Monsoon

I'm putting an electric bike together, one piece at a time.
Here's the hub thread: https://www.bikeforums.net/showthread...-hub-questions

When i'm done, i'll link everything in a single thread with pics of the final project.

So where's some of the better places to buy batteries from?
I'm particularly interested in something around 48v-60v @ 20ah - 30ah in a LiFePO4 battery pack.

I had been looking at BMS, because they have some nice compact batteries based on large sized LiFePO4 batteries. I particularly like their packs built around the big 40152 size batteries.
But i'm reading bad things about their customer service, so that's making me double think them as a source.

Next up I just spotted this place, and they've got really good prices, although the batteries are fairly large. I'm guessing they use a ton of 18650 batteries in their packs.
https://www.lifepo4.in/index.html
Anyone used this site yet for a purchase?

So toss your favorite links in here, and hopefully there will be a consensus or two to choose from.

dilkes

I purchased a battery and some other stuff from BMSBattery and had no issues with customer service. They answered my pre-sales Q's, shipped quickly, and answered a few post-sales Q's promptly. The battery has been working great so I have had no need for any serious support issues.

turbo1889

Are you limiting yourself only to pre-made packs or are you willing to build your own pack up from smaller packs ~ say for example reasonably priced decent quality 12.8V four cell packs that you would have to wire together in series to get the voltage you want (4 to 5 for the voltage range you are looking at)? Is that a viable option for you or are you only interested in plug and play packs made specifically for e-bikes?

Reason I ask is that you can get some pretty decent LiFePO4 packs built for the solar power industry and the motorcycle (starter) battery industry in that voltage (12.8V four cell series packs) for reasonable prices and wire them up together. That's what I've done with most of my builds.

chas58

BMS is spotty. If you know what you want, they will build it and ship it, but if anything goes wrong, you are pretty much on your own. So, use them, but with caution. Their specs are sometimes a little off, but usually they will provide you the details if you ask. The best thing for specs is to go to the individual cells page. For instance the bottle batteries are 0.8C with 1C max. They told me this when I asked, and it is on the individual cell page (18650), but it is not too obvious that an 8ah bottle battery is going to struggle putting out 8amps power. That is obviously a problem.

By far the best battery vendors are (in random order):
LiFePo4: Ping battery https://www.pingbattery.com/servlet/StoreFront
Lithium Ion: EM3ev https://em3ev.com/store/ Sells 2C (NCM), 4C (Samsung) and the renowned A123 batteries.

Keep in mind that lifepo is a bit heavier (it needs more cells to create the same voltage); Li-ion is as light as Lipo, but can't be recharged as often as LiFePo4

They aren't the cheapest, but have great customer support and high quality products

If you don't need the support and are a DIY hobbiest, you can use BMS battery or Hobbyking for Lipo.

Jimi77

Electricrider.com has decent prices on batteries. They don't say on their site, but they can build to order.

Hi power cycles has some really small battery packs, but they're pricey.

dilkes

Can you reference a site where you buy these packs? Also, when you string them together in series, do you bulk charge? or charge each pack individually? Also is a BMS needed? I might try something like this for my next pack.

Monsoon

@turbo1889 Yeah, maybe if there isn't any soldering involved.
But even then, I really don't want to have to put more than a single pair together.

@Jimi77 I did check out highpower for their batteries. I like the lithium nickel manganese mix. more stable voltage across many batteries than lifepo4, which avoids problems with one bad cell.
but as you mentioned, they're pricey. A 63v 12.5ah is over $1,000. that's way too much money for what you get.

so i'll probably stick with a LiFePO4, which will perform well enough anyway.

Like I said in the first post, I like the big series of headway LiFePO4's. There would be a lot less troubleshooting if I wind up with problems than a battery pack with 160 x 18650's or whatever.

