Cycle Analyst question

[dpe743]

I finally got the battery in for my first build (went with the ezee rear kit, Luna cycle bottle battery -- will have to post pictures when I get it tidied up). I've been playing with the CA computer. There's a screen that shows the average watt hours / mile (WHM), but this is averaged over the current trip (or charge cycle?). Is there a setting to display the current WHM (say over the past 5 seconds), so I can immediately see the effect of changes in riding style?

Also, is there a way to limit power based on WHM? Or is that really not needed once I get pedelec mode going, where WHM will somewhat follow the assistance level? (I still need to fabricate a part to mount the magnet ring on the sprocket before I can get the cadence sensor hooked up).

Finally, is there a display screen that has user selectable fields, so that I can have the specific stats that I'm interested visible on one screen? Currently I have to toggle between one that has the speed and another screen that shows WHM consumption.

Oh, and another feature that I'd like to see, is to invert WHM so it shows MKH (miles per kilowatt hour), which would be more similar to what I'm used to seeing with with gas vehicles.

 

[MrDude_1]

The average is from the last time you reset it.

While you're riding, you can also view the instantaneous one.. (although this feature may only be in the latest release, I forget)


I dont really use the watt-hours per mile figure much.. I find the amp hours used to be much more useful to me.. I can see how much of my battery I used up, and then since I charge through it, I can see it go back down to zero.

 

[Jon NCal]

You can download the manual at the Grin Technologies website. Also, it's more useful to see how many watts you are drawing at the moment and then you can infer how much power you are using in different situations.

 

[dpe743]

it's more useful to see how many watts you are drawing at the moment and then you can infer how much power you are using in different situations.

I kind of disagree here -- if I'm drawing 4 watts at 10 mph, and 5 watts at 15 mph, I'm better off with the 5 watts draw as I'd end up going further on a charge. But by comparing the watts per mile at any moment, I can optimize both my speed and physical effort so that I can make it to work on a single charge.

Now what would really be nice is to set a (soft) limit on the WHM (instead of just watts or amps), so that I know the my battery will get me through a given trip no matter how fast I go (to go faster, I just have to pedal harder, or be going downhill).

 

[MrDude_1]

it's more useful to see how many watts you are drawing at the moment and then you can infer how much power you are using in different situations.

I kind of disagree here -- if I'm drawing 4 watts at 10 mph, and 5 watts at 15 mph, I'm better off with the 5 watts draw as I'd end up going further on a charge. But by comparing the watts per mile at any moment, I can optimize both my speed and physical effort so that I can make it to work on a single charge.

Now what would really be nice is to set a (soft) limit on the WHM (instead of just watts or amps), so that I know the my battery will get me through a given trip no matter how fast I go (to go faster, I just have to pedal harder, or be going downhill).

mine reads more like 3400 watts at 40mph, and if it goes higher I know I am going up a slight uphill. :lol:
anyway back on topic.. I think that feature is in the new Beta, but I havent tried it or anything... You should check out the tail end of this thread:
https://endless-sphere.com/forums/viewtopic.php?f=4&t=37964

somewhere around the last couple pages is a feature list of the beta stuff.

 

[t_tberg]

it's more useful to see how many watts you are drawing at the moment and then you can infer how much power you are using in different situations.

dpe743, you have the answer literally under your nose. You either don't understand the units or choose to reject valid information. Glancing at the CA to see watts up ( :lol: sorry I had to ) is the most "realtime" reading that you can get. If WH/M refreshed every 5 seconds you wouldn't get any useful information if your trip had any hills or stops; you would see a very inaccurate representation of your power consumption after a stop or an accent up or decent down a hill. If you're worried about making it to your destination you can simply limit the amps in the set up menu. You can add a potentiometer to limit amps on the fly. I believe the CA updates (not refreshes) the WH/M reading every .25 miles which is long enough to average out power consumption factors in most cases. Once you get used to the units the CA seems to be set up nearly perfectly for its intended purpose. Go figure.

 

[teklektik]

Instantaneous Wh/mi, user selectable display fields, etc are available in the 3.1b3 download.
Link to the latest beta firmware is available in the post for the [strike]Un[/strike]official Guide - here.

Instantaneous Wh/mi is like instantaneous mpg on your car dashboard - sort of an indication of the cost of flogging the vehicle climbing hills, etc. The 'per mile' part takes into account the progress you are making so it's quite a bit different than just looking at the W or Wh which don't reveal the relative payback in distance for the energy expenditure.

 

[dpe743]

Instantaneous Wh/mi, user selectable display fields, etc are available in the 3.1b3 download.
Link to the latest beta firmware is available in the post for the [strike]Un[/strike]official Guide - here.

Cool -- I'll check out the latest firmware then. I wonder if I can adapt my existing rs232 to usb cable to work in the CA's data port? Or do I need a ttl voltage converter? (I think the specs for the CA mentioned TTL logic, which implies 0v and 5v, vs. rs232's -12v and +12v).

 

[teklektik]

You can use other than the recommended CA cable, but these 'thrift' episodes always seem turn a simple task into a Science Project...

Get the recommended cable and be done with it.
HPC has been dumping these cables on eBay for a good price if you don't want to go directly to ebikes.ca or a CA vendor - see here.

 

[ColinB]

An interesting idea - you basically want a "range until empty" type display, and vary the motor based on that.

If your battery capacity is that close, I'd choose a larger one. You won't want to do an economy run every ride. Plus, what happens if you extend your ride, have major head winds, or it gets cold (and capacity drops.) Also, capacity will go down with age, and sometimes it is great just to crank the throttle for fun.

I've wondered similar things - better to go up a hill fast at 700w, or slow at 300w? I find over the entire ride, wh/km goes up with speed.

Colin

 

[dpe743]

If your battery capacity is that close, I'd choose a larger one.

I've got a 22 - 25 mile commute, and have a Lunacycle 13.5 ah 52v bottle battery. So it should be good for 35 to 45 miles. Was planning on charging at work, but the charger's fan is kind of loud (I may end up putting the charger guts in a different housing with a larger diameter fan to remedy this).

But what I was thinking -- I used to cycle commute 15 miles each way many years ago. But am seriously out of shape. So, I thought I'd tune the bike for maximum assist, then once a week or so knock down the assist level by a notch, while trying to keep the same speed. This also helps, in that as the battery gets weaker over time, the rider gets stronger.

 

[Lurkin]

or get a laptop style charger with zero fans...