Battery draining 2x as fast on DD motor with similar controller

Hey all,

I have 2 ebikes I use the same (new) battery on. One has a TSDZ2 which I believe is 15 or 18 amp controller. I could ride to work and back (one way) on this about 4-5 times, so I'd charge every second day.
The second is a DD front hub motor with a 15 amp controller (max 30 amps) @ 48v. I can only ride there and back once before battery is nearly dead.
On the TSDZ2, I had the stock firmware set to max. On the DD motor, I only ride at about level 2-3 which is plenty fast.

Pic of DD controller specs:




The battery is draining almost exactly 2x as fast. This means I have to charge after every commute since it nearly kills the 11.6Ah 48v battery.

I assumed since this controller is similar the battery would last about the same? Obviously not though. For the record, I am only running at level 2 or 3 on average, not maxing it out. My speed is not 2x as fast that's for sure.

So my question is: What is going on here? Is this controller just that much more "power hungry"? Can I perhaps install firmware on this controller (it's a KT controller) to limit the power a bit?

Aquakitty said:

I have 2 ebikes I use the same (new) battery on. One has a TSDZ2 which I believe is 15 or 18 amp controller. I could ride to work and back (one way) on this about 4-5 times, so I'd charge every second day.
The second is a DD front hub motor with a 15 amp controller (max 30 amps) @ 48v. I can only ride there and back once before battery is nearly dead.
On the TSDZ2, I had the stock firmware set to max. On the DD motor, I only ride at about level 2-3 which is plenty fast.

Click to expand...

Without a wattmeter to watch what's being drawn by each system under various conditions, it's tough to say what's really happening.

But the most likely thing is that the DD system is using more current for longer during acceleration and hill climbing, and if there are any headwinds.

Pic of DD controller specs:

Click to expand...

Can't see the pics, but if you use the attachments tab and upload the files directly to the forum, they'll be visible to anyone that can see the post itself.

nearly kills the 11.6Ah 48v battery.

Click to expand...

Another issue is that if the DD *is* using significantly more current for whatever reason, it's going to be harder on the battery, sag it lower in voltage under load, making it cut off earlier, and also getting less total capacity out of it as some of the power is wasted as heat inside the battery. If the cells are not all well-matched, it''ll also unbalance the battery more.

You're riding faster and accelerating harder with a motor that spends more of its time in less efficient territory.

Also, the controller only puts out what you ask from it so idk why a pic of the controller is relevant.

If you're using twice as much power to do the same job, something is getting really effin' hot. That extra power is going somewhere.

Maybe verify correct hall/phase wiring?

amberwolf said:

Aquakitty said:

I have 2 ebikes I use the same (new) battery on. One has a TSDZ2 which I believe is 15 or 18 amp controller. I could ride to work and back (one way) on this about 4-5 times, so I'd charge every second day.
The second is a DD front hub motor with a 15 amp controller (max 30 amps) @ 48v. I can only ride there and back once before battery is nearly dead.
On the TSDZ2, I had the stock firmware set to max. On the DD motor, I only ride at about level 2-3 which is plenty fast.

Click to expand...

Without a wattmeter to watch what's being drawn by each system under various conditions, it's tough to say what's really happening.

But the most likely thing is that the DD system is using more current for longer during acceleration and hill climbing, and if there are any headwinds.

Pic of DD controller specs:

Click to expand...

Can't see the pics, but if you use the attachments tab and upload the files directly to the forum, they'll be visible to anyone that can see the post itself.

nearly kills the 11.6Ah 48v battery.

Click to expand...

Another issue is that if the DD *is* using significantly more current for whatever reason, it's going to be harder on the battery, sag it lower in voltage under load, making it cut off earlier, and also getting less total capacity out of it as some of the power is wasted as heat inside the battery. If the cells are not all well-matched, it''ll also unbalance the battery more.

Click to expand...

Hi, I've attached the image. So basically, I'd likely need a new controller or battery? It's a 13s4p 11.6AH w/ Samsung 25r cells. Link to cells: https://www.imrbatteries.com/samsung-25r-18650-2500mah-20a-battery/

Cell Specs:

The pic of the controller is relevant because the steps may be greater if the controller has more amperage, no?

Ok I think I've figured out the problem. My battery is made with Samsung 29E not 25R cells, which means the max discharge current is 25a not 30+ like the 25R cells. So this is basically overloading the battery. Is my understanding correct? Batteries 13S4P with Samsung 29E show 10A average and 25 max. So if I am getting up above or close to that it's too much for the battery?
So basically I can just buy a max 25a controller to fix this (or a battery with higher max discharge)?

Edit: Now that I think about this more, this can't be it, could it? My controller is only measly 15 amp continuous. Can someone tell me what a 13s4p Samsung 29E pack should be able to handle?

