PINNED - Lithium battery conversion/info

[terry2]

Look at page 62 in the PL8 manual, there's a diagram.

Sorry. I don't mean the balance wires on page 62. But where to put the connectors to hook up the batteries.

[Scooterman]

Upload a photo

[terry2]

Upload a photo

Photo of what dude

I haven't put the pack together yet as I don't know how

[expresso]

this is one way - 8 in a row -

[expresso]

then i realized it was much thinner smaller compact for my ADD ON if i turned them side by side which is how i left them now

this way -

[expresso]

when it was 8 in a row - just disconnect the two where the red line is - circled it

then turn the batteries sideways - - and reconnect there - you see where i have a Cable wire as my connector instead there in the Red Circle

to make it easier - build it 8 in a row first

then disconnect where its red circle - turn it sideways 4 x 4 and reconnect - you can add the balance wires also first so you dont get too confused after you turn it 4 x 4 -

[terry2]

when it was 8 in a row - just disconnect the two where the red line is - circled it

then turn the batteries sideways - - and reconnect there - you see where i have a Cable wire as my connector instead there in the Red Circle

to make it easier - build it 8 in a row first

then disconnect where its red circle - turn it sideways 4 x 4 and reconnect - you can add the balance wires also first so you dont get too confused after you turn it 4 x 4 -

Thanks.

Mine has got to go like the picture I posted.

4 at the front and 4 behind. Thin side facing the front.

[Gnomatic]

Thanks.

Mine has got to go like the picture I posted.

4 at the front and 4 behind. Thin side facing the front.

Do you think they'll fit for you in that arrangement? Or still not enough space in your battery area?

[elryko1992]

Look at page 62 in the PL8 manual, there's a diagram.

Just found out they won't fit my chair

My battery bay takes 2 MK 72 amp which are MK Depth 6.7 X width 10.2 X hight 8.2

My cells are 2 inch X 6 3/4 X 8.2

The battery bay is just 11 in width.

Stupid me thought I could of fitted them.

You have the same problem like me and other users... that i buy it 120ah cell. the size is a problem. First you or other users need to measure more times and better to see if have enough space, and i ask BM or Expresso, and now i buy 8 cells from Shirley, he help me... i waiting

[terry2]

Thanks.

Mine has got to go like the picture I posted.

4 at the front and 4 behind. Thin side facing the front.

Do you think they'll fit for you in that arrangement? Or still not enough space in your battery area?

That's the only way they will fit.
I can't have them length ways at that will be over 14 inches with 2 side by side.

[Scooterman]

I'm a bit confused Terry

Will your cells fit or not?

[terry2]

I'm a bit confused Terry

Will your cells fit or not?

If I can put them in a pack like the picture. With a bit of modding to the battery tray I should be able to.

But i don't know how to connect them together.
I hope that clarifies things

[expresso]

when it was 8 in a row - just disconnect the two where the red line is - circled it

then turn the batteries sideways - - and reconnect there - you see where i have a Cable wire as my connector instead there in the Red Circle

to make it easier - build it 8 in a row first

then disconnect where its red circle - turn it sideways 4 x 4 and reconnect - you can add the balance wires also first so you dont get too confused after you turn it 4 x 4 -

Thanks.

Mine has got to go like the picture I posted.

4 at the front and 4 behind. Thin side facing the front.

Look at my post above - i posted the pictures how you need them ? 4 x 4 - turn them how you need them to be -

[terry2]

when it was 8 in a row - just disconnect the two where the red line is - circled it

then turn the batteries sideways - - and reconnect there - you see where i have a Cable wire as my connector instead there in the Red Circle

to make it easier - build it 8 in a row first

then disconnect where its red circle - turn it sideways 4 x 4 and reconnect - you can add the balance wires also first so you dont get too confused after you turn it 4 x 4 -

Thanks.

Mine has got to go like the picture I posted.

4 at the front and 4 behind. Thin side facing the front.

Look at my post above - i posted the pictures how you need them ? 4 x 4 - turn them how you need them to be -

Thank you so much.

I will study it tonight. And do the pack when the plastic sheets come.

[Scooterman]

Why not arrange the cells on the bench as they will be going in your chair. Then take an overhead photo, upload it, and someone can draw on the photo where the connections go.

