Help Mixing pouch cells

[Lucifer]

From places like battery hookup you can buy batteries that have been professionally built used and you only have to put a BMS on it.

That is really cheap compared to anything we have here in the UK, BUT the $90 delivery kinda takes the edge off though, and we would probably get hit with import duty/tax (in theory that's on most imports), but they usually don't bother if its cheap item, not worth the effort. but the delivery alone would make it worth taxing it. So that's a bit of a deal killer, but the prices are great.

Thanks

K

 

[amberwolf]

That probably clarifies that, I was suspecting something like that. Also more than suspect my 3 Imax B6's are in fact Chinese rip offs , and they got the unit wrong in translation. LOL

That wouldn't surprise me in the least... :lol:

Thanks, that's a bit of a longer term project, if I'm not careful I start too many different projects at the same time, at the risk of never actually finishing any of them. Once the challenge has gone, I easily loose interest, I'M being strict with myself now (well stricter), try and remain focussed on one project at a time. Don't acquire anything for other projects except the current one UNLESS "Its def gonna be of use, AND its rare or hard to usually get hold of, OR it's stupidly cheaper than it should be). This is helping me keep focussed on one thing ("helping" LOL).

I've had to do those things, too. Sometimes I have to get rid of collected parts for projects not immediately useful, and it physically hurts when I do.

 

[amberwolf]

Hi Again, I took a look at the above, perhaps it's me but couldn't immediately see what I wanted (prob too impatient),

They have a comparison database, but I haven't used it. I almost always am just going there to get discharge curves and other data for various cells to post in people's threads where they are asking about whether that cell will work in their application (they don't usually know what cell they have, so I cant' often do this).

But I cannot see where it refers to the chemistry of the cells, I have been there before, and I thought they all had the same chemistry.
So as you raised the chemistry question, can you see if they are the same please? I did try, I'm not being lazy,

The green cell page doens't have any specs in it's table to compare to the purple one, so can't tell if they are the same.

The important thing isn't specifically the actual chemistry, but the voltage ranges they operate within. So fo the purple cell taht's 3.62v nominal (meaning average voltage near the middle of the total capacity usage), and 4.2v max (HVC), and 2.5v min (LVC). The green cell has no data there.

Going to the lygte-info.dk comparator

Battery test-review 18650 comparator

for
Samsung INR18650-29E (purple)
and
Sony SF US18650V (green)
also has no specification or voltage data for the green cell, so no comparison for matching htem up can be made.

It does give this chart showing the green cell is way smaller in capacity and doesn't handle loads as well as the purple, so it would take at least twice as many of those cells in parallel to make the same kind of pack as t he purple, if they were each their own separate pack.


and these are the pages for them

Test of Samsung INR18650-29E 2900mAh (Blue)

Test of Sony US18650V 1600mAh (Green)

showing the official specs in text and actual results in images below


Official specifications:

• Nominal Capacity: 2,850mAh (0.2C, 2.50V discharge)
• Typical Capacity: 2,850mAh (0.2C, 2.50V discharge)
• Minimum Capacity: 2,750mAh (0.2C, 2.50V discharge)
• Charging Voltage: 4.20 ± 0.05 V
• Nominal Voltage: 3.65V (0.2C discharge)
• Charging Method: CC-CV (constant voltage with limited current)
• Charging Current: Standard charge: 1,375mA
• Charging Time: Standard charge: 3hours
• Max. Charge Current: 2750mA (not for cyclelife)
• Max. Discharge Current: 2,750mAh (continuous discharge), 8250mAh (not for continuous discharge)
• Discharge Cut-off Voltage: 2.50V
• Cell Weight (max. (g): 48g
• Cell Dimension: Diameter(max.) : 18.40 mm, Height(max) : 65.00 mm,
• Operating Temperature: (Cell Surface Temperature) Charge: 0 to 45°C, Discharge: -20 to 60°C
• Storage Temperature: 1 year : -20~25°C, 3 months : -20~45°C. 1 month : -20~60°C

Official specifications:

• I could not find any.

