PINNED - Lithium battery conversion/info

[Burgerman]

Theres a 101 ways to do things.

Can you get cables soldered up?
If so its best to swap main battery connectors for something else. If not you can buy 4x adapters...
Then after that you will be using the T connectors, or something else. It all depends.

How many batteries?

[expresso]

Theres a 101 ways to do things.

Can you get cables soldered up?
If so its best to swap main battery connectors for something else. If not you can buy 4x adapters...
Then after that you will be using the T connectors, or something else. It all depends.

How many batteries?

sorry i am getting lost - does this refer to me ?

i been reading this section and more i read - i think more confused- worried i am about starting this - my main concern is this charging balancing- making wires etc,
soldering -

i am not sure i am able to make one of those balance cables from computer parts etc, - when you do it - looks so easy and simple etc, - and it is once you know - understand -

now if i get the 8 cells - comes with blocks etc - dont i just get a pos and neg. cable into a SB 50 end and thats it - charge from there also - this balancing cable is getting me worried - concerned that i wont be able to do that - and then have all these parts doing nothing after

a few pages back - Shirly posted a pic etc, and explained i can do it with no soldering - and simple - but with BMS which looks hard to me but i dont get it so maybe once i do get it and have the parts - it becomes clearer ?

when i meant what other cables i may need - i meanth more or less - buying them made - etc, - unless thats not a option - then i am stuck having to make something ?

i dont mind getting the parts needed and then asking for help here - but i have to make sure i can get this done once i start buying all this stuff - or else i be stuck with charger - PSU Cells etc, - doing nothing and waste of money - but worst of all - not having a ADD on pack for the summer - back to square one

[Burgerman]

The more we post, the more confused you get. You need to stop posting, and re read this thread. You need to understand how it works, and why it works rather than trying to find an easy no solder way to do something first.

Once you do, they YOU will know what you need, how to proceed that suits your own purposes and reasons. If you dont know what is happening it will all end badly anyway.

Theres 840 posts here answering all of these questions over and over!

[expresso]

your right - i have read this section in the past 2 days - some topics go off a bit - and i skip them but for the most part - i read the same things i am asking also from so many others -

i will think about it more and i guess with me - i do better with a one and one - gets too confusing when too much info at once - different info ways etc, -

My goal was and is right now - to just see if i can extend my range during the summer time - with no need to carry a charger or worry about finding a outlet and charging outside - even though fast charging is great - still have to find a outlet and still sit for at least a good hour - thats not bad if you find a outlet and keep busy while you charge - so its last resort if i have to -

so that brings me to here for a add on instead of charger in my backpack - i figure i fit a add on in there and connect the cable - ideally a Ready Made pack with just wires already connected is what i would LOVE To have - so i will decide and take my chances which ever way i go - being that i dont have plans at this moment to even consider doing the whole chair pack - for lack of knowledge at this point - and other reasons - that would be ideal - and i understand the reason for doing it and why - so i would if i can - rather not invest in a whole lot - at least till i test the waters first with as simple - dumb downed little add on pack -

then i can take it from there - i think that may be the best way for me to get started and find out - reading this section got me more confused at times - the other day i was ready to order all the parts - and now i am back to not sure if i am going to get this done - i guess thats what the BMS are for - for users like me - if it fails to give me the results i am looking for - at least i got a taste and it may make me take the next step with out later on -

if i dont do anything - i never get started and just be left with tons of questions and i am sure you are getting tired of trying to answer them - they are so simple for you to understand and do - i get it - - thanks alot for bearing with me here

i will try to ask questions more specfic once i actually get something - i expect to fail either way at first - either the BMS - or the whole ten yards of chargers etc, parts - in my mind i have no use for all that stuff if i dont continue to make a whole chair pack - i would invest and not get any results - thats my choice i have to make - try with BMS - simple easy and no big investment- - good chance it wont work as i intend - or it may be good enough - or invest in a ton of stuff - and make wires etc, learning curve and just for a ADD ON - not sure if its worth it for me that way -

one way or another i am going to do something - fail or not -

[Burgerman]

Then get the ready built pack from evassemble with BMS all built in. Charge with mobility charger.

