Inaccurate LED or controller problem?

B

bbells

10 mW
Joined
May 14, 2016
Messages
20
Sorry if this has been asked before. I can't find it in a search.
I have a 48v direct drive ebike that I just built. I put in 2 10,000mah 6s lipos in series with Anderson Powerpoles - Equals a 12s lipo @ 10k.
My voltage when I start out is 50.43. The kit specs show I should be able to go somewhere between 18 and 25 miles without pedaling.
I am guessing that the controllers low voltage cut-off is probably 42 volts. There are no specs on this in the kit.
When riding only about 2 miles my cheapo 4 light LED display goes from 4 lights to 1 light, even when I let up on the throttle. My voltage at that point is about 47.8. I am just doing test trips, but one trip my throttle cut off not too long after the LED went to one light.
My controller gets warm, but not hot. It is 26 amps.
I have checked for brake drags, etc. The wheels turn freely when raised up.
Question(s): Are the LED power meters this inaccurate? Is this a controller problem? Is there a way to change the LVC - It appears mine must be about 47v?
Thanks for any help!

My kit is similar to this one, except I have the 700c wheel.

http://www.ebay.com/itm/48V-1200W-D...hash=item3f6129be88:m:maVtvUbV80w8ypxyD8l3h4A
 
I am using lipos not life batteries. Lipos fully charged are 4.1 to 4,2 volts. Life are just 3.5 or 3.6.
I can easily do 13 or 14 with batteries on hand, but 14s lipos are 59 volts and 13s lipos are 55 volts. The 12s being 50.4 volts should be adequate, especially with a 42 volt LVC. Am I missing something here?
 
12s LiPo is fine for 48v motors. I'm running 12s LiPo with a 42v cutoff controller, no problem.
The low voltage you are getting after only 2 miles sounds like a false positive phase combo. Is it fast top end but sluggish low end? Noisy? Might be wrong color combo. Are the phase wires, controller or the motor real hot? Did the kit come with instructions?

the leds on a throttle were setup for lead batteries and since you are running 12s it is much more misleading.

All the range BS is just what it is BS. You can go 50 miles by pedaling hard at low speed but who wants to do that!?

There are ways to lower the LVC but I don't know your controller. Others are much smarter on this than me. I have the programmable ones for that reason.

Dan
 
bbells said:
When riding only about 2 miles my cheapo 4 light LED display goes from 4 lights to 1 light, even when I let up on the throttle. My voltage at that point is about 47.8. I am just doing test trips, but one trip my throttle cut off not too long after the LED went to one light.
Click to expand...

If you have a wattmeter, how many Ah (or Wh) does it say you used? (vs how much charge you had in the battery pack)

Also, how well-balanced are the packs you are using, and how fully charged are they?

Question(s): Are the LED power meters this inaccurate?
Click to expand...

Many of the LED meters seem to be made for SLA batteries, so may not read as expected for lithium types. Dunno about your kit but the ones I've used didn't read right for my lithium packs.



To see what your actual controller LVC is, you'll need to hook up a voltmeter to the battery, preferably at the input to the controller itself, and run the bike until it cuts out, watching the voltmeter to see what it reads when this happens.

I would do this with the bike just upside down in your testing area, so you don't ahve to try to watch the meter and ride at the same time. It's important to catch the reading just before the actual cutout, becuase it'll probably jump up in voltage as soon as it does, and then you won't know exactly what it cutout at.

If you have a wattmeter then it may have "Vmin" readout, and will keep this reading even after the cotnroller stops working from it's own LVC, so you can do this test while riding or stationary.


To make the test easier/shorter, you can first ensure your packs are only charged up to something near what you suspect the LVC is.
 
Where are all the Lipo gurus who talk newbies into going with Lipo batteries ?
They are fugitives in hiding now.
As if the balancing and other pack issues are not enough complications.
The optimal pack size for the common 48V kits, and the attendant battery cutoff circuit, is 13S, which goes really well with the 1s-6s charging equipment available.
 
Eteck said:
Where are all the Lipo gurus who talk newbies into going with Lipo batteries ?
They are fugitives in hiding now.
As if the balancing and other pack issues are not enough complications.
The optimal pack size for the common 48V kits, and the attendant battery cutoff circuit, is 13S, which goes really well with the 1s-6s charging equipment available.
Click to expand...

