Victron Shunt issues

[slowbutsure]

Hi

I have just installed a Victron Smart Shunt. I have 3 130ah batteries in parallel using two bus bars to connect them. The Victron Shunt says the voltage is 12.5, a multimeter says 12.4, I also have an Automatic Transfer switch which says 12.3! All are directly connected / tested at the battery terminals. I dont know which one is right! It is important as I have to set the voltage at which the Automatic switch changes over to grid power. If changes too soon it defeats the object, if too late it could damage the batteries.

The Smart Shunt is now saying 12.4 % and saying its 98% charged. Im not sure how 12.4% could be 98% charged? But they were fully charged when I connected the shunt.

Any help appreciated. thanks.

Trevor

 

[sunshine_eggo]

Hi

I have just installed a Victron Smart Shunt. I have 3 130ah batteries in parallel using two bus bars to connect them. The Victron Shunt says the voltage is 12.5, a multimeter says 12.4, I also have an Automatic Transfer switch which says 12.3! All are directly connected / tested at the battery terminals. I dont know which one is right! It is important as I have to set the voltage at which the Automatic switch changes over to grid power. If changes too soon it defeats the object, if too late it could damage the batteries.

Unfortunately, until you know which device is accurate via a calibration or correlation, you can't know. Absent other factors, I look to the most expensive device and/or reputation to likely be the more accurate.

The Smart Shunt is now saying 12.4 % and saying its 98% charged. Im not sure how 12.4% could be 98% charged? But they were fully charged when I connected the shunt.

It can't say 12.4% and 98% charged. I assume meant 12.4V.

Give that "I have just installed a Victron Smart Shunt," the shunt defaulted to 100% when energized. This does not mean the battery was fully charged. It means when the shunt loses power and is energized, it defaults to 100% unless you change the settings. It won't accurately reflect SoC until it the battery voltage and charge current meets the fully charged criteria you programmed.

You can force a manual SoC in the settings. I would force it to 70% to give something more realistic if these are lead-acid batteries.

 

[slowbutsure]

Unfortunately, until you know which device is accurate via a calibration or correlation, you can't know. Absent other factors, I look to the most expensive device and/or reputation to likely be the more accurate.



It can't say 12.4% and 98% charged. I assume meant 12.4V.

Give that "I have just installed a Victron Smart Shunt," the shunt defaulted to 100% when energized. This does not mean the battery was fully charged. It means when the shunt loses power and is energized, it defaults to 100% unless you change the settings. It won't accurately reflect SoC until it the battery voltage and charge current meets the fully charged criteria you programmed.

You can force a manual SoC in the settings. I would force it to 70% to give something more realistic if these are lead-acid batteries.

Yeah I meant 12.4v. The batteries are new and I installed them the same time as the shunt and I charged each battery individually before putting them together. So it says 12.4v and 99%. I am suspicious if these batteries are poor quality, they were quite cheap even though brand new. But that doesn't solve the different varying voltage readings issue. I am tempted to go with the multimeter as its in between the other two voltages. but I dont think you can change the voltage that the shunt is displaying, you can't calibrate that can you?

 

[sunshine_eggo]

Yeah I meant 12.4v. The batteries are new and I installed them the same time as the shunt and I charged each battery individually before putting them together. So it says 12.4v and 99%. I am suspicious if these batteries are poor quality, they were quite cheap even though brand new. But that doesn't solve the different varying voltage readings issue. I am tempted to go with the multimeter as its in between the other two voltages. but I dont think you can change the voltage that the shunt is displaying, you can't calibrate that can you?

Unless the DMM is a quality name brand noted for accuracy, I'd consider the shunt the more accurate device and 12.5V is more consistent with a very recently fully charged FLA battery. If you have a friend with a Fluke, that could answer the question. I suspect that 0.2V difference between shunt and ATS is not the catastrophe you imagine.

Cheap batteries are never high quality unless you "know a guy" and are getting a deal the general public can't get.

Did you charge the batteries according to their specification, or did you use a 12V charger you had laying around?

Again, the 99% from the shunt means it showed 100% when you powered it on, and 1% has been used . It won't be reliable until the shunt observes a charge that meets the sync parameters that you programmed. The shunt does not otherwise use voltage in any way to determine SoC.

 

[slowbutsure]

A bit of progress. I have a Victron Shunt, charger and temperature sense, so I took them off the network so that they all worked independently and they were all very similar. So it must be the transfer switch thats out.

 

[Supervstech]

A bit of progress. I have a Victron Shunt, charger and temperature sense, so I took them off the network so that they all worked independently and they were all very similar. So it must be the transfer switch thats out.

Make sure all your connections are clean and tight, resistance can throw off a voltage measurement.

 

[slowbutsure]

I will check them all again, thanks.

 

[slowbutsure]

I am also struggling with the settings. The batteries seem to always be in Bulk even though the charged setting = 13.2 in Shunt settings. Im not sure how this setting relates to the controller settings for bulk and absorption. There is a constant load on the system which is sometimes 20w and sometimes 70w, its a small freezer. Could anyone have a look at the settings of both attached and tell me what I need to change please? I have just done a manual synch to say it was 100% full. The battery seems to be automatically set to a Gel battery but there is not an option for Lead acid that I can see?

I am also confused on the display that says 100% SOC. Is that 100% of the full battery capacity at 390ah, or is it 50% of that given the floor is set to 50%?

