I have anderson power pole connectors. For diy ebike and diy battery. I dont use a bms, so I balance charge my battery probaly minimum one time a month. Would a dc circuit breaker in the system stop the spark when I hookup the battery to the bike? What are the advantages of having a dc circuit breaker in the system?
How many of u run a dc circuit breaker on your ebikes?
- Thread starter nalu808
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electric_nz
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You can run a breaker with soft start switch in parallel with it to prevent the Spark eroding the breaker contacts.
The soft start switch is a momentary switch with a resistor in series, you turn this on to charge the caps then switch on the main breaker.
I used an automotive breaker and it worked fine on 52V 55A
The soft start switch is a momentary switch with a resistor in series, you turn this on to charge the caps then switch on the main breaker.
I used an automotive breaker and it worked fine on 52V 55A
HillCruiser
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I used a solar system breaker (48v 30a) on my beach cruiser.
For some reason the 48v battery wouldn't charge if the motor was connected.
(The battery on/off switch seems to work.)
The motor is a Golden Motor black pie (that looks absolutely awesome on my black cruiser.)
So I just open the breaker to charge the battery and just leave it open until the next ride;
haven't seen any sparks either opening or closing the breaker.
I'm thinking about installing one on my daily rider as well.
it just feels safer sitting in the garage with the battery isolated and
totally eliminates the chance of a phantom battery drain.
(full disclosure: I also unplug my coffee maker for the night)
For some reason the 48v battery wouldn't charge if the motor was connected.
(The battery on/off switch seems to work.)
The motor is a Golden Motor black pie (that looks absolutely awesome on my black cruiser.)
So I just open the breaker to charge the battery and just leave it open until the next ride;
haven't seen any sparks either opening or closing the breaker.
I'm thinking about installing one on my daily rider as well.
it just feels safer sitting in the garage with the battery isolated and
totally eliminates the chance of a phantom battery drain.
(full disclosure: I also unplug my coffee maker for the night)
nalu808 said:
I have read running a ac breaker could be dangerous. Could arc, since its not ment for dc.
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LOL. just don't switch it off when running full throttle. Mine has had 110A at 80V through it and actuated as a switch a couple thousand times or more. 30A AC single pole, cheapest way to buy high current contacts if you don't need overcurrent protection, but you can spend more if it makes you feel better. I'm about to redo my connector box, so I may replace mine. If I do, I'll do an autopsy to check out the condition of the contacts.
Voltron
1 MW
You're both right.
When actually using a circuit breaker as a safety cutoff, high amp DC does need special breakers. We had to source ones for boat drives that had special electrode design, and were sand filled, so they don't weld themselves into not tripping right at the first microsecond of the electrodes starting to separate.
But for handling the inrush current to spare the Andersons, and not being counted on as over current protection, or as an emergency stop switch, either would probably be fine.
When actually using a circuit breaker as a safety cutoff, high amp DC does need special breakers. We had to source ones for boat drives that had special electrode design, and were sand filled, so they don't weld themselves into not tripping right at the first microsecond of the electrodes starting to separate.
But for handling the inrush current to spare the Andersons, and not being counted on as over current protection, or as an emergency stop switch, either would probably be fine.
DingusMcGee
10 kW
A fuse is cheaper than a breaker and they work.
CONSIDERABLE SHOUTING
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E-HP said:
LOL. just don't switch it off when running full throttle. Mine has had 110A at 80V through it and actuated as a switch a couple thousand times or more. 30A AC single pole, cheapest way to buy high current contacts if you don't need overcurrent protection, but you can spend more if it makes you feel better. I'm about to redo my connector box, so I may replace mine. If I do, I'll do an autopsy to check out the condition of the contacts.
[/quote]
I'd love to see it too; having something that cheap would be a big plus.
Voltron
1 MW
DingusMcGee said:
They work great for system protection, but not great for stopping the spark from damaging the battery connector when it's hooked up, or acting as off switch for the system.
JackFlorey
100 kW
LOL. Just don't have a short circuit fault when you are drawing a lot of current then!E-HP said:
miro13car
100 kW
it will not stop of course sparks , instead of carrying heavy breaker I would rather use small spark arrester cuirciut in paraller with main switch
I'd love to see it too; having something that cheap would be a big plus.
[/QUOTE]
I posted the autopsy pics on the different thread since I couldn't find this one to follow up on:
On/Off switch autopsy
Since I have to swap out my controller with a temporary unit, I'm going to redo my cracked connector box while I'm at it. I have been using a 40A AC breaker as an ON/OFF switch since my initial build, and it has several thousand actuations. I had it hot glued to the inside of my box, so I...
endless-sphere.com
Gruesome
1 kW
Would it make sense to put one of these DC breakers in line with the battery, near the battery, to protect against shorts? 
They come in different current ratings, from 20A to 150A. Or is this pointless?