Monsoon

Well i've been at this for about 6 hours straight, and I think I have a couple of good candidates. I'm dog tired so i'll have to wait until morning before I go at it again to make a selection.
I had just about decided to go with a BMS battery in spite of cautionary tales here, but then I noticed they don't include the battery charger, which was the deal breaker for me.
So it looks like it's down to these two 60v 20ah LiFePO4 batteries.

https://www.ebay.com/itm/60V-20Ah-LiF...item1c34a49313

https://www.ebay.com/itm/60V-20Ah-120...item1c3496f7e2

turbo1889

@ dilkes

I personally both prefer and have more experience with the packs designed for portable solar power stations due to their lower cost per real Ah capacity but they require more work on your end then a high quality motorcycle/ATV/sport battery. It should be noted that the solar station packs and cells are rated in their true lithium chemistry amp hours (of which 80% is useful on a lithium battery which should not be discharged below 80% capacity for maximum service live) where as the motorcycle/ATV/sport batteries are rated in equivalent Ah to a lead acid battery were the conversion factor between the two is 1.8 or in other words a motorcycle/ATV/sport LiFePO4 battery with a 36Ah rating is actually a 20Ah battery it is just that because the Lithium battery can be safely discharged deeper into its cycle a 20Ah lithium battery has the same useful capacity as a 36Ah lead-acid battery and since the buyers of motorcycle/ATV/sport batteries are used to buying lead-acid batteries and the LiFePO4 batteries are new for that application they are rating them in their equivalence to lead-acid batteries rather then in their actual capacity numbers so you must do the conversion to the lower number for comparing pricing when shopping to build an e-bike battery pack.

The solar power packs (and you can even buy the prismatic cells used in them individually) use screw top terminals and are available in cell sizes ranging from 10Ah to 200Ah with the 20Ah size being the most commonly available size on the smaller end of that size range (10Ah prismatic cells are available but not very common) and work great for e-bike applications.

I buy mine here: https://www.batteryspace.com/12-8v-li...-to-200ah.aspx

Specifically I buy these ( $124 ): https://www.batteryspace.com/LiFePO4-...thout-PCM.aspx

And install four of these ( 4 x $7 ) myself: https://www.batteryspace.com/Smart-LE...e-Current.aspx

Which gives me the same as this ( $179 ) and saves me a few dollars by installing the balance circuits myself: https://www.batteryspace.com/LiFePO4-...Balancing.aspx


That takes care of balancing and I rely on the motor controllers minimum cut off voltage to protect against over-discharge and trust the battery charger to protect against over-charging. Which has worked out great for me. Now on the other hand a quality motorcycle/ATV/sport battery will have a full battery management system built into it that not only balances the cells but has internal protection against over-discharge and over-charging built right into it in a full BMS usually with a water tight sealed case with just two terminals to hook up too so much simpler and easier for the end-user and with potentially better battery protection if your controller and charger aren't up to snuff in doing their end of that job but the cost will be higher. An EarthX brand name (what I have experience with) 36Ah lead-acid equivalent (20Ah actual) battery will cost $340-$360 so you end up paying twice or slightly more the price for the same capacity compared to using the solar cells instead but everything is there all ready to go and all sealed up tight as a drum and after all is a US battery rated for a service life of 4,000 cycles over 8 years with a BMS that continuously balances the cells during both charge and discharge rather then just top end balancing and has over-discharge and over-charging and short circuit protection built in BMS. So there is some extra quality there compared to the solar power cell set-up that are rated for 1,000 to 2,000 cycles with top end charging balance only and over-discharge and over-charging protection must be provided externally and there is no short circuit protection and the plastic case is not sealed and and just a container to hold the cells together. But with the solar pack it is also possible to easily remove and condition or replace individual cells in the pack if their is a problem rather then having to replace the entire 12V pack itself in entirety (this is also a significant advantage over most ready built e-bike packs which are one complete unit that does not allow for easy isolation and conditioning or replacement of an individual cell so a single bad cell can render the entire pack useless).

