Ebike shuts down with voltage error code at 500W

[iampaulpease1]

After many posts referring me back to the battery, I've decided to do the arduous task of ripping apart the pack and figure out where I went wrong. My bms wont display cell data all of a sudden so I hope I didn't fry it. I apologize for any spelling errors. I had eye surgery today and can barely read what I'm writing. Thanks for all the help. Ill post back when I figure out what went wrong

have searched for an answer here and elsewhere but none of the answers seemed to apply so here goes the same old question hoping for a fresher answer since 2015

I have a crappy Chinese bike which I bought from Amazon. The Hall wires came straight out the axle and we're pulled so tight that a couple broke. After ripping it apart, extending the wires a painfully putting it back together, some more broke. I bought a new 1000w motor on Ali baba.

I figured while I was at it I'd build a 14s5p battery from EVE 3200mAh 18650s (10 A max draw, 5A constant) (IR on 5 cell parallel range 67m ohms to 127m ohms)with a 100balance bms and active 1A balancer with Bluetooth. and a new controller with a "900W" display (controller 40A 36v to72v). Installed the rear hub motor and new spokes. Found out my throttle was bad from error msg on display. Replaced that. Aligned brake rotors and pads Set controller up for max 20A and 48v. Set wheel size, no speed control, 42v battery cutoff, and appropriate (I think) pedal assist settings

All connections seem secure and the cells in the battery were balanced to 3.7v prior to install then the balancer rebalanced them at 4.15v (I set that as max and min at 3.1v on bms and controller) I rewired everything with 22awg wire for low voltage and 12AWG wire for high voltage. Connections twisted, soldered, heat shrink with glued heat shrink.

Now at 500w in anything over PAS2 I get a brief low voltage error code then it shuts down. I set the amp draw on controller to a max of 10A thinking max 580W (58v 10A) on a 1000w motor should be no problem. No help. All cells in p configuration are balanced to within 0.01v and at 10A draw I can't imagine it's drawing anywhere near even 1C much less the 3C they are rated at max . There is a setting asking which magnet it should base the speed at. I didn't think that was it since I set the speed limiter off. Also a setting asking "assisted magnetic steel disc type " but I tried all 3 types and no difference.

Anyone have any idea what is going on?

 

[offGridDownUnder]

Just sayin...used cells. Didn't expect much. Got more than I planned. Pleased with the results. More a question of what I did to make the IR rise on average over a parallel string.

Ah, got it.

 

[docw009]

That's one heck of a 5P layout, but if you start with two long strips of nickel, looks like you could weld and fold starting with one cell.

With a 1000W motor, let's say top current is 4 amps per cell. So the strips on the end carries 16 amps and the other one will carry 8 amps, I don't think I would do it that way, but oh well. I've put 20A thru a short 1 cm length of nickel and I recall around .010 volt on it. that would mean .13 volt on your layout, In resistance, that's 13 milli-ohms.

About your high p-group readings, your B6AC is including the resistance of the alligator clips and the leads to the XT60 connector in that nunber, Bet the real number is probably half, but it's still high, It's not coming from the nickel though. I kind of thought it was, but the nickel isn't very high, It's your cells.
Too old.

What do you get if you just connect to a bare cell and reasure IR?

s

 

[iampaulpease1]

That's one heck of a 5P layout, but if you start with two long strips of nickel, looks like you could weld and fold starting with one cell.

With a 1000W motor, let's say top current is 4 amps per cell. So the strips on the end carries 16 amps and the other one will carry 8 amps, I don't think I would do it that way, but oh well. I've put 20A thru a short 1 cm length of nickel and I recall around .010 volt on it. that would mean .13 volt on your layout, In resistance, that's 13 milli-ohms.

About your high p-group readings, your B6AC is including the resistance of the alligator clips and the leads to the XT60 connector in that nunber, Bet the real number is probably half, but it's still high, It's not coming from the nickel though. I kind of thought it was, but the nickel isn't very high, It's your cells.
Too old.

What do you get if you just connect to a bare cell and reasure IR?

View attachment 363791s

I have pics above with the individual cell readings.
Your diagram is exactly how I build them. I have a jig set up with some pvc pipe and smaller pvc and threaded rod to push them together tight. I just added room for some 18AWG copper wire to replace the nickel. I spot weld the wire to the cells in the same way with small nickel pieces. That finally lowered the overall resistance of the strings. I'm now getting around 70-90 for the whole string.