[terry2]

Why not arrange the cells on the bench as they will be going in your chair. Then take an overhead photo, upload it, and someone can draw on the photo where the connections go.

Good thinking.

I will get someone in the morning to do that.

[Burgerman]

Its much better to learn WHY they connect how they do. Then you will know how to connect them.

[Scooterman]

Its much better to learn WHY they connect how they do. Then you will know how to connect them.

I agree. I always want to know why.

[swalker]

My battery bay takes 2 MK 72 amp which are MK Depth 6.7 X width 10.2 X hight 8.2

My cells are 2 inch X 6 3/4 X 8.2

Terry, I think we may use the same MK Gel batteries with the intent of replacing them with the same LiFePO4 cells.

From the size you gave for your batteries, I am guessing that you are currently using MK M24 SLD G FT gel lead acid batteries. If so, the specs for the MK M24 SLD G FT batteries say they are (in inches) 10.2 length x 6.8 width 8.24 height. I am assuming your 6.7 is a typo. That spec sheet also gives the metric size, which I find easier to work with. Those measurements are 259mm x 173mm x 209mm.

The 176 Ah LiFePO4 cells I purchased (and I believe are the same as yours) are 54mm thick x 173mm wide x 200mm tall.

Without any added insulation, 4 of the 176 Ah LiFePO4 cells will fit in a space That is shorter in length, the same in width, and shorter in height than the MK M24 SLD G FT battery. Since you use 2 of those MK batteries, there should be room for your 8 LifePO4 cells if no insulation is used.

Of course, you will need to use some kind of electrical insulation around each LiFePO4 cell. I am planning to use fish paper which is 0.010 inches (about 0.254mm) thick. The cell will then be shrink wrapped in PVC that is 0.15mm thick. Thus, I will be adding a bit more than 0.40mm to to each side of each cell. That will make each of my cells a bit less than 1mm wider than an MK M24 SLD G FT battery.

I have carefully measured the battery boxes on my wheelchair and they can easily accommodate a battery that is 174mm wide. I bet yours will too.

If you are indeed using MK M24 SLD G FT batteries currently, it seems to me that your cells are likely to be able to fit into your existing battery box(es).

Please let me know if there is any of the above that does not make sense.

Steve

[shirley_hkg]

Many chairs employ 2 sets of cables for the two 12V lead bracks, and wire them in series inside the PM. That makes user confused , which two terminals are 24V , and this is essential to how he put the balance leads in correct order . I gusee that's what he is looking for .

viewtopic.php?f=2&t=1813&start=3900

[terry2]

My battery bay takes 2 MK 72 amp which are MK Depth 6.7 X width 10.2 X hight 8.2

My cells are 2 inch X 6 3/4 X 8.2

Terry, I think we may use the same MK Gel batteries with the intent of replacing them with the same LiFePO4 cells.

From the size you gave for your batteries, I am guessing that you are currently using MK M24 SLD G FT gel lead acid batteries. If so, the specs for the MK M24 SLD G FT batteries say they are (in inches) 10.2 length x 6.8 width 8.24 height. I am assuming your 6.7 is a typo. That spec sheet also gives the metric size, which I find easier to work with. Those measurements are 259mm x 173mm x 209mm.

The 176 Ah LiFePO4 cells I purchased (and I believe are the same as yours) are 54mm thick x 173mm wide x 200mm tall.

Without any added insulation, 4 of the 176 Ah LiFePO4 cells will fit in a space That is shorter in length, the same in width, and shorter in height than the MK M24 SLD G FT battery. Since you use 2 of those MK batteries, there should be room for your 8 LifePO4 cells if no insulation is used.

Of course, you will need to use some kind of electrical insulation around each LiFePO4 cell. I am planning to use fish paper which is 0.010 inches (about 0.254mm) thick. The cell will then be shrink wrapped in PVC that is 0.15mm thick. Thus, I will be adding a bit more than 0.40mm to to each side of each cell. That will make each of my cells a bit less than 1mm wider than an MK M24 SLD G FT battery.

I have carefully measured the battery boxes on my wheelchair and they can easily accommodate a battery that is 174mm wide. I bet yours will too.

If you are indeed using MK M24 SLD G FT batteries currently, it seems to me that your cells are likely to be able to fit into your existing battery box(es).

