Climb Every Mountain (or what I learned on my first commute)

Completed my personal EV dream this morning by commuting to work for the first time. I, literally, have to climb a mountain to get to work. Wasn't sure I could do it with the budget I had, but it happened and I'm stoked (and already sore from pedaling!)! At least going home is going to be easy peasy! Ha!

Stats:
9.5 miles (got lost twice.. oops.. should shave a mile off Monday)
7.040ah (6-Pack of Milwaukees so I probably got close to max range.. I figured 8+ah max)
363wh used... ouch... I had budgeted like 280... good thing I brought 1 charger with me so the batts don't have to sit empty all day.. ha!
38wh/mi... ouch.
34Amax peak seemed to avg around 15-18A on a 20A controller, which stayed cool throughout
12.7mph/avg (was stuck in an easy gear so couldn't go faster.. will need to fix my shifter tonight)
44min37sec from home to office and that's stopping at the deli for a lunch sandwich, getting lost twice and walking for about 5 minutes to catch my breath
elevation gain about 1,600ft... ouch
Rear 4011 - hot... like fry an egg hot.. we'll see how long it lasts :? , but she sure pulls fine up those hills...
Had to pedal WAY more than I anticipated, but it felt great and I'll get in good shape (in terrible shape now). Don't ever kid yourself into thinking you can make it to the office unsweaty with this kind of climb. Doh! Lucky I have a shower and change of clothes. Phew!

Anyway... EV biking ROCKS! I'm so glad I spent the money I didn't even really have. The gas monkey is dead!

Props on your first commute. What do you mean by "stuck in an easy gear"? All except a modified trials bike should have gearing that you can spin comfortably at at speeds higher than 12 mph.

That 4011 is a good choice for a 500 watt hill climber.

You might want to add more cells, and go for a massivly parallel 36V ... that 20Ah controller is going to be your weak point here at 50+ Volts.

You'll go slower, but your hardware will last longer.

Toshi said:

What do you mean by "stuck in an easy gear"?

Click to expand...

Meaning my shifter is hitting my throttle so I can shift into "easy" gears, but couldn't shift back down so I end up peddling like a madman even at 12mph. :lol: My cycling buddy at work looked at it and it's going to be an issue. I'll have to re-work some stuff tonight. And my rear-view mirror broke already after one day. Ha!

kbarrett said:

You might want to add more cells, and go for a massivly parallel 36V ... that 20Ah controller is going to be your weak point here at 50+ Volts.

Click to expand...

I'm not following you. I was actually considering re-wiring my pack for 21s, which would be around 84v5.4ah. That would make my amp usage more efficient wouldn't it? I'm still too new to all this to know what's best, but I've got the whole volts = speed - amps = torque thing, but I also thought that when you increase volts you're decreasing amp usage at the same power level because of efficiencies? Knew I should have got the 35A controller, but it was considerably more expensive. I was told that +volts is cheap, but +amps is more expensive. Thanks for any tips you can throw my way.

pwbset said:

Anyway... EV biking ROCKS! I'm so glad I spent the money I didn't even really have. The gas monkey is dead!

Click to expand...

WOWZA.. that pic of your commute is worth a thousand words!! Congrats!!!!!

Problem is that when you apply a load ( like, say, hills ) at high volts, like maybe 72V, your momentary Amp usage will go through the roof.

At 36V, that same hill will inflict ( about ) half as many momentary amps on your motor and controller.

So ... it will go slower, but the controller and motor will last longer, and not get as hot. An added benefit is that by going parallel, you get more Amp-Hours in your battery to play with, which means more range.


Theoretically, a 72V 10Ah battery will go for more miles than a 36V 20Ah battery ... but this does not take into consideration two factors ... motor/controller heat, and wind resistance. These motors we are playing with were designed to originally go 36 Volts ... we can get away with more because they were a bit overbuilt ... but there in a real efficiency cost here.

One posibility here would be to use a really big double pole throw, and use it to go from 72V to 36V on the fly ... use 72V on the flats, and gear down to 36V on the hills.

Look into ways of cooling your motor asap.
Several threads here go into that.
You let your motor get that hot and you risk burning off the insulation on the windings turning you strong motor into a very weak motor.

Good thing about cooling set-ups is that you can cool both controller and motor at the same time with the right set-up.

Lessss said:

Look into ways of cooling your motor asap.

