PAS vs TAG for distance

[EwanG]

My morning ride is 10 miles, and my afternoon ride back is 13 to avoid traffic. I can almost ride the whole way in on TAG just by using the throttle carefully and coasting when I can. In the afternoon I have to add some pedaling just to make sure I have juice for the final hill. Bike is a Currier eZuma step through with a 36V system driving a 500w rear hub motor.

Given that on the longer ride I am doing full throttle some of the time, pedalling with and without assist part of the time, and coasting part of the time I have assumed that I am getting as much distance out of the battery as I would using PAS which works at 50% almost non-stop. But is that correct? Am I burning up more battery that way than I think? I ask just because it would be interesting/helpful if I didn't have to recharge every time - and if PAS would let me get significantly more distance I could possibly skip the recharge at work...

Would appreciate hearing folks with experience, though thoughtful speculation would also be welcomed

 

[Eskimo]

I have tried both. Standard 25 km/h allowing PAS is very economical on flat ground rides. You can go over the horizon with it, but it"s....you know...25 km/h
Second thing what i found was that it"s hard to make standard cheap PAS to work well. It engages randomly and after like three crank revolutions, sometimes refuses to engage at all, sometimes gives full 1000W boost on walking speed suddenly, sometimes on a steep hill gives only 200W, etc. It just made me mad pretty fast. Throttle is way more user-friendly, it gives you what you want.
I would try it again if i would find one which engages off around 35-40 km/h, and would work well otherwise. Maybe Thun or something is required for that.
But on flat ground, steady cruise, it"s very economical when it delivers.

 

[Punx0r]

The only way to increase range is to require less effort from the motor. Either by pedalling more or slowing down.

If you're being "lazy" with pedalling then PAS might force you to do more, but if you're already working hard then PAS might cause the motor to work harder. Some PAS systems have an adjustable level of assist, complicating the issue further.

A throttle lets you adjust assist infinitely between 0-100% but relies on the intelligence of the operator to maintain the level of assist you want.

 

[friendly1uk]

Intelligence? I just have to twist mine. I prefer pedal assist though.

Pas works in a number of ways. I'm using a ku65 atm, with 3 levels, or rather 3 speed targets. It expects no effort from me, It just wants to know the pedals are turning, then it takes me to speed 1 2 or 3. No nasty surprises.

The latest cheap controllers (the S-Series) are offering led displays with 5 levels of power assist, Or 3 levels using the cheaper led displays. Or you can pop in advanced settings are choose 5 speed targets instead of 5 power levels. I like a nice steady 20mph on good quiet bike paths, So being able to just select that speed and do as much or as little myself works really well. Downhill I will pedal to them speeds so the motor cuts off, un-needed. Up hill I might decide t just turn the pedals, making the motor do all the work to reach my speed target.

I don't like the all or nothing approach. It seems a very poor solution. Either full assist or nothing only works if full power is not too much. Often it will be, like moving through obstacles.

I don't like the system that looks how fast you are pedaling either. Offering proportional assist. So you simply must put in some effort.

I have not tried the S-series yet, but I expect they work how mine does. Achieving a pre-selected speed regardless of rider effort. The pedal just need to be moving. So you can contibute as little or as much as possible. Alternately it can be used as it comes to offer a fixed amount of effort, chosen on the scale 1-5




Does this bike have no means of telling you what is in the battery? I find my Ah meter a very important £10 tool. It gives a real good idea of what's left. Don't think I could get by without good battery metering. Perhaps that is what you need. I feel quite sure it would be money very well spent.

 

[GiantEV]

I have a cheap HobbyKing Wattmeter on one bike and a CA3 on another bike. They both are great tools to show you how much power you're using in a given condition. It helps you realize just how important speed is to power usage. Slowing down really does help a lot to increase range. The nice thing about the CA3 is the ability to limit power and speed, which in turn increases range.

I have ridden a couple of PAS ebikes at some bike shops here in town, but none of my ebikes use PAS. However, I don't believe you will see as big of gains switching from TAG to PAS as you would monitoring your power usage; mainly how heavy you are on the throttle during acceleration, and your cruising speed. This is where you can see some big gains in your range.

I would also advise against NOT charging at work. If you have the opportunity to charge at work, I would take advantage of that in order to increase the life of your batteries.

 

[Drunkskunk]

PAS requires human input, therefor you are contributing power to the ride. if you don't pedal all the time with a TAG, then PAS will get you farther, but with more effort on your part.

How much further depends on how fast you ride. if you're doing 30mph, consuming 800-1000 watts from the battery, and only contributing 50 watts by pedaling, then it's extra range is going to be ~5% versus a TAG with no pedaling. However if you ride at 15mph, using 50 battery watts and contribute another 50 pedaling lazily, you'll get twice as far as TAG with no pedaling.

 

[Avitt]

You can get a pretty good estimate with this simulator: http://www.electricbikerange.info/Electric_bike_range.html

Enter your route, and bike parameters. Then enter 0 watts and 100 watts into the "biker" parameters, and look at the difference in battery consumption...It should provide a fairly accurate answer to your question.

 

[Gregory]

For dummies like me reading this thread, TAG stands for Twist And Go. i.e. throttle.

Never heard that one before.

 

[Avitt]

For dummies like me reading this thread, TAG stands for Twist And Go. i.e. throttle.

Never heard that one before.

I didn't know what it meant either...Just assumed it was throttle-only.

 

[EwanG]

You can get a pretty good estimate with this simulator: http://www.electricbikerange.info/Electric_bike_range.html

Playing with this I get a "Very Low" rank for "Battery Capacity Failure Risk", but a "High" risk for "Battery Power Failure Risk". Since I can't find any definition of the terms on the site itself, is it possible to get an explanation of what this is trying to tell me?

My guess is that it's saying I won't run out of juice, but the fact that there are some significant hills toward the end of my ride means it might cut out going up hill due to too much draw at one point. Correct guess? If so, is this where a 48V would make a significant difference, or is the battery fine and I need to look at upgrading to a 750W or 1000W motor?

Thanks for all the education!

 

[Avitt]

I think you're probably right. The failure risk is probably based on the "C" rating of the battery, and the power requirements for your ride...But I'm not sure about that.

 

[dogman dan]

Bottom line is, to extend range ride slower. And pedal too extends range further. I never found throttle and coast to be as effective for range extension as slow down slightly and keep the pedals churning at moderate effort.

Only one way will show which is more efficient, with you riding. That is to get a wattmeter. The way that gets you the best watthours per mile is going to have the longest range. The wattmeter won't lie, by comparing wh/mi, you get the real answer, for how you ride, where you ride.

In general, you can extend range a great deal by slowing down a small bit. It's quite amazing to see on a wattmeter the difference between a 20 mph cruise and an 18 mph cruise. You may not have to ride 15 mph to get great range. But if you run 22 mph all the time, it can cut your range a lot more than 2 mph more justifies. Cost of battery alone is a good reason to ride 20 mph or less.

It is of course fun to have 30 mph. But my wh/mi at 30 mph is pretty horrible. It's a lot more cost per mile for the battery to fly.