Batrium Shunt inaccurate current measurment

madsci1016

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Dec 13, 2019
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My batrium shunt is reading inaccurate current. Both my charger and clamp on meter will show 100A charge current, the batrium reports 85A. This of course throws off the SoC counter.

Is there a calibration procedure for this? Googling doesn't reveal any.
 
Bit of a stretch but if the charger has a lot of electrical noise on it, some meters might read incorrectly.

More likely you might have another path for current around the shunt.
The battery -ve (0V) terminal should not have anything other than the shunt & a cellmon/longmon -ve connected.
ALL other -ve wires should go to the other side of the shunt.

Another cause might be if you have a load using some of the input current from the charger.
 
Mine's been working fine for a year now. Its very close (less than <1% difference) with my Midnite Classic Whiz Bang Jr (shunt) that is in series with it on the negative side of the battery bank.
 
A clamp meter is generally not accurate.
How is your charger meassuring? Clamp meter or direct?
 
Woah, lots of people attacking my question and not answering it ( Except Mike, thanks Mike I emailed them as soon as I saw your reply. ). Don't mean to be unappreciative, I bet there's lots of inexperienced asking these types of questions. For reference I'm an Electrical Engineer so I'm not your average enthusiast.

I'm using a Sunny Island 6048 to charge. I'd hope a $5k MSRP inverter has a good idea of the current leaving it, and my expensive and calibrated clamp meter agrees with it exactly, only the batrium is off. And it's only off on charge, on discharge they all agree.

AND the result is my SoC is constantly shifting down quickly and having to be reset on discharge (because it under-tracks energy going in but correctly tracks energy going out.)

I've made sure there's no possible explanation for current flow other than a mis-calibrated or defective shunt. Even disconnected my DC solar charge controller to make sure it wasn't trying to sink 500W magically somehow. Batrium requested detailed design of my system and their telelmetry logs which i sent them to review. Waiting back to hear what they say.

I agree its odd for a shunt to be inaccurate, and only in one direction. But I'm staring at one that is, I can't explain it. And I don't want to open it up till Batrium decides to cover this as a DoA and replace it. Someone on facebook said loose screws between the shunt PCB and the shunt itself could cause this, but I don't want to open it up till I hear from Batrium.
 
Not attacking at all, just trying to help - we only had minimal info to go on from your post & no idea about your setup or experience level, etc ;-)
Glad you've got the bases covered.

The (new info) clue might be in how it's only happening on charge but discharge reports normally.
Like suggested already, this might be from the Sunny Island unit making some electrical noise & this is hiccuping the shunt's readings.
The noise would only be there when charging....

Q: if you watch the current readings on screen reported by batrium when charging, are they steady (assuming of course input is steady...), or jumping around?
Q2: if you reduce the current output of the charger (assuming you can via s/w, switching out some PV, etc) does the inaccuracy track the reduction or do something else?
Q3: can you post a system diagram &/or pics?
 
As Said you should have given all that info from start what and howbyoubdid check :) that would have helped alot in answering.

Try to tighten the screws Tiny bit. They should dit right but not dead hard

I just myself had a shunt with 2 solder joints flawed so had to open mine. But my scenario was different.

That it should meassure wrong only One way seem very Odd to be true. That sounds like wrongly callibrated.
 
The error scales linearly based on charge current. No jumping around, dead steady. And since it's under-reporting instead of over-reporting, I doubt it's a bad solder joint on the shunt itself.

Really looks like a calibration error, hence my original simple question if there was a user calibration routine for it. Googling and their documentation did not reveal any.

I could buy a bad connection between the shunt and it's control PCB, as some impedance between the two could cause under-reporting, but I'm going to get Batrium's permission to not void my warrant before opening it up.

I do appreciate anyone that took the time to respond, thanks. As an engineer I get jaded when I'm bombarded with rookie level questions, but I'm sure most of the members in this hobby warrant such a response until proven otherwise. Sorry for being crass.
 
Yes and if you told all info directly me among others would have responded differently. 98% of the users are pretty new to this :)

I would Guess the problem sound like callibration issue a d No There are nothing available for us to callibrate it as of now.

My ref to bad solder was that There can be issues with urs though its not bad solder..

Mail batrium and with all info ie how you compare it and all such because otherwise they Will ask same questions.
 
Batrium confirmed its a mis-calibrated shunt and wants to replace it.

Disappointed I'm responsible for the $60-$80 return shipping on an item that arrived DOA as part of a $800 set though. For as much as they like to claim the extra price is worth the quality and accuracy, I'd rather see them fully stand behind that and cover all costs when it turns out not to be the case.

AIMs just took back two defective 100lb inverters and didn't charge me return shipping, so I guess i'm jaded.
 
I agree with you. I faulty product from the delivery should never ever be held on the customer side. I hope that was wrong info from their side
 
I checked the return policy and they will pay for the return if the issue is on their side. They need it to be returned as is. They check it out and then they send a new one back including the fee to return it. Sounds like the normal procedure.

If you need 0 downtime you either need to sign up for support contract regarding that but I dont think Batrium have that or just buy a 2nd unit to have meanwhile.
 
daromer said:
I checked the return policy and they will pay for the return if the issue is on their side. They need it to be returned as is. They check it out and then they send a new one back including the fee to return it. Sounds like the normal procedure.

If you need 0 downtime you either need to sign up for support contract regarding that but I dont think Batrium have that or just buy a 2nd unit to have meanwhile.

Where do you see that? Per their site"Returns for faulty goods:Please note, you will be responsible for paying your own shipping costswhen returning your item. Shipping costs are non-refundable."

They also told me this directly in an email.
 
Yes you have to pay for it initially. If the issue is deemed to be on their side they will get you the money back. As to standard procedures. You can cross check that with them.
1. You ship it back
2. They investigate
3. They will payout money for shipping and send you replacement when determined to be issue with the shunt.
 
I asked them this directly and they said no, not true, I will always be responsible for return shipping even if it's a DoA item. And if I'm unhappy with that i can return the entire system for a refund.
 
Wow, that's crazy. I thought that paying the premium over the Chinese BMS is that you get a company that stands behind a product. No way should a customer pay for the return of a defective product outside the customer's control. I just received my batrium bms last week and should have it fully installed over the next week or two. If I have the same problem, I'm going to be pissed.

How long has it been since you purchased? You could call your credit card and see if they could offer some assistance. Most credit cards in the US offer extended warranty protection, but not sure how that would apply for our DIY stuff.
 
Argh, the replacement shunt does the exact same thing. Accurate readings at 50A and 150A, but reads 100A when 120A charge passes through it, and 90A when 100A passes through it. IE, it appears there's an error range in the calibration and a new one has the same error.
 
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