Click to expand...

Hmm. Now I'm wondering about this a little. Why would the ebike.ca guys recommend this motor over a 5 series if they were worried about it. I even emailed them about sustained hill climbing and they weren't worried about it at all.

This was part of a back and forth from the first week in May:

Me said:

Which of these two [simulated setups] would you recommend for my daily 9km at 32-ish kph and 9% steady incline?
I've beefed up the 408 with more amps/volts, but I've heard the 40xs can
"burn up" under high load for extended periods.

Click to expand...

Ebikes.ca said:

I have not heard of a 400 series motor burning up due to the power
levels we're talking about here. It will get warm to the touch, but to
burn it out you will need to do more than put in 1700W.

Click to expand...

Guess it all depends on your definition of "warm".

Downhill commute stats for reference:

7.59 miles (got lost for exactly 2 miles this morning... doh!)
1.060ah
62.3wh @ 7.7wh/mi
Resting V after: 56.6v
Vmin: 53.5v
MaxS: 26.8mph
Amin: -3.96A (backed off on speed when I saw that..don't wanna hurt the batts)
% regen: 6%
Regen ah: .0674
Amax: 33.68A

This was the steepest part, with gravel... yuck...



It's weird going from backwoods with nothing for company but deer and bears to being surrounded by multi-bajillion dollar homes etc.

Hey , Nice place to work. 8)

Is that a ski field in the winter.

You might need to feather the throttle some. When the road gets steep it tempting to give it more throttle but you dont end up going any faster. These excess amps get dumped as heat and turn your motor into a bar heater..
Greg

tailwind said:

Is that a ski field in the winter.

Click to expand...

Yes it is a fairly large ski area as things go I guess. It's not Vail or Jackson Hole that's for sure, but it's home. Not a ton of vertical, but lots of acres and no crowds. The "fog" keeps the foo-fooey people with fur boots and bling away so it's usually only diehards that just love to ride. Great local community also. Very friendly. http://skiwhitefish.com

tailwind said:

When the road gets steep it tempting to give it more throttle but you dont end up going any faster. These excess amps get dumped as heat and turn your motor into a bar heater.

Click to expand...

That totally makes sense! Thanks Tailwind! I'll try to curb my amp appetite on the steep parts. I even remember twisting the throttle thinking... "come on baby almost there!" Ha! It'll help when my shifter is fix and I can actually change gears.

Feathering throttle = cutting voltage in half

Works just as well as a switch or re-arranging your batteries ... just requires discipline.

This morning I decided to take the "all pavement" way to work to compare against the "forest and gravel" way. Interesting stats though hardly surprising considering the drop in rolling resistance etc. The all pavement way is like 3.5mi @ 9% without a break. Uber-tough on the legs and on the 4011, but quicker and more efficient. It does use a lot less energy. I'll probably mix it up depending on mood and when I get in better shape etc.

Resting V after climb: 54.1v
7.25mi
5.376ah
281.43wh
38.9wh/mi
Amax: 33.12A
MaxS: 25.3mph
AvgS: 13.7mph
31m42s

That is an absolutely incredible ride!

Um are there cars on that journey? Please be careful. We don't need anymore ghost bikes!

needWheels said:

Um are there cars on that journey?

Click to expand...

If I got through the uber-exclusive club resort (that no one lives in full time.. ha!) and up the basin drainage then no... just furry marmots of various kinds and myself. If I go the paved way then yes, but thankfully a bike path is being put in for all but about 2 miles of the commute that way. I'm already in love with my rear-view mirror though! :lol:

This morning I took the gravel/nature way again and only used 5.5ah which matched the paved way... so... like... either I'm already in better shape or else Tailwind's suggestion to moderate the throttle a bit on the really steep parts helped dump less amps as heat etc. Either way I'm happy.

Someday soon I'm going to ride these 6 Milwaukee packs to their LVC point to see what kind of "real world" range I can get out of them. Max use 7.2ah so far and there was some juice left for sure and that was 7.5mi commute up the mountain and about 14mi around town afterward on Monday = 21.5+mi. Not bad for $480.

pwbset said:

Max use 7.2ah so far and there was some juice left for sure

Click to expand...

Well... not much juice left after 7.2ah I just learned. I decided to ride around the neighborhood after work tonight to hit the LVC and it comes on fast. One minute you're cruising along at 20mph, the next minute you're like... damn... *huff*, *puff*... pedal home!

