Battery Disconnect method.

[DogDipstick]

"there is such a thing a "derating" and whatnot... " .. is what I insinuated. Not exclusive to a single point...

Derating is the opposite of what your talking about. You're trying to use a component over its rated voltage. Derating is reducing the rating of a component. Not increasing. SMH. (YOU MISSED THE "AND WHATNOT".. but thanks for the educational rant on current derating. ) SMH!
https://en.wikipedia.org/wiki/Derating

You know what, I've been sucked into arguing with an idiot,

Argument with idiots are not very productive, honestly.. but still worth the amusement. Most cannot get past the communication. Like listening to a overtly safe engineer with a budget. Boring.

I am basing my "whatever" on Breakdown voltage, Dielectric Withstanding Voltage (DWV), Working voltage, and the gap distance.. Nothing to do with the current capacity or temperature?

Whatever. Current capacity ad Working voltage have little to do with each other.

 

[spinningmagnets]

Excellent link! now added to the tech section stickey...

 

[HK12K]

I use a 40A AC single pole breaker as an on/off switch for my battery. Since it's AC, it won't actuate based on current, when used in a DC circuit, so I'm only using it because of the contact ratings. Still working fine after a thousand plus actuations. $6 Home Depot.

I use a 100A version of the same. It's obviously never tripped due to current, even with the Adaptto maxed, but it has proven to have the side effect of tripping both times I managed to dump the bike hard offroad. (And not due to a short, or at least none between pack and controller anyway)

I consider it a feature, not a bug.

 

[amberwolf]

The rotating "fire truck" switch shown earlier is intended and designed to be use when the vehicle is off.

if you mean this:
https://endless-sphere.com/forums/download/file.php?id=268684
then i've been using one of those as my on/off switch, directly in the battery cable, for years on the sb cruiser trike. gets switched on and off at least four times a day five days a week, and sometimes seven days. 14s (57.7v full) battery, with two controllers, at least a couple thousand uf of capacitance (probably more like four or five thousand or more). it's not designed for the purpose, or the voltage range, but it has worked anyway.

(if it ever fails to shut off, i also have a dc-rated circuit breaker on the other battery cable wire...if it fails to turn on it's just ring terminals on the back so i can unbolt them both then bolt them together on just one of the switch terminals.

The SSR style of "on off" switch that uses FETs can be used as a battery isolation switch when the system is parked, and it can also be used as a kill switch when the system is running.

somewhere in one of methods' threads, there is a project for doing this too. i can't find it right now though. (i have one of them around here somewhere, so i could post pics if the thread isn't available anymore, once i find the unit).

 

[serious_sam]

Excellent link! now added to the tech section stickey...

Thanks. Happy to contribute.

 

[TommyCat]

Also just to clarify on the Solid state skate board option, When they fail how do they fail? Just stuck closed?

If you mean a SSR like the luna offering referenced. I've just had the one for over 2 years that has worked perfectly on a 52vdc nominal system with no failure. So no experience there.

But I wanted to say that I would recommend potting it, or isolation from any moisture problems. As I have heard it doesn't do well after getting wet. (as per most electronics I suppose)

I fit mine in the end of a bottle battery pack. Pictures taken during testing...

Lighted switch on cockpit panel (lower right)…

 

[Bokonon]

Try this out for size... a little pricey but rated for the load.
https://www.amazon.com/dp/B07WX168NV

 

[john61ct]

For that kinda money, go Blue Sea

 

[dfelzz]

so it will not work with regen according to description

Can anyone comment if some of the options listed here, like the flipsky or alien power units will work in systems that require regenerative braking? Or are those type of isolaters only good as "one-way streets"?

 

[TommyCat]

Enjoying using an SSR and regenerative braking with no issues. :thumb:

 

[Grant Adamson]

On my BBSHD 52V system I use one of these and so far no problems.

https://www.amazon.com/gp/product/B0859J823G/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

 

[Balmorhea]

On my BBSHD 52V system I use one of these and so far no problems.

https://www.amazon.com/gp/product/B0859J823G/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Spendy for a switch. I paid about $6 for my last 300A, 60VDC disconnect. No app required.

https://www.ebay.com/itm/Car-Boat-Battery-Power-Isolator-Master-Disconnect-Cut-Off-Switch-12V-300A-Y2US/313223301531

To be fair, I don't trust the rating. But I'm only running it at 48V and 35A.

 

[john61ct]

For a remote contactor that can switch 200-300A DC loads thousands of times reliably, $30-50 is dirt cheap.

Too cheap IMO, but worth buying for testing purposes.

What say you @methods ?

 

[markz]

On my BBSHD 52V system I use one of these and so far no problems.

https://www.amazon.com/gp/product/B0859J823G/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Spendy for a switch. I paid about $6 for my last 300A, 60VDC disconnect. No app required.

https://www.ebay.com/itm/Car-Boat-Battery-Power-Isolator-Master-Disconnect-Cut-Off-Switch-12V-300A-Y2US/313223301531

To be fair, I don't trust the rating. But I'm only running it at 48V and 35A.

