So reversing a shunt is almost as good as a BMS?

Gazoo

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Or did you mean by connecting it the one way, as per instructions.
And without touching anything, it will actually measure input as well as output?
Yes that's what I said. The shunt terminal on the left goes to battery negative. The shunt terminal on the right goes to the load negative. Load negative is also the terminal to connect the chargers negative. I am looking at figure 2.2 of the wiring diagram.

If not using a relay the only other connection you need to make is to battery positive. Battery positive is connected to VIN on the green terminal. It is recommended to use a fuse on the positive. A 2 or 3 amp fuse is all you need and I recommend a blade type fuse.
 

SherylinRM

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Yes that's what I said. The shunt terminal on the left goes to battery negative. The shunt terminal on the right goes to the load negative. Load negative is also the terminal to connect the chargers negative. I am looking at figure 2.2 of the wiring diagram.

If not using a relay the only other connection you need to make is to battery positive. Battery positive is connected to VIN on the green terminal. It is recommended to use a fuse on the positive. A 2 or 3 amp fuse is all you need and I recommend a blade type fuse.
Ok, very cool. :)
I did not know it detected in both directions. Only the one is mentioned in the instructions.
Unless I missed something which is possible. :)
 

Dzl

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I did not know it detected in both directions. Only the one is mentioned in the instructions.

On rare occasions I'm worth listening to ;)πŸ˜€ (If its not clear I'm only joking, I would never fault someone for being cautious/skeptical)

A shunt--at least those I am familiar with-- is bi-directional, it will measure the net current in either direction, but it has to measure all current in both directions to accurately report state of charge. This is why most people locate it very close to the battery so it captures all current in and out of the battery.
In that case, this is stated in the product description: "The measuring module can detect the current in both directions. It is not necessary to change the wiring mode during the charge and discharge of the battery"
At about 3:18 he mentions it measures current in both directions
 
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SherylinRM

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On rare occasions I'm worth listening to ;)πŸ˜€ (If its not clear I'm only joking, I would never fault someone for being cautious/skeptical)
Thank you.
Just that every video I have seen [yes some are old too] show that you had to turn the shunt around to make it work backwards.
Both Will's video and Bus' video say the same thing.
Will even turns it around for us to show us how it does it.

So that is why I am incredulous I suppose. :)
 

Hedges

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Bottom line is I have no charger or BMS and yet need to charge and use my batteries.
Seems to me if you made a harness (molex connectors or whatever) that connected the cells in series for scooter use, and in parallel for charging,
you could charge the cells in parallel with a simple current-limited supply up to a voltage representing a safe 90% SoC.
Your trips are short enough not to over-discharge.
So they should get balanced every time they are charged.
 

SherylinRM

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Seems to me if you made a harness (molex connectors or whatever) that connected the cells in series for scooter use, and in parallel for charging,
you could charge the cells in parallel with a simple current-limited supply up to a voltage representing a safe 90% SoC.
Your trips are short enough not to over-discharge.
So they should get balanced every time they are charged.
That actually sounds like something I had in mind LOL.
Scary isn't it :p LOL
So great idea there Hedges 😁
 

Gazoo

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On rare occasions I'm worth listening to ;)πŸ˜€
Well that's debatable ... lol J/K
Both Will's video and Bus' video say the same thing.
Does that really matter? You own a JunTek....I own a JunTek. Others on this forum own a JunTek. You can either trust the videos you are referring to, neither of which refers to a Juntek, or you can trust others that have them. If you don't trust others that have them then perhaps you can trust the instructions.. :p If you cant trust the instructions then maybe you can trust the people who have posted YouTube videos of these things. Even JunTek has a video posted that clearly explains how these things work.

When you own a device, always refer to the instructions for the device you own. Don't wander off into what others say unless it pertains to your device.
 

SherylinRM

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Well that's debatable ... lol J/K

Does that really matter? You own a JunTek....I own a JunTek. Others on this forum own a JunTek. You can either trust the videos you are referring to, neither of which refers to a Juntek, or you can trust others that have them. If you don't trust others that have them then perhaps you can trust the instructions.. :p If you cant trust the instructions then maybe you can trust the people who have posted YouTube videos of these things. Even JunTek has a video posted that clearly explains how these things work.

When you own a device, always refer to the instructions for the device you own. Don't wander off into what others say unless it pertains to your device.
Actually Bus owns the Juntek hence the reasons for my questions.
The video was inserted in page one.

I guess I will have to reread the instructions then.
Thanks gazoo. I will do that now.
 

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PS: Bus' video was the one recommended earlier by "someone". ;)
I didn't watch all the way through so maybe I missed some context, but at 3:18 he does mention it measures current in and out

I think (and here is where I am speculating and could be wrong) that logically, A "soc monitor" or soc based "battery monitor" must be bi-directional. It can't measure SOC if it only observes current in one direction. To keep track of SOC, it is subtracting energy out from energy in, if it only sees one or the other, it can't function. At least that is my understanding.

I haven't seen Will's review of this yet. Do you have a link or search term?
 

SherylinRM

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In the fine print on page 2 it says:
"The instrument can automatically detect the direction of the current".
Thanks again guys. :)
 

SherylinRM

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I didn't watch all the way through so maybe I missed some context, but at 3:18 he does mention it measures current in and out

I think (and here is where I am speculating and could be wrong) that logically, A "soc monitor" or soc based "battery monitor" must be bi-directional. It can't measure SOC if it only observes current in one direction. To keep track of SOC, it is subtracting energy out from energy in, if it only sees one or the other, it can't function. At least that is my understanding.

I haven't seen Will's review of this yet. Do you have a link or search term?
No link sorry. And I did a fast look too on his youtube channel.
 

SherylinRM

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Ok then. This is settled LOL.
Thanks a lot guys. You have been very helpful to someone that never done this before. :)
Now I almost know it all just like you guys right? 😁 :rolleyes: πŸ€£πŸ˜œπŸ˜πŸ™ƒπŸ™‚
 

Gazoo

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I guess I will have to reread the instructions then.
Thanks gazoo. I will do that now.
I explained this to you in post 25. I have been using mine for over a year. It has always measured current going in and out. It is mounted in a battery box in such a way I can't get to it to switch it around.
 

Dzl

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Now I almost know it all just like you guys right? 😁 :rolleyes: πŸ€£πŸ˜œπŸ˜πŸ™ƒπŸ™‚
If you are at the same level as me, you should be worried, I know just barely enough to get myself into trouble and stick my foot in my mouth near daily, and to grasp how little I actually grasp πŸ˜€;)

Real talk though, I do admire your inquisitiveness and tenacity to learn and keep asking until something becomes clear to you. Its a good skill to have.
 

Gazoo

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Actually Bus owns the Juntek hence the reasons for my questions.
The video was inserted in page one.

I guess I will have to reread the instructions then.
Thanks gazoo. I will do that now.
Ok I missed that video. Sorry. But still....
 
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