Battery Float Question

Good Afternoon -

I have a question about my SOC on my house battery bank. The 2008 boat (GB 47 Europa) is on the hard in Newport, RI area. No external power is connected except for three 200 Watt solar panels connected in serios on our Bimini. Toady I was looking at the information on the SOC for the battery bank and it appears to be all over the chart - so to speak. The three panels are in no shade and it was a beautiful sunny day up here, The screen shots I took were all around noon time today.

The Victron inverter is in the charge only state and the solar panel breakers are closed going to a Victron Smart Solar 100/50 MPPT controller. First attachment is the smart controller read out showing 10 Watts (very low for noon time) from the 3 panels - 67.58V with a current of 0.1A and on the same display it shows the battery bank on a Float batteries at 13.83V and 0.70A. Like the controller is limiting the amount going to the batteries because it believes they are full up on a Float. Second attachment is the overview of the Victron Inverter showing in the "Charge Only" state. Third is the Victron Inverter detail page showing the house batteries at 12.44VDC and a temperature of 4 degrees Centigrade. Finally the Electric panel DC Voltage meter selected to the house batteries reading out at 12.1DCV. So, if someone has some ideas as to why I am seeing three different DCV for the house bank I am all ears. Thanks for any help in advance.

Bob
"Serenity"

Oops - I guess I need to get used to posting on this new to me site. Here are the 4 thumbnail attachments in the order of the writing.

Good Afternoon -

I am having difficulty figuring out the SOC on our battery bank. The 2008 boat (GB 47 Europa) is on the hard in Newport, RI area. No external power is connected except for three 200 Watt solar panels connected in serios on our Bimini. Toady I was looking at the information on the SOC for the battery bank and it appears to be all over the chart - so to speak. The three panels are in no shade and it was a beautiful sunny day up here, The screen shots I took were all around noon time today.

The Victron inverter is in the charge only state and the solar panel breakers are closed going to a Victron Smart Solar 100/50 MPPT controller. First attachment is the smart controller read out showing 10 Watts (very low for noon time) from the 3 panels - 67.58V with a current of 0.1A and on the same display it shows the battery bank on a Float batteries at 13.83V and 0.70A. Like the controller is limiting the amount going to the batteries because it believes they are full up on a Float. Second attachment is the overview of the Victron Inverter showing in the "Charge Only" state. Third is the Victron Inverter detail page showing the house batteries at 12.44VDC and a temperature of 4 degrees Centigrade. Finally the Electric panel DC Voltage meter selected to the house batteries reading out at 12.1DCV. So, if someone has some ideas as to why I am seeing three different DCV for the house bank I am all ears. Thanks for any help in advance.

Have you checked the actual voltage at the batteries? Is that the 12.1V reading? I'm not the best at this, but from experience, voltage loss due to cable or other loss is my first hunch, but you have to understand the voltages first - I'd start at the batteries and work backwards.

There are some very bright folks on TF - hopefully they will chime in. The Bigger Brain of TF has proved invaluable to me to solve similar problems.

Peter

Peter is right. You need to first figure out what the actual battery voltage is using a meter. Then figure out who's reading it correctly and who's reading it wrong. Then figure out how to fix those who are reading it wrong.

I have similar different voltages that I have learned to ignore.
The shunt reads one voltage, the BMS another, both are from the battery. Then there are inverter chargers sending out a charge voltage which is higher. A volt gauge on dash at the end of a cable feeding DC breakers. I have found that while a charge voltage is higher than the battery voltage it is due to some of the charge being used before it gets to the battery. It may be that simple for you as well.

Something isn't right for the OP. Victron shows battery temp of 4C and 12.44V off Victron inverter. Not sure where he's located, but 4C is pretty cold for this time of year unless he's very far north. Temp isn't really important per se, but if it's way off, might be an indicator of other issues such as bad sensor connections.

He really needs to determine what is real with a meter than from there determine what the touch points are reading and explain any variances.

Peter it is 9C here and OP is in Rhode island. If we were all where you hang out it would be crowded.

I know nothing about the Victron displays other than what I can see on your screen shots, but I will take a shot at this.

The SmartSolar that reads 13.83V looks to me like it may be correct as by noonish on a bright late April day with 600 W of solar the batteries could very well be at float voltage, particularly as your refer is likely off (and empty) as you are still on the hard recovering from a long winter.
Plus the system is said to be "on".

The VE Bus (whatever that is) display shows no ac input or output, but knows the output will be 60 Hz (likely a setting) when it's "on" but at this point it is said to be "off". Could the 12.44 V and 4º C Temp. showing on the screen be the status of things the last time the system was on? Is it worthwhile to try turning it "on" and see if the numbers change to reflect those shown on the SmartSolar display?

