PWD's Rocky Mountain Element - 2WD

[pwd]

Thanks thundercamel. The pack is working out nicely and it seems that cell matching is definitely worth it (cells stay in excellent balance). If I was doing more pedal input at bicycle speeds I would have stuck with 14S too. I wanted a longer power band which is why I went up to 20S. My only complaint for this particular build is that the wheel base is very short. I may look into building a longer swing arm in the future.

 

[From-A-To-B]

I enjoyed reading through this thread, PWD— thanks for documenting and sharing the upgrade story of your bike! I hopped over here after reading through your Grom clone thread— another breeze of a read.

It sounds like you ride this bike all the time as a commuter. It’s fun to read threads from folks who are going the distance with their DIY builds. @mcintyretj was an early inspiration for me— it’s wild to see someone crank through thousands of miles on their commuter. At this point, do you have a sense of how many miles are on the frame?

 

[FuzzyWuzzy]

PWD, I just read through the whole thread. THANK YOU! You went many posts in so much detail.

Question for you: how did you wire your DC converter to the battery? The literature on this is surprisingly sparse

 

[pwd]

Thanks for the comments! Unfortunately this bike doesn't get ridden much these days since I got my Grom clone up and running and my off-road build keeping me active all year. This build is mostly just an occasional ride now.

At this point, do you have a sense of how many miles are on the frame?

I'd estimate around 4000-5000 km or 2500 to 3125 miles on the frame.

Question for you: how did you wire your DC converter to the battery? The literature on this is surprisingly sparse

The DC to DC is wired:

Battery + to VIN+ (red)
Battery - to VIN - (black)
VOUT is 12V+ output
Shared ground so just use battery negative for 12V-
I'm not using the 5V output at the moment

 

[ZeroEm]

Thanks for the comments! Unfortunately this bike doesn't get ridden much these days since I got my Grom clone up and running and my off-road build keeping me active all year. This build mostly just an occasional ride now.


I'd estimate around 4000-5000 km or 2500 to 3125 miles on the frame.



The DC to DC is wired:

Battery + to VIN+ (red)
Battery - to VIN - (black)
VOUT is 12V+ output
Shared ground so just use battery negative for 12V-
I'm not using the 5V output at the moment

It was a good old bike. enjoyed keeping up as you went thru building it. Guess we all must move on at some point.

 

[pwd]

I am having a slight issue with the motor temp gauge reading "sagging" or "dropping" when I really hammer the throttle. For example lets say I hit hit open throttle and am pulling peak current from my pack, the temp gauge will appear drop around 15%. When I let off the throttle, the temp reading jumps back up.

The temp guage is powered by a DC to DC board (pack voltage to 13.4 VDC) (positive and negative wire) and the 10K NTC thermister signal (one wire) is coming from the motor.

Any ideas?

I believe I may have found a reason/remedy for this temp sensor issue. I just stumbled on this Tradeoffs for NTC Thermistors regarding 10K vs 100K vs 1Meg etc and didn't realize that a thermistor with a higher resistance is more "noise" resistant (but more prone to self heating). Perhaps if I was to do another temp meter setup; I'd try and go with one that uses 100k ohm instead of 10k ohm and the signal would be more stable.