PINNED - Lithium battery conversion/info

[expresso]

Thank you everyone - and yes your right - i have to let it soak in a few days - all this information -

from the looks so far - i am not looking to solder - connect so many wires - adapters etc, - that seems more of problem then just getting the Cells with the blocks - looks to be the simplist way to me - so far -

the only difference in the 38120s and 38140s is the Ah and size of the cell ? i think 38120s is a good start - and once i get it them and ask here how to assemble correctly - will take pictures to show also - i can then move on to the next step

how much extra Ah would 8 38120s Cells give me i thats all i used - ? now with this setup - i can either use a BMS which i need help with for sure - OR i Dont have to use a BMS - but if i dont - i have to charge with the hobby charger only to get it correct Volts 3.55V to be safe -

and just charge the chair the normal way -

so with out the BMS - once the 8 cells are connected correctly - then i just have to add the Cables with the SB50 on the end thats it like a normal battery - ? dosnt sound that bad this way -

i was trying to look for cables - wires to use - the thicker the guague the harder the wire - is 8 guauge going to work -? fuse size 70A ? if i have to change it on my cable thats on my chair already - i am hoping to leave it with the 30A fuse thats there now -

but in the event i have to change it out - would 8 guauge and 70A fuse be enough - if i have to change - i want to make sure i dont have to do it over again later on -

hard to find a inline Bus fuse holder with 8 guauge wire attached already -

thanks for everything so far - i need patience from everyone - burgerman - shirley etc, and i am sure i get it done with all your help here - this is my winter project and want to have it done for the summer time -

[expresso]

http://www.evassemble.com/index.php?mai ... ucts_id=20

any reason not to use this one instead of the 38120s - this says High C rate - which is better right ?

its just 8ah vs 10ah -

it dosnt say the Rate of either one -

[expresso]

http://www.genuinedealz.com/8-awg-gauge ... y-the-foot

i found this site - for marine wires - etc, - they can make them which would be great for me -

what do you think of these wires - ? but i would have to use the same SB50 connector in order to make it fit in mines which is on the chair already - mines is Grey SB50 but i think its for 10 gauge wires -

if i get wires made with 8 AWG - and SB50 - would it still connect to mines on the chair - this says it has to be the same AMP Rating color etc, to make it connect -

http://www.genuinedealz.com/quick-connect-plugs


Also i just though of this - tell me if i am correct or make any sense - - lets say i make the ADD on pack - - i can add the fuse on the ADD on pack only - and wont need a fuse on the batteries inside my chair ? if its all going to be connected

the fuse on the ADD on pack would or should be fine then - that would make it easier to put a fuse there - and dont have to put it inline on the wire - ? does this make any sense ?

[ex-Gooserider]

With an SB-50 connector, you should be using AWG 6 wire! You can get away with AWG 8, maybe... (The 10mm^2 wire that BM uses is in between AWG 6 & 8) it is really not good to use AWG 10 on an SB-50, as it is very much undersized for the connector's capacity.

I have purchased wire and other things from GenuineDealz, and the stuff I've gotten has been good. I haven't had them make any cables for me though so I don't know how that service is...

However you don't want to even think about soldering heavy gage cables without the right gear and a lot of experience. (and the Deans connectors I've used are really NASTY things to try and solder!)

In general, I would suggest that until you have a MUCH better understanding of how all the pieces fit together than you have shown so far, you shouldn't attempt this kind of project - it is easy and safe ONLY if you understand what you are doing and why - without that understanding I could easily see you causing your self major damage and possibly even injury....

ex-Gooserider

[expresso]

thanks for the advice and your right - always safe first - - the wiring i have was made already and feels very well made - how ever it was put together - i dont know - if soldered or crimped - how ever it was done - its fine and i had it for a few years now with no issues -

moving forward now - with what i want to do this winter - i wont be soldering anything - unless i have no choice - when i reach that point - then i decide how to proceed if i have to solder - i would first have to buy all the items needed - so just that alone - i rather pay to have it done - since i wont be soldering much after making that one or two wires i may need -

i am leaning on what shirly has suggested and burgerman - i would love to get the ready made pack from EVO and be done with it - but i have that thing in my mind from here that it may not work etc, etc, and i dont want to believe that it wont work correctly - because i like to get the Ready made pack -