Aquakitty said:

Ok I think I've figured out the problem. My battery is made with Samsung 29E not 25R cells, which means the max discharge current is 25a not 30+ like the 25R cells. So this is basically overloading the battery. Is my understanding correct? Batteries 13S4P with Samsung 29E show 10A average and 25 max. So if I am getting up above or close to that it's too much for the battery?
So basically I can just buy a max 25a controller to fix this (or a battery with higher max discharge)?

Edit: Now that I think about this more, this can't be it, could it? My controller is only measly 15 amp continuous. Can someone tell me what a 13s4p Samsung 29E pack should be able to handle?

Click to expand...

Depends on a lot of things. I'd open the pack and take a few pictures to be sure. Check out which bms is built in, and how the cells are connected together. Most chinese read to use hailong packs are 15A max though, because they use super tiny bms.

If you add a watt-meter ($20?) you may find that the TSDZ2 only draws 18A very rarely. However, I suspect the DD hub is drawing the full 18A quite often, and for a longer amount of time during acceleration.

spinningmagnets said:

If you add a watt-meter ($20?) you may find that the TSDZ2 only draws 18A very rarely. However, I suspect the DD hub is drawing the full 18A quite often, and for a longer amount of time during acceleration.

Click to expand...

I agree with this.

Did you trade batteries to eliminate any battery related variables?


Sent from my iPhone using Tapatalk

So my question is: What is going on here?

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More then likely you are not riding the same on both bikes. A few mph difference, say averaging 22 mph instead of 19, is enough to do this and wouldn't be noticeable. Also if the pedaling effort is slightly different.

Also if you are more upright on one bike versus the other can make a big difference.

If you want to get down to the nitty-gritty as to why you are seeing differences you need a watt meter or cycle analyst or some other arrangement to measure the energy flowing from the battery to the motor. As well as a accurate speedometer. Then setup a controlled environment were you can maintain a constant speed with no pedaling input and see what the differences actually are.

The preferred way to describe energy usage for a motor is watt-hours per mile at a particular mph speed. Or km if you are metric.

Like:
23 wh/m @ 20mph

Ok thanks everyone. For the record the battery is in a shark pack, not hailong.

I just ordered a watt meter. I have seen it jump to 12-1300 watts in the stock LCD, but at level 2 the average is about 425 watts. Don't know how accurate this is. Obviously it is way more powerful in general than the TSDZ2 but at level 2 that is about in line with my TSDZ2 readings with the open source firmware.

Let us know how things work out.

999zip999 said:

Let us know how things work out.

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Well today after a commute home (I used "2" the whole way except for hill at the end, went to "3") and when I got home, the battery was down 2 bars. This is from a there and back commute of about 12 km total (~7.5 miles). 2 bars of the battery down from using "2" nearly the whole way. There are no hills on the way there, only the way back.

Anyway, I felt the battery and motor, battery not hot at all, motor a bit warm, but the controller was pretty hot. I have it in a waterproof bag. How hot should the controller be getting? I'm totally new to external controllers and whatnot. I'm wondering if it's possible I have some hall or phase wire messed up causing this high battery drain?

There is no doubt even in "2" this system is going way faster than even my maxed out TSDZ2. I'm just checking if the controller being quite hot when stuck in a bag is normal. Not too hot to touch but getting close.

Aquakitty said:

Anyway, I felt the battery and motor, battery not hot at all, motor a bit warm, but the controller was pretty hot.

Click to expand...

That's a pretty short distance to be draining the whole battery. See dustNbone's post above. Bad hall/phase combo could be the issue. The excess energy is going toward heating. I've seen a couple of similar posts in the last couple of weeks.

E-HP said:

Aquakitty said:

Anyway, I felt the battery and motor, battery not hot at all, motor a bit warm, but the controller was pretty hot.

Click to expand...

That's a pretty short distance to be draining the whole battery. See dustNbone's post above. Bad hall/phase combo could be the issue. The excess energy is going toward heating. I've seen a couple of similar posts in the last couple of weeks.

Click to expand...

Yea, I've done a bunch of reading on here since I posted. I guess I could have hit a "false positive" but I don't get issues like lack of torque or anything. When I first installed the motor, the phase wires were definitely incorrect and I swapped them, and it ran fine. I sure hope it's not the hall sensors that sounds like it'll be a giant pain in the rear.
Trying to figure out how to test the amperage to maybe rule this out without having to swap wires 36 times? lol

Aquakitty said:

but the controller was pretty hot. I have it in a waterproof bag.

