A friend of mine had a caliber backplate crack but it wasn’t under normal conditions.
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I’m fat (215lbs / 98kg) and I use my boards as tools to get around. I might ride with 25lbs of groceries and fast, over whatever is in my way… rain or shine…
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context:
- I accidentally left my board on charge. and powered on. for several days.
- If i leave this board powered on it slowly drains the battery.
- When i got back to it the charger green light was on as though full charge had occurred.
- voltage per cell was 4.05. ( measured by metr averaging. )
- I unplugged the charger and plugged it in and it went red to begin charging again.
So it appears that something triggeres the charger to stop charging, and it’s not state of charge that turns it back on on gain, but disconnect/reconnect.
The Question:
is this something in the charger? is it something the BMS is doing? what explains this behavior?
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It just means that’s a float charger and not a trickle charger.
I prefer float chargers.
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Is adding a spacer plate an alternative to cutting down the shaft of a motor going into a gear drive? The only reason I could think not to do this would be that the pinion would be on the very end of the shaft, and it would lead to the bearings in the motor dyeing faster. Maybe a support bearing in the spacer could fix that?
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in the context of CC/CV. I don’t understand the meaning of float vs trickle.
my understanding of float and trickle was that trickle chargers maintained a low current and were always on. so you could overcharge your 12v lead acid car battery if you didn’t shut them off.
float chargers were like trickle chargers but they also stop when the current level drops and the battery appears charged?
my understanding of a CC/CV charger is it’s basically continuous. it has a current limit, and a voltage limit. doing full current at a lower voltage. or limiting current at max voltage. effectively stopping when the battery voltage and charger voltage are equal.
adding: in the context of my question though you’re saying the behavior is controlled by the charger electronics. thanks. 
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Float and trickle can mean a lot of different things, depending on the battery type.
For me, float charging means keeping the battery (pack) at or near a certain voltage that is lower than the full charge voltage. For lead-acid that means a continuous low charge rate that roughly matches the self-discharge rate of the battery. This keeps the battery almost fully charged but does not damage it by holding it at the full charge voltage.
Li-ion should never be charged continuously (some companies call it float charging) but many chargers will turn back on once the battery voltage has dropped to a certain level. A common range is somewhere between 4.05V-4.10V per cell. Some companies might call this their float voltage. This keeps the battery fully charged but doesn’t accelerate aging a lot more by continuously holding the battery at 4.20V per cell.
For me, trickle charging means any charging of any chemistry done at a low rate. That is, the current is only allowed to trickle in to the battery. It’s often used as a term for the charging done to cells that are at very low voltage levels or the charging done when a battery has dropped down to the voltage where it needs to be “topped off” (the 4.05V-4.10V I mentioned earlier).
A CC-CV charger uses the full bulk charging rate until it thinks the battery voltage has risen up to its charging voltage. This is the CC portion of the charging.
This is never what is really happening though since the battery’s internal resistance and the wiring and circuit resistance make the battery voltage appear higher than it really is. But, there’s no harm to the battery if the charger thinks it has reached 4.20V but the battery is actually at a lower voltage internally.
At this point the charger switches over to the CV portion of the charge. The current level starts dropping as the battery tops off, getting lower and lower as fewer and fewer empty spots for the ions to be stored in the anode are available. If there is a lot of battery internal resistance and circuit resistance you will still see the battery voltage rising a little. High performance cells with a good charge circuit will read 4.20V at the CC-CV transition point and the voltage will stay at that level until the charge is done.
A CC-CV charge never stops unless we force it to. Even if you charged a cell for a week you’d still see current being supplied by the charger, equal to the internal self-discharge rate of the cell.
Stopping a charge is typically done by choosing a low current level cutoff point beyond which any additional charging is not worth the time. If we charge a cell at 1A then the charge would typically be stopped when the charging current had dropped to 1/10th of that, 100mA.
