PINNED - Lithium battery conversion/info

[Burgerman]

NOTE wall thickness. THESE are fine crimped. Designed for a professional crimp. All the rest are frankly not!
All the ones that look like this (click! And note wall thickness!) can be crimped, and once drilled slightly 10sqmm too.

Another here:



These below are useless crimped...

41A4EQqJAzL._SX342_.jpg (12.29 KiB) Viewed 8531 times

These can be just pulled off. And that's almost all of them you can easily buy. Not enough metal. These must be soldered.

[expresso]

Hi - looking at my charging over some time - i noticed that the purple line - Cell 6 - at the begininng of the charge it seems to be out of the pack and then settles back together after short time

i dont know if i noticed this before or not - Can you Tell BM - if this graph is Ok - or if you notice anything wrong ? its on my mind since i had the crash - afterwards checking the Wires - i feel are bent some and will be replacing them but want to hold off a few more months till winter - before taking it out and replacing the two end wires only - i dont think anything else needs any attention -

here are yesterdays results - i am charging now and i noticed the same purple line - Cell 6 i think acting same way -

[ex-Gooserider]

The SB-50 / PP-75 pins that I get here in the US are sized for AWG 6 wire, which is about 13.3mm^2 or 4.1mm diameter, between a 20 and 21 drill size.

I haven't tried doing a serious pull test on the crimps produced by either my hydraulic crimper or the PowerWerx crimper, but the hydraulic crimper gives me a hex squeeze that greatly reduces the diameter of the crimp, and certainly resists casual pulling....

Unfortunately I don't have access to a formal 'pull test' machine that can give actual numbers but it would be worth experimenting if I did...

Anderson doesn't say anything about the hydraulic crimper style crimps, but their assembly instruction document seems to imply that the PowerWerx crimper meets their requirements for crimping without soldering, when using AWG 6 wire

It is worth noting that a successful crimp needs to have the right amount of pressure applied - to much can be as bad as to little, and cause the wire to break at the crimp due to work hardening...

Many years back, at an employer I was working at doing harness build for industrial grade marine sonar systems (i.e. research vessels, not just a depth finder) the shop boss got into a debate with some of the employees about why we were using several hundred dollar ratchet crimpers on insulated terminals instead of the five dollar plier style from the local discount store.... Ended up doing a challenge - the employees favourite pliers vs. the ratchet, on the pull tester, including some solder only, and some crimp and solder....

EVERY plier crimp and EVERY solder connection failed - either by pulling out, or by the wire breaking at the crimp... The ratchet crimps held to the point where the wire broke other than at the crimp, at the rated strength of the wire....

ex-Gooserider

[Burgerman]

here are yesterdays results - i am charging now and i noticed the same purple line - Cell 6 i think acting same way -

Looks OK. Don't worry... You are talking about a few millivolts! Most multi-meters cant even measure that.

[expresso]

Ok thanks BM - i guess i am just noticing it more now - most likely all my graphs were the same - with in about 5 mins to about 15 or 20 min - i notice that one line out of the rest for a short time and then evens out till the very end when it starts to balance and finally all even done.

[Burgerman]

Nxt time. Choose monitor for 10 mins, And post that.

[expresso]

Nxt time. Choose monitor for 10 mins, And post that.

Ok will do -

[expresso]

15 mins monitor before charging

[Burgerman]

Well those are identical. As they will be if its healthy!

[expresso]

yeah i guess its just me - any little bit off and i wonder -

should be healthy - or else it would show up in the graphs ?

[Burgerman]

The graph you were looking at was scaled at around 0.000 of a volt. If it was out by 0.009 volts you see it on that graph as you did. But... Thats just 9x 1000th of 1 volt!

[expresso]

Ok other words - nothing to worry about

[Burgerman]

http://news.sky.com/story/samsung-halts ... s-10562253

In the news. Exploding phones, exploding laptops etc. All of these use 4.2V charge 3.7V nominal Lithium Ion (Cobalt variants like LiCo cells). The original lithium battery going back donkeys years. These burn! Nothing new here. As does lithium polymer.

Its thought that these types of cells have brought down 2 airliners over the years inc the recent one in the med on the way to egypt, and possibly also responsible for MH370 that went missing 4 years ago. They are in portable scooters, ebikes, portable powerchairs like the travelscoot, laptops, cameras, tools, etc in the millions. Because they are cheap, very energy dense.

These will inevitably be confused with LiFePO4 cells, that dont burn or explode at least without some external heat applied.

[granian]

I need to replace two 12volt 1.5ah drill batteries and two 12volt 1.5ah hedge trimmer batteries should I just replace with the originals
or can I replace and rebuild with new cells in existing cases, which I believe BM you have done before.
If replacement is possible can you give any advice on type of cells and where to purchase please.

[Burgerman]

Define 12V?

