C124 Problems

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PJD
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C124 Problems

John,

I picked up my C124 from the shop yesterday and got it back home. This morning, I was dismayed to find that, when charging completed (cell volts 3.60 to 3.66). I found the "fuel gauge" was reading at the 3/4 point, and sure enough, the SOC is shjowing only 75%. Another thing, I'm not sure this matters, but the BMS's reported pack voltage is about one volt below the voltage indicated on a couple different reliable voltmeters.

For my, and other owners benefits can you provide information on ho to rset/recalibrate the SOC gauge? Thanks.

MikeB
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Re: C124 Problems

PJD,

I ran into this problem earlier this year. The problem isn't that your SOC gauge is wrong, it's that the charger stopped charging before your batteries were full. Apparently, there's a signal noise problem between the BMS and the charger, and it sometimes results in an early shutdown of charging. There is a fix, and I already have it: a small box that inserts optical isolation between the BMS and the charger, it just plugs in between the two and fixes the signals. The guys at CuMoCo will have to ship you one, and you'll install it yourself.

Oh, and to answer your question, the SOC meter is automatically reset when the BMS detects that a balancing charge has completed, meaning that your pack is fully charged and fully balanced. There's also a reset on the empty end as the battery approaches empty, as various LVC triggers are hit.

Mike

My electric vehicle: CuMoCo C130 scooter.

PJD
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Re: C124 Problems

Mike,

I have the box installed. The pack was fully charged. As I wrote, cell voltages were all at "full" levels (3.60 or higher when the charger was plugged in and charging). However, one of the BCU-PC interface terminal functions is a ability to reset the state of charge indication to a known level-so I set it to 100% since I knew the pack is fully charged. Problem fixed, I think.

I've gone through three chargers so far. After a ride this afternoon, then recharging, other problems started. The indicator never shows "balance mode" although the mains current draw suggests it is in balance mode, The BCU-PC interface shows about 1.5 amps and "bulk-charging" during this pseudo-balance mode. Then when the pack (or cell?) voltage reaches a the full point, bursts of relay-chattering and weird flashes of various durations are emitted from the indicator light. This latter condition is not new, but is what it was doing with the old chargers before they quit completely. So, it doesn't look like they fixed this problem.

They have modified the new charger so the fan runs continuously whenever it is plugged in - even if charging stops (no flashing light), so it is no longer completely plug-and-forget charging, even when it is working properly.

This is pretty aggravating after what what was a horribly hot 580 mile round-trip drive (the old truck has no AC) hauling the scooter back from Ann Arbor after they had assured me that everything was working right.

Another thing. I notice that the BCU gets really hot when it is running. Is this just from the processor? I wonder how much power the BCU draws? Might this be one reason current can't achieve the efficiency numbers of the ZEV's?

MikeB
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Re: C124 Problems

Hmm, ok, I thought I knew the problem, now I'm baffled.

I do know the BCU box is also housing the DC/DC converter. Much of the heat is coming from powering your 12v components, mostly the lights. I was playing with better headlight bulbs earlier this year and managed to cause the BCU to shutdown due to overheating. Erik commented that they will probably separate the two functions on the next design rework, but that probably hasn't happened yet. You can reduce the wattage flowing through the DC/DC converter by changing to LED bulbs, particularly the tail lights (since they are always on).

My electric vehicle: CuMoCo C130 scooter.

PJD
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Re: C124 Problems

Actually, I now think I know where the charging problem is. I'll report back.

Yeah, I guess the DC/DC converter is the source of the heat. LED bulbs are a good idea - I assume a LED compatible flasher will be needed to do the turn signals too.

BTW, a lot of headlight brightness issues can be improved if the headlight aim is raised. There is an adjusting screw in the back of the headlight assembly (between, and below the rubber boots that cover the bulb sockets) This screw can be accessed with a extra-short stubby screwdriver from under the "beak". The adjuster spring was weak or unattached, so the screw just backed out. But a replacement headlight assy I got from Current adjusts properly.

MikeB
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Re: C124 Problems

I didn't do anything special for my turn signals, just a simple bulb replacement and I still get a regulation flash pattern.

Headlight aim isn't great, nor is the beam shape, but brightness is an entirely separate issue. The stock bulbs are 25w non-halogen (S1). I've swapped them to 35w halogen bulbs (HS1), which is an improvement. I was running 45w halogen bulbs (H4) when I had the overheating issues, but I may put them back in when winter rolls around. My real solution to forward lighting is to add LED driving lights on the forks, 10w LEDs put out ~900 lumens each: Vision X Solstice Solo pods. Not cheap, but great illumination for the watt.

