PINNED - Lithium battery conversion/info

[gcebiker]

...as i have actually done this....yeah it kinda works but its a real PITA .
...PITA as there are issues (complicated for me to explain succinctly at this time.)

I ended up purchasing a smaller chair charger (about 1/3 weight and size of the over night factory one).
Took it with me and just topped up if i needed to.

Its not always possible but it gave me peace of mind.

I then got a 'travel chair', a three wheel long range chair, and a 'house chair' .... now i never run out.

[Burgerman]

expresso, both of those batteries "may" (or may not) work or give problems related to the size/C rate and a few other things. The biggest issue is that the crappy built in BMS will cut out if your chair is programmed to go because the lead battery voltage drops a lot under load and those can only give 40A intermittently. That may or may not be a problem in your chair.

But the 2nd problem is that ping/other BMS equiped "easy" solutions will give less service life, and not predictably either. Week? Months? Years? No idea. We have been through this before. Esp if the above turns out to happen much.

And since you still need to make up connecting cables etc anyway, its just as simple to do it properly. And you can use the much higher rate cells and no BMS that hobby users use that I already linked to from hobbyking. And a simple cheap hobby charger. That way will give no problems, cost less, be smaller and more compact to carry, increase range predictably, and is just as easy to connect or use.

[shirley_hkg]

I'll keep money in my pocket, by JUST looking at :
Voltage range during discharge: 29.2V--20V

These are usually porch cells inside and that will deem to get swelling easily when overcharged.

[LROBBINS]

I think that the person here with the most experience doing and using add-on packs is shirley_hkg. His advice on this seems very good indeed, and if what you want is an add-on range extender, what he says is the place to begin. Ciao, Lenny

[Burgerman]

Why not one thing at a time.
Start by fitting a capable connector such as Anderson, or a hobby one, with a 50 to 70A approx fuse, to your existing chairs. Ready to use an add on battery.

Then go from there.
You can use that for charging, an add on, or for running other items such as an inverter or anything you wish.

Then build/buy a battery. And the easiest way would be ANY battery, but as an example of what can work buy 8x headway cells, pre built by evassemble, with an anderson connector. They include a bms. When/if that BMS causes you trouble, we can tell you how to fix it. Or lose it. You can ASK for an Anderson connector instead of whatever they normally fit. Then its plug and play. But dont expect massive gains from 10Ah. http://www.evassemble.com/index.php?mai ... cts_id=217

What it has inside is 8 of these http://www.evassemble.com/index.php?mai ... ucts_id=18

This is as simplistic and dumbed down as it gets. It may not be the best solution but stands a good chance of working.
Buy the 15Ah one if size/space isnt a problem.

You wont need a charger. The one you use to charge the chair will charge both at the same time.

[gcebiker]

That's a cool website, i use the Bafang motors in my three wheel mobility scooters.
Really really reliable and efficient.

They have a version they make for wheelchairs, brush-less and gear-less but its made under license for a wheelchair company.

...someone is making the brush-less, sensor-less, hub motor chair we are looking for...i am not sure who (possibly a Japanese company)
I bought one of Golden Motors kits but they dont free wheel very well at all, using them manually is a real pain in the wrists.

[expresso]

Thanks for the input- i have to look into that one - where i can use the same charger - would be great - i already have a anderson connection for my direct charging - its SB50

but i have a 30A fuse inline with those cables - would i be able to leave that fuse there - or else i have to take the chair apart to get to the cable and its an expesnive fuse - its a boat fuse - i didnt know better when i got the cables made and i had to add a fuse holder and fuse which i ended up with a boat type - and its expensive - the cables are 10 guauge in size for the direct charge with SB 50 on the end -

i dont have time to look at those links today but i will look at it and want to just add on a pack for now - simple easy and if i can use my current 8 amp charger for over night - that be fine - but if i need to fast charge it - i can just unplug the ADD on pack - fast charge the chair normally and then connect the ADD on pack and then use the 8 amp to continue charging the rest ?

would that be ok ?

