But we know the battery will not give up all it's 630wh's as Deep SOC is prevented and at a modest 0.5a draw 550wh is about the capacity, the last 0.4v of capacity to 2.8v only containing 80wh or so.

At 1a draw 530 wh is the capacity, most bikes in PAS 1 won't replicate the 0.2a discharge rate the graphs show us and 0.4a - 0.5a is amore likely rate.

Edited September 24, 20196 yr by Nealh

But we know the battery will not give up all it's 630wh's as Deep SOC is prevented.

o

True but the Panasonic cells are usually conservatively graded, they guarantee a minimum, so that you may be pleasantly surprised, not disappointed. Also, the 6.6WH/mile is an high estimate.

I wonder if John would want to ride it until it's totally flat?

John can get a theoretical range by riding till sag causes first LVC intervention then note mileage, at this point allow the sag a few secs to rebound above LVC then cycle off home using lowest assist. Once sag induces LVC then it is an indication of cell stress esp in higher PAS level, at this point one should be thinking low PAS (lower current draw) to see you home.

 

A one off discharge will do little harm at low to mid current draw, it is high current draw that will cause damage.

Any one using a battery to low SOC below the nominal voltage to LVC should do so at a very low assist rate so as not to stress cells, then you can eke out the wh's a bit more.

 

As we know the cell rating (amps) and mah(capacity) rating doesn't mean you can have the best of both worlds, even in 5P config you can't have both (all the power and capacity out of a battery), early on whilst voltage is high the user is best to use the current but as the voltage lessens you have to be more conservative with usage. It all depends on terrain and usage, if more of a touring type long range ride then frugality is what is needed, if short rides you can harvest more of the power.

Edited September 24, 20196 yr by Nealh

Asking again in case anyone who knows missed my question before. What are the trigger voltages between steps on the KM529 battery meter, and for flashing E?

Asking again in case anyone who knows missed my question before. What are the trigger voltages between steps on the KM529 battery meter, and for flashing E?

 

I have the programmer to flash the King Meter LCDs and Lishui controllers but don't have the software to edit the settings.

I have the programmer to flash the King Meter LCDs and Lishui controllers but don't have the software to edit the settings.

By 'flashing E' I meant the signal that comes up when the battery is very nearly empty; nothing to do with changing the firmware. I don't want to change the voltage levels, just wondered what they are to help me interpret what the battery level is telling me.

No update today folks as I'm a fair weather cyclist, so some further clarifications and queries.

 

1) USEAGE SO FAR - I don't claim to be an athlete, though my legs are fine but perhaps slowed down by my 73 year. My riding in the 61 miles has not been lazy - I try to put some effort in all the time. I tend to keep between 12 and 15 mph, nearly always on power setting 3. I've used setting 5 just for a few seconds on a couple of short hills only. Low wind speeds most of the time.

2) KING METER INDICATIONS - Why did my meter still say FULL after 30 miles? This seems to contradict all the reducing voltage graphs etc that you are all talking about?

3) PERCEPTION OF POWER GENERATED BY THE MOTOR - I've noticed that quite often the motor is very quiet, certainly quiter than my previous crank drive bike. almost to the point that I thought it might have cut out (lower than the cut off point) Does that mean that the power has reduced significantly to reflect the situation? Can Woosh explain how this works as I don't understand how the power is produced? Is it pedal pressure or a sensor somewhere? Thanks

4) SINE WAVE CONTROLLER - what are the characteristics of this controller? How is it different from my previous (non sine wave?) one?

5) ANTICIPATED FINAL FEW MILES - So it would be preferable then, at a certain mileage, to reduce the power, to reduce any adverse effects on the battery? I'm not wanting to break any battery range records as I'm really pleased with the performance. So the plan is to do another 10 miles, recheck my voltage and then perhaps recharge at that point.

6) COMMENT ON REAR HUB DRIVE - I keep reading about hub motors been inferior to crank drives on hills? Frankly I've been impressed so far in this respect with my rear hub motor, and I can't realy say that I've had to push any harder on hills than before

I keep reading about hub motors been inferior to crank drives on hills?

 

there are 7 years of progress in the motor and controller between your two bikes.

1. Although greater range isn't an issue try a test by comparing PAS 2 vs PAS 3, do 20 miles or so in each PAS having fully charged the battery each time then note the voltage of each test. You will likely find that PAS 2 is sufficient and only higher PAS is needed for inclines.

2. The meter readings aren't very linear, though saying that the KT ones are a bit better at giving a better idea of range left. The only way of knowing battery level is an lcd with voltage read out or the use of a watt meter to shoe ah/wh usage.

