Endless Sphere

Fun fact: the cheaper 300wh models have LG mG1 cells in that are 2850mAh...

Have to do more testing but when bypassing the bms i get 382wh from a 300wh rated pack....

If you bypass the discharge on your Yamaha battery pcb (cut the thick red/black wires going to the board from the discharge port, and solder them to the main leads of the pack, which are oval shaped solder pads on each end, the one closest to the port is positive) if you do this you won't be restri...

SamRich wrote: ↑

Mar 22 2019 6:34am

If you use a cycle analyst it can automatically reduce current based on battery temp, motor temp and SOC

Or build your pack and spec your motor that no overheating can occur.
I know i sounds crazy but imagine having a battery properly sized for the task....

The one i got costs almost 1000 euro with shipping and taxes.

Anything below that amount is basically junk.

What winding did you get?

Ps: make the battery 22S and slighty undercharge it to 4.05V or 21S for full capacitt. That will nudge you up to 90v limit of the controller and give a tad more power and makes you be able to hold your max rpm longer.

there is no chinesum magic. its a simple buck-boost converter with a fancy lcd screen. the real power is in the power supply you use to power the thing. that takes up the bulk of the power. this thing only has to change the voltage down (or up) to the desired level and then its just a matter of push...

You can stack as many cars on top of each other but you still only have the 4 wheels of the bottom car on the ground.
Even if you stack a dozen strips on each other you are still limited to the bottom 4 welds being abke to carry such current. Stacking welds only makes it worse.

Does stacking 2 cars make them go twice as fast?

Gross simplification but i hope it gets the point across.

Wire diameter has a huge impact on the power.
More turns means more volts means more power when resistance stays the same.

NEVER stack strips. shit dont work that way. use 0.25 strips and a welder capable that can hit the power needed to weld .25. first you make the series welds, make the batter as "wide" as possible so the pos-neg connections are as short as possible. the parralel connections dont carry any meanful cur...

i know, but i have done tests with bare cells from a tesla pack and i could use massive amounts of power and almost penetrating a .3 strip before the edge gets damaged enough to get even close to the + rim. the power levels were much higher then what a regular bottom weld coud handle. it would penet...

can we assume you are using a microwave transformer style welder? if so, what switching are you using? that will impact the welding power.

note that a diy transformer based welder usually ends up in the bin because they suck.

I have tried Chinese “smart” BMS, and there is always a catch. I ended up with the Energus, and am now the Canadian distributor. https://hilleater.ca/bms/energus-bms/ They do everything you need, the manual is in pretty good English. The 150/750 a version will drive a relay for higher power project...

V6 and 7 are bascially the same. V7 is more aimed towards 4.1V max charge. but in practice its the same cell wtih a different datasheet and slighty darker blue wrap.

i got a bunch on my test bed and cant find any measureable difference.

Make it 10S10P with 29e, charge to 4.1v and it will last forever

might want to consider putting some fans on the pack to blow air into the pack to cool it.

i dont buy those numbers. pulling those currents from that type of cell will kill it on short fashion.

if you think you will hit anywere near those currents you need a different appoach in the DIY world. increase voltages so you can lower currents is the first thing i would look at.

pouches run into the same problem of heating, and expansion prevention that requires massive steel support sturctures. 2 options remain: more cells to spread the load or cells with lower capacity and much lower IR to prevent temperature melting the pack. my option is just to make the pack bigger. it...

angusinalberta wrote: ↑

Mar 15 2019 2:34pm

Xiaoxiang V2.1.1022 screenshot:
Screenshot_2019-03-15-11-17-13sm.png
Anyone know what the values mean?

you passed your exam?

considering its a moped (usually constructed for SLA) there is pletly of room for a bigger pack. i put 4+kwh packs in them all the time. using cheaper cells and more of them increases the capacity, lowers IR, increases lifespan by several orders and makes for a better experience in general.

you can do it with a single cable and a big fat busbar. no question about that. but such a heavy and stiff cable might be cumbersome to deal with. i would use the "square" cell holders, not the honycomb. the latter gives more energy density but is very poor in cooling. due to the heat creation i rec...

22E IR is 22.7 from a random cell i pulled fresh from a new box (i got 3000 or so on the shelf here). most are between 19 and 25 depending on how you measure. and because the price is lower you can buy MORE cells increasing the current capacity, lifespan, range and so on. also the lifecycle is way w...

Try making that list with the 29E

No, you SET the voltage on the charger. The bms is only there to PROTECT the battery. Its the job of the charger to shut off at the proper voltage you have set. Only if there is a problem the bms will intervene.

for the people interested i got a brand new one open, also rated 400Wh. NCR186650PF cells, 10S4P. conformal coating on the BMS is -as usual for bosch- a utter shitshow. also no drain holes, they put all their money on the 1mm rubber edge they put on the edge of the case. it will fill up with water/c...