Samsung INR-18650-29E optimal charge/discharge protocol

[opperpanter]

What about balancing?

I have a 48V25Ah triangle pack from em3ev. The charger has three settings, 50%, 90% and 100%.
Because the pack is so big, I rarely need to charge it to 100%. Most of the times somewhere between 50% and 90% is enough.

How often should I charge till 100% to trigger the BMS balancing procedure?
I assume that it only balances at 100% (4.2V)?

 

[riba2233]

Well based on people's experience, they don't get out of balance, on larger packs.
Yeah, it only balances at 100%. Maybe you should do it on every 20th cycle?

 

[Nobuo]

Well based on people's experience, they don't get out of balance, on larger packs.
Yeah, it only balances at 100%. Maybe you should do it on every 20th cycle?

I would add 20th if you leave the battery 4 hours when the charger finish and BMS hits.

I think better 10th cycle and leave the battery 2 hours.

Anyway if you can't or don't want to make measurements to check if the balancing is getting done, you can just check BMS temperature.
When the balancing phase hit almost all the BMS's gets hot because they use to discharge higher Voltage cells while restarting the charging.
Also the chargers should show visually leds restarting several times until the balance finish.

 

[Mike Allred]

I run a pack of 98 29E's in a 14S 51V, 7P 20Ah config. The BMS cut's off at about 46V, which is 3.3V per cell. I'm pretty happy, I get 40km at 45kph. The CA tells me I've used just over 18Ah and I estimate that there is about 1 useful Ah left in the pack and 1 further Ah where I don't want to go. Sounds right ? My main concern is heat, The cells are packed closely but not touching and not ventilated. The pack is just warm, perhaps 40°C but the middle of the pack is hotter, maybe 50-60°C on a cool day. Is that a problem in terms of danger, cell capacity or cell life ?

 

[riba2233]

What current are you drawing? It would be better if temperatures in the middle of the pack were lower, but 40°C is ok.

 

[Nobuo]

I run a pack of 98 29E's in a 14S 51V, 7P 20Ah config. The BMS cut's off at about 46V, which is 3.3V per cell. I'm pretty happy, I get 40km at 45kph. The CA tells me I've used just over 18Ah and I estimate that there is about 1 useful Ah left in the pack and 1 further Ah where I don't want to go. Sounds right ? My main concern is heat, The cells are packed closely but not touching and not ventilated. The pack is just warm, perhaps 40°C but the middle of the pack is hotter, maybe 50-60°C on a cool day. Is that a problem in terms of danger, cell capacity or cell life ?

The LVC sounds right If we suppose you are draining an average of 10A, so in that case cutting 29E at 3.3V you leave on the cells ~200mAh thats reasonable for 2900mah cells.

Below 60º centigrades on the center of the pack at full use is by far safe, but if you don't tell at how much discharge rate it can't be analized.

In terms of cells capacity use, warm temperatures makes a pack being higher charged and discharged in terms of total energy than cold temperatures, but it doesn't worth if you take into account that an average of 20º centigrades of temperature differences along the life for cells makes them considerably long-lived.

If you are referring exclusively on the heat produced by the use, that means all the energy heat losses and how the efficiency is in your pack for the discharge rates you are doing.

 

[Mike Allred]

I'm effectively drawing 20Ah (1C) continuous although the controller will draw up to 35ah uphill or under acceleration for short periods.

 

[riba2233]

You are drawing 20 A, not 20 Ah. Ah is measure for capacity.

 

[Overclocker]

any insights/speculation on the longevity of this cell. it's NCA right, so should last quite a bit...

planning on building a 200 cell pack using these

 

[RiverRat]

I just ordered 200 samsung 29e's ffrom EVVA tech. Price was 2.70$ us pp. 145 freight to au. +35 bank charge on their side and my side also.

I did the get a quote thing on allibaba first and had cell quotes come back to me as low as 2.40$ pp including victpower which ive read some dodgy stories about. So I went back to Evva and asked for a lower price. She went down from 2.80 to 2.70 and told me there's no way the other vendors could sell genuine cells at that price and not make a loss unless they were fake.

So i bought from them.from evva.

Anyway just thought I'd up date you's with a current price for them.

 

[Overclocker]

I just ordered 200 samsung 29e's ffrom EVVA tech. Price was 2.70$ us pp. 145 freight to au. +35 bank charge on their side and my side also.