[expresso]

Burgerman - i am now thinking i am going to try - building it with the 8 Cells - and with Shirly helping me - i will use Shirly's BMS - -- this is going to be for a ADD on pack - and use it on my P222 Chair - i want to use my chargers i have already so i will give this a shot first -

i am looking ahead if this works out - in doing the whole chair - but not the P222 - i want to do the S646se - - my other chair - if this ADD on gives me good results - depending how i feel about it - i decide if i do the whole chair -

which at that point - i will invest in the hobby charger - PSU and what ever is needed then -

i came up with this size i may have to work with - - can you tell me if this is do able- i did not measure it yet - i am using the specs of the battery which give me this -

HIGH - 209 MM - so to be safe lets say 200 mm

Wide - 259 MM -

Length - 246 MM

with those specs - what can i do ?

[shirley_hkg]

28120*

38140*

40152*

Which one to choose ? if final goal is a 4X ah pack.

[expresso]

i am not sure - just trying to figure it out - - i have group 24 Mk Gel in there - but i dont feel it has alot of space -

but first i want to do your BMS Shirly - - for the ADD on pack - should i get http://www.evassemble.com/index.php?mai ... ucts_id=18

or this one - http://www.evassemble.com/index.php?mai ... ucts_id=21

if my math is correct - the 38120 should be about 7 inches long and about 4 inches wide - for 8 Cells ?

dosnt sound bad - good size to carry on my napsack - - how many AH extra does that give me ? 8 Cells -

[shirley_hkg]

17% per every 10AH.

[Burgerman]

Anything will work.

You want as many wires, and as much complication / connections as that to DIY? And the most unreliable, and actually a fundamentally wrong way to do it, after all?
I give up!

[shirley_hkg]

BM, doing add-on your way will make charging inconvenient. Two batteries have to be charge seperately.
You know that, don't you ?



expresso, all 3 cells are selling @ $1.6 per AH . I recommand to you the big brother 40152s if space allow.

[Burgerman]

Yes. And no. The hobby charger can charge both just like the dumb mobility charger. And do a better more controllable job of both. But its not the best way.

Although doing them at the same time should work exactly the same as using a BMS/dumb mobility charger at the same time, only with better control of termination current level, (you tell it 50mA etc) and much more precise termination voltage (you get to decide).

However. The best way is to charge the add on separately in any case, since the best termination voltage and current is not the same for both types of cell. The Hobbyking cells for eg can be charged at 40A with a hobby charger, and will only take a few mins (25 mins from a typical 80%DOD?) as they can be charged fast! So you can do those read for when needed as you eat dinner... Then put them in your pocket for later. No extra wires, no BMS, all pre wired, just plug and play.

http://www.hobbyking.co.uk/hobbyking/st ... ouse_.html
30C cells, and charge at 2C. So 30 to 40 mins to 100% full from 100% discharged with a 1A balance 40A charge PL8v2 charger... And small enough for your pocket! Just 6" x 2" x 2.5" in physical size. But you need 4 for 24V and 16.8Ah. And these are 30C, much better than typical 3 or 1C prismatics/headway etc.

But the lead battery NEEDS an 8 hour soak at CV AFTER charge to not end up sulfated. Doing both together isn't ideal for either Lithium doesent like long soaks at full voltage. Obviously it will work. But I wouldn't do it that way.

[expresso]

17% per every 10AH.

Ok - if i end up with 8 Cells - is that 10Ah - or 20Ah Etc,

[expresso]

Anything will work.

You want as many wires, and as much complication / connections as that to DIY? And the most unreliable, and actually a fundamentally wrong way to do it, after all?
I give up!

