What does a good battery pack go for in 2020?

Hi, like the title says, I'm wondering just how much to budget for the battery in my e-assist kit. I'd like it to be 52V. It seems like 20ah is the upper limit and that's fine. I've seen batteries like that for $500 from what I think is a reputable source but I have also seen a pack that size with similar cells (21700) for much more. On average, what do people pay for batteries?

There is not a huge price variance in battery price. I think em3ev are a good benchmark for battery price. If it is below, it is either a good deal or shoddy, if it is above it is likely overpriced. 21700 packs are not notably pricier than 18650 packs to build.

I think a good price for a brand cell battery pack 52V 20Ah should be around 500-700$. Still reasonable at 700$ if the cells ar high end. Over 1000$ and it's not a good deal. Under 400$ and the cells are not guenuine brand cells (unless the cells are repurpesed from other batteries that have not been used much, like the cells sold by Tumich)
Matador

I look at the number of cells (assuming they are quality cells), multiply by five bucks, add $100 for BMS, materials and labor, and if the pack is costs less than that, it would be too good to be true (scam, fakes). So 14S8P at $660 would probably be the minimum I'd expect to pay for the chance that the pack will have what the ad says it has inside.

E-HP said:

I look at the number of cells (assuming they are quality cells), multiply by five bucks, add $100 for BMS, materials and labor, and if the pack is costs less than that, it would be too good to be true (scam, fakes). So 14S8P at $660 would probably be the minimum I'd expect to pay for the chance that the pack will have what the ad says it has inside.

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Yes thats a good rule of thumb. Personally i have a hard time believing most online battery sellers so I buy the cells and build it mysef. Save myself the labor cost.

Bought muself 3 unused hoverboard packs (60 cells for 105$) from alarmhookup on ebay (LG cells)... And built a 14S4P (8.8Ah 40amp) pack for 185$ (including bms, copper sheets, wires, connectors, kapton tape, battery voltmeter/% charge indicator, and a 39$ charger with it).

So with that stategy, I could build a 14S8P (17.6Ah, 80 amps) pack for 290$ or a 14S12P (26.4 Ah, 120 amps) for 395$.
Battery looks good too (build, links to buy the components with their prices):https://endless-sphere.com/forums/viewtopic.php?f=2&t=93576&start=75#p1414963



Matador

Cells In the hoverboard (10S2P) packs were LG-Chem MF1 18650 cells, rated 2150 mAh and max 10A/cell. I'd say they are low to mid-range cells, but from a reputable seller. When I think a 20 cell pack costed me 35$, I comes down to 1.75$ per cell, which is really not bad at all. Better deal then buying shady unbranded chinese cells.

IIRC, the reason the hoverboard packs were not sold on mass market was because of faulty PCB/BMS. But the cells were perfectly fine ! Alarmhookup also sold cheaper overboard battery packs, but I think these ones were made of the chinese clone 18650 cells, so I did not take a chance on these.
Matador

Tommm said:

There is not a huge price variance in battery price.

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???

I shop for batteries every year for a decade, and never seen as much variance as this year. Various Li battery chemistries and quality are making as much difference as 5 to 1 for equal voltage and capacity.

A neighbor is using, I think, a QZH 52v, 20ah, 14s, 8p. He has ridden as far as 70 miles on a charge and this battery has worked very well for him.

I bought the same battery on Amazon and it has done very well for me too. Amazon purchase but it shipped from China and arrived in about half the time the seller mentioned, delivery took 18 days. The seller was Wallen power. There is no brand marking on my battery.

Specs: QZH brand, 52v, 20ah, 14s, 8p, BMS 50amp, power connector is XT-60, weight is 12.2 lb, included charger 2.5 amp, round silver metal charge connector. Price was $420.

Miles to date are 475, max amps 32.2, avg amps 5.7, avg watts 136, max watts 1778, avg miles per ride 29.7, avg mi/ah 5.14, avg mi/volt 6.38, avg amp hours 5.73, avg watt hour/mi 12.73, avg speed 11.9 mph. A CA V3 and Excel make it easy to keep track of this stuff. This battery is seldom charged to full charge, instead it is mostly charged to 4.05 to 4.15 volts per cell. Lowest resting discharge voltage has been 3.70 volts per cell. I set up the spread sheet to calculate the time needed to charge from the post ride rest voltage to whatever charged voltage I want, the spread sheet keeps track of historical charge times vs charge voltage increase.

Motor is a rear MAC 12 turn, controller matched the motor, a Cycle Analyst V3 is used. Bike is a 1997 full suspension mountain bike.

Hope this information helps you and perhaps others.

Edit to Add: I'm pretty sure the cells in this battery are 18650, 2.5 Ah.

As high capacity as the 3.5 Ah GA cells in my previous 13s, 4p battery? No, but good enough and probably closer to their advertised capacity. Good enough is good enough. Optimal is often equal to unobtainable. I'd rather ride an ebike with 2.5 Ah cells than not ride an ebike with 4.0 Ah cells. Riding is better than not riding.

