Battery range and notes for the magnum metro plus

[MetroDuck]

My wife and I are getting ready to take scenic trip on our bikes in a little over a week. The total distance is 42 miles. I wanted to do a test this week to make sure we were not going to be peddling a 57 lb bike for the final stretch. The magnum website indicates a range of 30-50 miles. I knew from previous use that 40 was probably a pretty safe number. I charged the bike on Tuesday evening and then made 3 round trips to work and back; 11.5 mile per round trip. My wife and I also took some rides in the evening. Tonight I went on a ride to see if I could get to 50 miles.


I was at 50.8 miles when the battery gauge went from flashing to empty. I give a moderate effort when I ride with my pulse maxing out at 110-120 which is what the dr. ordered for this 59 year old. I'm no lightweight either at 220 lbs (down 10 lbs after riding 415 miles during my first 7 weeks with the bike). So I think the Magnum estimates are good, even conservative. My wife got a cruiser 2 weeks ago. It has 97 miles on it and it still has two bars. We have only charged it once and when it dropped from 2 to 1 bar. She weighs much less then me so I think she would likely get 60 miles per charge. We forgot to reset the trip-one odometer the one time we did charge it so we don't know for sure.

As for the battery indicator I have been watching that and it seems to stay on full charge a long time and then drops bars quicker then expected. I watched more closely this charge and here is what I observed.

- A full charge for me is 54.4 volts on the BMS indicator

- The battery gauge drops drops from one bar to flashing at 44.9 volts on the BMS indicator

- At 42.9 volts the flashing will stop and the indicator will show empty even if the battery voltage goes back above 42.9 volts. I went a couple more tenths of a mile and the motor was still operating at normally at 42.6 volts.

I suspect that the battery cutoff might be 41.9 volts? Full discharge of the batteries to the danger point would be in the high 30's so I think the BMS is pretty conservative in protecting your battery.

So based on my observation this evening I'm pretty confident that once the gauge starts flashing that I have 6-8 good miles left before it shows empty. Another way I look at this is that at full charge I get 5-6 miles for a one-volt loss on the BMS. Towards the end (mid 40's volts) I get 3-4 miles per volt.

I didn't think too much of it when I bought the bike but being able to see the voltage on the indicator is a great feature for me.

I'll report back after we take our trip a week from Monday on the Banks-Vernonia State Trail.

 

[Trail Cruiser]

You can achieve the manufacturer's claimed range of 60 miles if you use the lowest assist level. You can even surpass 60 miles if you exert more pedaling effort. The pedal assist setting is programmed like a cruise control, at assist level 1, you'll be cruising at 13 something mph and if you pedal more and increase your speed to 14 mph, the motor power will also decrease further (saving your battery and increasing your range). If you pedal harder above 15 mph, the power meter goes zero bars (you're on your own without the motor).

Your power meter is your guide, as long as you maintain 1-2 bars or less (out of 6 bars), you will have very long range.

Choosing eco mode in the setting configuration further helps in the range (from the 3 options, eco, normal, and power).

 

[MetroDuck]

You can achieve the manufacturer's claimed range of 60 miles if you use the lowest assist level. You can even surpass 60 miles if you exert more pedaling effort. The pedal assist setting is programmed like a cruise control, at assist level 1, you'll be cruising at 13 something mph and if you pedal more and increase your speed to 14 mph, the motor power will also decrease further (saving your battery and increasing your range). If you pedal harder above 15 mph, the power meter goes zero bars (you're on your own without the motor).

Your power meter is your guide, as long as you maintain 1-2 bars or less (out of 6 bars), you will have very long range.

Choosing eco mode in the setting configuration further helps in the range (from the 3 options, eco, normal, and power).

I have no doubt you are correct on this. I was just interested in finding out if the Magnum advertising is accurate. I think it speaks well of the company that they seem to be on the side of conservative in a day and age when many companies stretch the bounds of practicality.

