wb9k
10 kW
riba2233 said:
Something is very wrong here, for sure.
72v 20ah SLA pack vs Samsung SDI 72v 24ah pack range!
- Thread starter General_Lee
- Start date
Something is very wrong here, for sure.
General_Lee
10 W
riba2233 said:
Ok yes about the 10 amp load and SLA. I will make other test with higher load but maybe the pack come hot more rapidly. (Lithium)
Your test with 2C is in continue? I mean you put the load and wait the pack discharge completely (cut off)?
About pictures, I post here tonight.
General_Lee
10 W
What is your suggestion to make a good test? Put a 40A load? if my lithium pack is around 21A?
wesnewell
100 GW
Do the test with some 20C rated rc lipo. Then you'll see why I don't use those weak ass 18650 flashlight cells that are only rated for 3C or less.
okashira
10 kW
wesnewell said:
I guess if you like a 3 minute battery life. And you don't mind to leave your bike/pack outside in case it catches fire. (gotta love Chinese/HK lipo QC)
Seriously, though... you are misinformed...
Don't get me wrong, HK lipos offer great bang power/volume and power/$. And easy to duct tape to a bike frame. But that's about where their advantages end ...
General_Lee
10 W
riba2233 said:wesnewell said:
Here we go again
It's obvious that something isn't alright with his cells. I have original cells, and they work great. But you prefer to be ignorant and only believe what you want.
What the difference between fake or original cell? can I see that physically?
okashira
10 kW
I've never heard of fake Samsung 29E. Your cells are probably good.General_Lee said:riba2233 said:wesnewell said:
Here we go again
It's obvious that something isn't alright with his cells. I have original cells, and they work great. But you prefer to be ignorant and only believe what you want.
What the difference between fake or original cell? can I see that physically?
Weigh one. Should be 45-46g each.
General_Lee
10 W
Ok, like I said, tonight I will remove the shrink PVC on BMS and Pack, I will put the photos here, you will comment. Maybe you can find something wrong. :?
I finding a higher load for other test. Maybe a heating complaint
I finding a higher load for other test. Maybe a heating complaint
General_Lee
10 W
riba2233 said:
All pack riba2233.
wesnewell
100 GW
All you have to do is look at the specs for the cells and note that don't work worth crap at more than 2C even when rated for 3C. I'd damn sure rather be ignorant than just plain stupid. Tying 100 flashlight batteries together to make a battery pack for an ebike is just plain stupid imo. But if you guys want to try and repair these weak ass packs that sag like crap, and cost more than rc lipo, more power to you.riba2233 said:wesnewell said:
Here we go again
It's obvious that something isn't alright with his cells. I have original cells, and they work great. But you prefer to be ignorant and only believe what you want.
General_Lee
10 W
parabellum
1 MW
Oh boy, you apparently got the wrong type samsung cells. They are 100mOhm
Edit. Wrong link. Specs attached.
Edit. Wrong link. Specs attached.
Yep, those are much worse then 29E:
http://www.dampfakkus.de/akkuvergleich.php?akku1=104&akku2=353&akku3=0&akku4=0&akku5=0&akku6=0
And also, they are 4.35 V cells! That means if you don't charge them to 4.35, they have lower capacity, but also much higher internal resistance. Here is the test that shows difference between charging to 4.2 and 4.35 on similar samsung cell: (30B)
http://www.dampfakkus.de/akkuvergleich.php?akku1=481&akku2=483&akku3=0&akku4=0&akku5=0&akku6=0
Pack looks good, bms is good one, only concern are weak serial links between parallel groups.
http://www.dampfakkus.de/akkuvergleich.php?akku1=104&akku2=353&akku3=0&akku4=0&akku5=0&akku6=0
And also, they are 4.35 V cells! That means if you don't charge them to 4.35, they have lower capacity, but also much higher internal resistance. Here is the test that shows difference between charging to 4.2 and 4.35 on similar samsung cell: (30B)
http://www.dampfakkus.de/akkuvergleich.php?akku1=481&akku2=483&akku3=0&akku4=0&akku5=0&akku6=0
Pack looks good, bms is good one, only concern are weak serial links between parallel groups.
parabellum
1 MW
It looks like those need to heat up to perform. Look the 5A discharge, their initial IR is huge and they catch up in second half of discharge curve. I wonder how cycle life is affected.
General_Lee
10 W
Thanks guys, the seller lied me! 