Please let me know if there is any of the above that does not make sense.

Steve

Thank you for your help.

I am trying to find some 500mm 1M PVC Heat Shrink Tubing in the UK. But it looks like getting it from China.

[terry2]

Many chairs employ 2 sets of cables for the two 12V lead bracks, and wire them in series inside the PM. That makes user confused , which two terminals are 24V , and this is essential to how he put the balance leads in correct order . I gusee that's what he is looking for .

viewtopic.php?f=2&t=1813&start=3900

My Puma 40 has 2 set of leads.

I was hoping to join both earths. And join both positive wires.
Then just put them on the right terminal of the battery pack?

[shirley_hkg]

NO!

Measure your MK gel , while they are conneted. Use voltmetre to find the only TWO terminals , that gives you 24V . Put a mark on them .

Disregard the other two . Connect your new LiFePO4 battery to the marked.

[Scooterman]

Many chairs employ 2 sets of cables for the two 12V lead bracks, and wire them in series inside the PM. That makes user confused , which two terminals are 24V , and this is essential to how he put the balance leads in correct order . I gusee that's what he is looking for .

viewtopic.php?f=2&t=1813&start=3900

My scooter is wired like that

[Burgerman]

No matter how the confusing cables look your chair runs on 2 lead bricks wired in series.

Like this. ------ is cable!

The battery is: 24v+CHAIR MODULE -------- 12v+ battery 0v- --- 12v+ battery 0v- ----------- 0V CHAIR MODULE.

Each battery has 6 cells
Each cell is 2 volts.
Two batteries together is 24v if connected in series.
Two batteries together connected in paralel is still 12V.

So while it may LOOK complicated, THIS is how every chair is actually wired up.

[terry2]

NO!

Measure your MK gel , while they are conneted. Use voltmetre to find the only TWO terminals , that gives you 24V . Put a mark on them .

Disregard the other two . Connect your new LiFePO4 battery to the marked.

Great info.

So I use 1 24V positive and 1 24V negative ?

How do I find out the 24V negative?
Sorry about this. But after an electrical accident when I was a child. I refuse to even change a fuse
So I know nothing about this kind of thing.

[Burgerman]

Use a multimeter.

Set to DC volts.

The neg or 0V terminal is the black wire.
The pos or 12 and 14V + connection is the red wire.

If theres a - on the screen you got it the wrong way around. If not then the red is the positive.

If it reads 12V then you are measuring across a single battery.

See below. This is how simple EVERY chairs wiring is. Once you ignore the mass of complicated looking cables and plugs.

[LROBBINS]

Note also that there is most often a circuit breaker or fuse in the center connection - you must keep that kind of protection too.

[terry2]

Use a multimeter.

Set to DC volts.

The neg or 0V terminal is the black wire.
The pos or 12 and 14V + connection is the red wire.

If theres a - on the screen you got it the wrong way around. If not then the red is the positive.

If it reads 12V then you are measuring across a single battery.

See below. This is how simple EVERY chairs wiring is. Once you ignore the mass of complicated looking cables and plugs.

Thanks for the picture of what I need to look for

Note also that there is most often a circuit breaker or fuse in the center connection - you must keep that kind of protection too.

I will look for that. Thank you.
It's very confusing to me. Don't use the centre wires, but use the centre fuse!

The battery box on the Puma 40 only comes down 3 inches. So I will have to get someone else to look at that for me.

[Burgerman]

You can re use the centre fuse, or breaker if it has one. But it will now not go in the centre, it will go in the + 24V end of the battery. Its likely easier to just throw all the olf stuff away, and fit a new fuse in your new wiring.

A 100A or 125A midi fuse (ebay) and 2 ring terminals and a bit of heatshrink is all you will need. About 2 uk pounds...

https://www.ebay.co.uk/itm/MIDI-STRIP-L ... zCXWSQFKKw

You can add the fuse holder too if you want instead of heatshrink. But its a bit bigger and not so neat.
The ring terminals you need are ones with a 6 ot 6.6mm bolt hole and a 10sqmm cable size. And you will solder them on. You will crimp them, first to hold in position to make it easy. One of those turbo cigarette lighters with a small pencil flame. Takes 5 seconds per joint.