question

blue-highways-traveler avatar image

Smart shunt

My battery bank is 250 AH and the smart shunt is saying I used 140 AH so far but is at 63% and the voltage seems low too for the percent of charge.

I have done all the settings in the Victron video and something still doesn't seem right. Any suggestions?

screenshot-20220104-094538.png

smartshunt
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3 Answers
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kevgermany answered ·

The shunt will synchronize state of charge once the batteries are full.

If you have already done this, maybe the battery capacity is entered wrongly, or there's a wiring problem.

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blue-highways-traveler avatar image
blue-highways-traveler answered ·

I left out some details. I have 250 AH of battery. I have the discharge floor set to 50%. I've had the shunt installed for a few weeks now. I have 300watts of solar and a DC to DC charger. I'm debating on which settings to use on the shunt. Right now these are my settings pictured below. I used a shore power charger to charge to float and used the shunt to see the tail current and it was around 2 amps. So if I did my math right that's 0.80% tail current setting. The rest are set to what I comprehend from the Victron video. The tail current setting seems off but that's what I measured from the shore power charger and it's built specifically for my batteries. I also tried to match the DC to DC charger settings to the shore power charger. Screenshot_20220104-103537.png

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doesn't look like your settings screen shot posted correctly, or at least I am not able to see it.
kevgermany avatar image
kevgermany answered ·

Synchronization occurs when three things occur.. Battery reaches charged voltage, tail current is met and this occurs for the specified time.

Tail current defaults to 4% whilst charging (at absorption voltage), your 0.8% at float voltage is very low and will probably prevent the automatic synch. Start from battery capacity. 4% of 250 is 10A. With solar people experiment with lower tail current and longer time to stop false synch when clouds slow down charging. But you shouldn't drop that far generally. And no need to do it unless you're getting false syncs.

Make sure the charge parameters are according to battery manufacturer specs.

Would be good to see the missing image.

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@Blue_Highways_Traveler

If you also had 'battery starts synchronised' checked and your batteries weren't at 100% then it will be out. You would need to pass through a charge cycle to correct it. By fully charged they have to go through the full absorption time and go back to float to sync.