3. With PAS as you reach the speed cut off or the motor rpm threshold point, power/watts supply by the controller ramps down. You see this with an lcd showing watts supplied.

4. Sine wave uses a different signal and provides smoother power to the motor vs square wave/unsensored drives, the three main sensors in the hub/controller communicate signals for a quieter smother drive.

5. Once you are more tuned in to the what the lcd tells you battery state wise and you are more accustomed to what to expected range wise, then yes it is better to manage your battery discharge by using a lower PAS level to be kinder to the cells. Being kinder to the cells/managing the discharge will maintain capacity longer over the batteries life.

6. Not all hubs are the same , some do the job better then others. Winding speed/rpm is one major factor.

3) PERCEPTION OF POWER GENERATED BY THE MOTOR - I've noticed that quite often the motor is very quiet, certainly quiter than my previous crank drive bike. almost to the point that I thought it might have cut out (lower than the cut off point) Does that mean that the power has reduced significantly to reflect the situation? Can Woosh explain how this works as I don't understand how the power is produced? Is it pedal pressure or a sensor somewhere? Thanks

the controller and pedal sensor work the same way as before, the main difference is the new motor has Hall sensors, making low power delivery much smoother and quieter as the electrical pulses are delivered much more accurately at low speed.

The quality of the ballbearings is also higher.

That why the new motor is quieter.

For optimum range, keep assist level low and use the throttle to boost power when you climb.

2. The meter readings aren't very linear, though saying that the KT ones are a bit better at giving a better idea of range left. The only way of knowing battery level is an lcd with voltage read out or the use of a watt meter to shoe ah/wh usage.

Are the meter readings linear in voltage (which is non-linear in capacity remaining because of the nature of the battery discharge)? Or not even linear in voltage?

 

An lcd with more precise voltage read out would give more information than the 5 bar voltage range; but would still suffer from the nonlinear discharge and the effect of load on voltage so need careful interpretation. A watt meter would clearly be able to be much more accurate.

 

With our 13ah 36v Samsung cells battery on the tandem we typically see a two bar drop on the meter between gentle 12mph pedalling on the flat on PAS 2, and moderate hill at 8mph on PAS3. We usually recharge when the meter gets to 3 bars on the flat, 1 bar on the hills. Not sure what it would be like on the hills if we let it get down to 1 bar on the flat.

With our 13ah 36v Samsung cells battery on the tandem we typically see a two bar drop on the meter between gentle 12mph pedalling on the flat on PAS 2, and moderate hill at 8mph on PAS3. We usually recharge when the meter gets to 3 bars on the flat, 1 bar on the hills. Not sure what it would be like on the hills if we let it get down to 1 bar on the flat.

 

This is voltage sag and is normal with the 3 bars, the Samsung 13ah will use the very mediocre 26F cell. One to avoid in the future unless you parallel 10 together.

The latter of indicated one bar doesdepend on the cells used some will hit lvc on a hill if high current is asked of it, others will cope.

My Panny PF cells cope nicely at lower voltage on hills, at 35- 36v they sag a little with current demand but don't hit LVC.

2) KING METER INDICATIONS - Why did my meter still say FULL after 30 miles? This seems to contradict all the reducing voltage graphs etc that you are all talking about?

The 4 bars are might be divided into 4 equal steps or they might be set at arbitrary voltages, like mine. I think mine are something like 39v, 37v, 35v and 33V. The first step from 42v to 39v is a bit bigger because batteries drop to 41v very quickly before stabilizing into a steady ramp down, as you can see in the graphs.

 

So, I ride for 30 miles while the voltage drops from 42v to 39v, then the first segment goes out, then I ride another 20 miles and the second segment goes out, 15 for the third and 10 for the fourth when my battery is at 33v. At that point, if I try to take any significant power from it, the voltage sag drops it to the cut-off point. I can limp for a maybe a couple of miles with the power turned right down, but the ramp has already turned down much steeper, so there is very little left.

Interesting. From battery performance graphs you and other have posted (*) it looks as if 33v really is near the battery dead point. I've never dared get it so it was down to the last bar when riding without much load. We are getting much lower mileage then you say even at mostly PAS2 of 5; but it is a tandem and 13aH battery, and not working ourselves that hard. And as Nealh says, probably not the best cells in that battery.

 

(*) https://www.pedelecs.co.uk/forum/threads/is-the-extra-5-amps-chewing-up-my-range.35664/#post-520066