I do it in a linear way so I can swap out bad strings of p connections easily. These are used cells that I'm making a temporary pack from so I have something to use while I rebuild the good cell pack

 

[iampaulpease1]

That's one heck of a 5P layout, but if you start with two long strips of nickel, looks like you could weld and fold starting with one cell.

With a 1000W motor, let's say top current is 4 amps per cell. So the strips on the end carries 16 amps and the other one will carry 8 amps, I don't think I would do it that way, but oh well. I've put 20A thru a short 1 cm length of nickel and I recall around .010 volt on it. that would mean .13 volt on your layout, In resistance, that's 13 milli-ohms.

About your high p-group readings, your B6AC is including the resistance of the alligator clips and the leads to the XT60 connector in that nunber, Bet the real number is probably half, but it's still high, It's not coming from the nickel though. I kind of thought it was, but the nickel isn't very high, It's your cells.
Too old.

What do you get if you just connect to a bare cell and reasure IR?

View attachment 363791s

Wow, you were almost spot on. I measured the resistance of the string with a load to find out the true resistance and it is just under 1/2 what the meter reads. Actually 38% of the reading. (That connection with the clips and xt60 was put together pretty bad with crimping not solder) So I took the resistance I had for each cell, did the math ((1/ir1)*.38) +((1/ir2)*.38)... and got almost exactly the same ir. Probably a tiny bit loss from the wires and heat loss? I can gladly deal with 28 milliohms per string from used batteries that have sat around for 3 years.

 

[iampaulpease1]

New question. Still related to my issue but I'm trying to understand why I can't make the math add up right. I've got 14s5p setup. I realize that I have some resistance issues with my cells but they are all charged up to 2750 - 2850 mAh at 4.18 volts. I arranged all the "P" packs so total resistance in each is 90 - 100 mohms. That includes the resistance from the nickel strip and loss I have through my testing device and alligator clips and such. (In reality a test through an voltage/amp meter and a 2Amp load showed I should be about 38% of that resistance without the additional nickel I'm using and the connection to my battery tester) At 14s using the highest resistance that should give me 1.4 Ohms of resistance. Let's make it 2 Ohms to add in the loss at the "S" connections and the XT60 connector. So, I have 51v nominal 58v max. V=IR so V/R =I. 51v ÷ 2 Ohms = 25.5 Amps. My cells work much better (no fear of overheating) under 2C load so under 5.3Amps per cell and 5P gives me 5.1 amp draw per cell or 25 amps total. Everything is welded super well, nothing loose, no shorts, why in the world am I still shutting down at 500w? The way I did the math 25 Amps x 51 Volts should give me 1250 Watts and that is using absolute worst case scenario. Best case would be V/R=I thus 58 Volts/1.5 Ohms = 38.6 Amps so 58 Volts @ 38.6 Amps (if I wanted totorture the cells with 7.7 Amp draw or 2.8C)= 2242 Watts! What am I missing?

 

[docw009]

One ohm is a big deal.

V = I x R. If you had 1 ohm in your battery wires. than 10 amps thru the wires will cost you 10 volts.

P = 1 squared x R, If an XT60 connector had 1 ohm in the contacts, that's 100 watts for 10 amps,enough to melt it.

 

[iampaulpease1]

I hear you but I don't quite understand. If I'm right and V=IR and therefore V÷R=I. Then 51V ÷ 2 Ohms (throughout the entire pack of p to p and s to s connections including any loss at the power connections and bms and heat or whatever) = 25.5 Amps. Is that at least correct? So the power I'm expecting should be Watts =Volts × Amps or 25.5 Amps x 51 Volts = 1300 Watts. I'm cutting off at 450W to 550W based on my display and lack of power I can actually "feel ". I should be able to cruise flat surface over 20 mph or go up an incline with peddling over 8 mph. If I hit the slightest incline it just shuts down when I'm not aggressively peddling.

 

[amberwolf]

I hear you but I don't quite understand. If I'm right and V=IR and therefore V÷R=I. Then 51V ÷ 2 Ohms (throughout the entire pack of p to p and s to s connections including any loss at the power connections and bms and heat or whatever) = 25.5 Amps.

The math is probably right, but the application isn't.

The problem is that if you have a battery pack with 2 ohms of total resistance, then if you draw 25A of current thru it, that's P = I^2 / R or 25A squared (25A x 25A) x 2ohms = 1250watts lost as heat inside the battery pack. That means the pack should get very hot very fast at a 25A drain. ****

Is any part of it getting hot? If so, that's where the resistance problem is. If it all gets hot, then it's all too high a resistance and incapable of the current draw you need.