so - i am now leaning on just getting 8 Cells 8120s and start from there - i am still unsure about this BMS thing - but i can give it a shot the way Shirly is suggesting and with his help and burgerman - others on here - i hope to go a step at a time till its done - i am leaning on the BMS just to make it simple after with the charging - i can use the same charger i have and not worry about - getting a whole new charger and wires kits -etc,

but if the BMS thing dosnt work out - i believe it can just be removed and then charge it the other way with the hobby charger -

so i see - - this hobby charger - is something i have no idea how to use etc, - from what i see - it will need a power supply also to make it work ? so i have to get that also unless it comes with it -

i hate to invest in so much money for an item which i may not never use or get any other use out of it - - but if this works out and thats the only other way i have to do to make it work - then i do it and that would be the charger for my ADD on pack - i have to see how it works out -

if i try the 8 Cell pack and it really does help and work with my current cables i have already on the chair - etc, - and with the BMS - and use my current charger - - if i notice a good boost in distance and not have to worry about carrying a charger during the times i am out - i be very happy and may just make me want to do more - and add to the pack - hopefully i learn more and feel better about doing more - which may just lead me to do the whole chair one day -

but let me start slow and easy - which would be the ready made pack - - thats the easiers to do - - but i hate to try that and have it fail on me - after knowing what everyone is telling me about it - the chances are high that it will fail

that be a waste of $400 - so at this point - if i get the 8 Cells - comes with the blocks and connectors - i do that first - then i see if the BMS from shirly - if i can get that going - and just use my charger - to keep costs down at least while i try this out and see the benefits -

i wont really know till the summer time when i really use my chair - but if i can get it done before then - i will use the chair to see how it feels and how my wires hold up - and if my fuse blows or not etc, - this is the direct cables and fuse i have already on my chair -

i am trying to avoid having to take my chair apart and do new wires etc, - if the fuse blows - then i would know now and of course - i would have no choice but to do the wires again with a larger fuse -

i dont understand something - if the chair itself dosnt seem to have thicker wires than my 10 AWG wire - how is it that the 10 AWG wont be enough - i understand thicker the AWG always better - i dont know for sure what the chair wiring is -

but they dont seem to be much thicker if any -

bottom line - if i need it to be 8 AWG then i do it - - but first i have to decide - 8 Cells and put it together like lego - sounds good to me - or ready made pack - sounds great to me - if it works

[expresso]

With an SB-50 connector, you should be using AWG 6 wire! You can get away with AWG 8, maybe... (The 10mm^2 wire that BM uses is in between AWG 6 & 8) it is really not good to use AWG 10 on an SB-50, as it is very much undersized for the connector's capacity.

I have purchased wire and other things from GenuineDealz, and the stuff I've gotten has been good. I haven't had them make any cables for me though so I don't know how that service is...

However you don't want to even think about soldering heavy gage cables without the right gear and a lot of experience. (and the Deans connectors I've used are really NASTY things to try and solder!)

In general, I would suggest that until you have a MUCH better understanding of how all the pieces fit together than you have shown so far, you shouldn't attempt this kind of project - it is easy and safe ONLY if you understand what you are doing and why - without that understanding I could easily see you causing your self major damage and possibly even injury....

ex-Gooserider

i checked that store front - on ebay - not bad - similar to this one - http://www.genuinedealz.com/marine-wire

actually its the same site - - i found this the other day - funny - but if i needed wires made right - i would call them - ask them to make what i need - and be done with it - i am sure they can do a much better job than i can

and if i do have to get new wires - i may just go 6 AWG and not worry about it at all - the fuse size - i dont remember what i should get if i need one - 60A or higher ? just in case - would be good if they can add a inline fuse for me - actually -
but i do have a marine fuse block already - just need a larger fuse if anything -

but i dont like the marine fuse block much because its in the way and cant keep it flush - i would love a inline fuse which i can just change easily if needed

[expresso]

http://www.genuinedealz.com/anderson-sb ... 2-awg-gray

this shows the SB50 for a 10 or 12 AWG - i guess it can be done in different AWG - depends how the size plugs they use - i would think they used the smaller plugs for the 10 AWG - i have - how ever they did it - it works just fine -

but you have to get the correct plugs for the AWG you would use - either way - i am leaving all this up to the professionals when i need them done - i will call and ask if they can make a wire with a inline fuse for 60 A - and SB 50 on the other end -
what size lug end would i need - 5/16 - 1/2 inch or 3/8 inch - for the headway cells - and would the same size for the headway cells work for the Lead battery also -

