PINNED - Lithium battery conversion/info

[Burgerman]

Thats great if someone else pays. But what it doesent address is reliability.

I replace everything that can fail as far as possible with stuff that doesent. Hence better wiring, soldered connectors, stainless bearings, proper lubrication, etc. And careful examination of every part every 2 years. And rebuild the chair as new And I replace motors every 2 if used regularly. Checking brushes takes a few mins, but lets you know whats happening. A brush can be new, and chipped. Or not sliding properly. Its not just wear. And gives you chance to blow out dust.

The idea is that you dont get stranded at 2am in a dark place in the rain... To me reliability is very important.

So I half life everything... If I expect a thing to last 4 years like a motor, I swap at 2 and ebay the old ones. Or keep as a backup. I never run till they fail. Worn tyres on rear is a liability, so I normally swap those sooner rather than later. I set any inhibits in software to not slow or stop the chair if they fail or are unplugged or out of position. Loctite battery connection bolts so they cant come loose, fit a heavier fuse, Etc. And I unplug every connector and spray ends switch cleaner regularly. I want to be able to get home! I am paralised, may need a toilet, may need to get off my backside to prevent a sore. The idea of breaking down isnt something that I can allow to happen. So I take all possible precautions to be sure its as unlikely as possible.

Happened twice. Battery failed catastrophically as I crossed a road. Internal strap failed inside the battery. That was a Haze AGM so I wont touch one again.
And a motor connection burned off due to corroded crimp... Before I decided stock cables are crap!

[expresso]

yes i agree - - dont want to be stranded - but i cant do everything the way you do it - i do my best - 2am - i be sleeping so not worried about that -

either way same idea - 2pm or 2am - dont want be stuck - i keep it as clean as i can - and what ever i notice - if i can do something i will - same thing with everything i have - same idea - its important so i have to pay extra attention - and worse case - the reason i finally got a back up and soon another chair on the way-

that should be good to keep me from being totally stranded - at least once i get home to change chairs - i can have my tech look everything over ever few years a more detail job than i can do or see - with the seat lift - that helps - once its up all the way - easy to see the frame etc, -

i found the brush kit -

https://www.quickie-wheelchairs.com/rep ... -s636-s646

i will call to double check but this is the one - may put in an order and have on hand -

[expresso]

what kind of spray cleaner - etc, do you use on the contacts - ?

that can be done when my battery is out of the chair - my PM is inside buried - have to remove the whole pack - then can unplug each wire and spray - replug

but i wont do that - i let the tech do it one day when battery needs to be removed - will take the time then and do it - i like to have the spray on hand -

can you link me to one thats good and safe to use -

[Burgerman]

Amazon
https://www.amazon.com/Hosa-D5S-6-DeoxI ... ch+cleaner

Also used for computer connectors, USB, hard discs, mother board slots, power supply connectors, and anything that needs to make a good contact. It works...

Ever had a crackly volume knob on your sterio? Quick squirt of cleaner and as good as new.


youtu.be/ygrlO_VacsY

[snaker]

When soldering a DSub , do you here usually solder the power wires or the balance wires first?

[Burgerman]

Doesent matter. But it may be easier to do the small ones first. Even easier if you position them all with blocks of blutac...

[expresso]

Amazon
https://www.amazon.com/Hosa-D5S-6-DeoxI ... ch+cleaner

Also used for computer connectors, USB, hard discs, mother board slots, power supply connectors, and anything that needs to make a good contact. It works...

Ever had a crackly volume knob on your sterio? Quick squirt of cleaner and as good as new.


youtu.be/ygrlO_VacsY

very good thanks - its in my wish list for my next order

[expresso]

testing today at 26V to motors - turns out - not much to really gain at full power - actually felt worse - front end and power didnt get any better

85% power felt fine - GPS shows 9 and hits 10 at times on and off - 90% power shows 10 more - and feels ok - anything after that - no real gains and dosnt feel as good -
6
i changed it to 24V now and will use it again to see if i get a good ride at 100% power - i feel no real gain after a certain point - i never hit 11 on GPS - so no use trying for it - best it shows is 10 which can be anything between 10 and 10.9 - since it only shows whole numbers - and i got this at 85 and 90% power at 26V

will see how it feels at 100% and 24V - - i think at 26V and 100% power - it felt worse - and no gain in speed over the 90% setting - i think it may be getting hot and slowing it down maybe ? i know i can change those settings also so it wont slow down - but i dont see much gain after 85 to 90 % full at 26V

so no reason to stress i think - i want to get it full power 100% - using the most volts - 26V was too much - maybe 24V will do it - in the end - i do at least a good 10 most of times - if not more but never hit 11 on GPS - maybe on a down hill havnt tested that - more speed creates more front end issues also -

9 is best stable all around i think for now - maybe when i work on the casters in the winter - can get it more stable

[dEknowmight]

Finally got my cells in. Performing initial single cell charge with 8 in parallel.
I noticed after my first bunch finished charging and sat there connected for several hours (cause I fell asleep haha) that the charge displayed was dropping from the 3.6xx as well as fuel percent would drop.

