Battery builder concerned over building a Luna Mighty Mini Clone

Hey, I've just sold my large 17.5aH Shark 48v battery and have been looking to start a new lighter project.

I'm going down the single speed route and re using my Q128C hub motor.

I've been eyeing up the Luna Mighty Mini which is a 52v 6aH cube battery: https://lunacycle.com/52v-mighty-mini-cube-samsung-ebike-battery-pack-30q-6ah-3-pounds/

Jimmy from Insat seems concerned about building this battery for me as 2 cells per string could result in short call life and running hot. He has said he can do it for me, but won't offer warranty.

Looking at the reviews for the mighty mini, people are using it on the BBSHD and getting 15 - 20 miles. My commute is 6miles and I can charge at work. I also only pull < 500w when riding as mainly use PAS and on a 20a controller.

Has anyone got experience with this size battery and share the concerns? I'm no technical expert, but if Luna have had success with the battery on a BBSHD I feel like I shouldn't be concerned.

He suggested another battery at 9ah and 3 cells per string but it would be 9 inches long and just wouldn't suit my project.

6ah mighty mini packs running both hd & 02 here

10-12 miles range w/02

8-10 miles average range w/hd

short 1500w (30a) hd peaks haven't reduced range after year regular use

kcuf said:

6ah mighty mini packs running both hd & 02 here

10-12 miles range w/02

8-10 miles average range w/hd

short 1500w (30a) hd peaks haven't reduced range after year regular use

Click to expand...

Hey great reply thanks. I never pull over 1000w with my setup even at max throttle and I am peddaling mostly so as mentioned im under 500w normally.

The 30Q cell is rated for 15A each, and I use that number as the peak when choosing a pack. A small 2P pack would not get hot if drawing 20A.

Some of the popular max-capacity cells are publicly rated for 10A, but they get pretty warm if they actually draw 10A frequently, so for those cells, you would advised to use 3P to provide 20A. Since you don't need the range of 3P X 3400-mAh, I'd stick with the proven 30Q cell at 2P.

Another factor is if your commute is short enough, the batteries won't have time to get overheated.

It all depends on the amp draw of your setup.
You will want overhead in your thermal design. I prefer to take the maximum continuous C rating of any cell and cut it by 1/4th so that it has tons of room to breathe:

1) When you hit the freezing point and the internal resistance jumps up by 4X, the battery still operates and gives you ~90% of what it's rated for.
2) When you're at reasonable temps, the battery never produces any heat you can detect.
3) When you've got 300+ cycles on the battery, you can still run it because the voltage sag might be doubled, but it's capable of kicking out more power than you require. Might even be able to stretch a pack designed like this to 1000 cycles.
4) You get ~99% of the watt hours promised delivered to the motor when the battery is brand new and the voltage curve is nice and stiff, thus you get the maximum performance possible out of the battery.

Q128C is not exactly a monster motor. A 2P battery is a lot more suitable for it than a BBSHD.

I've been using the "mini", mostly judiciously, for both BBS02 off road and 1000w DD road applications, and it's very functional. Range is easily what is stated above and it hasn't exhibited any loss of capacity (subjectively) in a year. I like it since it fits in a seat bag (with foam protection for pretty severe off road use), and is stealth.

No complaints on my Luna Mini, but I haven't used it but a few times with my 25A controller and 750W hubmotor. Mostly used to run a Q100H. I will criticize the XT60 charge plug, which is male and easy to short circuit on rivets and other small protruding metal parts. One of these days, I will change it.

If I were making a custom MM clone, I'd make it 3 rows high and 9/10 cells long. I feel this will fit better in bags and other places. I've got a 36V 10S-3P battery that is arranged a a 3x10 array. For stealth applications, the narrower form factor is a lot easier for me to fit in a bag.

docw009 said:

No complaints on my Luna Mini, but I haven't used it but a few times with my 25A controller and 750W hubmotor. Mostly used to run a Q100H. I will criticize the XT60 charge plug, which is male and easy to short circuit on rivets and other small protruding metal parts. One of these days, I will change it.

If I were making a custom MM clone, I'd make it 3 rows high and 9/10 cells long. I feel this will fit better in bags and other places. I've got a 36V 10S-3P battery that is arranged a a 3x10 array. For stealth applications, the narrower form factor is a lot easier for me to fit in a bag.

Click to expand...

I won't be ordering the MM but getting the Jimmy at Insat International to create a custom clone of it. I asked him to match the sizing as I feel like Luna have done their research on it.

Its going to be 52v using the 30q cells so exactly the same.