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EG4 Batteries Don't Read Below 2 Amps

solarpowermaniac

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Apr 30, 2022
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I purchased 12 of the EG4 batteries and because Signature Solar customer support is not returning my calls (their operator is very nice though) I decided to ask the question here.

I am using Solar Assistant with the 12 batteries and two LV6548s. I noticed that the batteries wouldn't show any current even though a few hundred watts were being pulled from them. After downloading Signature Solars BMS software and running some tests, I discovered that the BMS doesn't show any input/output unless the value is over 2 amps. So with my 12 batteries that is about 1,200 watts (12 x 2 amps x 50 volts) before anything is detected from the BMS.

One of their customer support agents said he would run some bench tests but then I never heard back even after calling and leaving messages the last few business days.

Anyone had the same issue and found a solution?

Attached some pictures showing the BMS info when 1.89 amps was being applied (notice it showing 0 amps) and then again with 2.09 amps.
 

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This is true for quite a few server rack packs. Pretty much all of them actually.

Sometimes it will register a lower current if it is steady for a long time.
 
This is true for quite a few server rack packs. Pretty much all of them actually.

Sometimes it will register a lower current if it is steady for a long time.
That's a shame. I was hoping there was a way to calibrate it. Even my cheap $150 daly BMS reads in 0.01 amp increments
 
I discovered the same issue with the ZEVA BMS I'm using. The sensitivity level is poor so once the current drops below about 150mA it just shows zero. If the batteries are being cycled all the time with not much stand-by time then the current levels are going to register and be fairly accurate BUT if your batteries are idle and the only current being used is from the Inverter, BMS and Active Balancer then several days go by but the SoC readings don't reflect the true usage due to small parasitic loads. I find that when charging the SoC hits 100% long before the batteries are actually topped up.
 
I will check to see what the BMS can read amp - wise, not sure. Will is right, a lot of the server rack packs are like this from what I've seen. They all pretty much have the same BMS installed. Just messaged our factory and when I hear back I'll update this post.
 
I will check to see what the BMS can read amp - wise, not sure. Will is right, a lot of the server rack packs are like this from what I've seen. They all pretty much have the same BMS installed. Just messaged our factory and when I hear back I'll update this post.
That would be great, thank you
 
Even some shunts have a difficult time reading very low currents. Very common. Use a clamp meter to get a rough idea. Probably easiest method.
 
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