You could let the charging continue for several hours longer, allowing every nook and cranny in the anode to be filled with an ion, but you might get at best a few more mAh into the cell and it’s not worth the time.
Rapid chargers might stop charging when the current has dropped to only 1/5th bulk charge rate (in addition to using a high charge current level). Chargers designed to give you maximum run time might stop when the charge rate has dropped to 1/20th or even 1/100th of the bulk charge rate.
Stopping at 1/100th though will considerably lengthen the charging time. It’s always a tradeoff between charging convenience and how fully charged the cell gets.
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Ok, I think I can think of the charger as float charging then.
float CC/CV: runs till charge current drops below some threshold. Turns back on when charge voltage drops below some level.
and maybe 4.05v/cell just wasn’t enough for it to turn back on but it might have eventually?
I do feel liike @b264 and @Battery_Mooch have given different definitons of trickle. but maybe it’s just different contexts.
maybe
a.) any low current charge.
b.) a CC/CV charger with no mechanism to shut off thus the tail end of the charge is a trickle as it approaches zero.
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That’s trickle charging, the literal opposite thing
That’s trickle charge, AKA true CC/CV charge that never ends until disconnected. The asymptote is 4.20V/cell and the cell’s internal discharge rate means you never actually reach 0.00mA charge current during the CV portion.
This is what float chargers do. An example float charge would be something like CC/CV/wait. Where it charges at a constant current like 4A for example, until it reaches 4.20V/cell. Then it switches to constant voltage until charge current drops to 40mA (one hundredth the CC charge current). Once that happens, it cuts off all charge and waits. {wait & monitor} If the voltage goes below some set amount, like 4.05V/cell for example, then the CC/CV cycle repeats over again, sometimes skipping the CC part if it’s just topping it off.
This is the phenomenon @fessyfoo was describing.
It’s unfortunate but all the chargers I’ve used, you just have to watch them charge to know what type they are; they’re not labeled as such. If you connect a voltmeter to it, and the meter turns on and off endlessly, it’s probably a float charger. (attempting to charge the filter cap in the voltmeter) If the meter turns on to 4.20V/cell and stays there, it might be a trickle charger. Some float chargers won’t power the meter at all.
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Alright guys, I seem to have finished my two motor build, but something strange happens when I turn on the board with the loop key and the remote on. If I turn on my remote at the perfect moment right after plugging in the loop key, both motors spin when the throttle is applied. If I do the same thing but turn the remote on a smidge later, only the master vesc motor spins. Anyone know what might cause this?
What remote? Is it UART or PWM (“PPM”)?
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Yes.
Imagine float charging being like the float in the back of a toilet tank. When the water level drops, it turns on the spigot. When the water level raises back up again, it turns off the spigot.
That’s probably the phenomenon float charging was named after anyway.
Trickle charging is just constantly filling the tank until it starts spilling over the side, and just letting it drip over…
Ppm, it’s the mini 2.4ghz remote everyone seems to use
Yes it is
Edit: not sure if it’s false in the slave, I’ll check right now
Just changed the slave to false. I’ll see if it works
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For some reason, I’m still getting the problem. Also, when I try to forward communication to the canbus, it says it cannot read the firmware of the second vesc. But when I plug the usb directly into the slave vesc, it connects fine.
Update the firmware on both ESCs.
Make sure you first write down all your motor detection results so you can type them back in if you want to.
Like these numbers:
R: 9.40mΩ
L: 4.09μH
λ: 3.76mWb
For each motor. After you retype them in, click “Calc Apply Old” and then write the changes.
You’ll have to redo the ENTIRE setup after upgrading the firmware but saving the motor detection results makes it not that bad. Just go through each tab one by one.
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Alright, thanks. I thought it automatically writes the motor detection numbers when you run the foc detection though?
You won’t need to run the FOC detection if you save those.
Of course you can just not save them, and run the detections again, if it’s easier for you to just do the exact same procedure you did the first time.
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