Ebike battery idea: can these prices be beat?

[Storx]

Im more than likely ordering a motor kit here in the upcoming days, but i am still doing my homework on batteries.. I was going to build one out of 18650 cells, but all of the named brand laptop batteries that people recommended buying for recycling of cells comes out around $3-4 a cell to gain access to genuine good brand cells and ive dropped in at 7 different recycle centers near me and noone would give up old laptop batteries that people turned in to recycle.. seemed like most stores have policies against it now..
If i was continue with the 18650 route with a target battery size of 18-20ah, i would need roughly 100 cells to get 37v@20ah $300-400+ soldering parts to build it.. so roughly $450 for a complete pack...

Friend of mine who built his electric motorcycle with nissan leaf batteries mentioned i should use cells from them to make my battery, he told me each module is 4 cells in a 2x2 configuration, 4.2v per cell w/ each module rated at 8.4v @ 62ah..
So, if i understand this correctly, each cell is 4.2v @ 31ah, so if i bought 3 modules that would give me 12 cells, i could take 10 of those cells and solder the tabs up to make a large 42v @ 31ah battery and just have 2 cells left over as spares
So, i had my friend call the guy he bought his cells from last year and he told me he would ship me 3 modules from a 2014 leaf pack for $350

So is that my best bet for a decent battery pack without buying one that is premade? because most 10ah premade batteries are running around $500

 

[Hillhater]

Look up (search function) some of the threads on the Leaf modules/cells, on this forum.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=52162&p=1139502&hilit=Leaf#p1139502
Earlier module units were enclosed into metal canisters, which were not easy to split or reconfigure.....which you will need to do.
More recent modules are simpler to dismantle.
You need to know which you are being offered.

 

[dogman dan]

Yeah, if you can source the cells affordably, and need 30 ah, great. I ride with 30 ah fairly often, but most rides I carry no more than 10 ah. Few bikes can easily carry 30 ah, but my cargo bikes can. So look hard at how much you need 30 ah, and how will you carry it. It is a lot of weight, even in leaf modules.

If you need only 13 ah or so, then you won't regret the money spent on a good triangle battery, or other battery that can mount in the center of the frame.

Lastly, 10 cells in series is considered 36v. But you could run 12s, though chargers are harder to find for that.

 

[Storx]

Yeah, if you can source the cells affordably, and need 30 ah, great. I ride with 30 ah fairly often, but most rides I carry no more than 10 ah. Few bikes can easily carry 30 ah, but my cargo bikes can. So look hard at how much you need 30 ah, and how will you carry it. It is a lot of weight, even in leaf modules.

If you need only 13 ah or so, then you won't regret the money spent on a good triangle battery, or other battery that can mount in the center of the frame.

Lastly, 10 cells in series is considered 36v. But you could run 12s, though chargers are harder to find for that.

the battery setup is for my catrike expedition

 

[dogman dan]

That should be easier to carry a big battery on then. I just cannot remember what each ES person rides. I just assumed you wanted to carry 30 ah on a regular bike, which can be done, with some panniers.

30 ah is nice, at low speeds potentially 60-80 miles. Or at 25 mph, long enough to have a nice 30-40 miles.

 

[Storx]

i decided against the car cells due to weight, was easily going to be nearly 3x the weight of lithium 18650 pack, so i looked into picking up old laptop batteries locally and managed to get 12 from local store, going to call around a few more places to see if i can get more, out of 82 cells, 79 of them had 3.0v charge or higher.. ordered an Imax B6 to test them for capacity along with 2) 3 cell 18650 holders, and 10) 6s balance harness's to charge 6 cells at a time... only crappy thing is the cell holders wont arrive for 2 weeks, so ill have time to collect more batteries while those arrive as well the chinese are going on holidays, so my Mac 10T motor kit i am ordering cant ship tell later in feb when they get back from holidays

 

[John in CR]

Since you don't pick up your trike and carry it around, weight is of little consequence. Using crap cells and having limited range is of great consequence. In the cans in stock for, the Leaf modules are only 3.75kg ea, so that's just over 11kg. Space and shape are the true physical battery limitations, so if you can easily fit the dimensions of Leaf modules, that's the way to go unless you're on an absolute minimalist budget.

 

[dogman dan]

Build your own a great idea for many, but not using craptop cells barely able to put out .5c discharge rate. You need like 25 in parallel to get 25 amps out of em.

However, making your initial mistakes and learning with cheap ass cells is a great plan. Gain skills, then get good 18650 cells.

