Do you plan to use this for a mountainboard? … will try to get my wattmeter working to tell how much 6s 192kv and 4.33 gearing consumes… So far, from theory it has been around 19-20wh per km…though, I need to do more careful tests as I have not taken careful measurement of average speed, the stops and some other stuff.
I also had the choice to go with sanyo’s, though they also seemed way too weak for building a pack… (at least in 4p configuration).
So I got my wattmeter working! Today when going against wind and pushing at around ~25-30kph my setup pulled ~60Amps / 1200watts. Max speed I got was around 35kph but I think the wind put quite a pressure on the motor / system as I could feel that it was hard to move forward.
I use Sony VTC 4, which are rated for somewhat like 23A, even though some labels say they are 30A. So it is hard to guess now whenever batteries were not able to push harder or is it because of 6s voltage.
I also plan to add a 3d printed fan to my motor, as the motor was a bit warm after this ride and I want to ‘‘heat-proof’’ it, so that I dont have to worry if it gets too warm or not (when not riding on best terrain)
Because i have read carfully the topic “Lets talk about voltage sag” and a mix of both worlds (capacity and discharge) would be too expensive.
I am currently using a set of jacob hubs and think that i will need more current than initially expected.
I need to log some real world data for the battery consumption to plan my build correctly… but for that i am missing a uart plug (thanks to cutting costs in the new vesc series…).
If that is really your concern you should go with A123 cells instead.
How many cells do you want to use in parallel?
In my opinion you should just go with Samsung 25R - best of both worlds and cheap.
The whole argument about voltage sag relies on the fact of how much difference there is between actual consumption and current rating.
So deciding on which battery should come after deciding on the current you want/are going to use.
A battery with 10A rating at 10P will be perfectly fine when your goal is 100A.
A battery with 20A rating at 5P will be perfectly fine.
A battery with 30A rating at 3P will be equally fine.
You are not going to use 100A however as that would equal 100A*50V = 5KW (I assumed 12S, at 10S it would still be 4.2KW) - that is way too much and will just make you street your face.
I already have the motors. Now i Need to measure what current i use at max.
When i have the Max value i can add 20% or more breathing room and now how much my battery should provide.
how are you going to measure that when you don’t have batteries? Also you don’t actually need to do this. You can just use the already established numbers: anything above 60A should be fine (remember a space cell has a 40A fuse as a comparison) - with Hub motors 80A will give you some breathing room. Anything above is ridiculous and the VESC rated at just 50A anyway.
i´d pick one of the common cells like 25r or hg2. Run them at least in 10s4p and you´re good to go. I´m planning hg2 at the moment in the next 2 builds. 10s4p with dual 6355 190kv. Both heavy rider at above 90kg and some good hills. I´m going with a 80A fuse and should be fine in every situation. There shouldn´t be any voltage sag
Currently I can ride with my dual hub drive (2x (11S LiPo + VESC + Jacob Hub)) test board. I am testing my stuff with LiPo Cells but i want to change it to Li-Ion. Before i can measure my setup i need some nasty “micro JST” plugs (the white plug in the picture) to use my hc-05 module…
I soldered my Nyko Kama to my VESC - soldering is recommended anyway due to the vibrations. Personally I find it good to not have the connectors and be able to solder the cables directly.
For your test system: What kind of VESC current limits do you set?
From where do you order them… and what quantity?.. nkon has 20R for something like 3+ eur… so these 30Q might be way better, considering they have 3ah instead of 2ah…
I would send you one down, but i just checked and i do have some 7 pin JST around…I ran out of the 6 pins lately…
My current idea is to buy that plug or just solder some wires to the vesc… still undecided
