Panny or Sanyo?

Dak77

100 W
Joined
May 24, 2019
Messages
151
I've been lurking around for a bit trying to decide on a 13s6p build for my wife's mountain bike and I keep flopping back and forth from Sanyo GA and Panasonic PF .I could build an 8p pack of PF for around the same price as a 6p GA , but I keep reading about resistance issues with GA. It's a 30 amp speed controller and has one of those cheap hub motors from amazon. 1000w I believe. I doubt she will pass 5 or 6 amps very often , per cell, but we do have some hills around so there's that. Price is up there on the priorities, but I do want it to last. Is PF my best bet?
 
Dak77 said:
.I could build an 8p pack of PF for around the same price as a 6p GA , but I keep reading about resistance issues with GA.
I don't know the cell specs for those, but if you can build a pack (PF) with more capacity and more current delivery ability (more parallel cells) for the same money as a less-capable pack (GA), that's a no-brainer right there, especially if the GA cells have higher internal resistance (which would mean more cell heating and more voltage sag for the same per-cell current).

That's assuming the PF and GA cells have equivalent specs, whcih I don't know--you'd have to look them up to find that out for sure.


As for the per cell current, bascially you want to keep that as low as possible. The higher the per-cell current, the more heating inside the cell, and the more voltage sag (and thus the less power total delivered).
 
the GA wear out faster and heat up more.

use PF panny's or samsung 29E depending on what's cheaper.
 
Not to pile on here, but I built my last pack with Panasonic 18650 PFs 12S6P and find them to be a good balance of capacity, durability and cost.

I bought them from IMR Batteries and they were graded as C cells, so that is one reason they weren't too expensive. I tested them and get 2700 mAh per cell on a regular basis.
 
Thank you all. This site has an amazing wealth of knowledgeable and helpful posters.
 
Dak 77, if you build 8p pack with GA, your wife will love it for next 10 years. And you also.
By the way, internal resistance GA and PF is nearly the same.
 
docware said:
Dak 77, if you build 8p pack with GA, your wife will love it for next 10 years. And you also.
By the way, internal resistance GA and PF is nearly the same.

the lifespan of the GA is considerably lower. this has been measured and proven.
 
Depends on the conditions. I know that my GA will persist long, long time with my slow charging, low discharging current, low DOD, low SOC, …..

But in fact, we have too vague information from Dak77 to be able to make proper advice. We would need mainly exact info about average and max current to the motor, then weight of the rider, condition of the rider, inclination of the hills, average trip mileage, …………
 
If one model batt A has greater longevity under lab-testing controlled conditions than model B,

then that relationship will still hold under different usage patterns, whether better, well coddled, or abusively worse.

Generally (please confirm) within a given chemistry and quality level,

those batteries supporting higher discharge rates (power density) seem to have shorter lifetime cycles.

This would to me imply that longer life is generally associated with greater energy density (range)
 
john61ct said:
This would to me imply that longer life is generally associated with greater energy density (range)
no, just no.
 
If you disagree with something, at least be specific about which bit you think is false, and please try to be precise stating what you believe is true.

If you really value high-C discharge rates and using every bit of range, then longevity is going out the window anyway so who cares, I get that.

But if maximum possible longevity is important, so using less of the possible range even if high discharge rates are required,

assuming top quality as given,

in chemistry tweaking my perception is that improving power density requires sacrificing energy density.

are you saying **both** approaches are at the expense of cycling longevity?

 
So far from what I've gathered there is a triangle of current, capacity, and cycle life with the common chemistries, right ? Any direction you pull to one side, shortens the others somewhat proportionally? She is 5"2 about 140 lbs and the bike is a 28-30 lb Trek . There is a budget of $500 for pack and charger , so it appears that a 13s 8p falls into that zone. The controller is a cheap chinese model that all I can make out is 30A for max I assume. It has a cheap "1000w" AWT hub motor. She isn't exactly a speed demon so she will probably only lay the throttle down on steep hills and likely won't offer much pedal assistance , since the only way I was getting her out on a bike was the electric power option. I totally expect the motor to do 90% of the work. 5 amps peak for maybe 20 secs and 3amps nearly constantly for each cell . Based on our budget , I'm thinking either a 6p Ga or MJ1 pack; or an 8p pack of Pf or 29E . I'm leaning toward the 29E now because of the lowest cost vs capacity , as long as it can handle that load and still have good life. I'm not biased to a brand or even a particular format .
 
