TexasElectric - eBike build

[TexasElectric]

California98Civic
I was reading you build thread yesterday. You were working on a battery box, did you ever finish (or, is that still an going project)?

6/22 update
Today was a 2 steps forward, one step back kind of day...

1. Yesterday I accidentally soldered the negative leads to the wrong side of the pack. (easy fix)

2. Then I soldered the positive and negative leads coming off the whole 'pack' to the wrong side and was getting a voltage of 19.9 volts. It took me a while to figure out what was wrong. (problem fixed, I moved them to the other side of the pack and got 26.5 volts).

3. I put two layers of heat shrink on the 'pack', only afterwards to realize that I forgot to solder the BMS leads. (really... geez...)

I removed the heat shrink and plan to solder the BMS leads tomorrow.

It's progress, but frustrating...

[Daox]

Yep, putting all that stuff together really takes time and thought. I remember dinking around with my Enginer PHEV kit for my Prius. It was a VERY time consuming process. I was also talking with a friend the other day who was building a Headway pack. He was working on it and dropped a wrench on the open leads... It toasted 2-3 cells right in the middle of the pack that he had glued together. So, take your time and do it right. Things can go bad quickly.

You're doing a great job though! Looking forward to more.

[California98Civic]

Originally Posted by TexasElectric

California98Civic
I was reading you build thread yesterday. You were working on a battery box, did you ever finish (or, is that still an going project)? ...

Maybe someday I will return to it. I kept my template shape with the outlines of the components. I tried some small cardboard-to-fiberglass projects before attempting the battery box. I concluded I would rather wait until I have more experience before building something that must combine sturdy, waterproof, lightweight, have ports for the charging plug and key, and still be reasonably good-looking.

So I just cut the stock aluminum box to fit my triangle and made my own bracket from the cut parts. Even that has some significant (not visible or severe) mistakes. Just today I dropped in at my hardware store for spring washers for part of the battery mount. And I concluded I need (removable blue) locktite for the frame mounting points. Rattles and looseness develop over lots of miles. A more experienced person I am sure would not need to find that out the way I did.

All good. Did nine miles on the ebike running errands this morning before 9am.

You're gonna love your bike when I gets fully operational. And your craft looks solid and experienced. Dig it.

[TexasElectric]

Daox
"dropping a wrench on open leads...", yup i've been there and done that. I use to own a used car dealership, I did most of the repairs myself. I remember one time I was jacking up a car and a wrench slid off the fuse box and landed on the battery (nice big spark and the wrench wet flying).

California98Civic
Adding the blue 'lock tight' to the triangle blots is probably not a bad idea. I'm excited to get my bike up and going, cant wait!



6/23 update
Today was kind of another 1/2 step back 1 step forward kind of day (but better than yesterday). I soldered the BMS leads to the negative of all the 'packs'. I have to wait until Monday/Tuesday for the heat shrink to arrive in the mail before I can solder those leads to the BMS.

I am planning to mount the controller and BMS to a 1/4 inch piece of wood that will sit on top of the battery pack in the rear bag (see picture below). I'm going to use plastic/rubber spacers to stand off the controller and BMS from the wood to allow for increased air flow/cooling. Additionally I have a small heat sink I'll be placing on top of the mosfets on the BMS (not pictured, yet).

It's foretasted to rain this weekend, plus I want to get out for a Saturday morning road bike ride with a local group of riders. I'll have something to report after this weekend (ie. more progress), but we'll see...

It's getting there... more progress!

[TexasElectric]

6/24 update:

It was rainy this morning... so, no road bike riding.

Anyway, I made more progress on the eBike. I applied two coats of primmer/sealer then painted the remaining wood pieces. I screwed the motor controller and BMS to the board. I left about 1/4 to 1/2 inch gap between the board and the motor controller and BMS. I also picked up some heat sink compound to put between the mosfet's and a heat sink (see picture, next to motor controller and BMS).

I mounted the BMS on top of a 7mm thick piece of EVA foam, I did this because I don't want the BMS to be ridigidly mounted to the board. I cut out a small section below the mosfet's on the BMS, this way I reduce the risk of melting the EVA foam.

I also glued a 7mm foam cut out on the battery box side panel that I painted today, (not pictured).

Last night I ordered a 35 amp AGU fuse/fuse holder. I'll mount the fuse holder to the board as well. I plan to wire the fuse before the BMS, (in an effort to protect the BMS from too many amps)

Tomorrow, I need to work on heat shrinking the big battery 'pack' and installing the second torque arm.