Not sure what you mean - i though this was the simplest way in terms of wiring for me - and just use my dumb charger - - I would like it to be where i dont have to solder - anything - - the way Shirley - explained it sounds best to me in that sense

i can just screw it on the ring termals already made up - - isnt this the same way as if i didnt use a BMS and had to use a Balance cable etc, - still have to connect the balance cables ? unless i am mistaken -

my goal is to make this as simple as it can be done- that would work - - IF i could get away with using my current charger - that would be great - i dont mind if i have to charge them separate - if theres no way around it - but if i can use the dumb charger and charge just the little pack - with out letting it sit on the charger after its green - - and charge the chair normally leaving it plugged in - thats fine with me - if i can leave it all connected and charge that way - even easier -

I though the Headway Cells - doing it with them would be the easier - ? less wiring etc, - as compared to those other Hobby king batteries ? and not plug and plug as much as with the Headway ?

i though the hobby king batteries are not as safe ? not Lifepo4 ? i though i read that on here the other day -

i want to get started - and get what i need - and be able to add to it down the line - if it works out for me - -

[expresso]

BM, doing add-on your way will make charging inconvenient. Two batteries have to be charge seperately.
You know that, don't you ?



expresso, all 3 cells are selling @ $1.6 per AH . I recommand to you the big brother 40152s if space allow.

Ok i think i can do that size - its may be just about the same size as the MK GeL battery - 8.24 inchs - the Cells are about 7.2 inches - and i guess higher when adding the blocks - this may be a good size for down the line to try to make same size as a MK GEL 24 - - after doing this - and hopefully workes out -

i like to try to make the same size MK GEL 24 - two of them and connect the same way as the LEAD in my other chair - but for now - i want to try this first time - with a Add on -

[expresso]

Yes. And no. The hobby charger can charge both just like the dumb mobility charger. And do a better more controllable job of both. But its not the best way.

Although doing them at the same time should work exactly the same as using a BMS/dumb mobility charger at the same time, only with better control of termination current level, (you tell it 50mA etc) and much more precise termination voltage (you get to decide).

However. The best way is to charge the add on separately in any case, since the best termination voltage and current is not the same for both types of cell. The Hobbyking cells for eg can be charged at 40A with a hobby charger, and will only take a few mins (25 mins from a typical 80%DOD?) as they can be charged fast! So you can do those read for when needed as you eat dinner... Then put them in your pocket for later. No extra wires, no BMS, all pre wired, just plug and play.

http://www.hobbyking.co.uk/hobbyking/st ... ouse_.html
30C cells, and charge at 2C. So 30 to 40 mins to 100% full from 100% discharged with a 1A balance 40A charge PL8v2 charger... And small enough for your pocket! Just 6" x 2" x 2.5" in physical size. But you need 4 for 24V and 16.8Ah. And these are 30C, much better than typical 3 or 1C prismatics/headway etc.

But the lead battery NEEDS an 8 hour soak at CV AFTER charge to not end up sulfated. Doing both together isn't ideal for either Lithium doesent like long soaks at full voltage. Obviously it will work. But I wouldn't do it that way.

I like the size part - but i do need 4 - double the cost for the batteries alone - - and then add in the cost of the charger - PSU - besides the fact that i never done this - wouldnt this be harder for me - connetions - wiring them together etc, - would i have to solder ? i want to do it - either way that would be best for me and my ability - or should i say knowledge on this -

[Burgerman]

I like the size part - but i do need 4 - double the cost for the batteries alone - - and then add in the cost of the charger - PSU - besides the fact that i never done this - wouldnt this be harder for me - connetions - wiring them together etc, - would i have to solder ? i want to do it - either way that would be best for me and my ability - or should i say knowledge on this -

No. Its designed to connect to the charger. The very worst would be that you would need to make a lead up to connect to the chair. I already explained all this. And took a lot of time linking to connectors and adapters to show you can do it even without soldering. And now we are back to going in circles again with complex BMS and millions of wires...

However you do it there will need to be connectors or some simple soldering to do it properly. Unless you buy 100 connecters and converters/adapters... But this is the easiest most plug and play way possible. With the least amount of wires, and no BMS required. Which is a good thing. But I am endlessely repeating myself. You really do need to do 2 things.