finding a place to charge outside where i usually end up riding is impossiable to find - and if i do fine one - i dont want to sit there to charge - will take a long time - isnt worth it - i carry my charger in the event i have no choice at all - i try to make it with out and usually drain my batteries down by doing that - get home in Red - fast charge while i eat and take a short nap - then out again at night -

i really want to just add on a pack and see what that does for me - it may be just enough to get me thru my day with - with out worry - thanks - i will get back with some help questions once i check the site over and pick the parts i need to order -

[expresso]

I'll keep money in my pocket, by JUST looking at :
Voltage range during discharge: 29.2V--20V

These are usually porch cells inside and that will deem to get swelling easily when overcharged.

thank you - i will check the site and start to get parts i need - i dont know what i need etc , so i will ask here after i check it over

i really want to just do an ADD ON pack and plug it in my cables i have already there direct with SB50 connector on it - i have a 30A fuse - i hope i dont have to touch it - its a pain to get to it - my chair is a P222 se - have to take it apart - i cant do that and need help

so i rather not have to

[Burgerman]

30A fuse, and cables to take more may be required. Its impossible to know because it depends on your existing batteries and condition, and motors, programming etc.

[expresso]

Chair is P222 se - motors are 8.5 mph - or at least close to that speed - thats what it rated for - but who knows -

pilot plus - 100 amp controller - batteries are MK GEL 24 - but i have the PC1500 in that chair at the moment - when they wear out - i will end up with MK GEL 24 there also -

i had the direct cable on both my chairs for a few years now - didnt have any issues - my chargers when i do fast charge - are 15 amp salmex and a 20 amp model - only 15 amp is Salmex which is set for the GEL settings - i use the other charger for the PC 1500 chair which is 28.8V

the fuse we are talking about is the fuse for the direct cable ? not the chair itself fuse which is from the factory ?

[expresso]

http://www.evassemble.com/index.php?mai ... ucts_id=35


i know this is too small in AH - but would two of these batteries work to replace the MK GEL - - even if the distance is the same - but they can be recharged many years over and not have to worry about replacement each year ?

would be good at least 60AH model - but too large to fit in the chair -

being the lead only gives me about 40ah usable anyway right ? then this model would give me the full 40ah - which means is about the same - nothing gained but just 5 years of use over each year for lead ?

and have the weight - and if you add the ADD ON pack to these two - - would be an improvement ? a small distance increase maybe but much longer life in years - over the Lead ?

nice site - i like it and will do something - i will need help from everyone here for sure - i want to do something simple for now - and then maybe later on work on making a larger set - to replace the lead in the chair - my chairs are very tight space for the batteries - i have to really make sure the size of those cells will fit and how many would fit -

i may just buy one cell when i get the ADD on pack - and use that cell to check one day how it would fit and how many - i may have to go less than 73ah or 75ah - to make it fit - maybe 60ah - i do what ever fits - its got to be better

[Burgerman]

Too small. No gain in range. Short cycle life because you will be working it too hard...

Its not that easy. If it was then I would be using those batteries. They are not using ANY balance mechanism other than overcharge. They are not intended as deep cycle batteries, but as car starter batteries. They are not suitable and will soon die if deep cycled.

Long service life? Nope.
Longer range? Nope.
Lower long term costs? Nope...

You can fit 108Ah Headway 12Ah deep cycle LiFePO4 cells in place of your grp 24 batteries. Then you get a VERY long range (3x better) and an easy life for the cells, because the battery is much bigger! Charge less frequently. Less deep discharges. Less stress per cell. Long life... Then you actually get the benefit that Lithium can give.

The idea is that lithium is more energy dense. So you CAN fit MORE AH in the same space as before. To not do so, means you lose the whole point of fitting lithium.


You should read this thread from the start. We already did all this!

[expresso]

i do want to try the whole thing one day - not sure if i can fit 108ah in my chair - its very tight and barely fits the MK 24 - no room on top or sides at all -

so it cant go higher wider longer - nothing - has to be the same or even a little less in size to fit nicely - thats one chair

the 222 se - thats another problem - the MK 24 fit in there different - one is sideways and one is straight in - so the size of the box is not the same and the case cover leans down in the rear -

that may be harder to make for that chair -

i am going to read this whole section for sure - but for now i think i want to try that add on from the link - i want to look at it more and when i am ready to buy -
i will ask here one more time to make sure i am getting the correct model and what ever else i may need and just order it - and go from there -

i have to do something because lead alone dosnt cut it for me anymore in the summer time at least -

[shirley_hkg]

Is it your chair ? Then you have plenty of space for an add-on.

