Battery voltage levels

CharlieRN

We're still in the process of outfitting our recently acquired 320S BD, and haven't yet been anywhere with it. Along with generally checking things out, I've also been tracking both the charging of the stock solar system and the battery voltage as it sat in our driveway. While I expected to see some variation in the voltage level over the course of the day, I've been a bit surprised to see it drop down to 12.30v and even to 12.27v one day.

I have not had any of the 320's 12v devices or lights for more than few minutes, with only one exception. That exception was running the Alde on propane for few hours on one day, just to ensure that the system was working properly (it was).

What could be using enough current to drop the battery to ~65% of capacity?

Marceline

Assuming that the numbers are from your solar controller, aren't the high voltages during the day time when the panels are sending power to the battery? The low numbers are probably at night. 
Assuming that your battery cutoff switch is in the "on" position, there's always going to be some parasitic draw. If you have a conventional (not lithium) battery the string of 12.6v figures represents a 100% charged battery. Then it starts dropping only around day 11 or 12. Was the weather bad (preventing the solar from topping up the battery)? Was it on Day 11 that you ran the Alde? 

Denny16

What size and type of battery did your dealer install, this will make a difference on your readings.  You need to check the voltage of the battery a bit after Turing off the battery switch, and letting the battery rest to get an accurate battery voltage reading.  

Cheers

Dutch061

You will also need to "turn off the solar charging" if you want to get an accurate voltage reading unless you are checking after it is dark and there isn't any charging from the solar panel going on.

Brad

CharlieRN

Some added information.

The battery is a stock Grp 24 flooded cell 80 Ah. The min/max measurements are from the Victron controller history. I've validated its accuracy via a Klein digital multi-meter, checking the output after dark. While the solar panel is not well oriented - the camper is in my narrow driveway and can only be faced north - the battery is more or less fully charged most days when checked at sundown (> 12.6 v).

I got my lowest reading this morning - 12.2 v; the battery was 12.6 v when checked last night. Those numbers are from the Victron, but as noted, I'm getting more or less the same values when using the meter. I've tried to post the table with the min/max values by day but can't figure out how to keep the format intact (it's an Excel file).

Sharon_is_SAM

@CharlieRN - save a copy of your Excel document as a PDF and post it that way.

pthomas745

The only way to get an accurate reading of your battery voltage and state of charge is with a "rested" battery.  Battery switch off.  No power coming into the trailer.  Barring turning the switch off, try to turn everything off that you can before looking at the Victron readout. Trying to measure a battery that is putting power out on one side and bringing power in from the other is.....hard.  Even running my fan for a few minutes brought my battery voltage down to 12.09.........turning off the battery for 10 minutes showed me a "rested battery" reading of 12.46V. 

What app are you using to monitor?  Do you have one of the Shunts or the Victron Controller app?  If it is the shunt, you might need to run through the charged battery settings, etc.

Basil48192

Just a long-shot...but could your refrigerator be running?  I found that when boon-docking, the fridge operating on DC voltage sucks up a lot of energy.

Denny16

CharlieRN (OP) has a 2021 TaB320, which has the new AC/DC Isotherm Cruise two-way fridge which has a low power draw on 12VDC (unlike the 3-way propane fridge) with its Danforth compressor.  You can run this fridge on a 80 amp hr battery for several days and nights.  

The solar package on his trailer (a Boondock 320S) is enough to recharge the battery during the day, so with just a partial day of sun or cloudy bright days, the solar will recharge the battery back uptown 100% charge.  

Cheers

Basil48192

@Denny16.  Agreed.  I have the same system and it's definitely manageable...especially if you're getting sun.  I think, when running, it consumes about 3.5 amps per hour.  Depending on the fridge setting and ambient conditions, it could be a significant draw.  It shouldn't be draining the battery overnight, but It's probably one of the big draws.  
@CharlieRN.  Do you by chance have an inverter on your system?

Marceline

CharlieRN said:

 I've tried to post the table with the min/max values by day but can't figure out how to keep the format intact (it's an Excel file).

Why not take a screenshot of the table and post that? I think that it would help if people could see the actual numbers. When I made my comment about day vs night you still had them up.

Denny16

True Basil, but the fridge does not run continuously for any length of time, and never for an hour.  So the actual load over an hour of time might be around 1.5-2 amps.  Mine running all night on battery, only used around 16-20 amps max, which the solar panels easily replaced.
cheers

CharlieRN

Marceline said:

Why not take a screenshot of the table and post that? I think that it would help if people could see the actual numbers. When I made my comment about day vs night you still had them up.

What happened was that the format was fine as an Excel extract (the table showed everything lined up properly) until I edited my post. After that, the table was pretty much impossible to decipher. I am adding to it with readings at sunset and in the morning and will post again as a pdf when I have few more days of data.

@pthomas745's question about what app, I don't yet have a shunt, so have been using the Victron controller app history for the min/max readings. I do check the voltage regularly with a decent digital multi-meter and have found that the reading almost always is identical to the controller.

MuttonChops

@CharlieRN ; Sorry this thread got too complicated for a " it's 5 o'clock somewhere " afternoon.

My advice is Stop Worrying About the little details & Go Camping

If you run out of electrical power than you will have a worthwhile data point.
Sunsets & Sunrises are still wonderful even without lights . . . .

ScottG

Ha ha. I agree with you , @MuttonChops, but remember, one T@bber's worry is another's passion.  ;-)

I'm not so into smartphone apps and high-tech power management, but hoo-boy, don't get me going on plumbing or wiring!  :-)

Verna

My passions are woodworking, actual camping and traveling, and helping others . As long as we realize what our actual passions are, we can be happy and be passionate about what we want.