 

[floydr]

YR1030+ YR1035+ IR meters. They should be under 75USD

IR Meter Recommendations

Does anyone have a recommendation for a good meter to check IR (Internal Resistance) of various battery types? I haven't checked this in the past as the testers I use (Opus) aren't very accurate. There have been a lot of requests to test this in some of my videos, so I'd like to start doing so...

secondlifestorage.com

I have an YR1030+ and while not quite as accurate as the YR1035+ it works.
the cheapest would be using the dc method of IR calculations
Later floyd

 

[amberwolf]

Anyone know an easier way to measure a cells internal resistance other that Ohms and Kirchhoffs Laws ? Is there a cheap gadget ?

Not exactly cheap, but this is one used in various cell testing threads here:
YR1035 Battery Internal Resistance Test Meter

Amazon.com

or this
RC3563 Portable Battery Internal Resistance Tester Battery Meter with Kelvin or Probe

Amazon.com

and this one in ohters

Amazon.com

There are even better ones, or ones that do more cells at a time, etc., but they can get more expensive fast.

There's also the stuff listed here

Li-ion cells cycle ageing

This topic arise from the Pajda´s idea in another thread : https://endless-sphere.com/forums/viewtopic.php?f=14&t=102387&p=1507776#p1507776 Frustrated and tired by never ending unfruitful debate about cycle life of various Li-ion cells, I finaly decided to start some long term cycling to see...

endless-sphere.com

for assorted types of cell testing

I haven't used any of these devices, so I recommend the various cell testing threads like those by Pajda, et al., to read up on their usage and differences.

 

[Lucifer]

Hi Again, I took a look at the above, perhaps it's me but couldn't immediately see what I wanted (prob too impatient), So I went here because I know how to navigate (its fantastically simple, quick and informative, it's a fantastic data base, it's v cool, well worth adding to your list if you don't already have it.

A Cell Database that I knew of (Start point...... really worth a look)

My better Blue Cells

These are the Samsung (BLUE) cells

The Best of my Matika Green cells

The Matika cells are mixed abut include these GREEN cells (These ones are Sony)

But I cannot see where it refers to the chemistry of the cells, I have been there before, and I thought they all had the same chemistry.
So as you raised the chemistry question, can you see if they are the same please? I did try, I'm not being lazy,

Links 2 and 3 take you straight to the data on the two diff cells I'm thinking of mixing. Top link is to look up any cell

Keith

Well as the cell database doesn't mention the cells chemistry, I have now looked up 50 different 18650 cells in the various makers descriptions, so far they are ALL Lithium-ion? Which is great for me, but looked increasingly like a total waste of my time.

SO I was going to ask if there is there actually any other type of chemistry for an 18650 cell apart from Lithium-ion? or have I just just been lucky?

Which is possible as all the Blue Samsung cells came from two identical e-bike batteries (and are all identical, so no surprise there). All my green cells were harvested from Matika Power tool batteries, and while there are lots of different makes, types, and numbers on them. I sort of assumed in the first place Matika would of sourced various supplies of technically identical cells from diff makers.

This is still all new to me, so then realised I could google various cell chemistries, had never occured to me before as I thought they were all the same and I didn't realise it was possible let alone likely they might be different. Having googled the chemistries I now found there appears to be the following;

• LiFePO4 which is Lithium iron phosphate.
• LiMn2O4 which is Lithium manganese oxide.
• LiNiMnCoO2 which is Lithium manganese nickel.
• LiNiCoAlO2 which is Lithium nickel cobalt aluminum oxide.
• LiNiCoO2 which is Lithium nickel cobalt oxide.
• LiCoO2 which is Lithium cobalt oxide.

So these are all collectively called Lithium-ion, right?

I then found this quote

"The 18650 batteries available in different chemistries can be used interchangeably. They are LiFePO4, LiMn2O4, LiNiMnCoO2, LiNiCoAlO2, LiNiCoO2, and LiCoO2 . All these batteries vary slightly in nominal voltage and capacity". At the link below

Interchangeability

From what was mentioned earlier, I understood you cannot mix these is a battery pack?

So can I mix these in a pack? If not (which isn't exactly clear to me), is there an easy source of info that tells you the exact internal chemistry?