If you ahve that much power loss inside the pack, then you won't be able to get much at the motor/controller because it's all been wasted as heat inside the battery.

The voltage drop on that is probably essentially the entire pack voltage, counteracting the actual pack voltage, leaving nothing to run the system from.

My whole battery pack for my 14s2p EIG 40Ah pack on SB Cruiser is estimated (not tested) as less than 40milliohm. That's < 0.04 ohms.

If your pack is actually 2 ohms, it is 2 / 0.04 = 50 (fifty!) times the resistance of my ancient nearly-decade-and-a-half old wearing-out battery pack that still drives my heavy heavy-cargo SB Cruiser trike handily at 20mph, accelerating it, me, cargo, etc. totalling several hundred pounds from zero to 20mph in 5-6 seconds. I dont' recall what the voltage sag is, but it's not all that bad, considering it's age. When new it was probably much better, but I didn't have it then.





****(Me and numbers often don't get along so you should check my math.... )

 

[amberwolf]

I've got 14s5p setup.

I arranged all the "P" packs so total resistance in each is 90 - 100 mohms. That includes the resistance from the nickel strip and loss I have through my testing device and alligator clips and such.

That is *very* high. That essentially means that each cell (plus interconnets) is half an ohm, or about 5 times what it should be, worst case, which is what you get for old worn out cells.

If this resistance is not from the cells, but from the interconnects, those are pretty bad connections, or some really high resistance metal.

If the resistance is from your test-equipment connections, you should make better connections to eliminate that. You can verify if it's that by clipping them to each other and testing, to see what it shows. If it has a zeroing function, use that when connected this way to "tare" them out of the measurements you're making.

(In reality a test through an voltage/amp meter and a 2Amp load showed I should be about 38% of that resistance without the additional nickel I'm using and the connection to my battery tester)

That's still way way higher than it should be.

At 14s using the highest resistance that should give me 1.4 Ohms of resistance. Let's make it 2 Ohms to add in the loss at the "S" connections and the XT60 connector. S

If you actually had half an ohm of resistance at a connector, that should be replaced; it's terrible, and will probably melt things.

Let's say you are drawing 10A. That's 10A x 10A x 0.5ohm to get the watts of heat generated there. So 100 x 0.5 or 50W. A good hefty soldering iron is that hot, and you know what that does....melts solder, plastic, heats up wires really fast, etc.

There are good testers for resistance, like the DE5000, to find out how much actual resistance is in your wiring, connectors, and battery interconnect strips. You can't use it to test cells with, just passive parts. But it reads down to the low milliohms; I have one to test shunts and motor / etc resistances with (it also does inductance and capacitance).


If it weren't for the shutdowns your'e getting, presumably caused by voltage drop, I'd suspect your cell testing equipment was not giving you anything like the real resistances.

But if your system is shutting down because of the votlage sag, then the resistances could be at least in the ballpark of reality (though I think they are still reading higher than they really are by quite a bit, unless you are finding problems with overheating in wiring, connectors, and cellls).

 

[iampaulpease1]

That is *very* high. That essentially means that each cell (plus interconnets) is half an ohm, or about 5 times what it should be, worst case, which is what you get for old worn out cells.

If this resistance is not from the cells, but from the interconnects, those are pretty bad connections, or some really high resistance metal.

If the resistance is from your test-equipment connections, you should make better connections to eliminate that. You can verify if it's that by clipping them to each other and testing, to see what it shows. If it has a zeroing function, use that when connected this way to "tare" them out of the measurements you're making.




That's still way way higher than it should be.




If you actually had half an ohm of resistance at a connector, that should be replaced; it's terrible, and will probably melt things.

Let's say you are drawing 10A. That's 10A x 10A x 0.5ohm to get the watts of heat generated there. So 100 x 0.5 or 50W. A good hefty soldering iron is that hot, and you know what that does....melts solder, plastic, heats up wires really fast, etc.

There are good testers for resistance, like the DE5000, to find out how much actual resistance is in your wiring, connectors, and battery interconnect strips. You can't use it to test cells with, just passive parts. But it reads down to the low milliohms; I have one to test shunts and motor / etc resistances with (it also does inductance and capacitance).


If it weren't for the shutdowns your'e getting, presumably caused by voltage drop, I'd suspect your cell testing equipment was not giving you anything like the real resistances.

But if your system is shutting down because of the votlage sag, then the resistances could be at least in the ballpark of reality (though I think they are still reading higher than they really are by quite a bit, unless you are finding problems with overheating in wiring, connectors, and cellls).

