PINNED - Lithium battery conversion/info

[shirley_hkg]

OK, been looking for the best cells to fit in my new Xplore chair. It uses MK Grp24 battes, and is very tight on height. So these ones will allow 125Ah in the confined space taken by group 24 batts.

http://www.wheelchairdriver.com/SINOPOLY.pdf

And take up less space than 2 grp 24s...

So Where can I buy them! ??????????




170 tall (less than grp24 by 30mm)
255 long (5mm less)
40.5 wide (x4 = 162mm so 10mm less)

While allowing 125Ah but only 3C. Less important with 125Ah, and less important with brushless... And 3000 cycles to 80 DOD which will be at the 70 mile point!

Roger that .

[Burgerman]

[Gnomatic]

How would these cells perform with a chair that uses brushed motors, given their lower C rate compared to Headways?

[shirley_hkg]

Will you consider this also ? Rated 3C .

Pretty sure you can put 2P8S @150Ah in G24 space

Claimed to be BYD's new old stock at less than @ £20.00.

[Burgerman]

No. New stock needed! Or at least a known history.

These are 1015 September, never used. 120Ah 80 us dollars. 120Ah measured tested 125Ah.

8 fits easily. Where group 24 MK came out with space in all directions.

[Gnomatic]

No. New stock needed! Or at least a known history.

These are 1015 September, never used. 120Ah 80 us dollars. 120Ah measured tested 125Ah.

8 fits easily. Where group 24 MK came out with space in all directions.

Where did you find these?

[Burgerman]

ebay...

But am actually looking for the other ones in the pdf...

http://www.wheelchairdriver.com/SINOPOLY.pdf

[Gnomatic]

On another note, should I be looking at 100A or 120A breakers for my pack? My chair sees frequent offroading in the summer.

[Burgerman]

Either. If you average 100 your motors would melt. So you are really only worried about pulses. Check the graphs / specs.

[Gnomatic]

I'm trying to come up with something like a bracket or housing to mount the Dsub connector on the chair.

Anyone have any ideas?

[Burgerman]

Mines currently loose on a cable. But I need do the same.

[LROBBINS]

There are circumstances where it's actually a good idea to have a connector on a flying lead rather than bolted to a solid structure. Especially if they have "bent and formed" contacts rather than machined ones. With a cable connected to a bolted down connector, vibration can over time take the "spring" out of the contacts. Years ago we had this problem over and over when we remote mounted the screen of Rachi's computer and had the rest of the PC behind the chair. And the ones that failed included DB25, SCSCI and even Centronics connectors. When I started leaving the connectors on leads that could flop about the failures stopped because the whole male-female connection moved as a unit.

[Burgerman]

However, being paralyzed I have to connect with one hand while sat in chair!

[LROBBINS]

I realized after already going to bed that what I wrote above is irrelevant for the charging/balancing connector - the cable's not connected when you're bouncing around anyway.

[Burgerman]

Well mines connected to a PL8 in a van, or regularly to various other devices to power them. Like my portable drill, mower, model planes via a PL8 to charge, etc. So in my case it does make some sense. Its actually quite easy as mine is just velcroed to the underside of the seat. If I want it I pull it out about 2 feet. (..7 meter?). So its sort of both fixed and not...

[Gnomatic]

My pack weighs ~60lbs. The lead bricks it's replacing are 104lbs total. I'm sticking a lead plate under my pack as a ballast, I go up/down/sideways on some steep slopes and don't want to tip.

The size of the plate I'm considering ordering is 13.5"x9.5"x.5" which should be ~26.5lbs directly under my pack. So my pack and the plate would be ~86.5lbs, still about 18lbs less than the pair of SLA bricks. With the lead plate at the bottom, I would think this would be a pretty good approximation of my chair's current CoG, no?

if I go for a .75" plate I'm looking at 40lbs underneath my pack, which would probably lower my chair's CoG.

Can I get away with a 1/2" plate, or do I need to go with a 3/4" plate to at least maintain my chair's current CoG?

[Burgerman]

Go with the lighter one. I am using none. And am just aware...

[expresso]

BM - what is your take on this reading - yesterday first day out since sitting all winter - 24 mile run - during charging - i noticed Cell group 1 - seemed a bit lazy - watching the graphs -

is this something i should be concerned about ? will go out again today to run it again and see how it acts during charging

Few Questions

1. - How Much locktite should be used ? where along the screw should you add it - at the tip end of it - middle or upper part etc, - If anyone has a picture they can post of a screw with the correct amount of locktite applied - Please post it -

2. - i like to purchase more of those screws that come with the headway cells - does anyone have a link to the same screw - correct size and length etc, ? please post -

3. - Would using the lock washers etc, that come with the headway cells instead of locktite - has anyone done that ? why wouldnt they work just as well - do they really come loose ?

thanks -

[Burgerman]

Maybe a loose connection on one cell in that group, or on the cell laid on top. Looks like you get with a loose bolt. Its why I check every one at least 3 times and then check again... Or may be fine next time...