So far I put quite a bit of time into making matters more confusing and all this has not exactly clarified things for me LOL

Keith

 

[Lucifer]

YR1030+ YR1035+ IR meters. They should be under 75USD

IR Meter Recommendations

Does anyone have a recommendation for a good meter to check IR (Internal Resistance) of various battery types? I haven't checked this in the past as the testers I use (Opus) aren't very accurate. There have been a lot of requests to test this in some of my videos, so I'd like to start doing so...

secondlifestorage.com

I have an YR1030+ and while not quite as accurate as the YR1035+ it works.
the cheapest would be using the dc method of IR calculations
Later floyd

Hi and thanks

I was hoping for something cheaper TBH (even tho I know you get what you pay for)

I found these two devices on e-bay, (several supplies same gadget)

Cheap gadget on e-bay

And this fairly thorough review on YouTube


YouTube review 55 Mins long, But worth looking if considering one

Certainly cheap enough (even cheaper if you buy direct from china BTW). I'm not bothered by the lack of a fancy case, I'm thinking of buying one and testing it, I can test a few cells, then do it the old way with formula, and compare the results.
Before I do has anyone tried them? Its only the Internal resistance measurement part I'm really interested in, as atm I don't have anything apart from wires, resistors and formulas to work that out.

 

[Lucifer]

Not exactly cheap, but this is one used in various cell testing threads here:
YR1035 Battery Internal Resistance Test Meter

Amazon.com

or this
RC3563 Portable Battery Internal Resistance Tester Battery Meter with Kelvin or Probe

Amazon.com

and this one in ohters

Amazon.com

There are even better ones, or ones that do more cells at a time, etc., but they can get more expensive fast.

There's also the stuff listed here

Li-ion cells cycle ageing

This topic arise from the Pajda´s idea in another thread : https://endless-sphere.com/forums/viewtopic.php?f=14&t=102387&p=1507776#p1507776 Frustrated and tired by never ending unfruitful debate about cycle life of various Li-ion cells, I finaly decided to start some long term cycling to see...

endless-sphere.com

for assorted types of cell testing

I haven't used any of these devices, so I recommend the various cell testing threads like those by Pajda, et al., to read up on their usage and differences.

Hi again

Below is an identical post sent to Floydr..... Not sure if there is an etiquette, issue there, but in case you all looked specifically at your own replies (Like me at the moment). I posted it to both of you.

I was hoping for something cheaper TBH (even tho I know you get what you pay for)

I found these two devices on e-bay, (several supplies same gadget)

Cheap gadget on e-bay

And this fairly thorough review on YouTube

YouTube review 55 Mins long, But worth looking if considering one

Certainly cheap enough (even cheaper if you buy direct from china BTW, but much quicker from us supplier). I'm not bothered by the lack of a fancy case, I'm thinking of buying one and testing it, I can test a few cells, then do it the old way with formula, and compare the results.

Before I do has anyone tried them? Not much point if anyone knows its crap, but it looks ok (for the price). Its only the Internal resistance measurement part I'm really interested in, as atm I don't have anything apart from wires, resistors and formulas to work that out.

Oh I just added a photo below, (Sorry Floydr, hope you see it as well I didn't think to do it before)

Keith

 

[Lucifer]

They have a comparison database, but I haven't used it. I almost always am just going there to get discharge curves and other data for various cells to post in people's threads where they are asking about whether that cell will work in their application (they don't usually know what cell they have, so I cant' often do this).



The green cell page doens't have any specs in it's table to compare to the purple one, so can't tell if they are the same.

The important thing isn't specifically the actual chemistry, but the voltage ranges they operate within. So fo the purple cell taht's 3.62v nominal (meaning average voltage near the middle of the total capacity usage), and 4.2v max (HVC), and 2.5v min (LVC). The green cell has no data there.

Going to the lygte-info.dk comparator

Battery test-review 18650 comparator

for
Samsung INR18650-29E (purple)
and
Sony SF US18650V (green)
also has no specification or voltage data for the green cell, so no comparison for matching htem up can be made.

It does give this chart showing the green cell is way smaller in capacity and doesn't handle loads as well as the purple, so it would take at least twice as many of those cells in parallel to make the same kind of pack as t he purple, if they were each their own separate pack.