1. Learn about basics of batteries and volts/amps etc. I already gave you links to learn about this earlier.

2. Learn to solder! Its cheap, easy, and essential. Thousands of hobbyists do this every day, from kids upwards. Its better to make up simple and correct leads than plug 10 things together and rely on others.

Then you can answer all of these questions yourself, and understand exactly what you need to buy/do and why etc. Because theres only so many ways to explain the same thing.

[Burgerman]

I like the size part - but i do need 4 - double the cost for the batteries alone - - and then add in the cost of the charger - PSU - besides the fact that i never done this - wouldnt this be harder for me - connetions - wiring them together etc, - would i have to solder ? i want to do it - either way that would be best for me and my ability - or should i say knowledge on this -

Every kid that buys a model plane or helicopter, or quadcopter also buys a battery pack, and hobby charger. They all figure it out and manage no problem. Have a little confidence.

[Scollard]

expresso,

Here is a cheap power supply on eBay.

http://r.ebay.com/6Qb3ph

It's essentially 2 computer server power supplies wired in series. This is what I use to power my Hyperion 1420i.

BM,

I just got my FedEx notification for my Lithiums from Hong Kong. I will be building my pack very soon. I will try and do a step-by-step on the forum.

[expresso]

expresso,

Here is a cheap power supply on eBay.

http://r.ebay.com/6Qb3ph

It's essentially 2 computer server power supplies wired in series. This is what I use to power my Hyperion 1420i.

BM,

I just got my FedEx notification for my Lithiums from Hong Kong. I will be building my pack very soon. I will try and do a step-by-step on the forum.

Hi - that would be great for me - to see it step by step - with Pictures if you can - Reading about it - etc, is good - but not everyone gets it as fast as others - and Pictures do ALOT in making some of us understand -

i dont even care if i have to buy a PSU - Hobby charger etc, to get this done - i was just unaware and would be nice if i didnt have to - and just use my current charger - - at least till i get used to this and see how it works etc, - before i can say ok - i will invest and in it and get the parts needed -

at the moment - ALL i want to do is make a ADD ON - thats it - - i would still need to ask questions - i have read this whole section - and i must read it again - but even though - i want to make sure when i have the Cells in my hand and connect them - i rather be safe then sorry - this is where Pictures come into play -

even though i know - connection in Series and Parelle etc, - i still get confused when i see the cells in a different way - as compared to TWO large LEAD batteries - anyway - i hope your comes out good - -

what are you building - an ADD on Pack ?

[Scollard]

I'm building a pack to replace 2 group 27 lead batteries. It's going to be a 7p8s pack made with 15AH Headway cells.This will yield a 24V 105AH pack. it is similar to the 24V 9s8p 108AH pack made from the 12AH Headway cells described on this site. The big difference is it only requires 56 Headway cells as opposed to 72 cells. It's a little cheaper as long as you have the room for the larger 15AH cell.

Very little soldering is required. I'm going to use a combo Sub-D connector to handle the power and balance wires all in a single cable. Exactly as BM made reference to. I'm extremely weak and cannot plug and unplug Anderson connectors easily. When I charge at home I'll just plug into the Hyperion and hit the button. If I'm on the road, I plug my Hyperion into my car's 12V system, bungie the charger onto the scooter seat and let it charge. It takes a little longer because you're only feeding the Hyperion 12V instead of 24V. By 12V system I mean the alternator/starter battery system, not a cigarette lighter port. I have a secondary battery in the back of my SUV and I have run 6' of 6 AWG to an Anderson Connector. This will reach my scooter which sits on an exterior carrier off the back of my SUV. I used to charge my 12V lead batteries by just plugging them directly into the Anderson Connector.

[Burgerman]

I'm building a pack to replace 2 group 27 lead batteries. It's going to be a 7p8s pack made with 15AH Headway cells.This will yield a 24V 105AH pack.

One thing worries me a little. You are throwing away much of the advantage that lithium offers. That is that its more energy dense, so you should be able to fit 1.4 to 2x the Ah in the same volume/space.