[Burgerman]

i do want to try the whole thing one day - not sure if i can fit 108ah in my chair - its very tight and barely fits the MK 24 - no room on top or sides at all -

so it cant go higher wider longer - nothing - has to be the same or even a little less in size to fit nicely - thats one chair

the 222 se - thats another problem - the MK 24 fit in there different - one is sideways and one is straight in - so the size of the box is not the same and the case cover leans down in the rear -

that may be harder to make for that chair -

It fits.

[expresso]

yes thats one of my chairs and thats the one i would do the add on pack -

i can put the battery in my napsack - and just let the wire out and down to my cable - i have my direct cable right in the rear frame so it would be easy to connect

http://www.evassemble.com/index.php?mai ... cts_id=176

i want to try this battery - now the question - i see two sets of wires coming off the battery in this picture - why are there two sets of wires

how do i connect a SB 50 on this battery to connect to my cable ? or would the company do it for me and then i just p;lug it in and charge it ?

[expresso]

http://www.evassemble.com/index.php?mai ... ucts_id=56


what about this one - maybe better ? i like to be able to use my fast charger also - which is 20 amp at 28.8V

[shirley_hkg]

Get 16 of these 16AH cells to build a 32A pack . ( OR GET 8 CELLS FOR TRIAL FIRST ! )

They are easy to connect. No welding at all. Can add more Ampheres easily at any time afterward.



I can help to get you THIS proper 3.65/2.5 BMS . (US$30.00) See how easy to connect.









Then you can charge ALL batteries in one go, with existing 28.8V charger.

Trust yourself.

[expresso]

charging volts say 29.2 V

i think one small charger i have may be 29.2V but isnt that too high for the Lead Batteries ? i have used it before with the lead- not knowing and i carry that one just in case if i ever need - i will use -

its 7amp charger compact - but has the normal wheelchair round plug to connect

[expresso]

that looks cool - but scary to me

i want to try that add on battery first - i think that is easier for me to see how it works and if any benefit - it may be just enough for me -

do i have to add that BMS thing to it ?

how safe is doing this - if i went the full pack - and even the add on - i just seen those videos of exploding batteries - not in rush to blow up

[shirley_hkg]

With an add-on, you are unnecessary to carry charger .

Usually it is set @28.8V for gel, itsn't it ?


3.6 X 8 = 28.8V ; so 29.2 is definitely OVERCHARGED , even at perfect balance.
Actually, we are charging at 28.2----28.4 with full LiFeSO4.

[Burgerman]

He is saying your lead charger is fine. Better than the one they recommend.

Just buy it and connect it, and charge simultaniously. Or seperately.

[expresso]

With an add-on, you are unnecessary to carry charger .

Usually it is set @28.8V for gel, itsn't it ?


3.6 X 8 = 28.8V ; so 29.2 is definitely OVERCHARGED , even at perfect balance.
Actually, we are charging at 28.2----28.4 with full LiFeSO4.

ok thats what i need to do then - so i dont have to worry about charging when i am out and do it all at night - i want it so i can use my charger now -

i have one charger i can set for gel or Agm - - that can be set to 28.2 for gel - 28.8 for agm - salmex one - the other is 20amp and 28.8 and 30 v for wet but i dont bother with that one - leave it at 28.8 - can i use a 20 amp charger also - with no problems ?

[expresso]

If i went with the 8 cells - get it all together - its then 28.8 v to charge - and how many extra AH does this give me ? i dont need a BMS ?

[expresso]

http://www.evassemble.com/index.php?mai ... ducts_id=6

they show a charging of 29.2 V also ?

isnt this high or something is wrong i dont get it - price is good - and i can get a SB50 connector on it i think - or the 7amp http://www.evassemble.com/index.php?mai ... cts_id=167


i can disconnet and charge it alone while charging the chair normally - if it cant be charged all together at once all conected

[expresso]

With an add-on, you are unnecessary to carry charger .