I use one on my motorbike to prevent the battery from draining when the bike is sitting (not for the starter motor, which is wired directly to the battery), and am thinking of adding one to an e-bike.
They come in different current ratings, from 20A to 150A. Or is this pointless?I use one on my motorbike to prevent the battery from draining when the bike is sitting (not for the starter motor, which is wired directly to the battery), and am thinking of adding one to an e-bike.
Guerney
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I switch my battery off before connecting to the bike, therefore haven't had cause to try these "Anti-spark" connectors:
https://www.amazon.co.uk/YOWOO-Anti-Spark-Connector-Quadcopter-Brushless/dp/B07NW9RX9M
https://www.amazon.co.uk/YOWOO-Anti-Spark-Connector-Quadcopter-Brushless/dp/B07NW9RX9M
Gruesome
1 kW
The shutoff as main function is for the motorcycle, where there are actually proper fuses behind this breaker.
For the (still to be converted) e-bike, the function would really be as a breaker, i.e. overcurrent and short protection mechanism. Unless you guys tell me it's absolutely not needed, or maybe even detrimental.
To get at one of the BMS wires, I would have to open the battery, I presume. Putting this breaker between the battery and its BMS would additionally protect against the BMS shorting out/going haywire. But that's at the cost of two extra wires in and out of the battery. I suppose if you assemble your own battery, then it would make sense to put the breaker right there? Except now you are adding more wire that could short out, instead of the short well protected run to the BMS inside the battery. The extra complication might add more harm than good.
For the (still to be converted) e-bike, the function would really be as a breaker, i.e. overcurrent and short protection mechanism. Unless you guys tell me it's absolutely not needed, or maybe even detrimental.
To get at one of the BMS wires, I would have to open the battery, I presume. Putting this breaker between the battery and its BMS would additionally protect against the BMS shorting out/going haywire. But that's at the cost of two extra wires in and out of the battery. I suppose if you assemble your own battery, then it would make sense to put the breaker right there? Except now you are adding more wire that could short out, instead of the short well protected run to the BMS inside the battery. The extra complication might add more harm than good.
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nicobie
100 MW
I really don't understand all the current love for BMSs. Back in the day we called them Battery Murdering Systems.
Gruesome
1 kW
Can you buy batteries (Li-ion accumulators would be the right word, I guess) without BMS built-in? When you assemble them from cells, you have a choice, obviously.
I could see where voltage and temperature monitoring via bluetooth would be worthwhile features for a BMS, but If you need the balancing, it just means your cells are unmatched. You could either fix the pack, or live with a sucky one, wasting your time waiting for the BMS to finish balancing when you charge. The math never works for anything but getting good matched cells.
Let's say one pack constructed with cheap generic Chinese cells costs $400 while another is constructed with well matched Panasonic cells for $600. If you charge both packs 500 times, but spend an hour more for the generic pack waiting for it to balance, that's $200 for 500 hours of your time, or 40 cents/hour. They pay kids $20/hr at McDonalds now. That means you value your time at 1/50th of what the kid makes bagging fries. You can tweak the assumptions, but it will always work out favoring good cells, BMS optional.
Let's say one pack constructed with cheap generic Chinese cells costs $400 while another is constructed with well matched Panasonic cells for $600. If you charge both packs 500 times, but spend an hour more for the generic pack waiting for it to balance, that's $200 for 500 hours of your time, or 40 cents/hour. They pay kids $20/hr at McDonalds now. That means you value your time at 1/50th of what the kid makes bagging fries. You can tweak the assumptions, but it will always work out favoring good cells, BMS optional.
Gruesome
1 kW
I'm totally new to this (but I do have power tools with rechargeable batteries). Do I really have to watch bike batteries while they are charging?
Guerney
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It's pointless watching them, if you're not fully prepared to do something about it before they burst into flames... which is why I assembled this (sorry about the awful editing and noises, I might get around to improving either or both at some point):
Measurements:
https://www.pedelecs.co.uk/forum/threads/home-ruination-by-ebike-battery-fire-expulserating-preterminator%E2%84%A2%C2%AE%C2%A9%E2%84%A0.46934/
Gruesome
1 kW
That's an awfully long video to watch. I thought it was done, and it turned out that was just the intro! I have to admit though, good sound! Maybe I should have been clearer right up front about the fact that I value my time (except when writing long-winded posts), hence the question about whether I really have to watch paint dry batteries charge. Maybe even more importantly the older I get the more I feel I can read faster than I can watch. Sorry to have made you make that video! I really appreciate the effort though.
Is there a kind soul who could watch that video and summarize it for luddites like me?
Until I get the all clear from somebody who watched this I guess I will charge outside.
What about the breaker though, not while charging, but on the bike? Yay or nay?
Is there a kind soul who could watch that video and summarize it for luddites like me?
Until I get the all clear from somebody who watched this I guess I will charge outside.
What about the breaker though, not while charging, but on the bike? Yay or nay?
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