As to charging ~ Yes, I charge all my 12V packs at 12V either separately or in parallel sometimes on the bike and sometimes off and then hook them up in series to power the bike. With the screw terminals that both the prismatic solar pack cells and the motorcycle/ATV/sport cells use this is an absolute breeze and you just need ring terminals with a light coating of dielectric grease and some nuts/bolts to fit the threads and a little wrench to fit them, or you can even make up some plug wire harnesses with a plug on the batteries and a plug on the bike and a plug on the charger and when you unplug the battery from the bike and plug into the charger the plug is already wired in the plug end to switch from series to power the bike and parallel to charge the batteries.

Both the 12.8V prismatic cell solar power packs and the motorcycle/ATV/sport packs can be charged using either conventional lead-acid 12V battery chargers or dedicated four cell LiFePO4 pack chargers although the solar cell packs will usually have a slightly longer service life if charged with a dedicated LiFePO4 chargers. Higher quality motorcycle/ATV/sport packs due to their internal BMS charge control circuitry don't care which they are charged with.

The MAIN benefit I find to using multiple four cell 12.8V LiFePO4 packs wired together in series to power my e-bikes is because I have the ability to charge almost anywhere I can get my hands on a 12V car battery charger or even just a car and a pair of jumper cables and in a pinch I can make do without having to have a specific charger.

The MAIN benefits I find to using the prismatic cell solar power industry LiFePO4 packs is their low cost for good quality cells and their repairable nature where with the screw top terminal individual cells the packs are made of there is no soldering of cell tabs and it is quick and easy to break a pack down and find the bad cell(s) and individually re-condition them with a single cell charge/discharge cycling unit or completely replace individual cells if necessary due to their standardized modular design.

For some applications the motorcycle/ATV/sport batteries can also be useful just be sure to get the high end quality ones otherwise you will end up paying more for the same or lower quality then the solar packs. And the only reason to go with these instead of the solar packs is because your application is such that paying more for higher quality makes sense so if you go that route for darn sake get the good ones.

turbo1889

@ Monsoon


Both of those packs are built from soft poly cells = less weight then hard cased cylinder or prismatic cells but more easily damaged (protect your pack, don't let it take a physical hit with poly packs !!!).

The first product you linked too is duct-tape/shrink-wrapped pack and thus very-difficult/impossible to repair. When the pack goes the whole thing goes, all or nothing.

The second product you linked too uses the soft cells inside a hard sealed case that can apparently be opened with a screw-driver. That pack may be repairable since it may be possible to access individual cells. Obtaining replacement cells to match could be an issue and it is an unknown as to whether they are glued, taped, etc . . . together inside the case or not. Could be a repairable pack but maybe not. The hard shell case probably offers better protection then just duct-tape/shrink-wrap in a bag like the first pack you linked too.


Price is excellent and lower then a Ping battery which is the usually "go to" for a soft poly LiFePO4 poly pack for an e-bike. Price is even lower then building a pack up from the prismatic cell solar power packs like I do (unlike Ping with is more expensive then that) but won't be a repairable pack like I get with using prismatic cells.

dilkes

@turbo1889 Thanks for the very complete answers to my Q's. I'm OK with batteries for my 2 bikes right now, but am planning ahead for replacements. Who knows? By then there might even be something new and better! and hopefully cost-effective.

Monsoon

@turbo1889 thanks for the intensive writeup. the information about repair for the duct tape batteries seems fairly critical, so I will try to avoid those.

now what about something where you have a pair of complete batteries (using headway 40152'ss) like this https://www.bmsbattery.com/packs/430-...tery-pack.html

could I combine two of those after the fact to get a 30ah battery at 48v?

and what about this link here which is basically the same 48v 30ah in a kit: https://www.battery-matrix.com/DIY-48...y-lifepo4.html

it looks like that comes with everything I need. Battery, charger, and BMS. Plus it includes shipping.

