Are these appropriate batteries? Drive thoughts.

Hello all,
I started a thread over here: https://endless-sphere.com/forums/viewtopic.php?p=1361223#p1361223, on a e-assist bakfiet cargo bike I am scratch building. I think I have settled on a Cyclone mid drive from Luna Cycles. There are clearance issues with the Bafang BBSxx motors as there is only 12mm between the motor and bottom bracket, which although I think I could get to work, is challenging with a wood frame. The Cyclone gives me more flexibility in mounting and I can fabricate custom mounts if necessary. I am going to use a 100mm bottom bracket to add rigidity in the area and ease construction a bit. There will likely be a Nuvinci n380 on the rear. The load will be in the 350 pound range, but we don't need quick acceleration or big bursts of power. with that in mind, I wont require all 3000w, so plan to run a 52v battery, and possibly further detune through a Cycle Analyst. Since batteries are such a large part of the budget, and I want at least 30 miles of range, I am looking at alternatives. I've looked at various R/C options such as running two of these: https://hobbyking.com/en_us/multistar-high-capacity-6s-20000mah-multi-rotor-lipo-pack.html, or other options such as 4 of these: https://www.aliexpress.com/item/Sunway-24V-25-9V-29-4V-10Ah-18650-lithium-battery-pack-electric-bicycle-light-weight-ebike/32836998508.html?spm=2114.search0104.6.6.57d118acgIReCg&s=p. The first option only gives my 44v, the later 52v. They both would give me 20 ah for under $300. Since I am new to the "e" side of an e-bicycle, I may be totally off base. If so, feel free to (gently?) set me straight.

Thanks in advance for your input,
Ward

Well, what happened to me was not typical, but nothing bit me harder than a cheap ass battery from Aliexpress.

The RC stuff, though still even more likely to burn your house down, I have had few problems with. They require you to diligently perform as a human bms though. But as a cheap battery, they sag less and perform better in each days use.

Charge and store outside, either choice.

Dogman,
Is your story archived on here someplace? I've used R/C lipos for years, and have yet to blow anything up, but having said that, I've seen the videos. I'd prefer not to need to remove the battery for charging, just plug it in when it is in the garage. Maybe try to find a comparable LiFe battery?

Ward

Maybe scratch build from A123 cells like these? as I remember it from R/C stuff, LiFe batteries aren't prone to spontaneous combustion. Link:https://www.ebay.com/itm/NEW-Case-of-160-Fullriver-LiFePO4-26650-3-2V-3300mAh-Rechargeable-Batteries/351864507828?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D50073%26meid%3D66c883e86c9c44c183be784d7b2dd1ce%26pid%3D100005%26rk%3D1%26rkt%3D6%26mehot%3Dpp%26sd%3D191987482937%26itm%3D351864507828&_trksid=p2047675.c100005.m1851

Ward

Those aren't A123 cells, the name of the "actual" manufacturer is on the paper wrapper of the cell in the image on the page. Assuming they are genuine, and actually new (and not just new-old-stock that's been sitting around for years, turning into junk). There are threads/posts about that brand, if you want feedback about them (I don't remember anything specific).

Any battery chemistry can burn, and the cheaper it is the more likely something could be wrong with teh way it's built, or using poor quality cells inside. (some cheap packs actually use recycled garbage cells pulled out of other batteries; they also sell those individually with "new" shrinkwrap on them, sometimes as fake name-brand name cells, sometimes as ultrafire or other *fire brands).

Unfortunately just costing more doesn't give you any guarantees about quality, but it can decrease the likelihood of it being risky, or even just junk.

A vendor that's at least on the same continent you are means if it does fail in a non-catastrophic way you can at least return it for warranty service (ground shipping), as long as you can find a shipper that will accept it. (many won't, unless you qualify as UN-certified for battery shipping).

Almost all the batteries you'll find anywhere, good or bad, are still made in China, or of Chinese parts (just like the ebike kits / controllers / motors / etc).

If warranty return service isn't something you're worried about, and you want a good quality battery that's rated at it's actual capabilities, there's places like EM3EV in China.

If you want on-continent, Grin Tech in Canada makes LiGo packs, but they are building blocks meant to be able to be carried in luggage so they have their limitations in how they can be combined, and some size packs can't be made from them.

There's probably other quality packs actually made here in the USA (not just claimed to be) but I don't know what they are.



That said, there's a lot of threads discussing various battery makers and sellers, usually in the "what battery should I use" type of threads, or in build threads for various bikes. I wish there was an easy way to search for that info, but there isn't.