So... as expected really... a 6 pack of Milwaukee batts in 2s3p is good for 7.8ish ah. I have my CA LVC set to 46v, but the Milwaukee BMS LVC tripped before that. Looks like the BMS LVC will trip around ~24v per pack, which still leaves plenty of headroom on the cells at 3.4v+ per cell at that point. Anyway... good stuff. 20+ mi @ 20mph for <$500 works. I could see bypassing the pack BMS, having no LVC cutoff on the CA and getting at least a couple more miles taking the cells to <3v per if you really needed to.

pwbset said:

Looks like the BMS LVC will trip around ~24v per pack, which still leaves plenty of headroom on the cells at 3.4v+ per cell at that point. Anyway... good stuff. 20+ mi @ 20mph for <$500 works.

Click to expand...

Yup.

Powertool BMSs cut high to extend cycle life. Saves everybody $$.

Man that is beautiful country,and probably cool in the summer! I'm green with envy
otherDoc

Beautiful ride to work.

To extend your range, you might want to current limit through the Cycle Analyst.
I increased my range by 10% when I go from no limit -> 20A limit with my 35A controller.

BTW: It's better to 1/2 voltage & 2x capacity.
I get 15 miles from 33V/8A vs only 9 miles from 66V/4A

Jonathan said:

I increased my range by 10% when I go from no limit -> 20A limit with my 35A controller.

Click to expand...

Thanks for the reply! There isn't much to limit with my Clyte 20A controller as is! :lol:

Thankfully now that I'm running much higher voltage the amp use is more efficient so my range seems about identical. 2p gives me 5.2ah useable now and this morning I used 4.1ah to get up the mountain. That's 1.4ah+ more efficient than when I was running in 3p (avg 5.5ah @ lower voltage). Leaves me about the same ah for getting home... which is almost all downhill anyway... though I won't be getting any regen now @ 80V+. :wink:

wait a second...

54 v times 5.5 ah equals 297 watt hours

81 v times 4.1 ah equals 332.1 watt hours

according to this math, you're MORE efficient (more than 10%) at the old 2s3p than 3s2p. isn't this what Jonathan was saying? doesn't the cycle analyst give you watt hours?

BTW, I'm using 27 volts as the working voltage for a pack (instead of 28 volts).

Check your readings again for watt hours.

jondoh said:

Check your readings again for watt hours.

Click to expand...

According to my spreadsheet at 2s3p/56v on Thursday I used 303.74wh and 5.809ah to go 7.861mi. On Friday at 3s2p/84v I used 321wh and 4.16ah to 8.129mi. My packs are 29.2v hot off the charger... they are brand new though. I see pretty big sag in 2p down to high 70s when I'm flooring it up hill otherwise it's low 80s most of the trip.

On Friday afternoon @ 3s2p I got home and read about 5ah and had a blinking single LED on the battery packs and about 25.5v so that's consistent with having about 5.2ah of useable energy in 3s2p. The pack BMS LVC cutoff seems to be at 24v, which still leaves plenty of headroom for these cells. I wouldn't have wanted to go much further though so yeah I'm losing a little range at higher voltage, but it's, strictly speaking, using less ah so therefore less energy, less money etc. for much, much more power to the wheel. I'm kind of a freak I suppose in that I use this ebike strictly for my mountain climb commute and built it to do just that and no more. Town, groceries, BBQs etc. are all on the cruisers with the girlfriend.

Less amp hours is less energy if the voltage is the same. Your 3s2p setting is actually using MORE energy because while the ah is a little lower than on 2s3p, your voltage is 50% higher at 3s2p. Watt hour is a unit of energy and 321 is greater than 304.

power is voltage times current.

power times time is energy.

jondoh said:

321 is greater than 304.

Click to expand...

Yes, but I also went a further distance on 321... like a 1/4 mile @ 14wh uphill... sounds about the same to me... anyway... I'll totally bow out of any argument because I'm waaaay too new to all this stuff to make an intelligent statement. Plus you were my inspiration to get this project done in the first place!! I'm just uber-happy to be able to pull myself up this damn mountain everyday at 15-18mph @ 80v+.

I hit 31mph tonight on a little test run on the flats... not bad for a lil' ole' 4011! Definitely felt too fast.