Favorite battery capacity meter.

[PCeBiker]

I didn't read all of it. I laughed at the cat.
It probably thinks if I'm gonna put it in the oven.

There's plenty of cat and dog recipes on the internet.
It's a delicacy in China.

 

[Rome]

I was at a wedding party some years ago they rolled out a 10' cobra snake cake

 

[PCeBiker]

There's plenty of cat and dog recipes on the internet.
It's a delicacy in China.

It was not real

Seriously,..
There was a guy in Toronto that fell to his death from an apartment building.
The police found his body with a garbage bag full of cats beside him.
He was collecting stray cats to sell to clandestine Chinese food restaurants.

That's no s*it of a lie.

In the America's, we eat cows, pigs, and chickens and keep cats and dogs as pets.

Some countries ride horses.
Some countries eat them.
Some countries eat cats and dogs,
Some countries keep them as pets.
Some countries eat cows,
Some countries worship them.

I want a golden eagle as a pet and friend.
They can hunt big game for me.

Some people shoot 's.
Some people have pet 's.

Some people hate 's
I 's...

Everybody hates Yellow Jackets, but I rescue them and set them free,..
The poor bastard fell into my V9.
(V8 vegetable juice + Vodka)

 

[Rome]

Canada are different from America.
I eat grass feed beef eggs from free range hens. Vegetables from my yard.

 

[PCeBiker]

My cat can be viscous too,..

Buts she's not nearly as cool as a Golden Eagle !!

(And she was just yawning,..
She's usually pretty sleepy,..

 

[Rome]

Cute man!
I gotta go Costco for pizza before the raiders and chiefs NFL game.

 

[PCeBiker]

Canada are different from America.

No,.. We're about the same.
We're just the little brother that lives up north, and you're just the cousin that lives off shore.

 

[m@Robertson]

My bad.. I hadn't realized that you guys were planning lunar voyages that require down to the millivolt accuracy.

These days all I care about is a numeric voltage readout. I've replaced all my displays with super simple ones that only serve as PAS panels, and show just speed, which I could do without, too.

I think all the preoccupation with data takes away from one of the core benefits of cycling: Just f**king ride and forget about all the extraneous BS.

 

[PCeBiker]

 

[6zfshdb]

I believe those rely on past/current load as a basis and that has its flaws as well, especially when the remaining future use is not equivalent.

This is true but someone should be able to come up with a % state of charge gauge based on voltage that compensates for the non linear voltage drop as the battery discharges. The accuracy wouldn't be perfect but it would be far better than the gauges I've seen on many bikes.

 

[6zfshdb]

Ahh, crap!!
I didn't know that. I've already got the 500A version.
The 50A version is $10 cheaper too.




I've been thinking about how and where to install the shunt.
I was thinking inside the frame in the hollow space above the upper battery bracket where the power cable connects to the battery bracket.

View attachment 167107




I've already got two holes with grommets coming out of the hollow space. I should be able to fish the cable through the grommet?

View attachment 167110

I was wondering if I could wrap the shunt with foam rubber to protect and isolate it?
It would be difficult to screw it down or glue it to the inside of the hollow space.
I could then remove the heavy acrylic bracket from the shunt as well.

View attachment 167113

I figure that the shunt would generate very little heat because it's only seeing 20 amps and it has a resistance of almost 0 ohms.

Do have any advice on that?

I did buy a cheap 20A shunt for $4 but it might not be accurate, and it's kinda big itself at 4½" long.

View attachment 167111


I want to use the shunt that came with the digital meter because I'm pretty sure that I can plug both the digital meter and my analog ammeter into it at the same time.
I'm pretty sure that I would just connect the ammeter to the B- and P- terminals, and the digital meter would plug into the connector?

That way I can tuck the digital meter away somewhere and have it set to monitor my battery's total capacity while I have the ammeter on the handlebars for quick reference.

I use that 500A model on one of my bikes and yes, it generates very little heat. Since it barely gets warm, I removed the shunt from it's thermoplastic housing to save space:

I bolted it directly to the plastic controller housing using stainless steel washer underneath.

I don't recommend encapsulating, or mounting it in a tight space with little air flow though. Heat could build up over time.

You can try connecting your ammeter across the B- and P- terminals but without knowing the circuitry, I can't be sure if the internal resistance of the ammeter will affect the digital readout.

FWIW, by comparison, the 500A gauge seems to be just as accurate as the 50A model, even at low current levels.

 

[PCeBiker]

Thanks for the reply @6zfshdb

I use that 500A model on one of my bikes and yes, it generates very little heat. Since it barely gets warm, I removed the shunt from it's thermoplastic housing to save space:
I bolted it directly to the plastic controller housing using stainless steel washer underneath.

I don't have any room for the shunt inside my controller, and it looks like the cable isn't quite long enough to reach my handlebars from the controller.

I don't recommend encapsulating, or mounting it in a tight space with little air flow though. Heat could build up over time.

I'd still like to put the shunt in the hollow space above my upper battery bracket. The power cable is right there with easy access.
Perhaps I could put the shunt in some kind of small box with a few breather holes and wrap it with some foam cushioning to stop vibrations?
That space is well protected from any rain.

You can try connecting your ammeter across the B- and P- terminals but without knowing the circuitry, I can't be sure if the internal resistance of the ammeter will affect the digital readout.

I just hooked up the ammeter to my bench power supply and it read full scale at 0.08V while the amps were reading 0.000 so it wasn't even drawing a full milliamp.
I figure that it should have no impact on the Watt meter unless there is some weird inductance or something going on that feeds back into the shunt and Watt meter?

FWIW, by comparison, the 500A gauge seems to be just as accurate as the 50A model, even at low current levels.

That's good to know, but even the smaller shunt would be kinda difficult to install.

I'm going to think on it for a while and see what I come up with.
I don't really need the ammeter or the Watt meter and cutting into the main power wire makes me a bit apprehensive. All the power that runs the ebike goes through the shunt so any sort of failure will shut down my ebike.

I do have the digital Watt meter built in to my display, which is useful but it has some kind of "digital damping" or something going on and I can't see the power spikes.