Whatever you use, 48v30 ah is a big hunk of weight. Over 20 pounds. But with your bike, weight won't matter much, under 50 pounds. One nice thing about a custom 18650 pack, you can make a large but thin pack, and mount it under the seat.

 

[Storx]

Build your own a great idea for many, but not using craptop cells barely able to put out .5c discharge rate. You need like 25 in parallel to get 25 amps out of em.

However, making your initial mistakes and learning with cheap ass cells is a great plan. Gain skills, then get good 18650 cells.

Whatever you use, 48v30 ah is a big hunk of weight. Over 20 pounds. But with your bike, weight won't matter much, under 50 pounds. One nice thing about a custom 18650 pack, you can make a large but thin pack, and mount it under the seat.

Ya, i see what you are talking about... but i think i will be able to atleast build my first pack while learning about all of this.. The tester is a gained peace of equipment that will benefit me in the future, so i honestly only have $28 in parts on order to build this DIY 20ah pack so far between the 100 pico fuses i ordered and 200 2x plastic spacers i picked up, the BMS and power supply is something i would have to get no matter if i used new cells or old ones...

I was going to order the toshiba $17 NEW replacement laptop batteries to gain new cells, but i found 2 post talking about them from ebay and they posted that they had resleeved cells in most of the packs with an average capacity of 1500-1600 only, so i figured that is no benefit of me if i can find cells closer to the 2000mah or higher capacity, i plan on starting testing with the higher factory capacity cells first before moving on to the no name/no markings cells...

 

[ecat]

A word to the wise... Don't mount that big pack that you are building on the rear rack of your Catrike. The handling will be scary. Put them behind the seat, or better yet under the seat. I know this from experience. I have 48v 26 ah in two packs under the seat, handling is good. It was scary with the old Pings in panniers.

 

[Storx]

A word to the wise... Don't mount that big pack that you are building on the rear rack of your Catrike. The handling will be scary. Put them behind the seat, or better yet under the seat. I know this from experience. I have 48v 26 ah in two packs under the seat, handling is good. It was scary with the old Pings in panniers.

could you post a picture of your bike with the battery layout, also is it 2 x 26ah batteries or 2 x 13ah packs?

 

[ecat]

Yup, its two 13.3 AH packs run in parallel. I soldered them using solder wick as the connecting strips. I know, almost everyone says don't do this. I used a temp controlled soldering station, and was very careful not to overheat, and cooled them immediately after each solder. The two packs tested out to within less than .1 AH of each other, and are working well, so far so good. I used Panasonic 18650PF.

I added cooling fans and vented the boxes, but I don't think it was really necessary. I inserted a temperature sensor which is read by the CA3, and even on a long hard ride pulling 36 amps up big hills, I only see 3-4 degrees Celsius temperature rise.

The boxes I made 4 or 5 years ago to hold two Ping 10 AH 36 Volt packs that are still working, but have lost some capacity. They are fiberglass. The lids are held on with bungee cord. The little window originally displayed the Ping BMS with its LED balancing indicators.View attachment 1

Visible in this shot are the front of the two boxes and one of two aluminum bars that attach them together, and to the trike. I drilled and bolted to the frame, probably not the smartest thing to do, better to put a clamp around it.View attachment 4

 

[Storx]

Mind if i ask what type of range your getting with those batteries?

I am going to more than likely copy your location, but i have to figure out what im going to mount them in.. i could do them in carbon fiber, i have a roll of it laying around, just gotta get more epoxy...

 

[ecat]

Getting about 50KM range max. Its hilly here, and I go fairly fast. Last trip I averaged over 40 km/h for 26 km. Yes to carbon fiber! be sure to reinforce the mounting spots. The bolts that I put in these boxes almost pulled through the fiberglass after many KMs. I ended up putting steel plates between the bolts, inside the boxes.

 

[jkirkeboe]

Yeah, if you can source the cells affordably, and need 30 ah, great. I ride with 30 ah fairly often, but most rides I carry no more than 10 ah. Few bikes can easily carry 30 ah, but my cargo bikes can. So look hard at how much you need 30 ah, and how will you carry it. It is a lot of weight, even in leaf modules.

I'm building a 30Ah 48V battery now, and it won't weigh much. Should fit most bikes. 13s9p 18650 using Sanyo NCR18650GA cells. Approx. 3350mAh at the discharge rate I will normally run. Total battery weigh incl. BMS, glue, nickel and wrap should be aroung 6,5kg I think.