View attachment 338024
and these are the pages for them

Test of Samsung INR18650-29E 2900mAh (Blue)

Test of Sony US18650V 1600mAh (Green)

showing the official specs in text and actual results in images below

View attachment 338020
Official specifications:

• Nominal Capacity: 2,850mAh (0.2C, 2.50V discharge)
• Typical Capacity: 2,850mAh (0.2C, 2.50V discharge)
• Minimum Capacity: 2,750mAh (0.2C, 2.50V discharge)
• Charging Voltage: 4.20 ± 0.05 V
• Nominal Voltage: 3.65V (0.2C discharge)
• Charging Method: CC-CV (constant voltage with limited current)
• Charging Current: Standard charge: 1,375mA
• Charging Time: Standard charge: 3hours
• Max. Charge Current: 2750mA (not for cyclelife)
• Max. Discharge Current: 2,750mAh (continuous discharge), 8250mAh (not for continuous discharge)
• Discharge Cut-off Voltage: 2.50V
• Cell Weight (max. (g): 48g
• Cell Dimension: Diameter(max.) : 18.40 mm, Height(max) : 65.00 mm,
• Operating Temperature: (Cell Surface Temperature) Charge: 0 to 45°C, Discharge: -20 to 60°C
• Storage Temperature: 1 year : -20~25°C, 3 months : -20~45°C. 1 month : -20~60°C

View attachment 338021
Official specifications:

• I could not find any.

Thanks.

The more you try and look into this the more complicated it gets. It's like going back to Uni. I'm actually finding it very interesting, apart from anything else when you get to my age it's important to keep the brain alive and keep learning new stuff. However it's equally frustrating, as I thought this was going to be a fairly simple job..... Build a battery.... Its not rocket science....How hard can it be LOL. That said I suppose if I bought all new components, I suppose it would be a lot easier, and I keep telling myself "This is just a brief initial learning curve to deal with" LOL But I so hope that's the case.

On the 24v bike power issues (if you remember), I'm thinking now that perhaps the 24v bike is basically underpowered, and as the objective is to get at least one working ASAP. (then continue to play). I'm going to switch my efforts to the 36v bike, that also needs a few minor mechanical repairs (not worth a mention), but I know the owner used to ride it 30 miles to work each day through London, I once had a test ride just for fun before the battery died, it had plenty of power. The orig battery was 20 big Lipo pouches (two are fried).

So as I have enough purple 18650 identical cells to build one 36v battery, that's my next move, so you will be pleased to hear that means I should not have any questions for a bit. Assuming this goes to plan... (What can possibly go wrong....LOL). Then I will come back and look at how I can replace those two dead pouch cells from the many I have (but none the same) have some physically almost the same size, just a bit bigger in fact, but they will fit in the case (I tried without actually connecting them.. But I'll leave that for now, focus on the identical 18650's which hopefully will be straight forward, and probably pester you with some new questions when I get back to fixing the original battery. In fact at this point if the bike is all working well it might be worth buying two identical pouch cells, (If I can find them). I think the rest are still good, they all fully charge, and don't self discharge, so promising, but have not done any other test on them yet.

The last part of the above ramble is based on my assumption that the pouch cell battery is actually a better battery if it works, that is solely based on the fact that he paid a LOT more money for it as an optional extra as a "heavy duty" battery when he bought the bike new (only 5 years ago BTW). Is that assumption right ?

Thanks again for all your time. Looking at the number of post you have....... Do you ever get chance to ride your bikes any more LOL?

Keith

 

[Lucifer]

You will laugh at this, I have only just noticed the bell at the top right that turns red when someone replies to you..... That will save a bit of time combing this thread, and worrying that I have missed someone's reply to me.

(I'm new to forums as well)

Keith

 

[Lucifer]

They have a comparison database, but I haven't used it. I almost always am just going there to get discharge curves and other data for various cells to post in people's threads where they are asking about whether that cell will work in their application (they don't usually know what cell they have, so I cant' often do this).



The green cell page doens't have any specs in it's table to compare to the purple one, so can't tell if they are the same.

The important thing isn't specifically the actual chemistry, but the voltage ranges they operate within. So fo the purple cell taht's 3.62v nominal (meaning average voltage near the middle of the total capacity usage), and 4.2v max (HVC), and 2.5v min (LVC). The green cell has no data there.

Going to the lygte-info.dk comparator

Battery test-review 18650 comparator

for
Samsung INR18650-29E (purple)
and
Sony SF US18650V (green)
also has no specification or voltage data for the green cell, so no comparison for matching htem up can be made.