That why my pack get in hot after one hour test load. This cell is very lower quality then the 29E. I will contacte right now this seller. And my charger stop to 84v total, I can't charge this pack in 87v.
That why my pack get in hot after one hour test load. This cell is very lower quality then the 29E. I will contacte right now this seller. And my charger stop to 84v total, I can't charge this pack in 87v.
General_Lee
10 W
Guys, the seller said to me this about the Samsung cell 30A: What is you opinion and if is not correct 8) what is your answers.
i am sorry to tell , you are got it all wrong.
you are not right about the conclusions, and you based on i dont know whos opinions, and i'm not sure about thier actuall knowlage.
so i'll just point the facts.
samsung INR 18650-29E are lower quality cells it even wont fit your needs becuase the capcity is lower and the discharge rate is smaller, the maximum continues working current is 1C which means at 24AH battrey pack you will be able to get only 24A working current.
samsung ICR18650-30A are high drain cells, its higher quality and more expansive cells, the max continues current is 2C-3C which is minimum 48A for 24AH battery pack - which match ecxactly you needs.
just point the facts , i attached for you , the ecxact specification data sheet you sent to me.
i marked the facts for you.
you can even see ebay seller selling from same spot samsung icr1865-30A is 4 times more expansive
if i had puts samsung irn18650 29-e to be able to reach 24AH capcity i had to use more cells, which mean you had to pay more to be able to get simillar capcity battery pack.
if you had samsung inr1865029-e battrey pack and you will load it with 40A you had damage the battery pack in few weeks it will be dead in no time.
best regards
i am sorry to tell , you are got it all wrong.
you are not right about the conclusions, and you based on i dont know whos opinions, and i'm not sure about thier actuall knowlage.
so i'll just point the facts.
samsung INR 18650-29E are lower quality cells it even wont fit your needs becuase the capcity is lower and the discharge rate is smaller, the maximum continues working current is 1C which means at 24AH battrey pack you will be able to get only 24A working current.
samsung ICR18650-30A are high drain cells, its higher quality and more expansive cells, the max continues current is 2C-3C which is minimum 48A for 24AH battery pack - which match ecxactly you needs.
just point the facts , i attached for you , the ecxact specification data sheet you sent to me.
i marked the facts for you.
you can even see ebay seller selling from same spot samsung icr1865-30A is 4 times more expansive
if i had puts samsung irn18650 29-e to be able to reach 24AH capcity i had to use more cells, which mean you had to pay more to be able to get simillar capcity battery pack.
if you had samsung inr1865029-e battrey pack and you will load it with 40A you had damage the battery pack in few weeks it will be dead in no time.
best regards
Attachments
wb9k
10 kW
So which cells did you pay for--the 29 or the 30? He makes the difference between the two clear, and based on the Samsung specs, your results would not be surprising if you had the 29-type cells. What is not clear to me is which you paid for. I see the cells in your pack say "30A" on them, but could they be mismarked? The seller seems to be suggesting that you bought the 29 version, not the 30. That's where my focus would go--establish with the seller what you paid for and show that the performance does not match expectations.
Looking at the Samsung specs against the German discharge test data, the German data is hard to believe. Could be that fresh out of the box the 29 performs comparably to the 30, but because of elevated impedance/heat will degrade much faster. Or the German lab made an error in their tests--which seems more plausible.
Looking at the Samsung specs against the German discharge test data, the German data is hard to believe. Could be that fresh out of the box the 29 performs comparably to the 30, but because of elevated impedance/heat will degrade much faster. Or the German lab made an error in their tests--which seems more plausible.
It's not hard to believe.
29E is 40mohm cell, and 30A is 100 mohm failure. Of course that the seller is lying to you, he is just defending himself, he got rid of his old stock of 30A (30B is a new model, still not good enough for electric vehicles, and also a 4.35 V model). Tests from dampfakkus are true, and you can see the huge difference.
29E is actually a 2C continuous and 3C peak cell, as I've already said. You can see that on Samsung SDI official page:
http://www.samsungsdi.com/lithium-ion-battery/e-bike
Also, you can notice that 29E is listed (and is frequently used by Bosch and other manufacuters) as an e-bike cell, while 30A is not, because it's too weak. It is listed as a laptop cell, and laptops are used at below C rate!
http://www.samsungsdi.com/lithium-ion-battery/laptop
29E is 40mohm cell, and 30A is 100 mohm failure. Of course that the seller is lying to you, he is just defending himself, he got rid of his old stock of 30A (30B is a new model, still not good enough for electric vehicles, and also a 4.35 V model). Tests from dampfakkus are true, and you can see the huge difference.
