Battle Born: Worse after upgrade from 2 to 3

[ckronvall]

Had the closest Airstream dealer ( 2 1/2 hours away) install 2 Battle Borns in our 2008 23FB Queen a year ago (spring 2022). All was fine except exterior solar connection installed by a non-Airstream dealer wasn't working on our 9/22 to 2/23 trip. Decided to have Airstream fix the solar connection (that's working OK-with good sun, that charged faster than the Champion is now) and add a 3rd Battle Born (now 3X100 Ah). On first trip out (to the Olympic Peninsula-rain for 6 days, so no solar option), batteries dropped to 60% in 2 days--temps in 40-50's with intermittent propane furnace operation, refrigerator on propane, and LED lighting at night-out hiking most of the day. Ran the Champion for over an hour and the battery reading only went up to 65%. Called the dealer and they said to manually set the SOC to 100% via the Victron app even though it only was reading 65%, which didn't make sense. Dealer also said that the SOC may need to reset at 100%, so moved to a State Park with shore power and charged back up to 100%. Drained to 95% after getting home and tried to recharge with the Champion--increased to 96% after 20 minutes, so feel like I'm back at ground zero. Any ideas on a solution would be appreciated.

[richard5933]

Couple of things...

When the third battery was added, did you adjust the shunt/app to reflect the new higher battery capacity?

Three batteries are going to take longer to charge than two. Not abnormal for your Champion to charge more slowly than you're used to - with more total capacity it will take longer to fill the bank.

The SOC % should be reset to 0 after you know that the batteries are full. What type of converter/charger are you using? If you're plugged into shore power, use the converter/charger for as long as it would take to charge from 0 to 100%, and then you can assume they are at 100% and reset the SOC.

[1StreamDream]

I agree the most likely issue here is increasing the victron settings ... for my unit (Victron 712) its on the same screen where the SOC can be reset to 100%. Make sure that yours is set to the correct value (300) so the degradation is properly scaled.

[Silvr_Bullet]

Don’t make the mistake of not letting your batteries charge to 100% before synchronizing. I would remain on shore power 24 hours after you first see your reading of 100% then synchronize.

[ROBERT CROSS]

I have found,(after 4 seasons), that the Victron SOC reading can be a very elusive target.
I just conserve and charge when the BMS tells me so.


Bob
🇺🇸

Is this correct or just a dart board guess?, not really concerned, it's been 2 weeks since the de-winter when system was switched back on.
I'll just charge up before our trip next week & enjoy.

[ckronvall]

It is a Victron 712. Attached screenshot shows that is correctly set at 300Ah.

[1StreamDream]

Yep, looks right. Since you have the Victron 712, a second suggestion is utilize the TRENDS tab in the Victron App, to observe your current (and SOC) over a 12hr or 24hr segment of time, see if you have an amp draw of some kind, possibly a weak short to ground that might have developed during install/upgrade time. For reference I pasted a trend line view from my trailer, the blue line is current, and values above zero are charge going into the battery (solar in my case), and values below zero are electrical loads pulling amps out of the battery. Mine is a 12hr segment, mostly overnight so a brief initial period was still some solar charging, then it becomes all load draw overnight. The large (negative) spike is when I ran my microwave to reheat some leftovers. Watching these trend lines should give you a good idea how your shore power charging and subsequent trailer power consumption are behaving, perhaps that will give you a better idea.

[waninae39]

best to read through the BMV manual for the setting

also go to the Victron site and read up the suggested values for the various types of lion batteries
https://www.victronenergy.com/

[daleyocum]

Fo verify the converter/charger has been upgraded to one with a Lithium setting. Lithium charges at a higher voltage and the stock one for your model year didn’t do Lithium properly.

Assuming it’s been updated, the more batteries you have, the longer it’s going to take to charge. The typical converter/charger charges around 50a so a 300ah battery bank will take 6hrs from zero with your generator capable of providing much more current that that, the charge rate is limited by the charger.

Battleborn’s site gives you recommended settings for the BMV712. I’d put my money on the charger not being Lithium capable or not being set properly for Lithium, though.

An easy way to tell is, when the batteries are somewhat discharged, plug it into shore or generator power and see what the BMV712 says it’s charging at. If it’s much less than 50a, the problem is the charger.

[uncle_bob]

Hi

As mentioned above, there are a lot of little settings on the shunts. Each one has an impact on how accurate the reading is. You very much need to spend some "quality time" digging into each setting. They come with lead acid defaults so assuming they are right is not a good idea. Also assuming the dealer understands this stuff is an even worse idea.

