U1 lithium conversion

[Biscuit240]

I’ve looked but the only reference I could find specifically for u1 is a statement that the info is somewhere on here. Specifically how many lithium cells do I need to replace two 12v u1 in a 24v jazzy that will fit the original batteries foot print?
Thank you

[biscuit]

Good morning other biscuit.

LiFePO4 batteries you need 8 in series as the cells are 3.2V. Makes a single 25.6V battery.
Any other lithium batteries you won't find on here, as they are not safe.

[davidpaul]

You'll need to measure your battery box and then search for appropriate size cells (LiFePO4) you'll also need to factor in 1.5mm of insulation between the cells, you'll also need new grade A cells,
my battery pack is 200ah which is the recommended capacity


I bought mine here-

https://woo-power.en.alibaba.com/?spm=a ... st_company

Be pre-paired for shipping times, manufacture and testing took a few weeks, mine came by sea took a month to get here and another month in port before being released

[terry2]

And you will need a great power supply and a charger\balancer.

Hope you got deep pockets

[Burgerman]

You wont get 200Ah into a U1 battery space obviously. Just get as much as possible in there. And definitely more than the lead you remove. Or its ultimately a waste of money.

[Biscuit240]

You wont get 200Ah into a U1 battery space obviously. Just get as much as possible in there. And definitely more than the lead you remove. Or its ultimately a waste of money.

If I’ve understood your other links correctly even if I do 8 quanity of the 10ah cells to get around 25.6 volts that gives me an 80ah battery right? Wait, that’s not right is it?

[Biscuit240]

Good morning other biscuit.

LiFePO4 batteries you need 8 in series as the cells are 3.2V. Makes a single 25.6V battery.
Any other lithium batteries you won't find on here, as they are not safe.

How many ah would this have? Just 10ah right? Since it’s wired in series? So I would need multiples of these paralleled together to get the ahs I want correct?

[biscuit]

Cells in series the Volts increase. Cells in parallel the Amps (or Amp hours) increase.
you definitely don't want 10Ah cells unless you make a few parallel groups. You probably be better looking for prismatic cells and just have 1 series of 8 of them.
terry2 has a point. Sort out what you're going to do about charging them as it's not straightforward.

[swalker]

Keep in mind that you need a battery pack from which you can pull enough amps. Wheelchairs can periodically have very high demand for amps.

If you are using a large LiFePO4 pack, say over 100 amp hours, then cells with a relatively low discharge C rate will work fine. I am using a 176 Ah pack composed of cells with a continuous discharge C rate of 1 and a brief discharge C rate of 2. That works fine for me.

But, if I had put together a pack with half that capacity, say something like 80 Ah, I would need to have cells with a continuous discharge C rate of 2 and a brief discharge C rate of 4.

Most prismatic cells will have a pretty low discharge C rate, so building a low capacity pack with prismatic cells might be problematic.

Steve

[Biscuit240]

Sweet lord y’all are speaking Latin.

[Biscuit240]

Hey look what I found!

[steves1977uk]

My old chair took U1 40Ah Lead bricks, I replace them with a 75Ah pack using 40 Headway cells 15Ah each. It gave me 3x the range, but maybe I could fit 8 130Ah cells in place and have even more range now with a simpler setup.

Steve

[woodygb]

Sweet lord y’all are speaking Latin.

If your considering making a battery pack out of Lithium cells ... which will potentially triple your battery capacity... then you will need to learn Latin ....or you could just buy a pair of those expensive "plug and play" batteries that you linked and they might give you an extra 10% - 15% .

[biscuit]

Sweet lord y’all are speaking Latin.

well said!
I found expresso's pinned thread about the add on pack he made helpful. I ploughed through it and consulted it a lot.

[Biscuit240]

My old chair took U1 40Ah Lead bricks, I replace them with a 75Ah pack using 40 Headway cells 15Ah each. It gave me 3x the range, but maybe I could fit 8 130Ah cells in place and have even more range now with a simpler setup.

Steve

Yeah I’d love to do that, just gotta learn how now.

[Biscuit240]

Sweet lord y’all are speaking Latin.

If your considering making a battery pack out of Lithium cells ... which will potentially triple your battery capacity... then you will need to learn Latin ....or you could just buy a pair of those expensive "plug and play" batteries that you linked and they might give you an extra 10% - 15% .

Yeah I’m working on it. The Latin that is. I just finished a 6000 watt solar power system for the house with 1080ah battery storage and 15000 continuous output watts and thought I knew quite a bit about this sort of stuff. I have an electrically engineering background as well as fabrication capabilities and automotive repair certs etc. looks like lithium battery tech is just gonna have to be another thing for me to geek out on.

[Biscuit240]

Sweet lord y’all are speaking Latin.

well said!
I found expresso's pinned thread about the add on pack he made helpful. I ploughed through it and consulted it a lot.

Yeah I’ve read through that a couple of times now. Lots kinda frustrating for me personally though because it’s not just laid out bare for me by just saying “ok you wanna replace 12 v u1s? Here’s how you do it.” Ten years ago I would have no problem with just a basic outline of what to do, now with my cognitive issues everything takes longer for me to figure out. That and my memory blows.

[biscuit]

frustrating for me

and for everyone else too! We most of us have physical and/or mental difficulties and

just saying “ok you wanna replace 12 v u1s? Here’s how you do it.”

isn't a thing that happens here - as you will have noticed, this forum discusses topics at length, with contributions from experts and rookies both. People here are sharing work they themselves did to figure out the best way to achieve this or that aim. It is a matter of following ddiscussions,and sifting them for important and relevant information and paying attention (e.g. when Burgerman says details matter, they really do! ). The search function is good.

[shirley_hkg]

Yeah I’m working on it. The Latin that is. I just finished a 6000 watt solar power system for the house with 1080ah battery storage and 15000 continuous output watts and thought I knew quite a bit about this sort of stuff. I have an electrically engineering background as well as fabrication capabilities and automotive repair certs etc. looks like lithium battery tech is just gonna have to be another thing for me to geek out on.

That's a huge system. What kind of battery storage are you using , Lithium or SLA ?

[Biscuit240]

Yeah I’m working on it. The Latin that is. I just finished a 6000 watt solar power system for the house with 1080ah battery storage and 15000 continuous output watts and thought I knew quite a bit about this sort of stuff. I have an electrically engineering background as well as fabrication capabilities and automotive repair certs etc. looks like lithium battery tech is just gonna have to be another thing for me to geek out on.

That's a huge system. What kind of battery storage are you using , Lithium or SLA ?

Sla electric forklift batteries,

[Biscuit240]

frustrating for me

and for everyone else too! We most of us have physical and/or mental difficulties and

just saying “ok you wanna replace 12 v u1s? Here’s how you do it.”

isn't a thing that happens here - as you will have noticed, this forum discusses topics at length, with contributions from experts and rookies both. People here are sharing work they themselves did to figure out the best way to achieve this or that aim. It is a matter of following ddiscussions,and sifting them for important and relevant information and paying attention (e.g. when Burgerman says details matter, they really do! ). The search function is good.

Oh yeah I completely respect that, it’s just I think my brain is about full.