Thank you. How and what can I connect in line testing that I can read while riding. I have some cheap 20 Amp voltage/amperage displays that connect through a common wire. I'm not sure how reliable they are because the shunt seems too small to me for 20A. The meter in the display on the bike just shows watts and I need either amps or volts to determine the other when it kicks off.

 

[amberwolf]

Thank you. How and what can I connect in line testing that I can read while riding. I have some cheap 20 Amp voltage/amperage displays that connect through a common wire. I'm not sure how reliable they are because the shunt seems too small to me for 20A.

WHich ones are they? A direct link to the sale page for them will give us some idea of what they could really be like, especially if they're a version we've seen before.

Some of these things use external shunts, that you can swap out for heftier ones, and recalibrate the unit to read them correctly. Some units can't be recalibrated, but if you have a 20A shunt and substitute a 200A shunt, if both have the same milliohms per A (meaning the 200A is 1/10th the resistance of the 20A), then you just move the decimal point over for the display reading you get with it. (if it says 20A, then you're seeing 200A, if it says 3.5A, your'e seeing 35A).

The meter in the display on the bike just shows watts and I need either amps or volts to determine the other when it kicks off.

Then you can hook up your voltmeter across the controller's battery input connection, and mount it (ziptie, tape, etc) next to the bike's display so you can see both at the same time.

Keep in mind that all of these displays (including the bike's) don't actually show you the instantaneous realtime values, there is significant delay between the input and what you see, and it is also filtered so you don't really see most of the spikes or dips, especially if they are short.

The usual best way to see what's going on is with a "wattmeter" that logs the lowest voltage, highest current, etc, while also showing a "realtime" reading that may actually be close to realitime (but still wont' show short spikes or dips). Those two typically occur at the same time, so it may coincide with the peak watts, but it will probably tell you what the most realistic watts you're getting at that lowest voltage moment was, when doing short test runs. Over a long run that uses signficant battery capacity, there's less correlation, depending on conditions.

There's a bunch of different kinds. I use the Cycle Analyst as a permanent installation on my rides, because it also does a bunch of other things I want, but there are plenty of much cheaper pure-wattmeter units, of varying function and quality. For quick simple testing of stuff, I may use a "Turnigy Watt Meter" (lots of variants that are basically the same, cheaper = lower quality on most of these), or an old WattsUp (the original basis for almost all of those types of wattmeters).

 

[iampaulpease1]

WHich ones are they? A direct link to the sale page for them will give us some idea of what they could really be like, especially if they're a version we've seen before.

Some of these things use external shunts, that you can swap out for heftier ones, and recalibrate the unit to read them correctly. Some units can't be recalibrated, but if you have a 20A shunt and substitute a 200A shunt, if both have the same milliohms per A (meaning the 200A is 1/10th the resistance of the 20A), then you just move the decimal point over for the display reading you get with it. (if it says 20A, then you're seeing 200A, if it says 3.5A, your'e seeing 35A).



Then you can hook up your voltmeter across the controller's battery input connection, and mount it (ziptie, tape, etc) next to the bike's display so you can see both at the same time.

Keep in mind that all of these displays (including the bike's) don't actually show you the instantaneous realtime values, there is significant delay between the input and what you see, and it is also filtered so you don't really see most of the spikes or dips, especially if they are short.

The usual best way to see what's going on is with a "wattmeter" that logs the lowest voltage, highest current, etc, while also showing a "realtime" reading that may actually be close to realitime (but still wont' show short spikes or dips). Those two typically occur at the same time, so it may coincide with the peak watts, but it will probably tell you what the most realistic watts you're getting at that lowest voltage moment was, when doing short test runs. Over a long run that uses signficant battery capacity, there's less correlation, depending on conditions.

There's a bunch of different kinds. I use the Cycle Analyst as a permanent installation on my rides, because it also does a bunch of other things I want, but there are plenty of much cheaper pure-wattmeter units, of varying function and quality. For quick simple testing of stuff, I may use a "Turnigy Watt Meter" (lots of variants that are basically the same, cheaper = lower quality on most of these), or an old WattsUp (the original basis for almost all of those types of wattmeters).

This is the cheap one I have.

 

[amberwolf]

That's identical in appearance to one I have here that has a 100A shunt, so it's likely that yours can use other shunts.

https://www.amazon.com/gp/product/B013PKYILS

This is a different seller's version of the manual, but it's essentially the same as the printed one in my box

https://manuals.plus/drok/200141-dc-multimeter-manual.pdf

https://manuals.plus/m/e3717cb46f565731bca20cb9987aa68e9193562555439aff6c14e317ec320a67_optim.pdf

You'd have to follow the steps to see what options yours supports for a shunt. If it doesn't have any other options, then if you use a shunt intended for twice the current, (say, 200A/75mohm if yours was 20A/75mohm) it will still work, just all current (and wattage) readings will be off by one decimal place.