Seems like too much power for someone like yourself, thats some good throttle hesitation to beholdenth to.

 

[Tommm]

Why not use the switch on your battery... Let the bms FETs switch the power... It's what they are there for.

 

[Balmorhea]

https://www.ebay.com/itm/Car-Boat-Battery-Power-Isolator-Master-Disconnect-Cut-Off-Switch-12V-300A-Y2US/313223301531

To be fair, I don't trust the rating. But I'm only running it at 48V and 35A.

Seems like too much power for someone like yourself, thats some good throttle hesitation to beholdenth to.

You of all people should understand that 1500W is just like 750W, if you're twice as big as the designers expected.

One of my e-bikes goes about 20mph at WOT due to winding. The other one has the throttle level indexed to the PAS level, so I ride it the same way, with the throttle pinned at cruising speed. No need for subtle technique with a Hall throttle that isn't good at it.

I'm planning to get a slower winding motor for the faster bike, to make it behave more like the slower one. But I haven't decided to turn loose the money yet.

I could relace the hub to a kid-sized wheel like John in CR, but that would be foolish. Especially for a titan-sized man.

 

[John in CR]

https://www.ebay.com/itm/Car-Boat-Battery-Power-Isolator-Master-Disconnect-Cut-Off-Switch-12V-300A-Y2US/313223301531

To be fair, I don't trust the rating. But I'm only running it at 48V and 35A.

Seems like too much power for someone like yourself, thats some good throttle hesitation to beholdenth to.

You of all people should understand that 1500W is just like 750W, if you're twice as big as the designers expected.

One of my e-bikes goes about 20mph at WOT due to winding. The other one has the throttle level indexed to the PAS level, so I ride it the same way, with the throttle pinned at cruising speed. No need for subtle technique with a Hall throttle that isn't good at it.

I'm planning to get a slower winding motor for the faster bike, to make it behave more like the slower one. But I haven't decided to turn loose the money yet.

I could relace the hub to a kid-sized wheel like John in CR, but that would be foolish. Especially for a titan-sized man.

Bad advice as is typical from Balmorhea. Large people need the lower gearing of smaller wheels much more than cyclist lightweights for whom the too high gearing of large wheels with a direct drive hubmotor works despite the motor not being happy doing it. As proof just look at the multitudes of burned up hubmotors in 26" wheels, but I you'd be hard pressed to find a burned up hubbie in a 20" wheel. Even pushing just 100kg all up loads the Ebikes.ca simulator shows the how efficiency is lower by several % throughout the operating spectrum running a DD hubbie in a 26" wheel vs a 20" wheel, because the motor is geared too high with a 26" wheel. Slower winding has no effect, because it is nothing like gearing except that it turns slower at a given voltage. For those who still think winding makes a difference, think of all the products with electric motors and gears, or even multiple gear reductions. Why go through all that complexity when they can just quite easily wind the motor to a lower rpm per volt and eliminate the complexity? That doesn't work because the torque the motor can make doesn't change and more torque would be needed. That's why DD hubmotors have to be so big and heavy for the relatively low power they put out.

 

[Ianhill]

John you got a valid point with the wheel size a 20 inch wheel the circumference makes a massive difference to a 26inch let alone a 29er, but I disagree on the winding config as it makes a difference in the torque handling characteristics and overall rpm that's why rewinds happen.

I had the same dc brush motor in 36v and 48v variants nothing different but the windings the 36v took 50v and 60amp while the 48v took 60v 50amp to produce a very simular feeling ride torque,speed and heat output at the motor it felt even Stevens the same top speed and motor rpm was reached with the same total wattage on both motors just differing voltage and current requirements to get it there.

Mind I'm not saying there's a wind that works on 1v to 1000v all the same but there's an efficient wind that makes use of the space best for its working voltage so for example a 1v motor would need hundreds of amps and massive conductor area vs the thousand volt needing small area but many many turns so in theory one of those motors was slightly better than the other but I could not detect it with out a test bench setup 36 to 48v was not a big enough leap to say 1 outshines the other in any way.

A hub motor in a 26 travels 2m per wheel revolution vs 1.5m in a 20 so it is the same as swapping a gearing from 1-4 to 1-6 plus there's a wider tyre used for more drag on abigger wheel in general.

I done a a2b metro I used a mxus 3k 4T and a 20 inch rim so it's the low kv motor in a small rim I run it on a 10s pack and a 40 amp sinewave controller underrated it and the climbing results were shocking, the bike topped out at 16mph but I could go off-road no probs crawl about everywhere and get decent mileage off a 330wh stock pack built in the downtube, I could drop power to 25amp and still have a decent climb ability below that became lumpy feel the phases firing chugging up hill.

Mobility scooters use the same trick to get decent range on their pyles of junk their motor will run at 48v but they feed it 24v and it's geared so low the torque is high, the motor never really sees any high current jumps then from excessive strain just keeps plodding on and even a lead acid can get 7 miles or so at crawling speed.