29E is actually a 2C continuous and 3C peak cell, as I've already said. You can see that on Samsung SDI official page:
http://www.samsungsdi.com/lithium-ion-battery/e-bike
Also, you can notice that 29E is listed (and is frequently used by Bosch and other manufacuters) as an e-bike cell, while 30A is not, because it's too weak. It is listed as a laptop cell, and laptops are used at below C rate!
http://www.samsungsdi.com/lithium-ion-battery/laptop
General_Lee
10 W
wb9k said:
For this pack I pay arround 1000$ US. My probleme is, I supposed to have 29E but I received 30A. What is the difference about total power and range with the same configuration? If the difference is so small, I will keep it.
Doctorbass
100 GW
General lee,
There is few questios here to discuss.
When comparing SLA and li-ion the first major diff is the weight. But we all know already.
The second thing is about the performances: the SLA suffer from Peukert effect ( please search on the E-S there is a lot of discussions already about that.
The peukert effect is a negative effect that the lead acid battery havd with make them to have their rated Ah to vary according to the discharge rate.. and it's not just a question of Ri. the usual lead acid battery are rated at a rate of C/20.. so if a battery is rated 20Ah it will give you 20Ah but at a discharge rate of 1A. If you discharge them at 10A they will give you around 15Ah. But it's not a question of Ri and heat loss at high rate.. it's more chemical and it's a particular effect that Lead acid have.
The real question you need an answer is how many Wh my pack is capable to produce at the average rate i'mm be using it!
In fact if you bought cheat cells from a seller that sell mostly cells for flashlight there is a chance that these cells will not be qualified for med-high discharge rate.
The best action is to buy cells from guys on E-S !.. there is a lot of group buy or guys offering to build pack and that also want to keep their great reputation to continue selling them as well.
If a 8p group became very hot at the discharge rate you tested it mean one thing:
these cells have abnormally high RI (internal resistance). Sometime if these cells are like that and are new it mean that they are counterfeit or original but very old witch make them to have increase of internal resistance, or just rejected cells.
When you want energy for ebike power ( Wh at med-high rate), you need both Ah and low Ri. These two requirement can be obtained with trusted sellers. :wink:
From my experience with the battery you pay for what you get on ebay about battery.
If you ordered battery that does not meet the spec that are displayed on the auction, then you can contact Paypal and ask for help, Paypal are hungry for fee and we all know as well but when you need help to solve an issue they do the job well and you get satisfied in most cases.
Doc
There is few questios here to discuss.
When comparing SLA and li-ion the first major diff is the weight. But we all know already.
The second thing is about the performances: the SLA suffer from Peukert effect ( please search on the E-S there is a lot of discussions already about that.
The peukert effect is a negative effect that the lead acid battery havd with make them to have their rated Ah to vary according to the discharge rate.. and it's not just a question of Ri. the usual lead acid battery are rated at a rate of C/20.. so if a battery is rated 20Ah it will give you 20Ah but at a discharge rate of 1A. If you discharge them at 10A they will give you around 15Ah. But it's not a question of Ri and heat loss at high rate.. it's more chemical and it's a particular effect that Lead acid have.
The real question you need an answer is how many Wh my pack is capable to produce at the average rate i'mm be using it!
In fact if you bought cheat cells from a seller that sell mostly cells for flashlight there is a chance that these cells will not be qualified for med-high discharge rate.
The best action is to buy cells from guys on E-S !.. there is a lot of group buy or guys offering to build pack and that also want to keep their great reputation to continue selling them as well.
If a 8p group became very hot at the discharge rate you tested it mean one thing:
these cells have abnormally high RI (internal resistance). Sometime if these cells are like that and are new it mean that they are counterfeit or original but very old witch make them to have increase of internal resistance, or just rejected cells.
When you want energy for ebike power ( Wh at med-high rate), you need both Ah and low Ri. These two requirement can be obtained with trusted sellers. :wink:
From my experience with the battery you pay for what you get on ebay about battery.
If you ordered battery that does not meet the spec that are displayed on the auction, then you can contact Paypal and ask for help, Paypal are hungry for fee and we all know as well but when you need help to solve an issue they do the job well and you get satisfied in most cases.
Doc
General_Lee
10 W
riba2233 said:
Thanks, is much clear for now 8)
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