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

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speedyebikenoob   100 W

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

Post by speedyebikenoob » Aug 01 2020 3:07pm

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.

donn   10 kW

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

Post by donn » Aug 01 2020 6:10pm

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.

markz   100 GW

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

Post by markz » Aug 01 2020 8:29pm

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
search.php?keywords=cycle+analyst+drain ... mit=Search

donn   10 kW

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

Post by donn » Aug 01 2020 9:43pm

I left my Cycle Analyst on, and my battery came up drain-o.

speedyebikenoob   100 W

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

Post by speedyebikenoob » Aug 01 2020 11:11pm

donn wrote:
Aug 01 2020 6:10pm
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.
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.

speedyebikenoob   100 W

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

Post by speedyebikenoob » Aug 01 2020 11:12pm

donn wrote:
Aug 01 2020 9:43pm
I left my Cycle Analyst on, and my battery came up drain-o.
So it drained it pretty quick then?

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MadRhino   100 GW

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

Post by MadRhino » Aug 01 2020 11:43pm

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.
Make it fool-proof, and I will make a better fool.
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Street:
Trek Session 10 mod. Variable geometry. 70mph
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Santa Cruz V10. 50mph

donn   10 kW

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

Post by donn » Aug 02 2020 12:51am

speedyebikenoob wrote:
Aug 01 2020 11:12pm
So it drained it pretty quick then?
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.

LeftieBiker   10 kW

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

Post by LeftieBiker » Aug 02 2020 1:22am

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.

markz   100 GW

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

Post by markz » Aug 02 2020 1:15pm

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 - viewtopic.php?f=14&t=68896&p=1108547&hi ... e#p1108547

A good line in this post - viewtopic.php?f=2&t=67710&p=1021791&hil ... e#p1021791

Ah I found it, here. viewtopic.php?f=14&t=60169&p=1130932&hi ... r#p1130932

MikeyMK   1 µW

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

Post by MikeyMK » Aug 02 2020 3:24pm

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.

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E-HP   100 kW

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

Post by E-HP » Aug 02 2020 5:07pm

MikeyMK wrote:
Aug 02 2020 3:24pm
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.
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.

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fechter   100 GW

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

Post by fechter » Aug 02 2020 9:46pm

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.
"One test is worth a thousand opinions"

speedyebikenoob   100 W

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

Post by speedyebikenoob » Aug 02 2020 10:10pm

fechter wrote:
Aug 02 2020 9:46pm
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.
Do you have a cycle analyst on any of them?

donn   10 kW

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

Post by donn » Aug 03 2020 12:00am

MikeyMK wrote:
Aug 02 2020 3:24pm
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?
Not that I know of. Come back out, display is still lit up.
CycleAnalyst3.1manual wrote: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.

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fechter   100 GW

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

Post by fechter » Aug 03 2020 8:14am

speedyebikenoob wrote:
Aug 02 2020 10:10pm
fechter wrote:
Aug 02 2020 9:46pm
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.
Do you have a cycle analyst on any of them?
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.
"One test is worth a thousand opinions"

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

Post by amberwolf » Aug 03 2020 11:50pm

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.

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