Bob

[Vlamgat]

Adding to the invocation to use the Victron web site for settings. I do not believe that the charged voltage of these batteries is in the 14 volt region. That's just the charge voltage to get to capacity. In addition, most LiPo batteries have a 100%SoC in the 13.7-9 region and mine are recommended at 13.8 which is also the Float charge level.

[ROBERT CROSS]

Remember..."float" is a charging voltage not a rest number.
Our BB's rest until charging is needed.

Bob
🇺🇸

[Life is a Highway]

Don’t let them discharge below 10 percent.

[ROBERT CROSS]

Originally Posted by Life is a Highway

Don’t let them discharge below 10 percent.

They won't, that's what the BMS does.

Unless yours aren't so equipped.

Bob
🇺🇸

[pcskier]

Once charged to 14.2 v, turn off solar (or wait till night) and shore power, then resynch SOC to 100%. And as others have said, make sure your app settings are all appropriate as per Victron for your batteries, and double check solar and converter/charger settings as well (for lithium settings).

Also here is a good video.

https://youtu.be/cpd6i3k31QE

[uncle_bob]

Originally Posted by pcskier

Once charged to 14.2 v, turn off solar (or wait till night) and shore power, then resynch SOC to 100%. And as others have said, make sure your app settings are all appropriate as per Victron for your batteries, and double check solar and converter/charger settings as well (for lithium settings).

Also here is a good video.

https://youtu.be/cpd6i3k31QE

Hi

Like a lot of little bits, the "resynch" thing is dependent on settings. I believe you can set a time and a voltage for the process. You may be able to turn it off entirely.

As noted in messages above, there are a range of possible voltages you could use to trigger the synch. There are also a range of float voltages you might have things set to. Do you set it at / below / above the float voltage? Watch the various videos and read all the messages. There are arguments infavor of each of the three answers. There is no one "correct" number.

Lead acid batteries waste part of the energy used to charge them. There are several settings that reflect this. They all pretty much need to be "shut down" for lithiums. Again, there are videos.

The one thing that the shunt can not tell you:

Did the dealer hook up all three batteries?

The shunt knows nothing about that part of things. Only a multimeter on battery posts can fully answer that question.

Bob

[Justinfinity]

Keep in mind that the Victron BMV-712 is NOT a charge controller; rather, it's only a monitor. Your charge sources (solar, shore converter/charger, alternator regulator, etc) need to be set to provide a charge voltage that will bring LiFePo4 (or whatever chemistry) batteries to their full charge. It's also good to measure the actual charge voltage that is being delivered to the batteries at their terminals because you can have voltage drop along the circuit. So, for example, even if you have set the charge source for, say, 13.6 volts for "bulk/absorption" charge voltage, you may not be getting that needed voltage at the batteries. I've had to boost the voltage on an alternator regulator to 13.8 in order to get the desired voltage of 13.6 at the batteries and 100% SOC. And, to echo my opening statement, you can't use the "14.2 charged voltage" except as a setting on the shunt so it "knows/thinks" that the batteries are fully charged. That "14.2 charged voltage" doesn't actually set the charge source.

[gblackburn]

Originally Posted by ckronvall

It is a Victron 712. Attached screenshot shows that is correctly set at 300Ah.

I think your Discharge Floor setting is incorrect. I don't think you want to discharge them all the way to 0%. I believe that 10-20% is the norm.

If you bring them down to 0 I think you are risking damaging the batteries.

[uncle_bob]

Originally Posted by gblackburn

I think your Discharge Floor setting is incorrect. I don't think you want to discharge them all the way to 0%. I believe that 10-20% is the norm.

If you bring them down to 0 I think you are risking damaging the batteries.

Hi

There a couple issues here:

1) The 712 does nothing to stop you discharging the batteries. It has no control over any of that.

2) The BMS internal to the battery *does* have control over this. It very much knows what is and is not going to damage things. You can't program it so there are no settings to fiddle. The BMS will shut off the batteries when they get low. That's what it's there for (along with some other things).

3) The raw cell capacity of the batteries is some number. We don't have access to that info. The folks who designed the battery *do* know what that is. When we talk about 100% or 0% we likely are not talking about raw cell numbers. We are talking about what we can get at before the BMS shuts us out.

4) If the raw cell numbers are 110% of the battery capacity *and* the BMS cuts out when the raw cells have 10% left, you would not have to worry about going "to low" on the raw cells.

5) Going to zero on the batteries (any battery) and having the shut down on you is never going to be the goal. Getting up in the morning with no power for the coffee is *not* a good thing

Best guess is that the BMS cuts out before there is a risk of damage.

Bob