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bournevexed

New member
Joined
Jan 21, 2019
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20
Hey all, I'm from the UK. I love doing diy stuff especially with 18650/26650/ & lifepo cells if i can get hold of them. I have around250-300 recycled 18650 cells that I intend on building a 24v portable power generator with these as a rough go. I bought two liitokala charges last week & they have assisted my imax b6 v2 & opus bt-3100 in charging them cells. I have ordered 140 brand new 26650 5000mah cells & I'm waiting for them (40 days or so) so I can build two 24v portable power generators that i can maybe also hook together for an EBike battery. Oh & by the way thank you all for your knowledge & work! I'll keep you updated as I go!


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chuckp

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Jul 29, 2018
Messages
396
Hi and welcome to the forum
 

hbpowerwall

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Joined
Oct 7, 2016
Messages
1,971
Welcome buddy, sounds like you have a good start on the project, pitty about the postage times - but I guess it's much cheaper that way. Plan on testing all new cells also?
 

bournevexed

New member
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Jan 21, 2019
Messages
20
chuckp said:
Hi and welcome to the forum

Thanks chuckp!


hbpowerwall said:
Welcome buddy, sounds like you have a good start on the project, pitty about the postage times - but I guess it's much cheaper that way. Plan on testing all new cells also?

Thanks HB yeah definitely will be testing them! Will take a while with 7 at a time on 4 chargers(2 liitokalas, 1 opus bt3100 & 1 imaxb6v2) but I'll get there lol
I am ordering that spotwelder & lipo battery today with help from my other half!
 

hbpowerwall

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Might pay to do them all on one device - 3 devices gets you three results.. try one cell in each slot across all slots and you'll be shocked at the difference
 

bournevexed

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Joined
Jan 21, 2019
Messages
20
hbpowerwall said:
Might pay to do them all on one device - 3 devices gets you three results.. try one cell in each slot across all slots and you'll be shocked at the difference

Will do & thanks for that HB. As we can only get 2 26650 cells in an opus or liitokala. 2 cells in 1 charger will take me 70 days with 14o cells LOL


Karlos said:
Heya fellow Brit! :D

Hey Karlos! :cool:


henryjones147 said:
Welcome man

Thanks henry! :cool:
 

hbpowerwall

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Oct 7, 2016
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bournevexed i spent the first 6months testing with one iMax charger one cell at a time 3-4 MAYBE per day at best lol
 

bournevexed

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Jan 21, 2019
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20
hbpowerwall said:
bournevexed i spent the first 6months testing with one iMax charger one cell at a time 3-4 MAYBE per day at best lol

:D :D :D I think I'll use the opus seeing I can use two 26650's (5000mah each) at a time @1amp discharge what do you think HB? That's 4 a day right?
 

LEDSchlucker

Member
Joined
Dec 20, 2018
Messages
157
Not sure if four per day. Let's say the cell is half full, 3h to charge it, 6h to discharge it and again 6h to charge it = 15h for one / two cells per day.

But you can make a spacer cell for the opus and charge two more cells at the same time:

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bournevexed

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Jan 21, 2019
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Thanks for the reply & good idea on charging LEDSchlucker! I think I'll get another Opus! :D :D
 

bournevexed

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Jan 21, 2019
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Thanks for the reply & good idea on charging LEDSchlucker! I think I'll get another Opus! :D :D

I see my mistake I meant @2A discharge not @1A. Apologies!! :D
 

DCkiwi

Active member
Joined
Sep 11, 2017
Messages
189
bournevexed said:
Will take a while with 7 at a time on 4 chargers(2 liitokalas, 1 opus bt3100 & 1 imaxb6v2) but I'll get there lol
I am ordering that spotwelder & lipo battery today with help from my other half!

Erm, not exactly bournevexed. I have six Opus's, four still working 100%, and I love them to bits. BUT they aren't used as chargers... welcome to the forum!

IMHO, The Opus BT3100 is NOT suitable as a charger -- ESPECIALLY for old/recycled cells. You may wish to thrash your new cells in them but I wouldn't recommend that either. I have TWO basic reasons for this assertion:

1/ Basically the method of charging it uses is very brutal pulses which can be way out of spec for the cells.

To quote from the battery charger testing master (!), talking about v2.1 ...

"The first version of this charger had some nasty 9A current spikes from the power supply, this made the charger show wrong mAh values when charging. In this version the spikes are reduced to 6A and the charge current is stable, this means the charger can measure correctly."
https://lygte-info.dk/review/Review Charger Opus BT-C3100 V2.1 UK.html

2/ In any case, if you are like me, the capacity TESTING is the bottleneck.