35 nice miles using a QZH battery today. Total miles is now 512.

MadRhino said:

Tommm said:

There is not a huge price variance in battery price.

Click to expand...

???

I shop for batteries every year for a decade, and never seen as much variance as this year. Various Li battery chemistries and quality are making as much difference as 5 to 1 for equal voltage and capacity.

Click to expand...

If you buy only brand name 18650 or 21700, the cost to make the battery will not be a big uncertainty anywhere in the world.
I am not a masochist so I stay clear of other chemistries and size formats.

Ok. There is not a big price difference if you shop for a specific battery type, size and capacity.

Tommm said:

If you buy only brand name 18650 or 21700, the cost to make the battery will not be a big uncertainty anywhere in the world.
I am not a masochist so I stay clear of other chemistries and size formats.

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This made me laugh. Having built packs that I welded up from cylindrical cells, and having built packs with large format cells or modules that came with screw terminals, hearing the quick, easy, reliable, cheap, easily serviceable way described as masochistic just strikes me as very funny.



Does this look more difficult than a pack stitched together from 280 vape pen cells?

Balmorhea said:

Tommm said:

If you buy only brand name 18650 or 21700, the cost to make the battery will not be a big uncertainty anywhere in the world.
I am not a masochist so I stay clear of other chemistries and size formats.

Click to expand...

This made me laugh. Having built packs that I welded up from cylindrical cells, and having built packs with large format cells or modules that came with screw terminals, hearing the quick, easy, reliable, cheap, easily serviceable way described as masochistic just strikes me as very funny.

IMG_20190111_144732.jpg

Does this look more difficult than a pack stitched together from 280 vape pen cells?

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Where do you buy them?

Balmorhea said:

Tommm said:

If you buy only brand name 18650 or 21700, the cost to make the battery will not be a big uncertainty anywhere in the world.
I am not a masochist so I stay clear of other chemistries and size formats.

Click to expand...

This made me laugh. Having built packs that I welded up from cylindrical cells, and having built packs with large format cells or modules that came with screw terminals, hearing the quick, easy, reliable, cheap, easily serviceable way described as masochistic just strikes me as very funny.

IMG_20190111_144732.jpg

Does this look more difficult than a pack stitched together from 280 vape pen cells?

Click to expand...

That looks very convenient indeed! Are these Nissan leaf cells arranged in 14S2P? How much capacity is that ? 24 Ah or something?

Matador

Matador said:

That looks very convenient indeed! Are these Nissan leaf cells arranged in 14S2P? How much capacity is that ? 24 Ah or something?

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They're not Leaf cells. I've heard them associated with VW e-Golf, but the modules I got said FoMoCo on them. They're made by Panasonic, nominally 25Ah. I don't have a coulomb counter I trust for accuracy, and I never run them all the way down, but they're close to that. The pack in the picture is 14S 2P for a pedicab. I have used a 13S 1P pack on one of my bikes for about 2 years now.

This looks good
https://bicyclemotorworks.com/product/52v-16ah-samsung-40t-high-output-lithium-ion-e-bike-battery/

999zip999 said:

This looks good
https://bicyclemotorworks.com/product/52v-16ah-samsung-40t-high-output-lithium-ion-e-bike-battery/

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Any experience with this seller? I could fit that battery, plus the pocket rocket II into my triangle in parallel, and have 24Ah and 115A continuous, which would provide a lot of fun.

He is making me a 20s6p Samsung 40t triangle BT pack. He doesn't sell chargers. I think he's in Pennsylvania.

999zip999 said:

He is making me a 20s6p Samsung 40t triangle BT pack. He doesn't sell chargers. I think he's in Pennsylvania.

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Cool. Does he charge more for custom configurations? I measured my triangle after looking at the site to see if I could fit two of the 72V rectangle packs, but it was a no go. I think they would fit easily if configured as a triangle.

Contact Matt and ask. He sold me on it when he had the Samsung 40 t 30 amp cell.

Check upp brand on aliexpress or something, very good pricing, i dont have any connection with them, im just a subjectivly satisfied customer with their product, price and so much after sales support, may i suggest plastic case frame battery

That makes it about 100km, so that is very very low pedal assist. I am on 52V 15Ah, dd, 30A, leaf 1.5kw, 25km one short hill, probably double their weight. Comparison he would have ridden 75km on 20Ah 52V battery.

More choices out there because hobbyists have time and need extra money.
I'd look at www.ebikes.ca
www.em3ev.com
Unit Pack Power
Luna Cycle

for prices

MikeSSS said:

A neighbor is using, I think, a QZH 52v, 20ah, 14s, 8p. He has ridden as far as 70 miles on a charge and this battery has worked very well for him.

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What do you think will there be massive drops on battery prices in near future?