The panel mounted voltmeter is said to be switched to show the voltage of the house batteries and displays 12.1 V. These types of voltmeters draw very little current and if it does not have a separate voltage sense circuit it measures the switched battery voltage. It could be that the contacts in the switch that you use to cycle from Battery Bank to Battery Bank are tarnished and causing a voltage drop. It does not take much tarnish to cause this kind of thing. Hopefully the contacts are at least silver and the switch itself is designed to wipe the contacts clean when switched. Try switching it to & from different Battery Banks multiple times and see if the voltage increases. If so, you may have just partially cleaned the contacts. Your choices are then, take the switch apart and further clean the contacts, buy a new switch or live with the low voltage reading.

Before you do any of this, measure and record using a good quality voltmeter, the actual voltage of the batteries at the battery posts so you know what the meters should read.

Just to satisfy my curiosity and if the readout is actually correct, what chemistry and brand of batteries do you have that float at 13.83 volts?

Hi everyone -

So, several of you are correct in that I should have taken the voltage at the battery bank terminals - will do. Also, the question of the temperature came up. Up here in the Newport, RI area we had frost on the ground and a freeze alert for this morning. Not to mention the Victron equipment is in the engine room and the C9 CAT engines just feel like big blocks of refrigeration right now. Spring does not really arrive here until mid June and the water temperature is running in the high 40 degrees F.

Bob

Hi again -

So at noon today I went over to NEB Safe harbor where the boat is on the hard. Attached are the picture of the data. Basically the Battery bank reads 12.38VDC. This is pretty close to the 12.44 VDC shown yesterday on the Victron Inverter in the "Charge Only" state. The reading that appears off is the DC Voltage meter on the electrical panel. possibly need to look at that and do some cleaning.

I think the solar is just confusing the issue and the data it is showing that the battery is on a Float does not make sense. Under normal circumstances the panels should be providing greater than 300W with the bright sunny days we have had lately. Not sure but I think the Inverter in charge only mode is preventing the solar system from operating normal. 10W makes no sense.

The banks are currently getting external power and when I left the boat we were seeing the second and third attachments showing the banks were in a Absorption Charge.

More to come I am sure. I will converse with Victron.

Bob

Not an expert, but I'd assume that your underlying problem is that the MPPT controller is "stuck" in float mode. There may be some useful report info on the History tab (eg was it doing normal bulk/abs/float and then changed to float only at some point). Regarding the battery voltage displayed as 13.8 this could be because it has lost connection to the battery (perhaps a fuse?) and is actually displaying the configured float voltage (check what this is set to in settings). A hard restart of the controller might also help.

I saw your OAT is 4 Celsius and I know that Victron has options not to charge below 4 Celsius, so may want to dive into that setting and see if the minimum charge temperature is not engaged.

No specificfix here but while Victron equipment is excellent it can be a bit confusing. Equipment can share voltage readings via a wireless or wired bus. So you need to go into the settings to determine where it is getting the reading from. For the solar charger it may determine its mode based upon another components state. Sorry I cannot be more specific but I amjust figuring this all out on my own boat.

RobertLeatch said:

Not an expert, but I'd assume that your underlying problem is that the MPPT controller is "stuck" in float mode. There may be some useful report info on the History tab (eg was it doing normal bulk/abs/float and then changed to float only at some point). Regarding the battery voltage displayed as 13.8 this could be because it has lost connection to the battery (perhaps a fuse?) and is actually displaying the configured float voltage (check what this is set to in settings). A hard restart of the controller might also help.

Click to expand...

After seeing that the bank voltage is 12.38 your thoughts makes sense. The bank voltage should have been at least 13.6 before float started. IMO.
A reboot of the MPPT? Or disconnect the input side from solar panels and then check voltage on output side cables to battery.

I think the process to reset the MPPT is to first disconnect the solar in cables (I have a breaker switch) and then the cables to the battery. Reverse order to enable (battery cables then solar).

Update - Late last week I had opened the breaker for the solar panels because in my opinion there was a solar system problem. Then Robert Leatch made a comment that struck a nerve. I had totally forgotten about the 40 amp fuse between the solar breaker and the battery bank. I didn’t think I had removed it for the winter so today I checked and sure enough no fuse. Replaced the fuse and voila the system started to act more normal - see first attachment. The boat batteries have been on a charge since last Friday.

So, I checked the other read outs and still think there may be a problem with the DCV Meter on the electrical panel. It reads about .3 to .4 DCV lower than Victron read outs. Any advice on where to find volt meter connection / contacts that should possibly be causing the lower reading?

Thanks Robert for your suggestion - it was right on the money.

Bob

A FUSE, who'd a thunk it.