problems with balancing, and increased impedance down the road. If it were me I woud only buy A grade cells. Esp if you plan on using a BMS which will really struggle with them. And some B grade ones may be USED, or very old. Beware! Theres a good reason they are a lot cheaper.

[lew247]

Hi all
I'm extremely new here, my background is in electronics and radio so I am familiar with a lot of things.
I've just got my first "2nd hand" mobility scooter and while I know it's not the same as a powered wheelchair I am hoping someone might be able to help
The scooter stalls in grass, I'm 17Kg under it's maximum weight so it might be part of the problem,it also slows down a lot climbing hills,
It has new batteries in it, 12V 12Ah X2 ie 24V 12A
I'm going to check it out later and find the speed adjuster pot and turn that up, but I suspect the main problem might be the batteries and
I'm hoping changing from lead acid to Lipo4 or even lto batteries could make this mobility scooter a decent runner that will have a longer range and not stall when its under pressure from hills etc
The main problem I have is the new batteries have to fit inside the original battery pack "swmbo" insists that it stays like that
Has anyone any suggestions on which batteries to make the new pack out of?
I often buy from China and I don't mind waiting for the delivery.
Other than the batteries what's the best (cheap) way to charge making sure I can monitor the current etc, I did read the bit that says don't use a BMS

The size of the SLA batteries is 151mm Width 99mm Height 100mm each battery

Lewis

[Burgerman]

I have some bad news for you. Expecting some minute 12Ah batteries (the same size as my model helicopter (which is also 37v nominal) , and smaller than my mower to drag a full sized human around is rather optomistic.

Not only that but the controller on that scooter will be sized to not collapse the voltage of it tiny battery too. So little in the way of torque to drag your self around either.

Do yourself a favour. Find a sensible sized scooter that takes 50 to 100Ah batteries to give yourself a chance. And leave that one on the car boot for flat smooth shopping centres. And then convert that to lithium if it still cant cope.

[lew247]

Unfortunately I live in an upstairs flat and it's impossible to have a larger one as it has to live in the car boot, there's nowhere to store it when I'm not using it and I cannot lift it up the stairs

[Burgerman]

Sorry about that. But the facts are the facts regardless of where you live.

[steves1977uk]

BM, can I have you advice please? I have 18 105Ah EVE-LFP cells to charge for saker98. Can I charge them at 50A with my Shirley PSU if I set the volts to 3.65v? Or is it better to use the PL8?

Also after a full discharge-charge cycle, what settings are best for storage? saker98 hasn't got a charger for these yet, and it'll be very hard to get a PL8 unless I get lucky and come across one.

Thanks,

Steve

[Burgerman]

You could connect all of them together in parallel and charge all to 3.60V with the power supply. I do them that way. Leave the lot at 3.60V if its a first charge at 3.6V for at least 45 mins to an hour. To allow all of them to soak up the power as they want. After that they will be totally charged.

Then ship them between 40 and 70 percent charged. If you want to be sure that they are all the same state of charge you will need to very accurately discharge each one, seperately, and count out the same exact Ah. Now if its going to be rebalanced later on by a BMS then each one will need to be in the exact same state of charge. Or it may take days at silly 50 to 100mA rebalance current..

If its going to be assembled and charged with a PL8 or similar like that iCharger for e.g those have 1 and 1.2A balance circuits. So even if 2 full Ah out that will only take 2 hours or less to properly rebalance.

Or build the pack, charge and balance with PL8 and then use it to remove say 40Ah.

[Burgerman]

Snaker already has a PL8?

[steves1977uk]

Not Snaker BM, as he's in Vietnam! Saker98 lives in Norwich, so it was easy for me to pick up his cells and charge them for him.

Thanks for the info on charging them BM.

Steve

[shirley_hkg]

Do not use those EVE_105 cells..
Their internal resistance will turn bad for no reason.

M4 thread hole made me crazy.

Learnt a lesson the hard way.

Buy CATL.

LiFePO4 for Shanghai made TESLA . Will get 8 of below for my Storm4 Xplore .

[steves1977uk]

Those EVE cells are not mine Shirley, they're saker98's batteries. He asked me if I could charge them for him and I obliged. How long do they last?

Steve

[steves1977uk]

These EVE-LF105 cells seem to take forever to get to a low current. At the moment I'm charging 2 in parallel as a test and initially they only started at about 2Ah at 3.65v 5 hours ago. They're now at 1.13Ah and dropping very slowly. I thought new cells were supposed to drop very quickly?

Steve