[California98Civic]

Sealed in a wood box are you worried that their will be too little ventilation? I have read that the aluminum boxes help cool the battery and controller by conducting heat so well. Wood will trap that heat, no? How do you cool it?

[TexasElectric]

California98Civic

I decided (about 2 hours ago) that I an going to cut out 'gills' on the sides of the battery box. I'll do it soon.

6/25 update

I took the ebike out for about 1 1/2 hours. I rode a total of 23.75 miles, 4 miles of that was 10-15mph "testing". Average speed of 16.3mph. I was maintaining an average straight line speed 20mph-21mph. I had a few occasions where I was using 800-900 watts to contend with traffic. I didn't want to exceed 500w-600w because (at this time) I only have one torque arm installed.

Battery voltage before ride: 53.2v
Battery voltage after ride: 52.6v

Assuming very little wind (if any) and a frelitivly flat road I was using about 375w to maintain 20-21mph.



I can tell that this motor (1500w) has A LOT more power than I am using. I had a few occasions where I accidentally twitched the throttle and the bike wanted to rocket down the road. No... It's not as fast as a 1000cc sport bike, but it's not a motorcycle, it's a electric bicycle! For what it is, (a 1500w eBike) it's like having 10x Chris Froomes power the bike. I LOVE IT!

[teoman]

A trained cyclist produces 400W of mechanical power.

So you have the equivalent of almost 4 people cycling for you

[California98Civic]

Originally Posted by TexasElectric

Battery voltage before ride: 53.2v
Battery voltage after ride: 52.6v

Whoa! I keep looking at these numbers and remembering the fact that you rode nearly 24 miles and finding myself in disbelief. If I rode my bike 24 miles my start voltage would have been 41.8 and ending would have been something like 36v (climbing several steep hills as much as a mile and a half long). Yours dropped less than a volt? How? You pedal a lot, it seems. Road must have been very flat, no?

Originally Posted by TexasElectric

California98Civic

I decided (about 2 hours ago) that I an going to cut out 'gills' on the sides of the battery box. I'll do it soon.
....

I thought that would likely be the solution.

[TexasElectric]

California98Civic
Yah... a 0.6 volt decrease over 23.75 miles has me in shock and awe myself. I should have documented (through video) checking the voltage before and after. I'll video tape it next time.

About 95% of the ride was throttle only. (I don't have a pedal assist sensor mounted at this time)

A little more info on the ride: (according to my Garmin)
'test ride'
- 4.26 miles
- 00:21:46 minutes (hh:mm:ss)
- average speed 11.75mph
- maximum speed 21.69mph
- ascent 65.6ft
- descent 72.2ft

'on the road ride'
- 19.5 miles
- 01:06:37 minutes (hh:mm:ss)
- average speed 17.53mph
- maximum speed 26.01mph
- ascent 528.2ft
- descent 524.9ft

The roads were mostly flat, I did have two hills (one small and one big). I decided I wanted to see what it'd be like to have to pedal up the big hill without any assist from the motor (should I find myself out of juice). The big hill wasn't that bad, I just keep a high cadence and chugged along at 6-7mph. The small hill I backed off the throttle and kept the watts between 500w-600w, (I slowed down from 21mph to 14mph while on the small hill).

I stopped about 3 times while out riding to check the motor, controller, and batteries to make sure they weren't getting hot. Everything felt fine. Yesterdays temperatures were in the high 80's, and all the bike components felt cool to the touch.



I do have a beef with the display that was provided with the kit I bought. The display only seems to show me watts in increments of 50/75 (even though it's a digital display capable of displaying numbers 0-9). It jumps around a lot. I'd be riding down a flat road then start to go up a slight hill and i'd see the watts read out change back and forth between 375 watts and 450, then it holds steady at 450, shortly thereafter it starts flashing back and forth between 450 and 515. If it's going to behave like this I can only estimate my power usage while riding.

To fix my display problem I placed an order for this https://www.amazon.com/HTRC-Precisio...=rc+watt+meter, i'll also buy a cheapo $15-20 spoke mounted speedometer to give me my speed.



I'm a little physically/mentally tired from obsessively working on the bike over the past 6-7 days straight. I'm going to take 2-3 days off (after I finish cutting the wood for the 'gills' on the side of the battery box).

Picture of the "gills" on the side of the battery box. I decided to go for an abstract look. I'll place a mesh over the holes to keep out dirt/debris.