I don't peddle particularly hard when commuting into work as I don't want to need to take a shower upon arrival. And yet with that and being 220 lbs I still get the upper end of the advertised range. I generally only show 1-2 bars when making the 11 mile round trip. I think what dings my overall total a bit is the major streets I cross when I get into town. I tend to use the throttle to start from a stop when crossing these very busy streets to minimize my exposure. That is when I see the bar jump to 5-6 for a short while.

I'm going to do more analysis on the PAS level. Intuition says higher PAS levels will draw down your battery faster but I'm not so sure that is as pronounced as you would think. I know when I hit the main three lane ave. going into work I am often using level 5. I still only see 1-2 bars. The other side of that is that you get there faster, so that means you are using the battery for a shorter period of time than you would at PAS 1. I suspect the amount of effort you put into peddling being the same at PAS 1 or PAS 5 will affect your overall distance per charge very little. At least that has been my experience so far. Something to study further I suppose. But the longer I ride the more I just use the PAS and peddle effort the way that feels right at the moment and that it what is great about an ebike. I don't have those options on a non-ebike.

 

[Trail Cruiser]

I have no doubt you are correct on this. I was just interested in finding out if the Magnum advertising is accurate. I think it speaks well of the company that they seem to be on the side of conservative in a day and age when many companies stretch the bounds of practicality.

I don't peddle particularly hard when commuting into work as I don't want to need to take a shower upon arrival. And yet with that and being 220 lbs I still get the upper end of the advertised range. I generally only show 1-2 bars when making the 11 mile round trip. I think what dings my overall total a bit is the major streets I cross when I get into town. I tend to use the throttle to start from a stop when crossing these very busy streets to minimize my exposure. That is when I see the bar jump to 5-6 for a short while.

I'm going to do more analysis on the PAS level. Intuition says higher PAS levels will draw down your battery faster but I'm not so sure that is as pronounced as you would think. I know when I hit the main three lane ave. going into work I am often using level 5. I still only see 1-2 bars. The other side of that is that you get there faster, so that means you are using the battery for a shorter period of time than you would at PAS 1. I suspect the amount of effort you put into peddling being the same at PAS 1 or PAS 5 will affect your overall distance per charge very little. At least that has been my experience so far. Something to study further I suppose. But the longer I ride the more I just use the PAS and peddle effort the way that feels right at the moment and that it what is great about an ebike. I don't have those options on a non-ebike.

If you are at PAS 5, it will hover at 21.xx mph and if there is a slight downhill and your speed goes above 23 mph the power bar goes down to zero. It's like a cruise control, the faster you are above target speed, the lesser the power assist, the lower you are from target speed, the higher is the assist from the motor.

Here are the approximate target speeds at different PAS levels (varies proportionally with state of charge of the battery).

PAS 1 = 13.xx mph
PAS 2 = 15.xx mph
PAS 3 = 17.xx mph
PAS 4 = 19.xx mph
PAS 5 = 21.xx mph
PAS 6 = 23-24 mph

Each bar of the power meter represents 2 amps. There are 6 bars total so the peak power at full charge is something like 640 watts (calculated as 54V full charge x 12amps). That's the electrical output from the battery but that is not the actual mechanical power from the motor. The actual mechanical power (also in watts) is calculated as Power (kW) = Torque (N.m) x Speed (RPM) / 9.5488. Not all electrical watts is converted to mechanical watts. There is real world efficiency factor of 70-80 percent (depending on speed and load). So that peak electrical output of 640 watts may actually be only 510 mechanical watts at the motor.

 

[Figs]

I have the Ui6, same battary/motor as the Metro. I am amazed at the range. I was hoping for 40 mile range as that would cover most of my rides. But I regularly get 65+ miles on PAS 2. And even then I still have 2 bars.

Exceeded my expectation.

 

[Citycrosser]

I've observed that the battery indicator on the LCD screen reads lower than actual. For example, yesterday the LCD screen indicated 44.9 volts but a multimeter read the voltage as 45.5. I'm curious if anyone else has noticed this. I think the BMS is erring on the conservative side.

 

[Figs]

@Mark Peralta - I find your pas speeds pretty accurate on my Ui6. Thanks for the info, it’s helpful to know as I like to peddle above the cutoff for cardio/strength benefit.