Please report on the charging problem when you have more info.

My electric vehicle: CuMoCo C130 scooter.

PJD
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Re: C124 Problems

Brightness isn't so much an issue for me as most of my riding is 35-40 mph or less.

But my headlight's aim on low beam was down to the pavement just 20-30 feet ahead of me.

The 35 watt halogens - offset by LED tail lights, and maybe turn signals, sounds good. With a little dexterity, you can change the headlight bulbs without disassembling anything, right?

I fixed the charging issue. When I noticed the erroneous SOC reading I thought it might be the charge current zero-offset (one of the BCU-user-settable parameters) was off, so it ran command "Z" - reset charging zero offset. This command displays a 10-second countdown, then displays a current offset setting (in some arbitrary units - "61" in my case) But the zero offset was not correct, which resulted in an erroneous charge current reading in balance mode of 1.3 to 1.5 amps. So, the BCU assumed it was still running in bulk mode, until an overcharge-protection point was reached. The rhythmic relay chattering was the charge current shutoff oscillating between on-voltage up, off-voltage down with each program loop.

So I messed with it some more and without going into a long account of what I did, I accidentally ended up trying the "Z" command with the winter switch off. This time it displayed a message to "set the winter switch to off so the BCU is powered only by the [PC's USB port] connection." Apparently the BCU terminal only displays this reminder message if the winter switch is already off! This time it set the offset value to 109.

I connected the charger and sure enough it now reads 0.4 amps in balance mode and then "shut off" normally. The fan still runs when shutoff due to Current's work-around for their latest failure-prone batch of Chinese chargers [one word hint - Meanwell, made in Taiwan]. And, it also automatically set the SOC to 100% upon completion.

So, John, if you are reading this, consider the "service ticket" closed, but note the program bug. Also, a BCU program manual is needed before too long.

MikeB
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Re: C124 Problems

Yea, my plan was to save power on the signal and tail lights and redirect it forward. There's also some extra capacity on the DC/DC, but we want to avoid pushing too far into that capacity. The first step to upgrading the headlights is actually to replace the plugs, the S1 bulb uses a bayonet mount, you need to cut those off and replace them with a 3-blade socket. After that, the HS1 and H4 bulbs will fit in the assembly. However, my BMS is mounted right up against the back of the headlight assembly, so there's no room to reach in and replace the bulbs without any disassembly. They changed the mounting of the BMS after my bike, not sure exactly when, so you might have room for your hand while I still don't.

You're pretty deep into programming the BCU, that offset was a good find. I agree, a manual is needed, but it's intended target is going to be service techs, not customers. Of course, at least for a few years, we are all our own service techs. :)

My electric vehicle: CuMoCo C130 scooter.

PJD
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Re: C124 Problems

...

PJD
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Re: C124 Problems

I agree, a manual is needed, but it's intended target is going to be service techs, not customers.

I've always done my own automotive repairs. Factory service manuals may be intended for professional mechanics, but I've never heard of any car dealer that won't sell a copy to anyone.

I'm not really programming, just setting some parameters that the program uses.

jdh2550_1
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Re: C124 Problems

Hi Paul (& MikeB)

I was actually on vacation and only just read this.

I apologize for the bike being returned to you without the charge sensor calibration done. I wasn't aware that your bike was being picked up last week (I was hoping to put the latest BCU software on it before it was returned - this will alleviate most of the SoC cal issues).

The plan is that the BCU commands will be documented in the service manual and that the service manual will be available to customers as well as service technicians. During the Test Pilot phase we expect to work with customers and you have access to the engineers (well, when they aren't on vacation!)

John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.

PJD
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Re: C124 Problems

John,

According to Terry, I did get the latest version of the BCU software installed. I just checked - version 0.0.29A; is that it? It now reads the scooter parameters about 4 times a second, instead of the once a second as the old version did. And, if you do a "C" command, it shows "full" "half" and "empty" gauge calibration numbers in the config data.

Regarding the parallel topic in this thread (of more interest to the greater Current owner community), would you have the bulb-type numbers handy for the scooter? I assume it uses two 1157's for the tail lights. What is the turn signal bulb numbers? I'm thinking of ordering LED's for all the lights except the headlights. I know that I'll have to get an LED compatible flasher too. In the slower traffic use in my area, I figure the lights may account for enough draw from the pack to matter. I figure the existing array of running bulbs is as much as 80-100 watts (considering the brake filaments are on much of the time) or as much as 1.5 amps from the battery pack - all the time.

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