john61ct said:
If you disagree with something, at least be specific about which bit you think is false, and please try to be precise stating what you believe is true. If you really value high-C discharge rates and using every bit of range, then longevity is going out the window anyway so who cares, I get that. But if maximum possible longevity is important, so using less of the possible range even if high discharge rates are required, assuming top quality as given, in chemistry tweaking my perception is that improving power density requires sacrificing energy density. are you saying **both** approaches are at the expense of cycling longevity?
yes, i said everything you previously said in your post was wrong and i dont want to derail topics so writing a whole essay on why your views are wrong is not something i can be botherd with on a phone.
 
Dak77 said:
The controller is a cheap chinese model that all I can make out is 30A for max I assume. It has a cheap "1000w" AWT hub motor. She isn't exactly a speed demon so she will probably only lay the throttle down on steep hills and likely won't offer much pedal assistance , since the only way I was getting her out on a bike was the electric power option. I totally expect the motor to do 90% of the work. 5 amps peak for maybe 20 secs and 3amps nearly constantly for each cell .

Go with 13s8p version, doesn´t matter what brand, but definitely 8p.
 
docware said:
Dak77 said:
The controller is a cheap chinese model that all I can make out is 30A for max I assume. It has a cheap "1000w" AWT hub motor. She isn't exactly a speed demon so she will probably only lay the throttle down on steep hills and likely won't offer much pedal assistance , since the only way I was getting her out on a bike was the electric power option. I totally expect the motor to do 90% of the work. 5 amps peak for maybe 20 secs and 3amps nearly constantly for each cell .

Go with 13s8p version, doesn´t matter what brand, but definitely 8p.

K. Thank you
 
Hm that's a bit worrying, I've just bought a load of GA's. https://endless-sphere.com/forums/viewtopic.php?t=85113 sais that they do 500 cycles fine, and up to 800 before losing 20% of their capacity.

Panny said that they would phase out the Sanyo brand, for the purpose of efficiency, they have access to the same chemistries and technologies, so I don't know what is different about them.
 
Hmm, charge 1,3 A, discharge 6 A, some ES members consider opinion that test data are erratic and methodology is wrong.

6 A discharge is really too high, charge current is in common life also lower. Wonder that cells made such results at this torturing.
 
Panny PF is 8P will outlast SanyoGa in 6P biiiig time ! PF all yhr way for you.
 
Comparison applys to using cells a a givent load.

For a given load (in amps) power dense (High amps or high wattage) cells (aka lower internal resistance cells) generally have longer life because they heat less. But they pack less energy (Wh) density because much of the cell can volume is occupied by a bigger cathode (to allow for higher currents without turning iron red hot). Thus leaving less space for the lithium which give you the range.

For the same given load, more energy dense cells (with higher amp-hours) will have smaller cathode (suitable only for low currents), and more space for lithium within the cell. But that smaller cathode means higher resistance. So for the same given load, thr more energy dense cell will heat up more. Thus lithium chemistry will degrade much faster and cycle life will be LESS than for mor power dense cells.

You are right about the triangle between energy density (long range but limited power and if power rating exceeded, premature failure and lower cycle life), power density (high power cells are the standard for lightweight EVs,) and life cycle.

Also, it is utopic to believe you will ever get 3400 mAh out of a 3400 mAh low drain cell. Run it higher than 0.2C, and the real usable capacity will start to take a plunge. On the other hand, higher density cells will sag less and thus you will be able to extarct much more capacity until you reach the low voltage cutoff threashold of your controller and your BMS (around 3.0v per cell).

Matador
 
Thanks Matador for taking the time to lay it out so fully and with precise writing, well done, and this does agree with other information on the topic.

There are so many variables, and of course shoddy quality, in materials purity or manufacturing QA will override these finer distinctions.