Monsoon

And then finally this seems like a really good deal on a limn battery.

https://www.ebay.com/itm/48V-20AH-LiM...item2a2ab75487

Very light weight, and good voltage/ah.

turbo1889

Don't get me wrong, I'm not saying that a duck-tape/shrink-wrap battery made from soft poly cells is a bad battery. I have a personal friend who is using two big 48V 20Ah Ping batteries on his e-bike in parallel to provide a monster 40Ah of battery at 48V (his bike is more like an electric moped than an e-bike and is set-up to only use the pedals to help with pulling out from a dead stop with a single speed low ratio on the pedals) but his batteries are stored in two big metal hard boxes mounted on each side of the rear wheel which is a 13" scooter hub-motor rated for up to 3-kW of power (front of his bike is an old steel frame mountain bike with a whole new tail end made from scrap steel welded onto it) and they have both been going strong for him for over a year now with one of those two packs being a little older then the other. But his bike is built with tough metal boxes to protect the batteries and I've seen some people run those type of soft cell wrapped packs naked with no protection what-soever. doing that all you have to do is lay the bike down just once and have that unprotected battery slam into the pavement and skid and slide and tear and its all over for that pack, hundreds of dollars down the drain in an instant of time.

For that reason I personally much prefer packs that use hard body cells either prismatic or cylindrical cells and I strongly prefer that those cells use screw type connectors rather then solder tabs. That makes for a much tougher pack to start with and one that is more easily maintenanced or repaired (especially true with screw type terminals). Usually the weight is higher then the soft cell wrapped poly packs and you can't usually get them for quite as cheap (although with some shopping around you can still do quite well) but for me it is more then worth it.

Whether or not it is worth it to YOU is a decision you are going to have to make for yourself.


As to the specific products you linked too, the first two links in post #12 are both packs built from cylindrical cells with screw terminals on their ends (Headway 40152S cells to be specific) and I personally would not hesitate to buy and use such a pack or even buy and put together a "assemble it yourself" kit like your second link using that technology rather then going with a soft cell poly wrapped pack provided the prices and quality level of the cells themselves were comparable (some brands do a better job of quality control on their cells and some places are better about making sure their customers get new fresh cells not ones that have been sitting on the shelf for a couple years) because I personally much prefer packs that are made from individual hard cells with screw terminals that are fully repairable and that I can get spare cells for so that if a cell either goes bad on its own or suffers physical damage I can just replace that individual cell and it doesn't wreck the whole pack, at the same time though I wouldn't want to go with absolute bottom of the barrel no name brand cells from some ultra cheap outlet that has had them sitting on the shelf for a couple years and by the time I get the pack half the cells are bad in it. So while I certainly prefer packs built from hard case cells in a modular design I'm not willing to go scrape the very bottom of the barrel either and will go with a fresh new name brand soft cell poly wrapped pack before I do that. Not saying those headway cylinder cells aren't good quality cells or that the places you linked too don't have a good reputation for getting fresh stock to their customers, just saying I'd google search both reviews and ratings of the cells themselves and the selling companies before I purchased (good to do with any purchase by the way). The reason I say that is because I personally don't have experience with those specific cells or those specific companies. Also, for a newbie you might be best off buying the pre-built pack(s) rather then going with the "assemble it yourself" kit. I wouldn't hesitate to go with the kit myself even if the price was the exact same because I've got all the tools and I'd like to individual cycle test each cell before I assembled the pack so for me with even the exact same price for a kit or an assembled pack containing the exact same components I'd go with the kit but I wouldn't suggest that for most people.