RC Lipo is fine as all the connections are standard JST for balancing, lipo bricks are modular so you can mix/match (eg 7s + 7s or 6s + 8s) for better frame placement. If you think RC LiPo is difficult to build your own packs, the alternative is 18650's a bunch of nickel strips and a battery welder... standard RC Lipo comes with a high enough C rating for most ebikes in a 1P configuration (eg 5Ah 25c for small packs if you only need 30-40km range).

I should make a RC Lipo guide for newbies with step by step instructions to not frock up...
 
We were out riding our bikes man, what did you think?

12s lipo is at least one cell less than your meter is calibrated for. So you start out 4.2v less, and it reads empty too soon. Like about three people told you already. Similarly, you are hitting the lvc early as well. The batteries sag enough under load to hit the controller lvc, then snap back to 47v when you stop.

For running lipo, ignore the cheap meter that came in the kit, You need a watt meter, or at the very least a voltmeter that reads in volts.

But to solve your lvc issue, adding 2s packs to your battery will make it a 14s, and that will give you more speed, a bit more range, and a setup that can be drained 100% without hitting lvc.

But then, you will have to watch your voltage, and not over drain your battery.
 
Thanks for all the responses.
So, let me get this straight. Fully charged lead acid batteries are about 55.2 volts. My 12s lipos are 50.4 volts. I can understand the meter being calibrated for the higher voltage, but not the lower end. The lower end should be somewhere near 42 volts when the last light flickers. But, you are saying that even though my voltmeter is showing the lipos are not going below 47 volts while in use I still need an extra cell? Doesn't compute, but I can live with that. I have dozens of lipos around my house. It would be easy for me to add more cells.
But, I am NOT looking for maximum performance. I am perfectly happy with the 12s speed and power.
From what I understand, if I ignore my power meter and just continue riding my power should not cut out until I hit the LVC. But, my controller is cutting power when my VOM (while the bike is running) is showing 47 volts. Is that common? That is the part I do not understand and that makes me think there is a problem with the controller. And that makes me want to change the LVC of the controller, if it is possible.
 
bbells said:
So, let me get this straight. Fully charged lead acid batteries are about 55.2 volts. My 12s lipos are 50.4 volts. I can understand the meter being calibrated for the higher voltage, but not the lower end. The lower end should be somewhere near 42 volts when the last light flickers. But, you are saying that even though my voltmeter is showing the lipos are not going below 47 volts while in use I still need an extra cell? Doesn't compute, but I can live with that. I have dozens of lipos around my house. It would be just as easy for me to add another 6 cells as 1 or 2. From what I have read on the net it appears if the controller can handle 55v, it should be able to handle 75v correct?
Click to expand...

No on the 75. Most 48v controllers have 63v caps and the fets are maybe 75.
I guess I read it wrong but I didn't see that you hit LVc at 47v. If so you might have a really bad cell in a pack.
I have been running 12s 16ah Multistars for a year now. have gone 42miles at an average speed of 15mph. About 250 weight of bike and me. 8 turn MAC 26" wheels but big tires so almost 28". No way should you be killing a 10AH pack in a couple miles. Oh one other thing, my peak amps on my CA is 50amps. So no way am I babying them. Another thing is that they test at almost the 16ah after a year.

So either your batteries aren't charged fully, bad cell or you have a problem with the setup. Forget that led crap, it doesn't work right. As others said you need a way to see when the battery hits LVC and if it's that fast you have a problem with the motor, controller. How fast does it go? And how hot is the motor, controller and the battery. If they are hot to touch it's a problem. Asked before about wiring and did they supply and directions as how to wire it?

Dan
 
Thanks Dan. Your post helps. Yep, it is clear now that the LED display is not accurate. It is pretty much just an on/off switch. The stuff in your post is why I was thinking something was wrong. I tested my cells with a cell tester after running and they are all within 1/10 of a volt. I have triple checked the connections with my 12s setup. Checked wires, connections, batteries and controller for heat. Ran with my VOM connected (waiting for volt display to be delivered). That is why I am leaning towards a controller with an LVC that is too high. I will do another test later today with my controller out in the wind in case the problem is temperature related.

FYI: Sorry, I edited my previous post to the following while you were writing your response:
"But, I am NOT looking for maximum performance. I am perfectly happy with the 12s speed and power.
From what I understand, if I ignore my power meter and just continue riding my power should not cut out until I hit the LVC. But, my controller is cutting power when my VOM (while the bike is running) is showing 47 volts. Is that common? That is the part I do not understand and that makes me think there is a problem with the controller. And that makes me want to change the LVC of the controller, if it is possible."
 