It does give this chart showing the green cell is way smaller in capacity and doesn't handle loads as well as the purple, so it would take at least twice as many of those cells in parallel to make the same kind of pack as t he purple, if they were each their own separate pack.

View attachment 338024
and these are the pages for them

Test of Samsung INR18650-29E 2900mAh (Blue)

Test of Sony US18650V 1600mAh (Green)

showing the official specs in text and actual results in images below

View attachment 338020
Official specifications:

• Nominal Capacity: 2,850mAh (0.2C, 2.50V discharge)
• Typical Capacity: 2,850mAh (0.2C, 2.50V discharge)
• Minimum Capacity: 2,750mAh (0.2C, 2.50V discharge)
• Charging Voltage: 4.20 ± 0.05 V
• Nominal Voltage: 3.65V (0.2C discharge)
• Charging Method: CC-CV (constant voltage with limited current)
• Charging Current: Standard charge: 1,375mA
• Charging Time: Standard charge: 3hours
• Max. Charge Current: 2750mA (not for cyclelife)
• Max. Discharge Current: 2,750mAh (continuous discharge), 8250mAh (not for continuous discharge)
• Discharge Cut-off Voltage: 2.50V
• Cell Weight (max. (g): 48g
• Cell Dimension: Diameter(max.) : 18.40 mm, Height(max) : 65.00 mm,
• Operating Temperature: (Cell Surface Temperature) Charge: 0 to 45°C, Discharge: -20 to 60°C
• Storage Temperature: 1 year : -20~25°C, 3 months : -20~45°C. 1 month : -20~60°C

View attachment 338021
Official specifications:

• I could not find any.

On re reading your post, it confirms what I suspected that the purple ones are much better that the green ones, (nice and technical), and confirms that my best simple quick solution to get one bike on the road working is to build a 36v battery for the second bike made entirely from those purple/blue cells, I got enough cells and space in the original case to put ten groups of ten identical cells. I also got several Li -po 36v BMS that claim in big letters to be 70 Amps (from the pouch batteries), so I ASSUME they will be just as happy with the Li-ion cells? (don't think it would make any dif to the BMS the cell type) ? That should quickly and easily make one good 36v pack with "sufficient" range and power for me in the immediate term.

See anything wrong with the plan? Or like to make any comment or watch out notes?

Keith

PS Comment on your other post, it breaks my heart to dispose of anything that I think I might want, but I'm getting better at doing it.

PPS. Hopefully later I'll be able to put something back into this forum, as in make some informative contributions instead of constantly asking questions. But obviously I'm not experienced enough to even think about it atm.

 

[Lucifer]

On re reading your post, it confirms what I suspected that the purple ones are much better that the green ones, (nice and technical), and confirms that my best simple quick solution to get one bike on the road working is to build a 36v battery for the second bike made entirely from those purple/blue cells, I got enough cells and space in the original case to put ten groups of ten identical cells. I also got several Li -po 36v BMS that claim in big letters to be 70 Amps (from the pouch batteries), so I ASSUME they will be just as happy with the Li-ion cells? (don't think it would make any dif to the BMS the cell type) ? That should quickly and easily make one good 36v pack with "sufficient" range and power for me in the immediate term.

See anything wrong with the plan? Or like to make any comment or watch out notes?

Keith

PS Comment on your other post, it breaks my heart to dispose of anything that I think I might want, but I'm getting better at doing it.

PPS. Hopefully later I'll be able to put something back into this forum, as in make some informative contributions instead of constantly asking questions. But obviously I'm not experienced enough to even think about it atm.

Having said that, and starting to tidy up, I realised while I'm not exactly up to speed, I have a lot of "OLD" knowledge that others could possibly benefit from. Like having recently fixed and upgraded, and modified a cheap spot welder, which now works a treat and has done hundreds of welds in no time (it will probably do 1500 building this 36v battery). The relevance being that one mod involved soldering a big capacitor to one side a tiny diode, target being about the size of a pin head (and also to the pcb ground), soldering to such a tiny component can be problematic, this small cheap battery soldering iron (green in pix) is much better for such jobs than my soldering station, or any of my other irons. At the opposite extreme, also in the pix is one of my first soldering irons, (you heat it on the gas stove). The tip is a block of copper about 1/2" square shaped to a point, When it comes to soldering pouch batteries, this does it easy, a LOT of heat instantly applied and removed, puddle of molten solder, instantly cooling, again better than any of my other irons or the solder station, they take too long to do the job, risk conducting too much heat into the cell and damaging it.