[LROBBINS]

Anderson has different internal-diameter contacts for different sized wires, so you can crimp smaller wires using the contacts made for them. Anderson also makes inserts to convert large to small. An industrial supplier can easily buy all the different contact sizes and/or insert tubes, but most suppliers that we deal with only carry the one, large-wire, size (some do offer more than one size contact). The different contacts all fit in the same shell - their outside dimensions are identical. If I have to put a smaller wire into a large-hole pin, I add a short bit of another wire to bring the total diameter up to what's specified for the pin. An SB50 is rather oversize for 10 AWG, but if 10 is suitable for the given use one certainly can use an oversize connector for connection compatibility. Ciao, Lenny

[shirley_hkg]

When I'm using 40Ah add-on with 73Ah MK Gel , the wire is 1.5mm with XLR plug. Current is around 10A, occationally near 20A.

Don't bother too much on wire size and heavy duty connectors.

[Burgerman]

Remember though that your 20A is with your efficient brushless motors. Esp efficient at stall etc.

That may well easily be 30A+ with brushed motors, Or 40 with tired lead batteries that don't take the strain.
And so at the limit of his fuse, and really needing 4 to 5 sqmm cable. I would hate him to melt!

[shirley_hkg]

As BMS systems go this is better than most but still intended to allow diy conversions by those that don't realise you don't need one! It only does 12S anyway I think. Most real EVs are using high voltages and probably 5x this. My battery is already too many at 13S..

Lets see..
What a charger does is to apply power to each end of a cell or a battery untill it overlows. They go to the fullest and dont stop making the cell voltage goes mad like you said.
Its like filling a bucket with sand untill it passes the top.
And what a BMS does is analyzing it ONLY AFTER it already passed the top and then when sees the overflow the BMS unplugges the thick charger cables and connect his litle board ones and kind of slowly sweeps the exccess of sand out untill its all leveled with the bucket.
It does this to all the buckets/cells several times until they are all at the same lever/voltage.
The result is that with this the cell are not only going through the roof getting damaged in the first tick cables charge because they pass the expectable safe voltage and also get into a kind of cycling methog that the BMS does when discharging and recharging again taking of life cycles that should be used by us.
Am i right untill now or all wrong?

What you hobby charger does is, because it is pre-programmed to charge a cell only untill certain limits, it does not exceed it.

Here is your NEXT bms, which handles up to 28S.

All parameters are user adjustable :

1, high cut cell voltage,
2, low cut cell voltage,
3, voltage to start balancing,
4, delta voltage to start balancing,
5, balancing current ( 200mA MAX ).
6, six temp probs

COST LESS THAN US$85.00

[shirley_hkg]

AND ALSO CAPABLE OF DISPLAYING THESE

[Burgerman]

It still keeps allowing a cell to go high over and over, keeps disconnecting the charger repeatedly for hours to stop a cell going too far over voltage. And has a feeble balance current of 200mA, and all the rest of the battery stuff it does isn't wanted or needed. Yes you can use a lower voltage charger to try and stop it bouncing. But its all a bit messy.

So why would I want or need one?
The chairs controller does a better job of max amp and lowest voltage control already, and a decent hobby charger is far better for charging than any BMS, with much better accuracy and 1 to 3 amp balance capability as well as data storage, graphing, monitoring and 40A charge capability with accurate proportional throttling so the balance can happen smoothly to =/- 0.003V accuracy. What is there for a BMS to actually do now?

Other than fail, cause fires and other issues, or shorten service life.

The data displayed is useful, but not the BMS. That's only there to stop people using the battery incorrectly!


They just add a load of extra unneeded complication, extra wires, etc. Better to properly integrate the battery and charge with a more advanced charger.

[expresso]

When I'm using 40Ah add-on with 73Ah MK Gel , the wire is 1.5mm with XLR plug. Current is around 10A, occationally near 20A.

Don't bother too much on wire size and heavy duty connectors.