If you have the controller inside a bag or something, it's likely over heating and that's why it's cutting out before reaching lvc. That controller also looks like a smaller 9 fet controller, so it may not be rated for a full 1000W. That could also cause it to overheat and cut out if used a full power too long. These controllers should not be enclosed. They need free air to cool them. 42V is common lvc for 48V controllers. That's perfect for 12s lipo.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=47294
 
12S is no problem witha 48v kit. The cut off voltage will be something around 39v, which is a OK for 12S too. Your LED battery meter will read incorrectly, because it's expecting 13S. That's why the lights go out so early. Whenever using lipos, it's a good idea to use a wattmeter to show the voltage and the amp-hours you've used so that you can judge how much further you can go because once the lipos go below 44v, they accelerate downwards.
 
Thanks guys. Here is what I found out in my latest test:
It goes down to 1 LED at 48v, 50.3 has all 4 LED's lit.
I put the controller outside the bag and had no cut out at 47v. Did not get warm at all, but it is only about 45 degrees F outside.
Before riding I noticed a crimp in the yellow wire going to the motor. I cut it out and re-soldered a connector on it. This could have been the cutout problem. Maybe, maybe not.
I rode without pedaling 5.4 miles on a very hilly road. Starting voltage was 50.3, ending 46.7. That would be about 1.5 miles/volt. So, if my math is accurate, if I ride down to 42v I should be able to go about 12.5 miles on a hilly road without pedaling. That is acceptable to me so I figure whatever was wrong is fixed. If I need to go further I will add a couple more 10K 6s batteries I have laying around.
I think the key was when you guys told me 3 things: The LED's are inaccurate on both ends. 12S should be fine with a 48v system. And, that the controller needs a flow of air to keep it cool.
Thanks!
 
3 things: The LED's are inaccurate on both ends. 12S should be fine with a 48v system. And, that the controller needs a flow of air to keep it cool.
Click to expand...

Just 3 problems with this assessment.
There is no proof your LED's are inaccurate since "My voltage when I start out is 50.43" which is a little less than the meter is meant for.
If 12S is "fine" why are people saying you need to add some more S ?
"but one trip my throttle cut off not too long after the LED went to one light" this is totally normal behaviour and not necessarily controller heat related since
the voltage meter is in the throttle control or your main display and not around a would be hot controller.
 
Eteck. I don't agree.
1) Accuracy of LED: At full charge all 4 lights are on and it goes to one LED when the voltmeter shows 48 volts. When it cutout the voltmeter showed 47 volts. Since the LVC is supposed to be 42 or 47 volts, the cut off was not normal behavior and the LED was inaccurate since there should only be a single LED at around 44 or 45 volts.
2) People have opinions. 12s appears to be fine on my system and many others have said the same. A quantity of people saying something different has nothing to do with facts, it is just opinion.
3) I mentioned the cutout could have been heat related or a crimped wire that I cut and re-soldered before the last test. Or maybe a combo of both.
 
1) Accuracy of LED: At full charge all 4 lights are on and it goes to one LED when the voltmeter shows 48 volts. When it cutout the voltmeter showed 47 volts. Since the LVC is supposed to be 42 or 47 volts, the cut off was not normal behavior and the LED was inaccurate since there should only be a single LED at around 44 or 45 volts.
Click to expand...
The cutoff is usually the job of the controller not some cheesy bar graph voltmeter on your handlebars.
I guess your LCD display or whatever could also could have system cutoff priveleges. I don't know. If it doesn't then you could have multiple problems.
At any rate the bike LED meter will be a little different with different battery types/ cells so that can be confusing in it's own right.

2) People have opinions. 12s appears to be fine on my system and many others have said the same. A quantity of people saying something different has nothing to do with facts, it is just opinion.
Click to expand...
Well it is worth noting though if that's the info/advice that will come up. The low voltage cutoff of 40-42 volts is compatible with Lipo 12S protection since for example 12x3.3=39.6V.

3) I mentioned the cutout could have been heat related or a crimped wire that I cut and re-soldered before the last test. Or maybe a combo of both.
Click to expand...
I agree, poor or corroded battery connections could probably cause the problems the thread describes, which would have nothing to do with the LED V reading
mumbo jumbo, unless, once again you had multiple problems.