Usually it is set @28.8V for gel, itsn't it ?


3.6 X 8 = 28.8V ; so 29.2 is definitely OVERCHARGED , even at perfect balance.
Actually, we are charging at 28.2----28.4 with full LiFeSO4.

Ok - i want to try this - do i need to get 8 of these ? what else do i need to get to put this together correctly -

so i need a special charger to charge each cell first ? how much extra AH would this give me ?

this seems better than the already made pack and cheaper -

http://www.evassemble.com/index.php?mai ... ucts_id=18

or should i go this way - which is best - http://www.evassemble.com/index.php?mai ... ucts_id=56 -

the 15ah is about a $100 less than the 20 Ah pack - not sure if 5ah is worth $100 more - ?

if i can do the 8 cell and put it together - no BMS - would be cheaper and not hard for first time add on ?

i want to get started and place a order - so when you get a chance - please link me to what i need - anything - parts - chargers etc, and i get started -

thanks

[expresso]

actually i just realized - its 3.65 V charging - so x 8 is 29.2V -

if thats the case - i can just uplug the pack - charge it - while charging the chair with the 28.8V - and then connect again when fully charged - both -

unless 28.8V is fine or enough for these - i want to understand so i dont kill them from under charging or over charging -

do the charger cut off when fully charged with these cells or trickle on float mode like the others ?

http://www.evassemble.com/index.php?mai ... ducts_id=6

says Auto cut off - i would think it stops charging when full - like the OLD Dumb chargers -

this is starting to look like i can do this and get it done - looking clearer now the whole picture - i like that i can start with 8 cells and who knows maybe end up with full replacement on the other chair -

thanks for all the input and info - help from everyone here -

[LROBBINS]

expresso,

You can't do better than to trust Shirley and John (Burgerman) for this. 8 (or 16) of the cells Shirley showed + exactly the BMS he pointed to would give you a very capable add-on that you can charge with a 28.8 charger. The battery pack would take some careful assembly (correct polarity everywhere and the bolts MUST be tight) and some wiring to connect the BMS to the cells, but from then on it's just plug in your regular charger at night, charge both the add-on and chair batteries together, and the next day get going. You will probably (but check with Shirley on this it may not be necessary) want heavier than 10 ga wire from the add-on to your internal batteries. Ciao, Lenny

[Burgerman]

Shirleys BMS is better. But if its too complicated to connect, or too complicated to wire up, the packs that are ready built from evassemble already include a BMS that will work. Those just need to be bought and then plugged in to your chair.

Theres a 100 ways to do things. Thats the simple plug and play way. Its less good for a number of reasons. But should work in a fashion. And it will charge fine with your existing charger. While plugged into your chair or otherwise. EVAssemble will probably fit your Anderson 50 connector(s) as needed. Or you can.

After this, IF YOU WANT there are better ways. Better or bigger packs. Better lower charge voltage and higher Amp BMS boards, and so on.

Personally I would not use a BMS at all as they are all pretty crap and simply charge with a hobby charger instead and then its even more simple to use 2 OR 4 hobby king ready to go high rate 30C 8.4Ah 12V packs...

Or build a full proper 100Ah plus battery. And use a hobby charger. OR a dumb charger and shirleys low charge voltage type BMS. But a bigger higher Amp one.

Theres only so many ways or times you can say the same things! You must understand the reasons. Then this will all make obvious sense. Which is why I say you should read every post in this thread.

[Burgerman]

3.6 X 8 = 28.8V ; so 29.2 is definitely OVERCHARGED , even at perfect balance.
Actually, we are charging at 28.2----28.4 with full LiFeSO4.

I charge to 3.600v per cell if its been stored. For faster charge and balance. 1A balance and cells never exceed 3.600v (+/- 0.003V)
Otherwise I charge to 3.550v per cell normally for long service life. 1A balance and cells never exceed 3.550v (+/- 0.003V)

I end charge at the point where there is all 100% balance and charge current is below 15mA per 10Ah approx dep on pack.

In both cases the cells are 100 percent charged.