Ok thanks - good to know - - i will give it a shot with the current wiring i have already and the 30A fuse - i think i may want to just by pass This BMS thing - i see too many little wires and boards i have no idea how to do it correctly - unless someone is here in NYC and wants to do it for me

i think less is better also - so if i can keep it simple - and just 8 Cells - and two wires with the SB 50 at the end to connect to my chair - - and i can charge from that end also - disconnect from the chair and would have to connect the ADD on pack to the Hobby charger - which i have to get it and what ever cables needed for the job - - then i would just use the hobby charger for the ADD on pack -- and my normal chair chargers for the chair -

when both charged - i can just plug it back in before i go out - ?

sound good - am i correct the way i am thinking ?

[expresso]

http://www.usastore.revolectrix.com/Pro ... Lab-8_1318

Burgerman - your telling me that this unit is the best and the one needed to get the job done - - besides me learning how to use this unit - what else would i need in terms of little parts - extra wiring etc, in order to use this to charge the ADD on pack ?

also - do i need to get a power supply for this unit - i dont see a power cord attached to it - would that be extra cost or does it come with the unit for the price - ?

if i can know before hand all the items needed so i can place one order - and hopefully wont need anything else -

but i am sure i will need your help with the hobby charger till i get the hang of it -

[Burgerman]

Hobby charger is the best at the moment. But things change fast in the hobby industry.

It can charge any battery, fron something like a watch battery, to a full sized Eelectric Car. And any chemistry. And any voltage or cell count up to 24V and 8 cell lithium, 12cell Lead etc. Or 10 cell unbalanced LiFePO4. And more cells on nicad, nickel metal, and more.

Its very configurable, and you must get the USB connetor too. So you can set it up and control it, as well as monitor whats happening on a PC.

Your mobility charger can charge at 24V and at 8 Amps usually. Thats about 200 watts. This charger can charge at 50mA which is nothing, up to 1340 watts...

It needs to run from a 12 or 24 volt (up to 32v) power supply. To get absolute max power from it you need 27Volts. I have one in my van, and can charge from an anderson connector on the dashboard, via the charger if I want. Although only at about 2/3rds power. Which is plenty.

I also have a couple of these chargers in the house. These run from a power supply. To use full power you need a big powerful 24 to 28 volt supply. I use two of these: http://www.ebay.co.uk/sch/digimess/m.ht ... 7675.l2562

But the SM3040 MODEL. 30V 40A. But there are none today. This seller usually has a couple a month, as new for 200 pounds. But there are many power supplues available.

[Burgerman]

Other connections?

Yes you want a few battery charge leads. Depends what battery or batteries you get as to what will be needed.

[expresso]

Hobby charger is the best at the moment. But things change fast in the hobby industry.

It can charge any battery, fron something like a watch battery, to a full sized Eelectric Car. And any chemistry. And any voltage or cell count up to 24V and 8 cell lithium, 12cell Lead etc. Or 10 cell unbalanced LiFePO4. And more cells on nicad, nickel metal, and more.

Its very configurable, and you must get the USB connetor too. So you can set it up and control it, as well as monitor whats happening on a PC.

Your mobility charger can charge at 24V and at 8 Amps usually. Thats about 200 watts. This charger can charge at 50mA which is nothing, up to 1340 watts...

It needs to run from a 12 or 24 volt (up to 32v) power supply. To get absolute max power from it you need 27Volts. I have one in my van, and can charge from an anderson connector on the dashboard, via the charger if I want. Although only at about 2/3rds power. Which is plenty.

I also have a couple of these chargers in the house. These run from a power supply. To use full power you need a big powerful 24 to 28 volt supply. I use two of these: http://www.ebay.co.uk/sch/digimess/m.ht ... 7675.l2562


Ok now this is what i wanted to avoid - the extra PSU - the cost is high - when i add this all up - is there a less expensive option or combonation to get this done correctly - i have no idea what to even do with that PSU in the link

i though i just needed to plug it in the wall and plug the hobby charger in the PSU and thats it -

this is going to run about $600 maybe and thats with out the 8 Cells - i know you know its the best to use etc, - but is there another option to get the job done for less - ?




But the SM3040 MODEL. 30V 40A. But there are none today. This seller usually has a couple a month, as new for 200 pounds. But there are many power supplues available.