Keith

 

[floydr]

Certainly cheap enough (even cheaper if you buy direct from china BTW). I'm not bothered by the lack of a fancy case, I'm thinking of buying one and testing it, I can test a few cells, then do it the old way with formula, and compare the results.
Before I do has anyone tried them? Its only the Internal resistance measurement part I'm really interested in, as atm I don't have anything apart from wires, resistors and formulas to work that out.

Sounds like a plan.
Later floyd

 

[Lucifer]

Sounds like a plan.
Later floyd

Cool thanks, IF I don't hear from anyone else that its a waste of money, I'll buy one try it and report back, IF it does what is supposed to could be useful to other DIY people as well. This stuff always starts expensive and the price drops like a stone, Obviously you get what you pay for, but that doesn't mean some of the new recent chinese rip offs, do not offer good value for money from a functionality point of view (not all tho LOL), but it's by trying them we find out whats worth having and what is a waste of money.

Keith

 

[999zip999]

The best working I.R. testers are 4 wire. If you use more cells in parallel you can have a more stable battery.
Dr Angel has a great build thread using used cells.

 

[Lucifer]

The best working I.R. testers are 4 wire. If you use more cells in parallel you can have a more stable battery.
Dr Angel has a great build thread using used cells.

Sorry Dr Angle ??? I'm new to this, any chance of a link to get me started on his work?

Keith

 

[Lucifer]

The best working I.R. testers are 4 wire. If you use more cells in parallel you can have a more stable battery.
Dr Angel has a great build thread using used cells.

Also on cells in parallel, was going to use 10 groups of 10 cells so 100 cells. that would be good I would hope.

BTW did you see the tester I was thinking of buying. (I put links). I'm on a budget, I know its not the best, but its very cheap and "LOOKS" like it works, at least in someones youtube review. Prob going to buy one and test myself unless i get a flood of "No its crap"

Keith

 

[999zip999]

I looked and couldn't find as E.S. has changed their format here on this form. But A.W. can find it in a heartbeat for you. Here is a 72 volt 8 AH battery I built for 100 bucks it can easily do 100 amps 8,000 watts I use it at 45amps it's bolted together. And here's a cell log that has a balancing function on it it don't work that well but here's what I do when I don't have a BMS. Because he's are such strong cells. Spaim08
Here are four balance leads for this 20s battery they're each 5S and there's four of them.

 

[Lucifer]

Thank you one and all, for all your help.

I have built my first battery pack, for my 36 volt bike, Just got to fully charge it, then I can road test the bike, fingers crossed.

 

[Lucifer]

Might have spoke too soon there.

Wrapping the whole thing up I suddenly saw smoke, I have never run so quick, I got it into the garden pulled off the BMS connection, strange thing is cautiously handled it all over, nothing felt hot. So its laying in the garden atm. I checked and double checked everything. Going to leave it for a while, remove the wrapping that I did get on, and double check everything again.

Hoping it was just the last heavy duty soldered joint that I had just soldered and that it was still hot enough to heat the foam I was wrapping it in at the time.

Keith

 

[Lucifer]

There was a problem, I think it was the fact that the temporary insulation tape I put round the Pack -ve wire had come off and when I rolled it over to solder the last connection it shorted, that's what it looks like.

Going to leave it another hour then reconnect the BMS. probably wishful thinking, but as I caught it immediately and obviously soon as I lifted it up to run I also removed the short, any chance I got away without damaging something, I would expect the cells are ok, I'm concerned about the BMS?

Keith

 

[Lucifer]

Reconnected BMS, no smoke LOL, so charged the battery with the orig bike charger that came with it, no heat, reached fully charged, all packs of cells at 4.v, so looks like got away with it, but instead of casing battery I'll rig a box on rear rack, and run battery down on bike and recheck cells see if they remain balanced. But think I got away with it.

