PINNED - Lithium battery conversion/info

[woodygb]

8 LOTS OF 2 CELLS CONNECTED IN PARALLEL ..BUT NOT YET CONNECTED IN SERIES.

[woodygb]

NOW the 8 lots of 2 CELLS IN PARALLEL are connected in SERIES.

[Burgerman]

Is this an addon pack?

Will it be charged alone? Or while connected to the powerchairs lead battery as one?

So I can make a profile or so that expresso can upload his addon pack and combined presets.

[frogsuk]

NOW the 8 lots of 2 CELLS IN PARALLEL are connected in SERIES.

8 CELLS IN SERIES PLUS 2 IN PARRALEL.png

Thank you.
So This is the best layout I need as BM was mentioning?

[Burgerman]

Its the only layout. Although that diagram leaves me baffled.

All the 3.2v parallel cells, must be connected together as one big 3.2v cell. And then in series.

[woodygb]

Best?! ...It is the ONLY way to connect the cells.
The SHAPE of the pack is entirely up to you.

[frogsuk]

Is this an addon pack?

Will it be charged alone? Or while connected to the powerchairs lead battery as one?

So I can make a profile or so that expresso can upload his addon pack and combined presets.

This is a standalone chair I'm making that allows me to have a seat height of 200mm of the floor and a lifter that allows me to standard hight. Hence why the battery is laid out to undersling the chair

[frogsuk]

Best?! ...It is the ONLY way to connect the cells.
The SHAPE of the pack is entirely up to you.

Sorry. Okay thats the way it will be :-)

[Burgerman]

Its not got adequate capacity. It will die an early death. And you will have about the same crap range as a grp22nf at best.

[woodygb]

Balance wires .

[frogsuk]

Its not got adequate capacity. It will die an early death. And you will have about the same crap range as a grp22nf at best.

I know that it is but it is to suit a need I have.
I am replacing the 2 x grp22nf which were providing more than adequate performance on the original chairs fitted with DX2-PMA90.
This is not my main chair and I do have a 65Ah 24v LiFePo4 8s pack on another chair and an NHS provided spectra XTR2 HD on standard batteries

[Burgerman]

As long as you understand the issues of working a small lithium pack hard. Will it work? Yes.

If you follow the link to the lipo config website, you will see where the balance wires go.

[frogsuk]

NOW the 8 lots of 2 CELLS IN PARALLEL are connected in SERIES.

So this layout should be okay?

[frogsuk]

As long as you understand the issues of working a small lithium pack hard. Will it work? Yes.

If you follow the link to the lipo config website, you will see where the balance wires go.

Yes, and thank you for pointing it out.
I still have a further spare 16 of the same cells left that I may add as a piggyback pack at a later date, but for my purpose at the moment. This size pack is adequate.
So, could I trouble you for a profile file for this setup please?

[Burgerman]

The way its drawn just confuses me. But the balance wires all 7 seem backwards. Only red/black are correct. There will be smoke.

[frogsuk]

The way its drawn just confuses me. But the balance wires all 7 seem backwards. Only red/black are correct. There will be smoke.

Okay.

This is the pack layout I've got to work with along with a cardboard mockup of the cell box.

[Burgerman]

Attached - remove .zip

LiFe PO4 30Ah 24V 8S 100mA term.PS8.zip

(3.19 KiB) Downloaded 364 times

Heres what you really needed!
download/file.php?id=4286&mode=view
download/file.php?id=4457&mode=view Yes, I know... Wont fit.

At least it will be cheap to swap if and when I suppose.

[frogsuk]

Attached - remove .zip

The attachment LiFe PO4 30Ah 24V 8S 100mA term.PS8.zip is no longer available

Heres what you really needed!
download/file.php?id=4286&mode=view
download/file.php?id=4457&mode=view Yes, I know... Wont fit.

At least it will be cheap to swap if and when I suppose.

Huge thank you. Druling here but as you say, it won't fit :-(
Okay... I've swapped the wires and I'm hoping that this will be ok?

[Burgerman]

Yep.