[Gnomatic]

What is the max torque that can be applied to a Headway bolt?

Is using a drill and setting the clutch to a specific number the best way to do this?

[Burgerman]

I just use an allen key, loctite, and my torque wrench fingers. I suppose a small torque wrench would be best. 4nm max. But have fine tuned fingers. Its really easy to go over them all twice. Then find a couple you missed! Quite amazing how some hide. I now touch them with a blue marker pan, then a black one on the 2nd go.

Loctite? A stripe, full length of thread.

[Gnomatic]

Will you consider this also ? Rated 3C .

Pretty sure you can put 2P8S @150Ah in G24 space

Claimed to be BYD's new old stock at less than @ £20.00.

Hi Shirley.

Do you still have access to these cells? If so, what would there price be in USD? If any info on the background of these, it'd be much appreciated.

Thanks!

[Gnomatic]

I just use an allen key, loctite, and my torque wrench fingers. I suppose a small torque wrench would be best. 4nm max. But have fine tuned fingers. Its really easy to go over them all twice. Then find a couple you missed! Quite amazing how some hide. I now touch them with a blue marker pan, then a black one on the 2nd go.

Loctite? A stripe, full length of thread.

Good idea on the marker.

And for torque, 4Nm = 2.95foot-pounds. just need to find a wrench.

[Burgerman]

Good idea on the marker.

Used to do it when building bike engines. White paint dot was assembled and torqued. Red dot was checked - re-torqued. Then you dont get a rod sticking out the side so often at the strip! Head, mains, casing, big ends, cam bolts, etc as you go.

Extra fun advice. Always kept a bit of broken piston ring and a ball bearing in my pocket to drop onto the bench of my competitor/friends when they were about done building a motor! Sets that seed of doubt! Err lads, wots this???

[expresso]

Maybe a loose connection on one cell in that group, or on the cell laid on top. Looks like you get with a loose bolt. Its why I check every one at least 3 times and then check again... Or may be fine next time...

Ok so you think something is off ? i need to take it out and recheck the bolts - ? i started the charge just now and i notice its the same Cell group 1 which is lazy also again -

this is now a job for me - - where should i begin once i take it out ? what if i dont find any loose bolt on the top row ? what would be my next step to check ?

i am wondering if i should redo the wiring that connect to the top row ? i wonder if i added too much locktite the last time i had to remove it - ?

in the meantime - Can i use it this way till i take it out and recheck it ? as long as it dosnt go below 2.8V etc, - ?

thinking of making new wires with the better lugs i found -

Do you have a link to the screws - same size and length - i like to buy some in case i want to replace them when i take it out ?

i am think also if i added too much locktite - maybe it spilled over - would that case a issue if that happened ?

[expresso]

i just checked my graph charging it - i notice Cell 1 is not even with the rest - about 13 min. into the charge

where yesterday it was alot longer before they connected as one line - about one hour - i think - or at least 35 mins -

its an improvement -

[expresso]

I just use an allen key, loctite, and my torque wrench fingers. I suppose a small torque wrench would be best. 4nm max. But have fine tuned fingers. Its really easy to go over them all twice. Then find a couple you missed! Quite amazing how some hide. I now touch them with a blue marker pan, then a black one on the 2nd go.

Loctite? A stripe, full length of thread.

just one stripe down - not all around it ?

[Burgerman]

As long as some gets onto the threads and is able to lock it it doesent much matter how you apply it. But you dont want to waste it, use excess, or get it all over the contact areas if you can avoid it. And one day you might want to undo it!

[Burgerman]

Ok so you think something is off ? i need to take it out and recheck the bolts - ? i started the charge just now and i notice its the same Cell group 1 which is lazy also again -

this is now a job for me - - where should i begin once i take it out ? what if i dont find any loose bolt on the top row ? what would be my next step to check ?

i am wondering if i should redo the wiring that connect to the top row ? i wonder if i added too much locktite the last time i had to remove it - ?

in the meantime - Can i use it this way till i take it out and recheck it ? as long as it dosnt go below 2.8V etc, - ?

thinking of making new wires with the better lugs i found -

Do you have a link to the screws - same size and length - i like to buy some in case i want to replace them when i take it out ?

i am think also if i added too much locktite - maybe it spilled over - would that case a issue if that happened ?

Stop typing, and over thinking!.

Just monitor it on a longer ride and post the graphs.

[Gnomatic]

I just use an allen key, loctite, and my torque wrench fingers. I suppose a small torque wrench would be best. 4nm max. But have fine tuned fingers. .

Is 4Nm your best guess or is that how tight Headway says to tighten? I don't have finely tuned fingers. So I'm looking at these options:

https://smile.amazon.com/dp/B010T6L6C0? ... F8J8N43NHE

https://smile.amazon.com/TEKTON-TRQ2110 ... NCH+in-lbs

https://smile.amazon.com/TorQ-Armour-Mi ... sktop&th=1

and the cheapest .....

https://smile.amazon.com/Prestacycle-To ... sktop&th=1