(Unintuitively, it's not safe to go the other way, to use a 2A shunt on a 20A device, because the otherwise-identical lower-current shunt makes twice the output voltage for the same current, and could overload or damage the analog input of the device).

 

[iampaulpease1]

Thanks. I'll order the 100A one. That's way more than I need anyhow.

 

[iampaulpease1]

FYI, I I replaced every connector and wire from the battery to the controller to the motor and even to the 5v system I used XT 90 and JST connectors. Even hard wired the motor to the controller..I upgraded every wire to every component by at least 1 size and used stranded copper wire with silicone insulation. Today I was able to pull consistent 700-800 watts and hit 1250+ on one hill without even pulling top power or top gear. All without PAS! My hard work has paid off thanks to the help of everyone here. Thank you all very much!

 

[iampaulpease1]

Ugh. Blew up my controller. Battery ran superb. Too superb. 48v 50A and.....peddling up a steep hill. Should have set it to turn off at rated 40A

 

[amberwolf]

If the controller failed, then it's either not mounted where/how it can shed the heat, or not designed well enough to do so, or not properly designed to limit it's current / etc to whatever it's really capable of in continuous operation.

Or it's operating beyond it's rating, which normally requires "hacking" it in some way (anything that's in it's settings, accessible to the end user, should be something it's actually capable of, so changing those settings isn't really hacking or running beyond it's ratings (ability, possibly, but if it's in the settings and allowed to be used, it's "rated" for that or else it's incorrectly designed)).

When you replace it (or repair it), pick something that can truly do what it's rated for continuously (because that's what you'll need for steep hills, etc).

If you need 50a to get up that hill, make sure the controller is able to do that "forever" and you shouldn't have problems like this one did with it.

Make sure the battery can really handle that, too (meaning the cells are able to handle it without heating up or having major voltage sag), and that the motor can also handle that (without overheating).

 

[iampaulpease1]

Will do. I'll report back but it will be awhile until I get it. I'm going to go 7P instead of 5P while I'm at it. After load testing the EVE cells, they can carry 10A each without even getting warmer than a cats belly so that should be good. The controller I'm getting says 72v 100A so that should work well. Next I'm gonna blow the motor cuz 58V @50A is 3000W in a 1500 W Chinese motor so.... How much is a 3000W motor?

 

[Chalo]

After load testing the EVE cells, they can carry 10A each without even getting warmer than a cats belly so that should be good.

Why you using lipstick cells to do a full sized job? Automotive modules laugh at 50A discharge, even years after they retired from automotive service.

 

[iampaulpease1]

Why you using lipstick cells to do a full sized job? Automotive modules laugh at 50A discharge, even years after they retired from automotive service.

I'm not building a car.

 

[Chalo]

I'm not building a car.

But you're building something that makes you stack up lots of parallel cells to do the job. That's like running a boom box on watch batteries. Technically you can do it that way, but it's kind of dumb when there are single cells with the Ah capacity you require and a whole lot more current capacity than you need.

I use automotive modules as small as 12S 8.5Ah on my bikes, and even that one delivers 60A with negligible voltage sag.

 

[iampaulpease1]

But you're building something that makes you stack up lots of parallel cells to do the job. That's like running a boom box on watch batteries. Technically you can do it that way, but it's kind of dumb when there are single cells with the Ah capacity you require and a whole lot more current capacity than you need.

I use automotive modules as small as 12S 8.5Ah on my bikes, and even that one delivers 60A with negligible voltage sag.

Could you give me a suggestion of what cells you recommend and what is needed to connect them without burning through the connection as soon as I twist the throttle. Sure, I'd love to run a 108v 200A bike but it all has to fit in about an 18" (46cm) x 2 1/4" (6cm) x 4 1/2" (12cm) space with the BMS and suitable fiberglass housing.

 

[Chalo]

but it all has to fit in about an 18" (46cm) x 2 1/4" (6cm) x 4 1/2" (12cm) space

Why? Electrons don't care where you keep them. Is it inside the frame? That's a self-imposed problem, but even in that case you don't have to put the battery there.

And you don't have to let someone else's infantile design decisions limit how you use your own bike.

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[amberwolf]

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[Chalo]

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