My DIY builds: GMAC, BBSHD, 9C RH212, CYC Photon, ToSeven DM01

[linklemming]

Im guessing that motor had about 250 miles on it. I dont deny I beat on it but it was using factory settings. I was trying to find its limits and I succeeded Many others in discord have reported blown controllers running 30A during hill climbs.

Thanks for the positive Ali feedback, I just ordered two controllers from To7 on Ali. Supposed to be here in 2 weeks

We will see if these controllers have newer firmware that locks out many settings or even worse limits speeds.

IMHO. the CYC can be reliable at lower power levels (750 watts or less). I am running it at its highest unrestricted power levels but I always monitor temps and have only overheated it once or twice and most of the time I'm probably using 3-500 watts. Its pretty impressive for its size.

 

[linklemming]

Reduced Battery Capacity after 3-4 years
I do most of my rides using two EM3EV 52V 17AH(14S,5P 18650) batteries. The first (BATT1) uses 35E cells and was bought in 9/21. The second (BATT2) uses GA cells and was bought in 9/22.

I seem to be doing about 6k miles per year between these two batteries with an average ride length of 25 miles so thats about 240 cycles per year. This 6k miles also includes 1-2 rides per week (20-40 miles) in spring/summer/fall on dedicated eMTBs with different batteries.

While testing the DM01 and comparing against BBSHD I was seeing reduced efficiency on the DM01. In the end I believe a big part was one of my batteries starting to give out. As it turns out, I think I was always running the DM01 on BATT2 and the BBSHD on BATT1. The DM01 eventually had a FET failure so who knows how that affected efficiency before final failure.

Did a load test of 4A on a fully charged battery(BATT1 and BATT2) and saw 1.9V drop on BATT2 and .9 on BATT1 so roughly speaking twice the voltage drop on BATT2 which equates to twice the Internal Resistance(IR) which is the factor that ages a battery.

I have always 'fully charged' the packs. Everytime I have tried charging to 80-90%, I get too much range anxiety. Im willing to live with the reduced battery life in doing this.

While its hard to quantify 'exactly' due to all the various ride conditions like temp/wind etc..., Over the last BBSHD rides, it appears that BATT2 consumes about 3wh/mile more than BATT1.

The 35E cells and GA cells new seem to have the same IR new and the GA cell is 'supposed to be better'. Im guessing something in the GA pack isnt up to par (for instance it takes a really LONG time to balance at end of charge).

Both packs are the "Jumbo size" (14S,5P 18650 cells).

Looks like its time to retire BATT2. I could keep milking it but batteries to me are wear items like chains, cassettes, brake pads and tires. This will be the fourth pack I have retired since 2019.

New EM3EV 21700 packs
EM3EV is now selling 21700 14S, 4P 52V 19.6AH 'King' shark packs. Unfortunately they are 2# heavier than the 'Jumbo'. On the plus side they are $100 cheaper than the 'Jumbo' 18650 based packs but have increased current output (i.e lower IR). There are alot of new trails opening up around me this year which could increase trip distance and I really could use the additional range of the 'King' pack.

Just ordered a new 'King' Pack, most likely a second soon.

 

[Gionnirocket]

The GA cells are rated with a higher max discharge rate of 10a compared to 8a of the 35E and this was my reason for trying them in a small battery. Though they've worked well they just don't seem to be as robust compared to the 35E batteries I've used, especially in cold weather.
My experience is very anecdotal as my GA battery is only 10ah and my 35E batteries were/are 17.5ah and 21ah... So I'm kinda comparing oranges to tangerines. The GA battery has and still is working well... but it doesn't see much action lately.
Point being... I really don't have one
I think moving to the 21700 cells is a good choice as I have only heard good things about them.
I'm contemplating a light weight 12ah battery for my typical 20 —25ml daily exercise ride and if I do pull the trigger.. it'll be with 21700

 

[Slaphappygamer]

I would love to get a battery with 21700 cells. Unfortunately, my battery is integrated in to the frame and the case can only fit 52 18650 cells. I’ve been looking for a Hailong or triangle battery that would fit, but there isn’t much space. For the ride1up 700 series, they now (since ‘22) come with 21700 cell packs. These are longer (441mm) than the battery I currently have (362.5mm). I have been thinking “I might be able to cut the frame to fit the larger battery”, but that’s pretty desperate and then I’d be limiting space for my controller, unless I mount fit outside the frame. The existing 35E pack runs well for my needs.

 

[Gionnirocket]

I would love to get a battery with 21700 cells. Unfortunately, my battery is integrated in to the frame and the case can only fit 52 18650 cells. I’ve been looking for a Hailong or triangle battery that would fit, but there isn’t much space. For the ride1up 700 series, they now (since ‘22) come with 21700 cell packs. These are longer (441mm) than the battery I currently have (362.5mm). I have been thinking “I might be able to cut the frame to fit the larger battery”, but that’s pretty desperate and then I’d be limiting space for my controller, unless I mount fit outside the frame. The existing 35E pack runs well for my needs.

Have you tried @Jenny Mao ?
She can custom build batteries using different cases.

 

[Slaphappygamer]

Have you tried @Jenny Mao ?
She can custom build batteries using different cases.

Yes. I contacted her. I think there was some misunderstanding on my part. The case she was talking about was the larger (IR-7/IR-21700) version of what I have. I have been looking around and I don’t see my batttery (Reention Rhino IR-5) with anything other than 18650. I was thinking of contacting her again and requesting different cells. Maybe molicel, I hear good things about those.

 

[JRA]

SHG, I was an early adopter of 2170 cells as I thought they were perhaps marginally better for use in eBikes. I am going to put an emphasis on marginally.....as time has gone on for sure companies have adopted them and why not as margins are good for business. But if as you say your current 18650 cell pack is doing well for you don't feel left out as you would probably never even notice any difference.