Keith

 

[amberwolf]

I obviously wrongly assumed that all 18650 cells had the same chemistry, (I did jump in at the deep end), So no idea, So I will have to look the cells up somewhere on the net and find that out

Most of them are lithium of some flavor, but there are a bunch of different chemistries, some of whcih only have tiny variations ffrom the typical range, and some of which are very diffferent.

I would recommend only paralleling cells that are the same chemistry, same operatingg voltage range. Otherwise you have to not charge the pack any higher than the lowest-voltage chemistry's HVC or max voltage, and not discahrge it any lower than the highest-votlage chemistry's LVC or min voltage. (basically narrowing the usable range of the pack to only the part that is common between them, so you don't overcahrge or overdischarge any of the cells.

If you don't know what a cell is, it's safer to not parallel it with anything else.

Yeah about ten years older, surprising what a difference that makes. At college, we cross wired the emitter and collectors of glass valves to make a single "Dual Nand Smitt trigger" or as it's better known a flip flop, connected a cascade of these devices, to make a ripple counter, then build and-gates, or-gates, inverters etc out of them. Stick loads of transistorised versions of these circuits into a semiconductor and you have a TTL logic chip, stick thousands of them circuits into a bigger chip and you get a gate array. Put thousands of arrays in an IC and "eventually" you get a Z80 CPU, etc. etc etc. And all that happened over a fairly short time (see Moores Law). LOL

I remember when a 16k static ram chip cost £16,000 and that was when £16k was a lot of money, as in you could buy a house with it and have change.

At college we actually built a basic computer, out of glass valves it was the size of a ping pong table, threw off more heat than my central heating system, and the program was hard wired into, and the huge thing could only answer one question, that had been set by the tutor to achieve..... But it worked. LOL

Now I'm back to struggling to learn how to make a battery feels like it's gone full circle, and its a bit harder than a LeClanche cell this time. LOL

Sorry if this is all Latin to you, just assumed you had an electronics background.

I do...I learned vacuum tubes (valves) in ham radio as a kid ffrom a neighbor a ways down the gravel road we lived on in farm country...later i learned solidstate stuff at school, but I'm no engineer.

 

[amberwolf]

I also got several Li -po 36v BMS that claim in big letters to be 70 Amps (from the pouch batteries), so I ASSUME they will be just as happy with the Li-ion cells? (don't think it would make any dif to the BMS the cell type) ?

Depends on what HVC and LVC it has for each of the cell groups it monitors. As long as the LVC is the same or higher than the cells you're using, and the HVC is the same or lower than the cells you're using, it is safe enought to use....except:

It's not uncommon for the BMS to be what kills cells, by having a balance shunt in one or more channels fail stuck on, so ti just keeps draining these groups all the time, utnil they finally are below empty or even 0V.

There are some tests youc an do depending on what parts you can access ont eh BMS. If you can post a pic of both sides of ti we can draw arrows to points you can test and what to set the meter to and what you'd expect for good or bad results.

 

[Lucifer]

Depends on what HVC and LVC it has for each of the cell groups it monitors. As long as the LVC is the same or higher than the cells you're using, and the HVC is the same or lower than the cells you're using, it is safe enought to use....except:

It's not uncommon for the BMS to be what kills cells, by having a balance shunt in one or more channels fail stuck on, so ti just keeps draining these groups all the time, utnil they finally are below empty or even 0V.

There are some tests youc an do depending on what parts you can access ont eh BMS. If you can post a pic of both sides of ti we can draw arrows to points you can test and what to set the meter to and what you'd expect for good or bad results.

HI, again.

By the time I got your reply I had already built and charged the battery, But as I was aware the Bms was used, I was going to test the finished pack on the bike without casing it, (wood box on parcel carrier). then Monitor the cell voltages, left it on bbq over night (in case, had a smoke incident, now dealt with...... I hope), just checked all parallel groups in the fin battery, they are still all the same as last night. But I'll check them often at first. Next time I charge it I'll check the voltages at the point where BMS balance wires connect to pack see if they are what they should be.

Decided to simplify things on this battery, as much as poss so for this pack just used 10 x 5 cells all identical (the blue samsung cells and all previously well tested by me. (didn't think to monitor the BMS when charging, but will next time)...Fingers crossed. Thanks again