[expresso]

sorry i wanted to say - was - this is becoming too much in costs just for a test run sort of speak - the PUS is another $200 - before i am done - this is going to cost $ 800 about - thats alot for something i may not have no use for later on -

you have many uses for your charger - your hobbies etc, - i am just going to end up using this for the ADD on pack only - and maybe down the line if i ever do the whole chair one day -

now i am wondering if this is all worth the money - or just try the Ready Made Pack from EV - even though it has a built in BMS - i would only need to get two wires made and can use my current charger ?

is there another option for charger - PSU combo which is less expensive that will be correct and suit my needs at the moment if i get the 8 Cells ?

[Burgerman]

There are hundreds!

From extremely cheap and low power and Chinese to the best that you don't want.

http://www.hobbyking.com/hobbyking/stor ... ouse_.html

Will run from a tiny laptop type power supply. But you get what you pay for...


Cheap power supplies: https://www.hobbyking.com/hobbyking/sto ... wer+supply

[expresso]

well its not that i dont want the best - just not feeling to spend $500 to $600 for a charger and PSU - even if its the best - these things change often - tomorrow another BEST unit comes out - not that i would need to keep up with that -

i was willing to get the Cellpro 8 etc, - but didnt know i need a PSU also - so - which charger - PSU combo would be somewhere in the middle of the road - something i can charge at 20A so wont take for ever if i choose to charge at 20A -

7A seems to slow now since i went to the 20A charger - i guess it can work since its a small ADD on pack anyway - but if the 8 Cell pack can take a 20A charge - i rather do that and get it done faster

http://www.hobbyking.com/hobbyking/stor ... duct=70998 -

something like this ? would this be OK or do you find a better one for a little more - thats fine also - this is the PSU - - maybe get the good charger and this PSU - or a lesser charger also - ? i dont know whats needed if i look at the chargers and browse them - i may pick one that wont be what i need or do what i need it to do -

so many to choose from - unless a person knows what to look for -

[expresso]

http://www.hobbyking.com/hobbyking/stor ... arger.html



http://www.hobbyking.com/hobbyking/stor ... duct=57703

http://www.hobbyking.com/hobbyking/stor ... V_AC_.html


http://www.hobbyking.com/hobbyking/stor ... 0amp_.html

not sure if some combo of charger PSU would work for what i need to do now and for future proof - not sure what i am missing out compared to the HIGH END Chargers PSU - ?

[expresso]

https://www.yahoo.com/parenting/family- ... 46792.html

this is what worries me also -

are these the same batteries chemistry as the ones we use here ?

when i see this - and others - makes me worry to even try it

[Burgerman]

Way too much to explain. Apart from better hardware, and about 2 digits better accuracy, power levels, balance capability, reliability, better components, etc (and PC control and logging/setup, easy firmware updates to add new cell types, bug fixes, etc) you are losing out on the software/firmware side. That's where all the cleverness, is. Its also where all the problems and bugs are on cheap Chinese stuff are...

You would be better with the Cellpro charger and a cheap small power supply for now.

[Burgerman]

http://batteryuniversity.com/learn/arti ... boeing_787

[Burgerman]

are these the same batteries chemistry as the ones we use here ?

No. Those are lithium ion (LiCo) type. Like the Dreamliner... Or a phone, laptop, etc
And a BMS that allows the explosive cells to go bang. Or in fact cause it. Those types of cells or a generic BMS really have no place in a powerchair.

[expresso]

Ok - i think thats a good comprise - get the good charger to be safe and work with a lower cost PSU - worst case down the line - i can always get a better PSU - and i do want the PC option to look at it on the screen etc,

ok so - i have the Cellpro 8 - charger - i would need the 8 Cells 38120s - - i may just get 10 to be safe in case i need an extra one -

now whats a decent PSU - anything for the lower end list can do the job ? even if its 20A Max etc, - not too slow - i linked a few -


for a moment back to the link about the House fire with the lithium battery on the hover board !!! - what do you think of that - is that the same type of battery i will be working with ?

[Burgerman]

No. See 2 posts higher...

[Burgerman]

i may just get 10 to be safe in case i need an extra one -

That's 2 extra...

You wont need one.

[expresso]

Ok then - Cellpro 8 charger

8 Cells - 38120s -

now the PSU - which should i get that will work - decent - dosnt have to be the cheapest - but if i can stay least cost that will get the job done -

does this charger come with everything i will need besides the PSU ?

if not - what other items i will need - so i dont have to reorder later - cables - wires - etc,