So I use 'big 4s20p trays on a CC/CV buck converter to 'slow cook' my precharging batts (anything <3v) to get them up to 3.8V ish then top them off with an iSDT balance charger. Takes 5-10 days. but then I have 160 cells to test (I generally process my cells in pairs). And for day to day use I use 6s4p yoke's on balance chargers to keep things charging for the Opus capacity testers.


I mention this all now, as you are ready to blast away at your task, and thought it prudent to tweak your method so you dont end up changing the way you grade / measure cells half way through your mission. Hope That Helps.

PS you may want to pop open your Opus and future ones if you get more to check that J1 is set the same on all of them, as this setting fundamentally changes the capacity values it gives.
 

bournevexed

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Jan 21, 2019
Messages
20
Thanks DCKiwi, yeah I have the Opus V2.2. Yeah!! I was aware of the hidden switch I came across one of averagejoe's videos about it before the thing arrived!
so I was quite lucky there & did check it when it arrived! Though I am not actually ready to blast away at my task. I've had my used cells sat in 4 boxes for a good while now. I charged all up I will give them another week! Then I'll start to capacity test them. most of my cells were paired but i thought i should split them so I did! Thanks for the link very good info on that I have come across it a few times!
I tested the 4th & final box last night for voltage to pull only 8 cells that were below 4.15v As I'm not using any that drop below 4.15v. I want a good marker/leeway for my 24v system at 28v max the cells would be at 4.0v each. majority of my cells are still at 4.19/18v with the a small amount at 4.16/17v. My highest cell a Panasonic CGR flickers between 4.21/20v still after 3 weeks!! :D :D why can't they all be like that LOL. My new 26650 cells have not arrived yet. but will take a few pics when they do! I may even do a short video of my excitement :cool: :cool: who knows I may even rig up a system to capacity test 12 26650 cells per 24hours a small supports right above each charger with connections to the slots.
I have a picture of it in my head lol.
 

DCkiwi

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bournevexed said:
Thanks DCKiwi, yeah I have the Opus V2.2. Yeah!! I was aware of the hidden switch I came across one of averagejoe's videos about it before the thing arrived!
so I was quite lucky there & did check it when it arrived!

Thats all good, but not at all what I meant. (a switch is not a jumper, AND that switch is always shipped set correctly/4.20V).

I referred to J1 -- this is a jumper on the PCB, by way of solder bridge. It matters less which way it is set, than all your Opus's being set the same. Just like it doesnt matter if your tape measure is wrong, so long as its the only one you use for all measurements ... if you get my drift. refer this thread which has images too


bournevexed said:
most of my cells were paired but i thought i should split them so I did!

why did you split them?

I process all my cells in pairs ... dont have time or inclination to double my workload without adequate reason.


bournevexed said:
I tested the 4th & final box last night for voltage to pull only 8 cells that were below 4.15v As I'm not using any that drop below 4.15v. I want a good marker/leeway for my 24v system at 28v max the cells would be at 4.0v each. majority of my cells are still at 4.19/18v with the a small amount at 4.16/17v. My highest cell a Panasonic CGR flickers between 4.21/20v still after 3 weeks!! :D :D why can't they all be like that LOL.

wow, thats really harsh! I too like cells that dont drop down, but many when they are so hot (charged to limit) lose V ok. I generally go by the rough rule of >4.12V after a weeks storage. BU has a nice graph to illustrate self-discharge:
https://batteryuniversity.com/learn/article/elevating_self_discharge

but yeah, I do love it when after a couple of weeks checking for selfdischarge the cell measures 4.20V ... makes me smile for sure. are we sick people? lol ....
 

bournevexed

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Jan 21, 2019
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YEAH we are sick!! :D :D & thanks for that link DC appreciated!! I unpaired the cells due to already having single cells.
& a few paired cells I liberated weren't spot welded together very well & came apart quite easy!
 

bournevexed

New member
Joined
Jan 21, 2019
Messages
20
hey all,

just letting you all know my (140) 26650 liitokala cells & the malectrics spot welder have arrived in the UK!!

I started capacity testing my sourced 18650s. I'll share the results when I'm done
& also upload a few shot of the new 26650 cells.

Hope this post is in the right place if not sincere apologies. :D :D
 

bournevexed

New member
Joined
Jan 21, 2019
Messages
20
My parcel arrived!! Full of Liitokala 26650 5000mAh cells :D :cool: :cool: I tested the lot for voltage & they were all sat at 3.66v.

Anyway here are some pics & a video i did lol


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