As to the third link you provided in post #13 that pack uses "pouch cells" according to their listing which is another way of saying they are using soft cells instead of hard case cells. But instead of being wrapped up in duct-tape/shrink-wrap type material which is also soft they are packed in a really nice aluminum hard case so although the pack itself probably isn't that easily repaired (mainly an issue of obtaining replacement cells, cylindrical and prismatic hard case cells are fairly easy to find and buy individual replacement cells but individual soft cells are a little harder to find and buy individual cells that are sure to be compatible) it is well protected from damage and will take a lot of abuse before the cells inside could be physically damaged so I would personally certainly consider that a significant improvement over a soft cell wrapped poly pack and would certainly go with it over a similar priced similar capacity soft cell wrapped poly pack.

Monsoon

@turbo1889 I know well what you're saying about being able to access and repair, test, replace the cells.
i'm a hobbyist from way back. i've built power amplifiers, preamps, speakers, customized guitar electronics, etc etc. and other than being in a bit of a hurry, i'm not really intimidated by the kits at all.
but i'm not worried about the risks of a well put together soft pack battery either.
in fact that LIMN204 pack would already be on it's way if they offered faster shipping. but I just don't want to be waiting until late august to finish this project.

so if I can do a pair of those 48v 15ah 40152S batteries from BMS and get a 48v 30ah battery out of it, that might just be my best bet.
If something failed in those kits, there would only be around 32 batteries to test, vs. over 200 in some of the 18650 battery packs that i've seen.
in fact, if I did the pair of batteries, there would only be 16 to test, as I would easily be able to narrow down which pack was bad.

so back to my question, would it be hard to wire a pair of those in parallel to get 30ah?
as long as I don't have to add more battery management to them, i'd probably be ok with that kit.

my main concern here is whether I can simply splice the leads together, or if I need a controller that has a pair of inputs on it.
on the surface it's easy to assume that each battery having it's own BMS, I wouldn't have to worry about just splicing them together, but I'd need to be sure there's nothing i'm missing here.

Monsoon

well what do you know, I emailed the guy for that LIMN battery from ebay, and I already got a response from them.
apparently the batteries are custom made, which "takes 5-7 working days to make and another 8-10 working days to reach you after delivery".
and since we're talking working days here, I could expect at least 2 weekends in there for a total of 21 days, maybe more depending on actual shipping time.
so i'm now leaning towards that 48v 30ah battery kit from battery-matrix.com, and I might just pull the trigger on that one tonight.
i'll run through all my saved links one more time and if something doesn't change my mind i'll have that on it's way tonight. then i'll probably order one extra 40152 battery to keep as a spare, in case on should fail.

Monsoon

oh geez, I meant to ask this a week ago but I forgot.

this listing for example, it mentions that you can get either a 30-60A or 60-100A BMS with this battery.
https://www.bmsbattery.com/packs/534-...tery-pack.html
can someone explain the difference?
with the 60-100A, does that mean that you literally cannot output LESS than 60A?
i've seen that sort of variable on a lot of listings for batteries.

turbo1889

Provided the chemistry and series cell count is the same for both packs running them in parallel is as simple as just wiring the leads together.

As to BMS amps rating choose according to the maximum power you are going to be actually going to pull from the battery. The BMS job is to protect the battery pack. You can pull just a trickle of power from the pack if you so desire regardless of the BMS rating but it is important to choose a BMS that is designed to operate in the same draw zone as the motor pulls when running in its normal power zone. So if you had a motor that normally pulled something the neighborhood of 30A but should not pull more then 60A then you would choose the 30-60A BMS the same is true if you had a more powerful motor that normally pulled something in the neighborhood of 60A (maybe a little less, maybe a little more) but should not pull more than 100A then you would choose the 60-100A BMS.

That's the basic idea. Some battery BMS circuits just list the one number which is the high end number and the person buying the pack just understands to pick the appropriate BMS for their motor. For example another company might just list the two BMS options as a 60A and a 100A and it is understood in general that the customer should be smart enough to pick the lower 60A BMS if their motor should not draw more then that and not use the big 100A one if they don't need it, and also to help protect the motor as well because the top end cut off on the battery BMS can also help protect the motor from burning itself up although usually the limit on the controller is used for that purpose and the batteries upper BMS limit rarely comes into play, but it can.

