BBSHD / Shark pack - Battery switch & watt meter

[TorEddy]

I guess there must be loads of BBSHD/Shark pack combos out there..
I have this combo myself, and since the shark pack does not feature a battery switch, I'm looking for a solution to cut the power to the BBSHD while not in use.

My previous bottle battery had a switch on the bottom which was very practical, and I want something equally stealthy and simple.
I guess the alternatives are:
- Using an external high amp/voltage power switch like the red plastic key switch. http://www.derek.com.au/narvabatteryswitch.jpg
- Using a relay to cut the power (complex and hard to source) Could be placed in the metal controller room of the shark pack.
- Mounting a switch in the shark pack for braking the BMS power somehow..? Easy to find a small low power switch.
- Disconnecting the XT90 connector or removing the battery is not the way I want to do this.

The easiest way would be the high amp/voltage switch. What kind of switch do they use in the Dolphin pack or similar, to handle this power?

And... since the Bafang dashboard is pretty useless at 52v (or any other voltage), I would like to have a watt meter installed.
I already have this watt meter:

I'm thinking of making a combo battery gauge/switch box to place between the battery and the BBSHD. Maybe in the bottom of my frame triangle.
I don't need to see my watt meter while riding, I just like to check my remaining capacity etc. from time to time.

Did anybody else find a nice solution for the battery switch or battery meter?
Some creative input on the battery gauge/switch-box would also be appreciated....

 

[TorEddy]

Ok.. so I guess most people just connect and disconnect the battery connector to the motor, to isolate the battery from the controller.

https://www.electricbike.com/the-onoff-switch/

I found a switch with specs like 50 A, 12 V (25 A, 24 V)
I found another switch with specs 600 v, 10 A.
Does this mean the latter switch can handle 300 V @ 20 A, or 150 V @ 40 A
How does this Work??

 

[amberwolf]

I found another switch with specs 600 v, 10 A.
Does this mean the latter switch can handle 300 V @ 20 A, or 150 V @ 40 A

No, it means it can handle 600v, 10a.

Some switches have dual ratings for AC vs DC, with DC ratings often lower because of arcing under dc vs ac being harder to break.

Some are only rated at one level, and specify just ac or just dc.

While you might be able to use a switch or breaker outside i'ts ratings, there is no guarantee it will be able to perform it's function reliably.


As for a battery meter, I prefer the Cycle Analyst from http://ebikes/ca as it does a lot more than just monitor voltage.

Many of it's control/limiting functions won't work well directly with a BBS system but there is a thread in the items for sale section about a CA/BBS setup that fixes that, if you're interested in using the CA for more than it's monitoring functions.

 

[Voltron]

Re putting a switch in.... you prob wouldn't have to worry about arcing too much, as long as the system is off when you disconnect the battery each time. It just has to be built for the amps flowing thru it, unlike a circuit breaker that has to switch off a live load. And I'm pushing my theoretical knowledge here, but you would only need one of the wires from the battery to have a switch and it will still be disconnected enough to isolate the controller? I would go for the positive, but maybe somebody else knows different?

 

[tomjasz]

These packs from a well known source have a tendency to arc and then shutdown. It's a BMS issue. They even have a procedure for flashing, or resetting the BMS. But as another poster pointed out, having the system shut down before removing and when replacing the pack ought to stop the arcing. Newer packs have a different BMS and fewer problems.

I used this switch for a two battery system. on/off/on, DPDT

http://www.nkkswitches.com/pdf/stoggleshighcap.pdf
http://www.newark.com/nkk-switches/s823d/switch-toggle-dpdt-30a/dp/10X9548?ost=10X9548&selectedCategoryId=&categoryNameResp=All%2BCategories&searchView=table&iscrfnonsku=false

 

[TorEddy]

I see.. the difference in the switch specs is for AC vs DC..
I too have a feeling that finding a switch withstanding the 30A (->50A) should be sufficient as long as the BBSHD is off when flipping the switch. I don't think any arcing will occur.
That means i only have to worry about the current part of the specs. Nice find on those switches tomjasz.., but i'm going with the red plastic key switch, as it is easy to source and plenty on the safe side.

Looks like I end up trying to 3d-model and 3d-print a combobox for the switch and wattmeter.

I am working on a 3d model now, but its compilicated... and my first time.
I'm thinking input/output XT90 connectors at the bottom of the triangle box, Display on the top, and key on the side.
Not that expensive to have it 3d printet locally.. gonna be fun to see the result.