So, my conclusion, again, is **if** the use case does not involve high discharge rates, say under .2C

**nor** cycling down to very high DoD, say 70-80%

then better longevity will come from energy-dense / higher capacity cells, rather than those designed for power density / higher discharge rates.

 
Matador said:
Comparison applys to using cells a a givent load.

For a given load (in amps) power dense (High amps or high wattage) cells (aka lower internal resistance cells) generally have longer life because they heat less. But they pack less energy (Wh) density because much of the cell can volume is occupied by a bigger cathode (to allow for higher currents without turning iron red hot). Thus leaving less space for the lithium which give you the range.

For the same given load, more energy dense cells (with higher amp-hours) will have smaller cathode (suitable only for low currents), and more space for lithium within the cell. But that smaller cathode means higher resistance. So for the same given load, thr more energy dense cell will heat up more. Thus lithium chemistry will degrade much faster and cycle life will be LESS than for mor power dense cells.

You are right about the triangle between energy density (long range but limited power and if power rating exceeded, premature failure and lower cycle life), power density (high power cells are the standard for lightweight EVs,) and life cycle.

Also, it is utopic to believe you will ever get 3400 mAh out of a 3400 mAh low drain cell. Run it higher than 0.2C, and the real usable capacity will start to take a plunge. On the other hand, higher density cells will sag less and thus you will be able to extarct much more capacity until you reach the low voltage cutoff threashold of your controller and your BMS (around 3.0v per cell).

Matador

That actually removes a lot of mystery and confusion . PF it is. Thank you !
 
Matador said:
Comparison applys to using cells a a givent load.

For a given load (in amps) power dense (High amps or high wattage) cells (aka lower internal resistance cells) generally have longer life because they heat less. But they pack less energy (Wh) density because much of the cell can volume is occupied by a bigger cathode (to allow for higher currents without turning iron red hot). Thus leaving less space for the lithium which give you the range.

For the same given load, more energy dense cells (with higher amp-hours) will have smaller cathode (suitable only for low currents), and more space for lithium within the cell. But that smaller cathode means higher resistance. So for the same given load, thr more energy dense cell will heat up more. Thus lithium chemistry will degrade much faster and cycle life will be LESS than for mor power dense cells.

You are right about the triangle between energy density (long range but limited power and if power rating exceeded, premature failure and lower cycle life), power density (high power cells are the standard for lightweight EVs,) and life cycle.

Also, it is utopic to believe you will ever get 3400 mAh out of a 3400 mAh low drain cell. Run it higher than 0.2C, and the real usable capacity will start to take a plunge. On the other hand, higher density cells will sag less and thus you will be able to extarct much more capacity until you reach the low voltage cutoff threashold of your controller and your BMS (around 3.0v per cell).

Matador

Matador, your explanation is over-simplistic as doesn´t involve numerous degradation modes of li-ion cells. Low temperature issues, parasitic chemical reactions, lithium loss, SEI layer build up , lithium plating, dendritic growth, …….
Here is one of numerous articles at highly recommended Electropaedia pages :

https://www.mpoweruk.com/life.htm

Warning : danger of the information overload !!! 😊


And here another interesting file :

View attachment ALLPlus+ Technology.pdf

Regarding your concentration to internal resistance only, here is small comparison of DCIR at 3,8 V, 24 °C :
PF …. 34 miliohm
GA …. 36 – 37 miliohm
29E …. 31 miliohm
As you can see, the DCIR is similar.

Compare please GA versus PF voltage sag at the same load. Equipment : calibrated ZKETECH EBC A-10H, BF-2A fixture, 25 ±1 °C.

GA v PF 1 A b.jpg

GA v PF 2 A b.jpg


IMHO, your conclusions are erratic.

There is also problematic use of the battery in Dak77 case. Mode of intended use will be probably much more as electric scooter than ebike. That means enormous battery load, high DOD, ….. Therefore 13s8p battery cca 1,36 kWh (GA) or 1,1 kWh (PF) may not be enough for good lifetime. Moreover, we haven´t accurate information about real max and average currents.
So 13s10p or more could be more appropriate solution.
 
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