108Ah (or with care 120Ah as in my rebuilt BM2 chair) replaced the Group 34/24 68Ah Odyssey batteries. Of which say 38 to 40Ah is usable. It fits in the same space. Thats a huge gain from 38 /40 to 108 / or 120Ah. Or a range/capacity increase, of approx 2.7 to 3x. A 270% to 300% gain in range. Or charge every 3 days...

A group27 is bigger physically. And already 100Ah or greater approx. Say just over half or 60Ah is usable (about 60%). So you should be replacing it with 140 to 150Ah of lithium approx (which should be possible?) to get full advantage. If you only fit 105Ah in its place, then you will only get around 40 to 45% increase in range.

[expresso]

BM - If My Battery Tray in my other chair is this Size -

13 1/2 inches Long - Depth. x 10 inches Wide x 9 inches high of usable space -

With this Space - Can a pack be made - ? i dont feel it can fit 72 Cells in this space - but my math isnt great - so i am sure i am missing something -

this is a future vision i have - and i want to fill this space - to replace the 24s i have in there now - Can this be done - how many Cells would i need - even in the end if its not 108Ah or more etc, - at least as much as i can fit in that tray -

and yes by the way - i will end up getting that Cellpro8 Charger and PSU - if i get this far that i want to do the whole chair - thats an investment i will make - among other items -

[Burgerman]

You need 240mm height. Which is official height of group 24 max.

[expresso]

i feel its too tight on top of my pack - i dont want to squeeze it in there - the specs show 235mm - high for my battery -

lets assume for a moment - with just the specs i posted - can a pack be done - even if its not a group 24 replacement pack - lets say i can only get a group 34 pack to fit - that would still be a huge improvement i think ?

my batteries sit in a tray which is excate size - - i would only want to fill the tray as much as i can - - the batteries fit in there one in front of another - - unlike how you made your pack - and turn it on the side the long way - -

the PC1500 didnt fit in this chair - i need it and want it to fit in the Tray itself only - i can and will of course double triple check the hight if and when i decide to do that - i would buy a few cells and blocks to do a test fit if i have to -

Which Cells do you recommend for that project - ? standing up or lay them on the side ? http://www.evassemble.com/index.php?mai ... cts_id=175

this cell should fit standing up i believe - - would this be do able with this Cell - i think 6 of these across would fit - with holders with in 10 inches - i figure 8 rows down x 6 across - 8 x 6 = 48 cells - not sure if this is correct - and if it is - what can i do with 48 cells ? anything ?

[Burgerman]

i feel its too tight on top of my pack - i dont want to squeeze it in there - the specs show 235mm - high for my battery -

lets assume for a moment - with just the specs i posted - can a pack be done - even if its not a group 24 replacement pack - lets say i can only get a group 34 pack to fit - that would still be a huge improvement i think ?

The spec for a group24 is 260 long. 174 wide. 240 high. They can be less, they cannot be more. If your chair is designed for grp 24 batteries that will fit.

Which means your 235 figure is allowing 5mm (3/16ths inch) clearance for the metal terminals. The lithium pack doesn't need that...

If the battery can be 240 high (9.4 inches) then its 6 cells tall.
If the battery can be 260mm long (10 inches) then it can be 6 cells long. That's 36 cells. Times 2 for 2 batteries... That's 72 cells. That's 108Ah and a long service life with about 2.5 to 3 times more range.

If its 13 inches long as you said, that's another 3 inches per battery. That's another 6 cells per pack possible. But just another 4 makes more sense so another 12Ah added and 120Ah. That's 3.5 to 4x the range.

48 cells means just 72Ah. Same as the lead you take out. Kind of misses the point whole point of lithium. Which is that you can fit more ah in a given space. It will mean daily charging instead of every few days, so shorter life and only about 1.6 times as much range.

[Scollard]

One thing worries me a little. You are throwing away much of the advantage that lithium offers. That is that its more energy dense, so you should be able to fit 1.4 to 2x the Ah in the same volume/space.