Monsoon

I picked a 48v 20ah headway battery pack with the 38120 batteries.
The tabs are soldered, but at least i'd still be able to work on the pack if a single cell failed.

It comes with a 60amp max BMS, but this is only for hill climbing, so i'm not too concerned with hitting top speed anyway.

One of the issues i'd been dealing with is I have a good bit of money in my rear bike rack and bag, and I wanted to find something that would fit in it, and the space is very limited at 6.5"x6.5"x12".
My escape plan if I couldn't find a small battery, was to put a larger Topeak bag on the rear, and use my current rig up front.
Fortunately i'll be able to keep it the way it is. And the bag's side pockets are large enough to hold what I carry with me anyway.

It's not the prettiest job of assembly i've ever seen, but I like the small number of large batteries in these.





I got it from an ebay seller out of San Fransisco with the username of electronicstore.

Monsoon

So now I just need a controller to finish this project.

To be continued here: https://www.bikeforums.net/showthread...7#post15875607

Monsoon

Oh, and about BMS battery, since the topic came up a few times in the two threads I started.
I had actually worked my way down to a final choice of their 60v 20ah battery that uses 40 pcs of the 30182 batteries.
This battery would have given me more than the performance I need, and I think it's a fair price at $759.
Only problem is that they don't list the dimensions for that battery. And while I could have changed my rear rack/bag if necessary, I was hoping to find a battery that fits in as is.
Well they seem to use a generic pic for some of them, in that they don't match the specs on the battery listed. For instance several of them are approximately 6"x6", and yet you see in the pic it is more rectangular.
So not being able to count on the pic for a rough reference, I contacted them through the online chat. I happened to be up very late the one night, and I thought it might be business hours in China, and was lucky and got someone online.
I asked if they could give me the "size" of the battery.
I was told it was it was 15kg.
I realized that there was a language disconnect, so I quickly checked their site and the term they use for size is "dimension", so I said no that's the weight, I need the size/dimension. I then said it's not listed on the site.
The person took a moment, and came back and said "it's not on the site".
I paused, a bit speechless now, and said yes, I know it's not. That is why I contacted you. I need to know the size before I purchase this.
The person replied, i'm sorry I don't have the information.
To which I replied, and i'm sorry, because I can't purchase your battery without knowing the size, and ended the support chat.

That was my only contact with them, and it didn't go very well for me.
Which is really disappointing, as I looked at a LOT of batteries before narrowing it down to theirs.

Monsoon

I thought I might update this thread, to point out the unfortunate fact that this battery was shipped from China, and not from San Fransisco as one would expect from a seller who lists their location as actually being in San Fransisco.
I can't help but think that they are taking advantage of people looking for US based purchases with this address.
Knowing this in advance, I would have purchased one of the kits with the larger 40152's in it that have the screw on button end for easier maintenance.

chas58

Yeah, that is pretty typical for BMS battery. Information that is obviously wrong or missing, and not much feedback to questions.

Sometimes you can get a better answer with email, but often not. It is hit and miss. That is why I went with Green bike kit.

And yes, pretty much all of that battery stuff is made and shipped from Asia. You could probably get something local, but that would cost twice as much. I found some nice Bosch batteries in Germany, but those cost about 3-5 times what an asian battery would cost. $1000 for a 36v10ah battery that may last two years is pretty hard to swallow.

Monsoon

no, I wound up getting the battery from the ebay seller I mentioned.
https://www.ebay.com/sch/electronicst..._sop=12&_rdc=1

admittedly the price is pretty excellent, but I hate that it was disguised as a US based purchase.
on the other hand if they truly are US based, it will make it a bit simpler to handle a return.
and since they list San Fransisco as their location, I would have paypal on my side in a claim.