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I don't recommend keeping controllers inside bags; they usually need airflow (this is why they have heatsinks as their outer casing). Really small ones of a few amps are ok, but when you get to 15-20A controllers and up there's enough waste heat inside them that they do get hot if they don't have airflow to cool them off.

It's unlikely that the heat is causing your problem, but it will age the controller prematurely and can cause them to fail over time.

I'm wondering if it's possible I have some hall or phase wire messed up causing this high battery drain?

Click to expand...

It is possible there is a false positive. You can test it offground with a wattmeter or ammeter (multimeter on 20 amps setting). You should see about an amp or so of current at full throttle with the wheel offground. If it's significantly mroe than that, it could be a false positive.

FWIW, if you did have a hall sensor problem, the motor would probably run rough, if it worked at all. (unless the controller has a "sensorless fallback" mode; a few do, but they also tend to not startup smoothly from a stop unless you're pedalling first).

There is no doubt even in "2" this system is going way faster than even my maxed out TSDZ2.

Click to expand...

If you're going faster you are using more power to overcome air resistance. "Way" faster could easily use twice the power to do that, but since you don't define the speeds in either case, I couldn't tell you what power it should take for either situation.


Between that, and the things I listed in the first reply, it could easily use your batery up at least twice as fast.

amberwolf said:

If you're going faster you are using more power to overcome air resistance. "Way" faster could easily use twice the power to do that, but since you don't define the speeds in either case, I couldn't tell you what power it should take for either situation.

Between that, and the things I listed in the first reply, it could easily use your batery up at least twice as fast.

Click to expand...

Load graph from Grin motor simulator for reference; compare 22 mph (400 watts) vs. 27.5 mph (800 watts):

Yes, sorry. I haven't done a good job of recording the actual speeds. However I can say if I ride with someone on a TSDZ2 motor, I can leave them in the dust on level 2, if they are on say, 11/44 gearing, without expending any extra effort.

I've also purchased a brushless motor tester which might be handy in the future. I will try the amperage thing though. The motor seems very smooth to me. No weirdness. I tried switching the phase wires again just to see and yea, it's pretty obvious when those are messed up. I also did the simple "touch two phase wires together" test and the motor did the proper "rough turning" when each combo was touched together.

I've removed the controller from the bag and will see tomorrow if it still gets hot.

The only other weird thing about the bike build I did is I have the phase wires to the motor on 3 bullet connectors at the moment while I wait for MR30 connectors for them (to enable removing the wheel easily). The hall sensor wires I soldered the 5 into a 9 pin higo-style waterproof connector I had extra from some LCD's. I figured I should not put the phase wires onto tiny wires like that, but I see ebikes.ca does this with their motors so maybe overkill? It's possible I messed up the wires, but I tested them many times when I did it to make sure they were correctly wired. If it is messed up it must be from inside the motor. Since these motors are so ubiquitous, is it that likely they would be messed up? The motor came with decent instructions, though the phase wires needed swapping.

Aquakitty said:

There are no hills on the way there, only the way back.

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If you returned to the same location that is a physical impossibility unless you and the bike rode an elevator part of the way to work.

Check speeds. How much difference is there?
As others have pointed out, higher speed makes all the difference.

John in CR said:

Aquakitty said:

There are no hills on the way there, only the way back.

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If you returned to the same location that is a physical impossibility unless you and the bike rode an elevator part of the way to work.

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Uphills. My bad. Downhill on the way to town, I live in a hilly area.

Another update: On way to work today, I stayed in level 3 and went about 35 KPH (22 miles an hour) average, which is about the max I can keep up with pedalling with my current gearing. The controller was out of the bag fully aerated. It still got very hot.

Aquakitty said:

Another update: On way to work today, I stayed in level 3 and went about 35 KPH (22 miles an hour) average, which is about the max I can keep up with pedalling with my current gearing. The controller was out of the bag fully aerated. It still got very hot.

Click to expand...

How many watts does the stock display show with the wheel off the ground and running WOT? Seems like around 70 watts would be "normal".

E-HP said:

Aquakitty said:

Another update: On way to work today, I stayed in level 3 and went about 35 KPH (22 miles an hour) average, which is about the max I can keep up with pedalling with my current gearing. The controller was out of the bag fully aerated. It still got very hot.

Click to expand...

How many watts does the stock display show with the wheel off the ground and running WOT? Seems like around 70 watts would be "normal".

Click to expand...

It spikes to about 200 on first hitting throttle then steadys at about 63.

I suggest having more fun on your commute. Buy more battery and set the power setting on high. Ebikes can be as fun as an amusement park ride, but with no lines and literally pennies a ride, and still chuckle to yourself about the suckers in their steel cages stuck in traffic. If you really want to stick it to the man, as well as have post-apocalyptic transportation, then get some solar panels to charge your ebike(s).