Searching low € / kWh battery chemistry

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DasDouble   100 kW

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Searching low € / kWh battery chemistry

Post by DasDouble » Feb 25 2019 3:22am

Hi, Im looking for a low price / kWh battery with low volume, low weight, price round about 360€ / kWh or ~400USD / kWh + less voltage drop under load. As high max. output as possible. + Should be easy to build together as it will be in a 5kWh+ battery pack. So LiIons with welding etc will be a pain in the ass.
Do you have any ideas? I think about LiPo.
Mechatronics-Engineering Student
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

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flippy   1 MW

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Re: Searching low € / kWh battery chemistry

Post by flippy » Feb 25 2019 3:26am

stop looking at chemistry.

in this case you ony care about Wh per dollar.

cheapest in this regard is the samsung 29E6 edition. the 29E7 is a tad more expensive but has better lifespan when liming the charge to 4.1v. the 7's can handle 8.5A continous and have about 500 cycles before losing serious capacity.

i build batteries this size and bigger for a living, during my testing i measured that high capcity cells simply get killed off with high currents. with high currents i mean 1C or more. the 2900mah range gives the best performance for large packs.

nkon is the closet and cheapest supplier.

welding is the only choice or you will burn up the pack due to the added heat from shitty connections.
Lithium beats liquid dinosaurs.

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DasDouble   100 kW

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Re: Searching low € / kWh battery chemistry

Post by DasDouble » Feb 25 2019 5:38am

Alright, thats really low cost. I will shoot you a pm.
Mechatronics-Engineering Student
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

leffex   100 W

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Re: Searching low € / kWh battery chemistry

Post by leffex » Feb 25 2019 2:21pm

I second that. Samsung 29e cells or (Panasonic) with good cycle life and performance.(10a or 2-3c continuous)

For a big pack I like it to keep its kwh and not lose capacity after 100-200 cycles. Some that I recently researched. Samsung 35e, and 30q,LG m1j did for some reason lose maximum capacity and became a weaker cell. weird. You'd think that batteries become better but somehow they have added capacity that just disappear after light use.

35q, 30e, vs 29e
https://endless-sphere.com/forums/viewt ... 6#p1434017

35 vs 30e cycle life
https://endless-sphere.com/forums/viewt ... 14&t=97844

LG mj1
https://endless-sphere.com/forums/viewt ... 5#p1444922

all from the same thread kinda :thumb:
emotorcycle 22kw. Salestech in an ebike store

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flippy   1 MW

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Re: Searching low € / kWh battery chemistry

Post by flippy » Feb 25 2019 2:49pm

leffex wrote:
Feb 25 2019 2:21pm
I second that. Samsung 29e cells or (Panasonic) with good cycle life and performance.(10a or 2-3c continuous)

For a big pack I like it to keep its kwh and not lose capacity after 100-200 cycles. Some that I recently researched. Samsung 35e, and 30q,LG m1j did for some reason lose maximum capacity and became a weaker cell. weird. You'd think that batteries become better but somehow they have added capacity that just disappear after light use.

35q, 30e, vs 29e
https://endless-sphere.com/forums/viewt ... 6#p1434017

35 vs 30e cycle life
https://endless-sphere.com/forums/viewt ... 14&t=97844

LG mj1
https://endless-sphere.com/forums/viewt ... 5#p1444922

all from the same thread kinda :thumb:
not really according to my test data, i am running lifecycle tests on sony GA's and both versions of the 29E's and the sony just basically commit suicide under constant high currents. anything above 1C will kill one in a few hunderd cycles or less. the same goes for almost any high capacity cell. the 2.9Ah range (samsung and pannies) are nigh indestructable by comparison and if you dial the top voltage back down to 4.05v and keep the charge currents as low as you can they will last longer then any product you use them in.
Lithium beats liquid dinosaurs.

Hillhater   100 GW

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Re: Searching low € / kWh battery chemistry

Post by Hillhater » Feb 25 2019 4:37pm

Sony GA ???
or. Sanyo GA ?
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tigcross   100 W

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Re: Searching low € / kWh battery chemistry

Post by tigcross » Feb 25 2019 5:01pm

I second the general sentiment from the above responses.
Build the biggest pack you can fit in your vehicle and justify based on range and power demands. The less you challenge your battery pack the longer it will last. I run a 72 volt 20 AH Panasonic PF pack, charge to 85% most of the time, and rarely let my draw exceed 18000W. My pack is 3 years old, has 8,000 km on it and is still going strong. To be honest I've not done a capacity test in a year, but when I last did one at 6000 km I had only lost about 2 or 3%. I have also never drawn this pack all the way down to the manufactures suggested limits. My system cuts out at 60V. It's true that I'm leaving a lot of power on the table, but given that the battery is often the most expensive part of an e-bike I think it pays to make it last as long as possible.