I did the get a quote thing on allibaba first and had cell quotes come back to me as low as 2.40$ pp including victpower which ive read some dodgy stories about. So I went back to Evva and asked for a lower price. She went down from 2.80 to 2.70 and told me there's no way the other vendors could sell genuine cells at that price and not make a loss unless they were fake.

So i bought from them.from evva.

Anyway just thought I'd up date you's with a current price for them.

thanks for the info! very timely since i'd probably be getting 200+ of this cell

so why'd you choose this cell over something else, like e.g. panasonic ncr18650be?

 

[madin88]

any insights/speculation on the longevity of this cell. it's NCA right, so should last quite a bit...

planning on building a 200 cell pack using these

from where do you know that 29E is NCA?
There is nothing written about it's chemical composition in the datasheet and specification from other sources are often bullshit.
The 25R as example is declared as true NCA.

 

[Overclocker]

any insights/speculation on the longevity of this cell. it's NCA right, so should last quite a bit...

planning on building a 200 cell pack using these

from where do you know that 29E is NCA?
There is nothing written about it's chemical composition in the datasheet and specification from other sources are often bullshit.
The 25R as example is declared as true NCA.

https://www.electricbike.com/lithium-cobalt-manganese/

you think ncr18650be is a "true" NCA?

 

[riba2233]

BE is 100% nca, it's cell form tesla...
All NCR panasonic cells are NCA.

29E is nca. Em3ev states that, and he gets his cells from reliable source. Suppliers get more detail on cells then we do (leaked 25R datasheet for instance), also that data is stated in some safety datasheets.
Also, it makes sense, since other chemistries has capacity limits.

 

[tomjasz]

What about balancing?

I have a 48V25Ah triangle pack from em3ev. The charger has three settings, 50%, 90% and 100%.
Because the pack is so big, I rarely need to charge it to 100%. Most of the times somewhere between 50% and 90% is enough.

How often should I charge till 100% to trigger the BMS balancing procedure?
I assume that it only balances at 100% (4.2V)?

I do 1 overnight charge every 10 to balance. I feel safest using the Satiator since EM3ev didn't have a 36V charger capable of 50,90,100. I usually use a custom 80% setting for typical usage days. I try to plan my 100% charges for days where I will need more mileage.

This from Grin,

"One of the only downsides to partial charging is that many inexpensive battery management system (BMS) circuits will only do active bleed balancing of the cells when they are at or near the full charge voltage of 4.2 V/cell. This means that with partial charge profiles that don’t reach that voltage, the BMS circuit will never be able to rebalance cells if they are drifting apart. Over time you may have less available capacity from the pack as certain cells will hit the low voltage cutoff on discharge well before others.

If this is an issue it can be easily remedied by occasionally (like once every month or two) leaving the pack connected to a 100% charge cycle overnight.

Good quality programmable BMS circuits will usually attempt to balance the cells whenever they see more than a certain voltage spread between the highest and lowest cell in the group, and in that case there is no problem with partial charges. Similarly, good quality cells rarely drift out of balance in a series string, and can easily handle 100 or more cycles and maintain a perfect voltage matching even if the BMS circuit doesn’t do any active balancing. But if you aren’t sure of the makeup of your battery pack, then the protocol of occasionally giving a 100% top-up is a good bet to ensure both a long cycle life and evenly matched cell voltages."

 

[opperpanter]

What about the charge current? I think by default most spec sheets list a charge current of 0.5C, which is about 1.4 amps?

The default charger I have from em3ev.com is 5A. My pack is the big triangle pack, almost 25Ah. So I guess I could safely switch to a 10A charger?

My em3ev charger died, so I might as well buy a 10A new one while I am at it.

 

[Nobuo]

basically if the cells don't heat-up, even slightly warm, the charge ratio is ok. Generally less than 3 hours start to be harming. 0.3C or less is better for healthy chemistry.

 

[tomjasz]

What about the charge current? I think by default most spec sheets list a charge current of 0.5C, which is about 1.4 amps?

The default charger I have from em3ev.com is 5A. My pack is the big triangle pack, almost 25Ah. So I guess I could safely switch to a 10A charger?

My em3ev charger died, so I might as well buy a 10A new one while I am at it.

The BMS may not allow a 10A charge. That was the case with 3 EM3ev batts I have and 2 i sold. But they were 36V 13.8AH. Best to confirm with Paul first!