Many thanks,

Trevor

 

[Zil]

I would trust the Victron meter for voltage.
Here is an article for setting the Victron monitor. After you read, please click on "About Us" and discover Rod Collins. Then click on "How to Articles".
https://marinehowto.com/programming-a-battery-monitor/

 

[HRTKD]

In the Victron Connect app, bring up your solar charge controller. Get into the parameter configuration screen. On the "Battery preset" line click on the drop down and select "User defined". There is no option to select "Lead acid", at least not in the demo library that I'm using with the app.

Once you are in the "User defined" mode, you'll set the charge voltages according to what the manufacturer of the battery calls for. Be sure you also set the battery voltage and max charge current at the top of the list.

 

[sunshine_eggo]

I am also struggling with the settings. The batteries seem to always be in Bulk even though the charged setting = 13.2 in Shunt settings. Im not sure how this setting relates to the controller settings for bulk and absorption. There is a constant load on the system which is sometimes 20w and sometimes 70w, its a small freezer. Could anyone have a look at the settings of both attached and tell me what I need to change please? I have just done a manual synch to say it was 100% full. The battery seems to be automatically set to a Gel battery but there is not an option for Lead acid that I can see?

I am also confused on the display that says 100% SOC. Is that 100% of the full battery capacity at 390ah, or is it 50% of that given the floor is set to 50%?

Many thanks,

Trevor

If you don't understand something after watching this video, please ask.

 

[slowbutsure]

In the Victron Connect app, bring up your solar charge controller. Get into the parameter configuration screen. On the "Battery preset" line click on the drop down and select "User defined". There is no option to select "Lead acid", at least not in the demo library that I'm using with the app.

Once you are in the "User defined" mode, you'll set the charge voltages according to what the manufacturer of the battery calls for. Be sure you also set the battery voltage and max charge current at the top of the list.

Thanks, thats helpful, i've done that now.

 

[slowbutsure]

If you don't understand something after watching this video, please ask.

That was helpful, thanks. Ive done the settings now. Im going to remove the load and let the batteries fully charge and synchronise. Hopefully that will sort everything.

 

[slowbutsure]

I would trust the Victron meter for voltage.
Here is an article for setting the Victron monitor. After you read, please click on "About Us" and discover Rod Collins. Then click on "How to Articles".
https://marinehowto.com/programming-a-battery-monitor/

Information overload on this link for me. I have managed to sort the settings out, and will remove the load and let the batteries fully charge and sync, hopefully that will sort out all issues. Thanks for your help.

 

[slowbutsure]

Thanks everyone for your help. I think that will be most of the issues sorted, will be able to tell after a full charge tomorrow. One thing I am still confused about in the shunt. When it says the batteries are at 90% State of Charge, is that 90% of the the full amp hours (390) or does it take the lead acid floor of max 50% charge, so its 90% of 195 amp hours available?

 

[sunshine_eggo]

Thanks everyone for your help. I think that will be most of the issues sorted, will be able to tell after a full charge tomorrow. One thing I am still confused about in the shunt. When it says the batteries are at 90% State of Charge, is that 90% of the the full amp hours (390) or does it take the lead acid floor of max 50% charge, so its 90% of 195 amp hours available?

% is always % of total programmed capacity, 390Ah
The 50% discharge floor is what's used in the "time remaining" value, e.g.,

390Ah battery
50% discharge floor
39A draw

At full charge, it will say 5 hours remaining, 100% SoC
At 292.5Ah remaining, it will say 2.5 hours remaining, 75% SoC
At 195Ah remaining, it will say 0 hours remaining, 50% SoC

The Peukert effect is ignored in this example.

 

[slowbutsure]

% is always % of total programmed capacity, 390Ah
The 50% discharge floor is what's used in the "time remaining" value, e.g.,

390Ah battery
50% discharge floor
39A draw

At full charge, it will say 5 hours remaining, 100% SoC
At 292.5Ah remaining, it will say 2.5 hours remaining, 75% SoC
At 195Ah remaining, it will say 0 hours remaining, 50% SoC

The Peukert effect is ignored in this example.

Thanks, thats good to know. So for using the SOC % to see how much usable power you have left, would there be anything wrong with putting the 50% amp hours in the battery capacity setting (195) and make the floor zero? With the desired result of the SOC 0% = all usable amp hours are gone (but the battery is 50% charged).

 

[sunshine_eggo]

You could do it that way.

I prefer an accurate reading at all times. There are times when not everything goes right, and your choice is to 1) lose a critical function (RV furnace for example) or 2) use more than 50% of your capacity.

I would always choose #2, and I would prefer to know the battery's true state of charge when it happens.

 

[slowbutsure]

You could do it that way.

I prefer an accurate reading at all times. There are times when not everything goes right, and your choice is to 1) lose a critical function (RV furnace for example) or 2) use more than 50% of your capacity.

I would always choose #2, and I would prefer to know the battery's true state of charge when it happens.

That's a good point, thanks.

 

[slowbutsure]

A battery question on this system. I have 3 x 130ah lead acid leisure batteries in parallel. I have 360w panels on my shed roof but while its overcast they are struggling to charge the batteries. Two days and still not fully charged. So tomorrow I am buying some larger panels, 3 x 410w panels. The new panels will have their own Victron charge controller because of bigger volts and amps.

My question is, how many amps could, in general, 3 lead acid batteries in parallel cope with when charging? The most I have had out of the 360w panels when its sunny is 15 amps. With the new panels, im guessing there would be (from all panels) about 30-40 amps. I don't want to fry the batteries! I have had no success trying to get any information from the ebayer I bought them from and the batteries have no brand names on them. Thanks.