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flippy   1 MW

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Re: Searching low € / kWh battery chemistry

Post by flippy » Feb 26 2019 5:08am

Hillhater wrote:
Feb 25 2019 4:37pm
Sony GA ???
or. Sanyo GA ?
autocorrect is a wonderful thing when typing brands... :cry:
Lithium beats liquid dinosaurs.

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DasDouble   100 kW

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Re: Searching low € / kWh battery chemistry

Post by DasDouble » Feb 26 2019 7:22am

I don´t care about how big it is. Its more important to last about 300 cycles and have as much capacity as possible. Budget is 2000€. Will be built into a boat.
Mechatronics-Engineering Student
-Built own ebike: ✔
-Built own 3.2kWh LiIon battery (300Amps): ✔
-Overtake Porsche with own Ebike: ✔
-Take off with ebike: ✖

~14kW, 3.2kWh LiIon, QS 205 8ml ff, hubsink

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flippy   1 MW

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Re: Searching low € / kWh battery chemistry

Post by flippy » Feb 26 2019 8:01am

DasDouble wrote:
Feb 26 2019 7:22am
I don´t care about how big it is. Its more important to last about 300 cycles and have as much capacity as possible. Budget is 2000€. Will be built into a boat.
i would defenetly install heating and insulation in that case (and waterproofing, lots of condensation inside boats). performance is shit if the battery is not heated. i got plenty of people complaining about this after a install in a boat and wonderd why the voltage just tanks under full load. cells dont preform well under 20c with sustained high loads.

i have custom made heating pads you can use for this application. send me a message if you need some.
Lithium beats liquid dinosaurs.

leffex   100 W

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Re: Searching low € / kWh battery chemistry

Post by leffex » Mar 10 2019 10:43am

I'd try Samsung 21700-50E. 10A rated. I'm looking at it right now... less weight, size and volume and half the amount of battery cells and negative is less estimated charge cycles from it and price about 10% more expensive.
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Pajda   100 W

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Re: Searching low € / kWh battery chemistry

Post by Pajda » Mar 10 2019 3:02pm

Actually Samsung 50E seems to be very good choice. I did not ran the entire cycle life test, but I already did 500 cycles in some tests. I am surprised with the test results so far, because it shows much better results than 35E in 18650. It seems it has the same performance in comparison with LG M50 "B-grade" under low loads (up to 1C discharge) and much better performance under high load (3C) and fast charging (1C) torture tests. (I do not recommend to use it in high continuous load applications). But I have to apologize to ES community, that I still didn't start testing of the LG M50 "A-grade" cells. I suppose that "A-grade" M50 at least equals the 50E. And also M50 is after the recent price increase still about 10% cheaper than 50E.

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Honk   100 W

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Re: Searching low € / kWh battery chemistry

Post by Honk » Mar 10 2019 3:18pm

flippy wrote:
Feb 25 2019 2:49pm
The 2.9Ah range (samsung and pannies) are indestructable by comparison and if you dial the top voltage back down to 4.05v and keep the charge currents as low as you can, they will last longer then any product you use them in.
Looks like I will have my four 12S8P 1kWh 29E packs to old retirement days hehe.
Charge voltage is 4.1V as it gives a decent Wh.
I discharge them by 0.54C and recharge by 0.175C.
When not in use I store them in a small fridge at 2 degrees C and approx 40% SoC.
My chargers has a selectable 40% charge setting and it makes is easy to keep track of the SoC level, especially when stored for a long time over winter.

If you wonder what I use them for, it's for my 2.6hp electric outboard during summer season.
Efficiency is king!

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flippy   1 MW

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Re: Searching low € / kWh battery chemistry

Post by flippy » Mar 10 2019 4:40pm

dont bother with a fridge unless you see mad temperature swings in your storage space. its not worth ot just to keep a frige running for that. those vales are great, those will last years if you use them all at once that is.
Lithium beats liquid dinosaurs.

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Honk   100 W

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Re: Searching low € / kWh battery chemistry

Post by Honk » Mar 10 2019 6:05pm

The fridge is needed from mid spring to late autom due to the temperature swings you mentioned.
At vinter there is no need for extra cooling.

And yes, the packs are all used at the same time in parallel as one big 12S32P battery bank.
That's why each cell only sees 0.54C discharge at max load.
Efficiency is king!

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