I hear you BM. But range has never been an issue. I have a pretty big box to work with and could probably get 200AH into the area. The advantages I'm going for is weight and service life without breaking the bank. Right now the cost is 3x lead, so my ROI is about 7-8 years.

J.

[Burgerman]

With 3x the range, its half the weight.

But there are 3 things lithium hate. (You wanted service life)

1. working hard. Larger battery means the discharge Amps (the affective C rate) is lower per cell. So more cycles.
2. being discharged heavily (lower end voltages). So the lower the daily average discharge level, the longer the service life.
3. The less often they see a full charged voltage the longer they last. So a larger pack can be charged less frequently.

The more time they are sat around 30 to 80 percent full the more they like it. And the more gently it is charged and discharged the more they like it. Also the cooler they are the slower they age so ventilation and store in shade!

With that in mind it also pays to fit as much Ah in place as you can fit because apart from charging less often, working the cells less hard, discharging less deeply, you get a longer life, and more range to boot.

By fitting a smaller battery that possible, and working it harder, you lose some of this advantage. Failing to take advantage is what the big manufacturers do, because they don't get it, and get the same result as fitting a lead brick replacement that has half the space wasted internally.

In an extreme case, if you fitted a battery that gave you the same range as stock, say a 60Ah lithium in place of 100Ah lead, you would lose all of the advantages entirely. It would not last longer, you would not see more range, And changing to lithium would be ultimately pointless. The plan is to maximise the advantages to your benefit £££. And improve range too...

[expresso]

i feel its too tight on top of my pack - i dont want to squeeze it in there - the specs show 235mm - high for my battery -

lets assume for a moment - with just the specs i posted - can a pack be done - even if its not a group 24 replacement pack - lets say i can only get a group 34 pack to fit - that would still be a huge improvement i think ?

The spec for a group24 is 260 long. 174 wide. 240 high. They can be less, they cannot be more. If your chair is designed for grp 24 batteries that will fit.

Which means your 235 figure is allowing 5mm (3/16ths inch) clearance for the metal terminals. The lithium pack doesn't need that...

If the battery can be 240 high (9.4 inches) then its 6 cells tall.
If the battery can be 260mm long (10 inches) then it can be 6 cells long. That's 36 cells. Times 2 for 2 batteries... That's 72 cells. That's 108Ah and a long service life with about 2.5 to 3 times more range.

If its 13 inches long as you said, that's another 3 inches per battery. That's another 6 cells per pack possible. But just another 4 makes more sense so another 12Ah added and 120Ah. That's 3.5 to 4x the range.

48 cells means just 72Ah. Same as the lead you take out. Kind of misses the point whole point of lithium. Which is that you can fit more ah in a given space. It will mean daily charging instead of every few days, so shorter life and only about 1.6 times as much range.

My math must be wrong then - what Cells are we talking about - the 38120s ? for some reason the pictures - make them look so much bigger - i have to actually buy a few to see for myself -

i will make a copy of my battery tray - with cardboard - using the loose batteries i have laying around - just to see - how would they be - laying down flat the cells - ? 6 high and 6 across ?

i was figuring the other Cells - larger 15ah model - i may just have to buy the blocks and put them together one day to make sure of this - like i said before - i was not able to fit the PC1500 batteries in there -

i understand and agree about using all the space and get more Ah - i get that - use them less - last longer - and longer distance etc, - but worse case - i would still do it even if i cant get the extra amount in there - would still cut the weight in half - still give me more distance because i can use more of the batteries -
but downside is the service life - instead of 10 or 15 years - maybe 5 at least -

either way - i will do and use the most cells i can fit - what ever it may be - if i can find a tray from the parts depts on sunrise - i may just buy it and use that as the test bed to be %100 sure - i am thinking ahead here a bit -

since i am still going ahead with a Add on Pack first on the P222se - chair - the whole pack is going to be on the 646se chair - i would like to make it as 2 12 volt packs just like the lead - use the same wiring it had now - to connect - but then add another set of cables for charging - not from joystick

[expresso]

this pic is the same way its installed in my chair - same fashion - and its a tight fit on top - just makes it -