 

[opperpanter]

What about the charge current? I think by default most spec sheets list a charge current of 0.5C, which is about 1.4 amps?

The default charger I have from em3ev.com is 5A. My pack is the big triangle pack, almost 25Ah. So I guess I could safely switch to a 10A charger?

My em3ev charger died, so I might as well buy a 10A new one while I am at it.

The BMS may not allow a 10A charge. That was the case with 3 EM3ev batts I have and 2 i sold. But they were 36V 13.8AH. Best to confirm with Paul first!

I already checked with Paul, it can handle the 9A charger he sells (16S Lifepo4).

 

[RiverRat]

I just ordered 200 samsung 29e's ffrom EVVA tech. Price was 2.70$ us pp. 145 freight to au. +35 bank charge on their side and my side also.

I did the get a quote thing on allibaba first and had cell quotes come back to me as low as 2.40$ pp including victpower which ive read some dodgy stories about. So I went back to Evva and asked for a lower price. She went down from 2.80 to 2.70 and told me there's no way the other vendors could sell genuine cells at that price and not make a loss unless they were fake.

So i bought from them.from evva.

Anyway just thought I'd up date you's with a current price for them.

thanks for the info! very timely since i'd probably be getting 200+ of this cell

so why'd you choose this cell over something else, like e.g. panasonic ncr18650be?

Im not too savvy when it comes to knowing what batteries are the best. Just went on what i thought was the consensus here for a good bang for buck battery. Now you got me wondering if i made the correct choice.. lol

 

[riba2233]

You did, 29E have by far best Ah to dollar value.

Be are better, but at much greater cost.

 

[Overclocker]

I just ordered 200 samsung 29e's ffrom EVVA tech. Price was 2.70$ us pp. 145 freight to au. +35 bank charge on their side and my side also.

I did the get a quote thing on allibaba first and had cell quotes come back to me as low as 2.40$ pp including victpower which ive read some dodgy stories about. So I went back to Evva and asked for a lower price. She went down from 2.80 to 2.70 and told me there's no way the other vendors could sell genuine cells at that price and not make a loss unless they were fake.

So i bought from them.from evva.

Anyway just thought I'd up date you's with a current price for them.

thanks for the info! very timely since i'd probably be getting 200+ of this cell

so why'd you choose this cell over something else, like e.g. panasonic ncr18650be?

Im not too savvy when it comes to knowing what batteries are the best. Just went on what i thought was the consensus here for a good bang for buck battery. Now you got me wondering if i made the correct choice.. lol

haha. so i contacted evva:

NCR18650BE: USD 2.75;
INR18650-29E: USD 2.70;
NCR18650PF: USD 2.85

prices are too close. makes choose much harder LOL

 

[riba2233]

For that price dont think, BE is first choice. I cant believe its so cheap compared to 29e. But on the other side, 29e is too expensive.

 

[markz]

I found Evva Tech's homepage, is their also a Evva Tech eBay and/or Aliexpress/Alibaba store?
http://www.evvatech.com/

Those are good prices. Freight seems high, but it is 200 cells and its Australia so.

RiverRat » Thu Jul 02, 2015 9:12 pm
I just ordered 200 samsung 29e's ffrom EVVA tech. Price was 2.70$ us pp. 145 freight to au. +35 bank charge on their side and my side also.

I did the get a quote thing on allibaba first and had cell quotes come back to me as low as 2.40$ pp including victpower which ive read some dodgy stories about. So I went back to Evva and asked for a lower price. She went down from 2.80 to 2.70 and told me there's no way the other vendors could sell genuine cells at that price and not make a loss unless they were fake.

So i bought from them.from evva.

Anyway just thought I'd up date you's with a current price for them.

Overclocker, you going BE? Im getting different specs. My sheet says BE is 1C discharge. PF is 10A and 29E is ~3-6Acont. or 10Acont. depending on website. http://endless-sphere.com/forums/viewtopic.php?f=14&t=58463#p1024073

Overclocker
haha. so i contacted evva:

NCR18650BE: USD 2.75;
INR18650-29E: USD 2.70;
NCR18650PF: USD 2.85

prices are too close. makes choose much harder LOL

 

[riba2233]

That sheet is wrong, BE are 3C cells, and they are used in tesla S. Read this thread, whole:

http://endless-sphere.com/forums/viewtopic.php?f=14&t=56549&start=25

Although I was wrong, BD are also 10A,but much more expensive.