Another problem with cheap batteries, aside from build quality, is which cells they actually use, and how badly overrated the seller marks them. I have an old 18650 pack from Luna that was rated significantly higher than it's actually really capable of. Used at those rates it gets hot and sags a lot, so unable to deliver it's full capacity. Used at lower rates it's more reasonable though it still gets warm; seems to be the nature of small (low numbers of parallle cells) 18650 packs.

I got spoiled with EIG NMC cells that don't have those problems, designed for EV use, but expensive and hard to get except in huge quantities (palletfulls) unless you can find someone with used ones (there is a thread in the for sale section with some, but I don't know their providence/quality).

A123 cells are also good, but there is only one place to get guaranteed real ones (lots of fakes and recycled junk ones out there), at StorTronics.

If I had to go out and buy new batteries these days, knowing what i know now, and had the money to spare, I'd get two of whatever had enough capacity and c-rate and was conveniently packaged (like the Shark or Dolphin easy-to-mount packs), so that when the first one failed I'd have an easy-to-swap-out spare. Or realistically more than two, so I can run mulitple packs in parallel for higher power with less voltage sag, but still have spares for when one or more fails.

I'd buy from an on-continent vendor that had good warranty ratings (meaning, they'll actually honor any warranty they offer), or sufficiently low prices that I would simply not worry about warranties and deal with problems myself if I had the money and time to do that.


Or more likely I'd build my own, but if I did that I don't think I'd use 18650s, I think I'd get a source for Leaf or other EV-grade cell modules (even though they're used cells), and build a couple of packs from those (again, so I'd have a spare so as never to be down).

I'd prefer to keep getting EIG cells but they're a lot harder to find than Leaf packs and the like, as those turn up from totalled cars often enough.

Amberwolf,
Thanks for all the info. One of the challenges of Endless Sphere is the shear volume of information available. It is a bit daunting, even for someone who has spent a lot of time on various technical forums. I hear what you are saying, and fall back to the old saw, "you kinda get what you pay for"... if you know what you are looking at.
My criteria are such that weight and size are not as much of a concern as they would be for someone on a trail bike. There will be room under the child seat in the cargo area to place the controller and battery, and I'll be able to place it roughly in the center fore/aft and down low so the CG will be relatively good. I'll keep researching LiFepo4 batteries and consider how lucky I am feeling!
Thanks,
Ward

Just keep in mind that most LiFePO4 cells sag a lot under even 1C loads, so generally don't believe the claims they put on the sale pages for most of the ones you see.

Generally, cut everything you see in half for claims, and it's probably a safe bet--then you can be pleasantly surprised when it works better than that. Some may actually even exceed tehir claims, but I would never bet on that--marketing is all about getting away with exaggerations and even outright lies.


Regarding battery compartments, look at Wheazel's red bakfiets type build
https://endless-sphere.com/forums/viewtopic.php?f=28&t=70500
He built his 18650 packs under the deck of the cargo area.

amberwolf said:

Just keep in mind that most LiFePO4 cells sag a lot under even 1C loads, so generally don't believe the claims they put on the sale pages for most of the ones you see.

Generally, cut everything you see in half for claims, and it's probably a safe bet--then you can be pleasantly surprised when it works better than that. Some may actually even exceed tehir claims, but I would never bet on that--marketing is all about getting away with exaggerations and even outright lies.


Regarding battery compartments, look at Wheazel's red bakfiets type build
https://endless-sphere.com/forums/viewtopic.php?f=28&t=70500
He built his 18650 packs under the deck of the cargo area.

Click to expand...

Too bad Weazel's photos cannot be seen, I would have liked to look, damned Photobucket, I lost a lot of photos to them as well due to refusing to pay their ransom.

Also LiFePO4 are heavier and bulkier then equivellant other batteries.

wardo said:

Dogman,
Is your story archived on here someplace? I've used R/C lipos for years, and have yet to blow anything up, but having said that, I've seen the videos. I'd prefer not to need to remove the battery for charging, just plug it in when it is in the garage. Maybe try to find a comparable LiFe battery?

Ward

Click to expand...

Quality LiPoly keeps getting better all the time
The Multistar batteries trade smaller size, lighter weight and lower volatility for a lower C-rate and there is no other chemistry that can beat it in terms size and price. They have proven to be very stable and aside from the rare sluggish cell, there are no reports here of serious problems posted here since their inception a couple of years ago.
There two biggest advantages are;
1)They are avail. in larger size bricks, which make bulk charging easy.
2)They are often on sale which takes their already low price down to an amazingly low power/cost ratio.
My last 12S/20,000 mAh pack was $270 shipped!
I bulk charge 12S using the Mean Well HLG-320-48A and Battery Medics and also bulk charge 15S(55V nom.) using the HLG-320-54A.
Zero problems in 2 years.