Do I really need a switch for the battery if I have a controller switch?

S

speedyebikenoob

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My battery doesn't have a built in switch, but my controller has one. If my controller has one, is there really any need to get one for my battery? Is it bad for the battery? With the controller off the only thing it would be powering is the cycle analyst, which I'm assuming consumes very little power.
 
Cycle Analyst will run your battery down. But it's drawing power from the controller, isn't it? So you hook up a power switch to the controller, and then you can turn everything off. Maybe I'm missing something.
 
A BMS would drain the battery, we're talking mAh or uAh, nothing came up for the CA, user Justin_le and search term "Cycle Analyst Drain" came up Blanko
https://endless-sphere.com/forums/search.php?keywords=cycle+analyst+drain&terms=all&author=justin_le&sc=1&sf=all&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
 
donn said:
Cycle Analyst will run your battery down. But it's drawing power from the controller, isn't it? So you hook up a power switch to the controller, and then you can turn everything off. Maybe I'm missing something.
Click to expand...

Actually no, my controller doesn't have a cycle analyst output plug so I had to use the external shunt that came with my cycle analyst, so it's drawing power directly from the battery.
 
I use no switch on my batteries. I unplug them after every ride. :wink:

Many RC lipo users are doing the same, safest habit.

Typical ebike batteries are drained by their BMS, the reason why it is recommended to charge them every month when not in use.
 
speedyebikenoob said:
So it drained it pretty quick then?
Click to expand...

No ... honestly I don't remember how many days and how full the starting charge was. It isn't a hot draw, but it's like when the guy rifling through my pickup truck for something to steal left the glove box light on. Low battery, small drain, a few days.
 
If you don't want a switch, you can put a fuse on the battery + lead. That's a good idea anyway, and you can always remove the fuse for a total power-off.
 
With lipo, its best to be as safe as possible. I was trying to find the link to Justins post on his thoughts on Lipo and why he doesnt really talk about it at all when it comes to the Satiator

This is one here - https://endless-sphere.com/forums/viewtopic.php?f=14&t=68896&p=1108547&hilit=lipo+safe#p1108547

A good line in this post - https://endless-sphere.com/forums/viewtopic.php?f=2&t=67710&p=1021791&hilit=lipo+safe#p1021791

Ah I found it, here. https://endless-sphere.com/forums/viewtopic.php?f=14&t=60169&p=1130932&hilit=lipo+satiator#p1130932
 
My 48v displays switch themselves off after a couple of minutes (KT3 and SW900) but I'm currently building a 96v bike and intend to use a CA display. Does this not have such a feature?

I have a key switch on a twist throttle for the new set-up, just to get the bike functional, but I don't want to use that. Still, if I'm going to need a hard switch, I may as well switch the batteries for added safety. The problem here is it's a 96v 40ah pack (consisting of 4x 48v 20ah packs) and will draw a 3-figure sum of amps at over 100 volts - so a little rocker switch on the handlebar isn't going to be up to the job... Obviously the key switch just used the controller's on/off line but leaves the battery input live. Iran that's been fine for four years with 48v bikes..

The key switches on the batteries will be bypassed, as using 4 (+1) keys would be ridiculous. So ideas as to the best way to go here will be welcome.
 
MikeyMK said:
My 48v displays switch themselves off after a couple of minutes (KT3 and SW900) but I'm currently building a 96v bike and intend to use a CA display. Does this not have such a feature?

I have a key switch on a twist throttle for the new set-up, just to get the bike functional, but I don't want to use that. Still, if I'm going to need a hard switch, I may as well switch the batteries for added safety. The problem here is it's a 96v 40ah pack (consisting of 4x 48v 20ah packs) and will draw a 3-figure sum of amps at over 100 volts - so a little rocker switch on the handlebar isn't going to be up to the job... Obviously the key switch just used the controller's on/off line but leaves the battery input live. Iran that's been fine for four years with 48v bikes..

The key switches on the batteries will be bypassed, as using 4 (+1) keys would be ridiculous. So ideas as to the best way to go here will be welcome.
Click to expand...
I use a single pole, 40A, AC breaker as a switch for my battery. It's AC, so it won't ever trip as a breaker, but the contacts can handle a lot of current and voltage. I've flipped it on and off probably a couple thousand times and it still works great.
 
I have several bikes that don't have a switch on the battery and I don't unplug it (unless doing service). No issues with it draining while off.
 
fechter said:
I have several bikes that don't have a switch on the battery and I don't unplug it (unless doing service). No issues with it draining while off.
Click to expand...

Do you have a cycle analyst on any of them?
 
MikeyMK said:
My 48v displays switch themselves off after a couple of minutes (KT3 and SW900) but I'm currently building a 96v bike and intend to use a CA display. Does this not have such a feature?
Click to expand...

Not that I know of. Come back out, display is still lit up.

CycleAnalyst3.1manual said:
The CA3 turns on whenever there is voltage on the CA plug. With direct plug connections, if the controller has an on/off switch this would also turn the CA on and off. If the controller does not have an on/off switch or the Stand Alone CA shunt is used, then the the battery itself should have an on/off switch for turning the CA on and off.
Click to expand...
 
speedyebikenoob said:
fechter said:
I have several bikes that don't have a switch on the battery and I don't unplug it (unless doing service). No issues with it draining while off.
Click to expand...

Do you have a cycle analyst on any of them?
Click to expand...

Not on those bikes. My bikes with a CA have a switch. It would be possible to have the CA turn off with the controller by using a little solid state relay powered by the 5v throttle line.
 
Or just power the CA off the "ignition" line to the controller. That way whenever the controller isn't getting power to it's brain, neither is the CA.
 
Alright so I experimented a little myself. I let the bike sit for a few days with only the Cycle analyst on and surprisingly for me it seems to draw very little power. There was I think a 0.1v drop over two days. I don't see that being a problem, so I'm probably just not going to add a switch at all for the battery.
 
speedyebikenoob said:
fechter said:
I have several bikes that don't have a switch on the battery and I don't unplug it (unless doing service). No issues with it draining while off.
Click to expand...

Do you have a cycle analyst on any of them?
Click to expand...

I do and often forget to turn the system off, and have NEVER had a battery lose any voltage. You must have another drain when CA is on.
 
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