Shore power charging too slow

DenverJaguar

I went out to charge my batteries today. I have 200AH Battleborns The Victron app said there was a low voltage alert, but the state of charge was 100%. This was wrong; it was really about 20%, based on it being at 12.9 volts. I connected shore power -15 amps - and the Victron app showed 10 amps. This slowly dwindled down to 3.5 amps over an hour. It's been charging for 7 hours and I only went from 20% to 39%. I disconnected shore power and reconnected, and it went back to 10 amps, but it's already down to 7 amps after 10 minutes. The batteries are nowhere near charged enough to warrant such a slow charge.

Why is it taking so long? Why isn't it charging at 10-15 amps consistently? Why would the state of charge show 100% in the app, but also show a low voltage alert? Why would I even get a low voltage alert when lithium batteries can be depleted to 0? Why would my solar controller stop charging upon a firmware update (it suddenly showed only 17.5 volts despite being in direct sun, no issues with loose wires, and Victron won't turn the charger on unless the voltage is +5 VDC over the battery voltage, which is about 13. 

I can't find any good answers to these questions online. 

Marceline

It sounds like your Victron devices might not be set up properly for your batteries.

First of all, the SOC of charge number isn't reliable unless the app has been equalized to 100% when you're absolutely sure that the batteries are completely charged up. 

If you didn't get hard copies of the relevant Victron manuals for your devices, you can find them here. 

https://www.victronenergy.com/support

rfuss928

The charging is not correct when on shore power which indicates the convertor is not set for the Li batteries.  Possibly the WFCO Auto Detect issue discussed in other posts?
https://tab-rv.vanillacommunity.com/discussion/16210/wfco-wf-8735-ad-lifepo4-fyi-on-annoying-auto-detect-quirk/p1

dsfdogs

@DenverJaguar what year is your trailer and what WFCO converter do you have? Does it have the "AD" sticker on the front? If it does have that sticker, then it appears to need the fix/jumper so it will always charge lithium per the link above. If it does not have the sticker and you have an older trailer, then the WFCO will need to be upgraded to one that will charge lithium, or it will always be short and slow in charging. If you don't want to upgrade your WFCO, then you can purchase a separate battery charger. I used Noco 10amp and directly charge the batteries as it can be set to lithium. (I plugged into a separate solar port with adapters and charged that way).

If you want to post screen shots of your solar controller settings page, we could help you ensure the settings are correct for lithium.

DenverJaguar

dsfdogs said:

@DenverJaguar what year is your trailer and what WFCO converter do you have? Does it have the "AD" sticker on the front? If it does have that sticker, then it appears to need the fix/jumper so it will always charge lithium per the link above. If it does not have the sticker and you have an older trailer, then the WFCO will need to be upgraded to one that will charge lithium, or it will always be short and slow in charging. If you don't want to upgrade your WFCO, then you can purchase a separate battery charger. I used Noco 10amp and directly charge the batteries as it can be set to lithium. (I plugged into a separate solar port with adapters and charged that way).

If you want to post screen shots of your solar controller settings page, we could help you ensure the settings are correct for lithium.

It's a 2022, and the converter is set to Lithium. I've had it on shore power for two full days and two full nights, and it's still not 100%. It seems to be stuck at 13.5 volts. I have the shunt set properly for lithium, with 14.4 volts designated. Shore power is currently only delivering 2 amps. 

DenverJaguar

rfuss928 said:

The charging is not correct when on shore power which indicates the convertor is not set for the Li batteries.  Possibly the WFCO Auto Detect issue discussed in other posts?
https://tab-rv.vanillacommunity.com/discussion/16210/wfco-wf-8735-ad-lifepo4-fyi-on-annoying-auto-detect-quirk/p1

It's set for lithium. 

DenverJaguar

Marceline said:

It sounds like your Victron devices might not be set up properly for your batteries.

First of all, the SOC of charge number isn't reliable unless the app has been equalized to 100% when you're absolutely sure that the batteries are completely charged up. 

If you didn't get hard copies of the relevant Victron manuals for your devices, you can find them here. 

https://www.victronenergy.com/support

I went through the settings for Battleborn lithium batteries. They are supposed to charge to 14.4 volts, but the shore power amperage steadily drops over the course of an hour, to where it just sits at around 2 amps. Even at 2amps, I would expect to be fully charged over 48 hours. 

Bayliss

@DenverJaguar, I previously copied the below information from "RVelectricity.com" (Mike Sokol), so you might give it a try as part of your troubleshooting efforts, if you haven't already:

"With shore power connected and the circuit breaker feeding the converter/charger turned "on," set your multimeter to the 20-volt DC range.  Place the red meter probe on the positive battery terminal, and the black probe on the negative battery terminal.  If the battery measures something over 14 volts, then the charger part of your converter is working and it’s likely not the problem.  So, something else must be wrong.  However, if you’re reading mid to low 12 volts across your house battery, then your RV converter/charger is no longer charging the batteries and they’ve discharged so low you can’t run anything that needs significant power."

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Beyond that, some of what you are describing may be associated with the Battle Born BMS "low voltage disconnect," which is described by Battle Born below.  I am suggesting this, mainly because your Victron displayed a "low voltage" alert, plus you wrote that the SoC is 20%.  Maybe try disconnecting the battery from the WFCO power center and charge the battery with a stand-alone lithium capable battery charger (at least partially) to get it out of that "low voltage disconnect" state: 

"Sometimes, after fully discharging a Battle Born battery, a user won’t be able to get any more power out of the battery, even after charging it. To troubleshoot batteries, measure the battery’s voltage.  A voltmeter will register a low voltage of between 0V to 5V, or maybe a little higher.  It may seem like the battery is malfunctioning, or damaged, but actually, the battery has gone into low voltage disconnect.  In this mode, the internal Battery Management System (BMS) is protecting the battery from falling below 10V and won’t allow a charge to be drawn from the battery, even to a voltmeter.  To get a battery out of low voltage disconnect mode, simply take the battery out of the system, connect it to another 12V source for about 5 to 10 minutes.  This process is similar to jumping a dead car battery and will “awaken” the battery.  After the battery receives a charge in this way, it should register above 10V and will be able to accept a charge from your normal charger."  

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Finally, here's an interesting article that showed up in my inbox today, regarding why voltage is not a reliable indicator for a lithium battery's state of charge.  It provides helpful info for anyone interested in the topic:

Why Voltage Isn't a Reliable Indicator for Lithium Battery State of Charge - Camper Smarts

Bayliss

@DenverJaguar, did you figure out what the problem was?  It is always helpful to learn how situations like yours works out.  Thanks!