Is this normal expected if I don't get them pulled off right away?

Or does it matter? I'm inclined to start the charge again and pull them off right when finished so I can start the 2-4 week storage period.

[expresso]

yes its normal - they will drop some and stay stable around 3.4V - i believe so

leave it for 4 weeks if you can at least - any longer - even better

[Burgerman]

You are looking for natural self discharge rates. So after charging, seperate them rapidly. Of they will pull each otherdown and screw up your recharge mAh in a few weeks.

[expresso]

ahh - good point - i recall doing mines one at a time - takes a bit longer - but safer so you dont forget to take them apart -

[snaker]

Please help me to check if the pins and holes on DB13w3 are correct?
- Red: positive pin/hole
- Gray: negative pin/hole
- Blue: unused pin/hole

[Burgerman]

Theres no correct way. As long as both halves match up!

I did mine this way. 1 error on schematic. Pos on the top, should be pin zero! (neg) And 12345678 are the pos ends of the cells. And I also decided to join the two large neg terminals (that are close together), and on subsequent cables by splitting the wire into two. But thats not essensial. Works fine anyway.

[Burgerman]

power lab as you look at it...

Main pos/neg connectors.

Then balance connector has 9 pins.
Pin 0 (or zero), negative is the closest pin. Black on this drawing.

After this, counting to the right, is pin two which is cell1pos, then cell2pos cell3pos cell4pos cell5pos cell6pos cell7pos cell8pos.

So pin 9 is cell8 positive, and battery positive. As long as these all end up correct at the battery it will work and no smoke from charger!

Balance port: 0neg then 1 2 3 4 5 6 7 8 (NINE wires)

[dEknowmight]

Thanks guys. I got my cells topped back off and disassembled immediately after charge completed to get a more accurate self discharge measurement. Storing now for just 3 weeks (since my lead is so bad right now).

[snaker]

When assembling cells to build the pack, should all cells be 100% full or a little discharged (e.g 90% remain)?

[Burgerman]

If all are full, then initial charge and balaning will be faster. Otherwise it doesent matter. But if say group 3 are 8Ah higher than the lowest group, it will take 8 hours to balance at 1000ma.

[shirley_hkg]

YOU can hardly tell the SOC of a cell , other than FULL . So let them be FULL .

[snaker]

When connecting cell groups in serial to build the pack, is the steps order below correct?
1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8

Can sparks happen during connecting? If so, how to prevent them happen?

[steves1977uk]

Sparks can happen if you short them out by accident. Just make sure you keep any metal tools away from touching the terminals or buss bars!

Steve

[Burgerman]

No sparks if you get it right. Huge sparks, and melted things if you get it wrong or touch the wrong parts together. So take care wear glasses, and use tape to protect things as you add connecting strip/bus bars.

[shirley_hkg]

Actually , you shoud be more careful when doing the parelle thing .

[expresso]

When connecting cell groups in serial to build the pack, is the steps order below correct?
1-2, 2-3, 3-4, 4-5, 5-6, 6-7, 7-8

Can sparks happen during connecting? If so, how to prevent them happen?

Look at pictures - how others have done it - at least you have an idea where to connect the buss bar etc, -

[snaker]

Actually , you shoud be more careful when doing the parelle thing .

Yes, I experienced it Would not sparks happen when parallel connecting If all cells are 100% full?

[Burgerman]

If connecting an empty cell, to a full one, in parallel, one will try to charge the other at hundreds of amps. Which causes sparks and possible cell damage. They are very low resistance. So huge currents can flow. So best if all are at the same level of charge. Full is OK. Or full, then take say 3Ah exactly out of each one with the pl8.. You cant really tell the state of charge by measuring volts unless they are full, or empty...

[shirley_hkg]

This is for Furio ,

This is the correct link to 13W3 that is meant for soldering .

The male / female picks are as photos below .

https://item.taobao.com/item.htm?spm=a3 ... 7566706439

[Furio]

Hi shirley_hkg,

Thank you very much.

Furio.

[snaker]

@Furio: I bought 2 pairs of DB13w3 like in the link Shirley shows above. In the pics they look fairly large but in real they are very small. I should buy large ones with more pins.

[Burgerman]

Heres how they actually look.

http://www.wheelchairdriver.com/BM3-con ... -pl8v2.jpg

http://www.wheelchairdriver.com/BM3-con ... nector.jpg

http://www.wheelchairdriver.com/BM3-con ... le-40A.jpg

http://www.wheelchairdriver.com/BM3-con ... arging.jpg

http://www.wheelchairdriver.com/BM3-con ... DCABLE.jpg