Cell count, in series presuming these are lithium. Because they may be 3.7V LiCo or 3.2V LiFePO4 and that's different chemistries. 4X 3.2V series is OK for 12V. It actually gives a nominal 12.8V just like lead. But LiCo cells are 3.7V and so 4 is too many, and 3 isnt enough... And thats likely what they are.

So more info needed...

[granian]

I got the drill batteries wrong they are Ni-Cd 1.2volt 1500 mAh giving 9.6 volts.
The hedge trimmer batteries are Ni-Cd three banks of three at 3.6 volts 1500 mAh and one at 1.2 volt mAh giving 12volt 1.5Ah.

[Burgerman]

Yes just replace.

[granian]

Thanks but just to clarify, are you saying that I should purchase the complete original batteries.
The hedge trimmer batteries are £40 each and the drill batteries are £30 each so total £140 plus postage.

I fully understand if this is the way to go but would be interested in replacing individual cells if possible.

I presume that if I had a PL8 then I would be able to tell which individual cells where ok or not, is there any other way that is less costly to find this out.

[Burgerman]

No, replace cells. ALL at once. You cannot use old/new together.

[granian]

Thanks, yes I fully understand, any pointers on places to purchase from.
Regarding my question on testing cells can you advise please.

[Burgerman]

Are these AA cells? If so fit Enerloop from Amazon.

[granian]

Hi BM sorry for late post, I believe the batteries are SubC with tabs on both ends spot welded and linked between all batteries.

[Burgerman]

http://www.ebay.co.uk/sch/Sub-C-Recharg ... 914/i.html

Buy branded or good known source...

[granian]

Thanks for your help BM, I will have a good look and purchase some of the better ones, if I know the difference.
The awkward part next getting them all back into there small cases, possibly with a shoehorn.

[expresso]

https://www.bloomberg.com/gadfly/articl ... ry-assault

[shirley_hkg]

DIY: Ni-Cd To Lithium Battery Conversion By Using 18650 Cells https://www.youtube.com/watch?v=7W3-M50uE8w

[granian]

Hi shirley_hkg thanks for the link, I have had a quick look and it looks promising but will study better later and price things up. Cheers.

[ex-Gooserider]

Don't know if it will work or not, but in an effort to get a better answer to the SB-50 / PP-75 crimp vs. solder debate, I've posted a message on one of our Asylum mailing lists asking if anyone has access to a wire pull tester that can handle AWG 6 wire.... If I get an answer, will try making a variety of samples with different methods, and putting them to the torture machine...

ex-Gooserider

[Burgerman]

Ask them how they will crimp well enough to stop movement between strands, oxidation etc too... Seen too many that were done well that failed. And plenty of others that were done badly. On production powerchairs no less.

Pull tester not required. Put the Anderson connector in the vice and pull the cable by hand hard. They come out easily enough! No metal in the shell...

[JoeP]

I am thinking of using the dual 24/12 volt Image B set up (see image below) for my upcoming LiFePo build per this thread.

I'll use 72 12Ah Headways in a 8 series, 9 parallel configuration for a total of 108 Ah. It would be set up as two 12 Volt batteries connected in series.

My hands not being very functional, I'd probably just leave the Image B loom set up in place rather than disconnect and reconnect as shown in Image C. My thought had been to have a compartment where that SB 50 could be tucked away so it would not be flapping around. But I may not have the room to do so. We'll see.

BM, you appear to use 10 sq. mm marine grade, hard insulation, tinned cable for your battery connections. I assume that ex-Goose uses the same in 6ga. Either way, that cable is not very flexible.

Using the dual 12V/24V charging set up shown in images A,B & C above, how the heck do you cram all that wiring into your battery compartment? Can the wiring loom be up so you can easily pull out the batteries without having to do a lot of disconnect work? My TDX -SP battery compartment would be very tight when it comes to installing the LiFePo battery shown above. I wonder about the practicality of routing all that wiring.

Now, I haven't had the opportunity to actually pull out the battery tray on my TDX-SP, but my building's multi-talented handyman did. Taking a look at the loom connector on top of my two MK gel batteries I see that the factory installed loom has an Anderson SB50 that 'blind mates' into a receiving SB50 at the front of the chair.
I think these are just standard SB50s and there is no purpose made 'blind connector'. (For example:
https://tinyurl.com/zkjhq34
http://www.andersonpower.com/us/en/prod ... dmate.aspx

Setting up a battery loom in the Image B mode above, I suppose that you could still have a blind mate connector to connect the batteries to the controller lead, but it seems that all the other cables required in the Image B set up would be problematic and you might have to do some manual disconnections for getting the battery out. I would like to make my LiFePo battery as idiot proof as possible. A LiFePo battery set up with all 'blind connects' would be ideal since it would allow the battery tray to simply be pulled out without any need for manual disconnections. Have you guys managed to set up your batteries & looms for easy removal?