Above in my links is just 120Ah. I think Snaker has 200Ah, and Nandol who we think may no longer be with us was awaiting shipment of a 180Ah pack, shirley has about 200, and the smallest packwas 90Ah in Expressos chair, but has a 36Ah add on too... And his other lead chair is 73Ah, plus 36Ah add on lithium. Mostly because we can! And because the range and longevity is remarkable. Snaker ran out of country!

[frogsuk]

Snaker ran out of country!

HAHA... Love to know more.

[Burgerman]

He literally ran out of road. Has about 100 mile range now.

[frogsuk]

Attached - remove .zip

LiFe PO4 30Ah 24V 8S 100mA term.PS8.zip

Well, at last, today I fitted all the links and balance leads and connected to the charger after testing all wires with a multimeter.
Thank you for all your help.
One question on the preset you kindly did for me, do I have to select in the Detection menu, Parallel Packs, 2P OR leave it as None?

[Burgerman]

None. Dont touch! You dont have parallel packs. If you set to parallel it will allow you to choose 2 packs when charging. It will think you have 2 chairs. And charge at twice the amps, but its dumb. It will try to use the same 100mA termination point regardless... So will spend too long at CV. So dont! Dont change a thing. Yet. Post the screenshots of the first charge which will look a mess. Leave till done.

[Burgerman]

Lithium likes to charge relatively slowly for a long life. And the preset is set to 12A from memory. Thats going to charge quite fast, under 3 hours from 90 percent used up. So if you are not in a hurry, or say overnight, you could set that to 6A if you want. The cells will like it better. On the other hand if you are in a hurry, on occation, charge at say 20A. Its a compromise.

The CV timeout is set to 8 hours, which is too long for ultimate safety. But it may need a long time to balance on a new pack. Maybe not yours since its small. So after the first charge ends, reduce CV limit to 4 hours if you wish. Termination is set to 100mA which should be about right. If CV takes longet than say 2 hours then increase that to say 125. If it ends in 20 mins, then decrease to say 75mA. Every pack slightly different.

[frogsuk]

None. Dont touch! You dont have parallel packs. If you set to parallel it will allow you to choose 2 packs when charging. It will think you have 2 chairs. And charge at twice the amps, but its dumb. It will try to use the same 100mA termination point regardless... So will spend too long at CV. So dont! Dont change a thing. Yet. Post the screenshots of the first charge which will look a mess. Leave till done.

Heres the screen prints:

Thanks for the extra info... I've set it at 6A now

[Burgerman]

That shows that some cells were almost full when you pressed go. Some not. Just wait till it ends! Strange how 1 and 8 are the low ones. Hopefully just a coincidence. You do have it wired correctly re parallel pairs?


That computer looks terrible. Havent you got a real windows box?

[frogsuk]

That shows that some cells were almost full when you pressed go. Some not. Just wait till it ends! Strange how 1 and 8 are the low ones. Hopefully just a coincidence. You do have it wired correctly re parallel pairs?


That computer looks terrible. Haven't you got a real windows box?

Yep, wired as per

Lol... The Charger is connected to an Intel NUC, fitted inside the battery charger and 2x Dell server power supplies, in a Flight case.
I can then monitor the charger via Teamviewer on my iPhone, Ipad, MacBook Pro or my Windows laptop from anywhere.
So the screenshot was via Teamviewer on the Macbook Pro this time

[QUADPHONICS]

Hello there is there anyway you could do this battery configuration to a Bounder plus power chair ? what I mean is I use a lithium ion battery in my Bounder plus power chair .

[frogsuk]

Hello there is there anyway you could do this battery configuration to a Bounder plus power chair ? what I mean is I use a lithium ion battery in my Bounder plus power chair .

I would think you would need at least twice the capacity as your Bounder Plus has 100AMP batteries and this cell pack is a mear 30AMP, similar size to 50 lead acid. But I should be the last to comment

[woodygb]

what I mean is I use a lithium ion battery in my Bounder plus power chair .

Two of these and charge via a PL8 ?



If so then NO .

The problem is "our" incorrect use of terms & incomplete understanding.

Yes it is a "12V LiFePO4 BATTERY" ...however the correct term would be a 4 CELL 12V LiFePO4 BATTERY ... and you cannot access the 4 cells without chopping open the case.
Then you would need to throw away the built in B.M.S. and connect the PL8.