Eteck. I don't agree.
Click to expand...
It's your thread, I'm just commenting.
 
Etek. please reread my posts and the others in this thread. I take it English isn't your first language?
FYI: The LED just shows power left in the battery. In my case the LEDs go out at about 47.3 volts. The controller controls the cutoff. But, and I don't know how to say this any clearer, there is a relationship between voltage and the voltage cutoff. If the voltage gets below a certain point the controller cuts off the voltage. If the LEDs are inaccurate they do not reflect the actual power left in the battery so the voltage cutoff should be several volts after my LEDs go off. No where has anyone in this thread said that the LEDs control the LVC. That is ludicrous.
When I say voltmeter, I mean voltmeter. Not the LEDs. The voltmeter showed the cutoff happening at 47 volts. This was soon after the LEDs went off. It did not show 40 volts or 42 volts.
And yes, people already mentioned the LVC is perfect for 12s on a 48v system.
Please read the entire thread before saying anyone is wrong or giving an uninformed opinion. Thanks!
 
before saying anyone is wrong
Click to expand...
I'm not saying that. What I would say is that this thread reads a little confusing.
You are assumedly all caught up in an actual problem so maybe you can't see that right now.
 
Raged said:
48v requires 13S or 14S. 12S is for 38v kits. You need to buy an additional 2S battery to bring the battery up to specifications for that motor.
Click to expand...


This isn 't correct... 12s is 50.4v fully charged... and is perfectly fine, and in many cases more optimal than 13s or 14s. The "juice" often isn't worth the squeeze, especially if you are using 4s bricks.
Eteck said:
Where are all the Lipo gurus who talk newbies into going with Lipo batteries ?
They are fugitives in hiding now.
As if the balancing and other pack issues are not enough complications.
The optimal pack size for the common 48V kits, and the attendant battery cutoff circuit, is 13S, which goes really well with the 1s-6s charging equipment available.
Click to expand...

12 s is just fine to use. His issue is with the meter on the throttle, not him needing 13s as much. Never trust the throttle LED anyways. Get an actual meter on the handle bars showing amp draw and voltage.

I have over 13,000 miles on a bulk charged 40Ah pack of 12s. I go literally 6 months without having to balance anything. A properly put together, broke in, and balanced pack will stay for a long time. Using regen can shorten the time things stay in balance, but I even use regen for 70% of braking and slowing down. I've only replaced 2 bricks out of the pack during that time, and they are only out like .07 or so on one cell on each. I still use them on projects and they are fine. I had spares so I swapped them out while I had everything apart checking cells. Again, a pack build of quality cells will go for a long, long, long, long time in most cases without issue.
 
Eteck, if you need clarification ask for it rather than making inane comnments. Everyone else understood it with no problem.
 
10Ah can be lean on a lot of systems. My throttle LED is the same way on my Magic pie 3. It is setup for 13s stock, but I run 12s. For all those building new packs, the more Ah you have the better they stay in balance as well. The more often you run the pack down real low, the more often you risk going out of balance. I think the lowest I've ran the pack is 45.6v when testing to get a rough idea of range at full throttle, which is how I always ride it. Cruise control set max throttle 90% of the time. lol
 
Eteck, if you need clarification ask for it rather than making inane comnments. Everyone else understood it with no problem.
Click to expand...

Request for clarification sir or ma'am:
In my case the LEDs go out at about 47.3 volts ... The voltmeter showed the cutoff happening at 47 volts
Click to expand...
After all this expert troubleshooting throughout this thread, what exactly do you attribute the coincidence to that:
both the meter read low unfit battery AND the controller cut out at about the exact same 5-7 volts above the normal 40 to 42V ?
Could someone clarify in detail so we may learn from your wisdom ?
 
What can not be posted here?
DON'T post personal attacks based on sexual preference, religion, nationality, race, etc
I take it English isn't your first language?
Click to expand...

3. Posts, topics, reply, or profiles which go beyond simple expression of opinion and edge toward unfounded accusations will be removed. Repeated problems with a user will result in account termination. Everyone is entitled to their own opinion but don't take it too far.
saying anyone is wrong or giving an uninformed opinion
Click to expand...

Since I never said anyone was outright wrong and since I own a kit from Ebikeling, it seems you don't know what your accusing me of.
I think the mods should step in and put us both in our place here as needed.
 
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