Electrical troubleshooting help

[kavm]

I describe our situation below and would very much appreciate some help. Our knowledge of anything electrical is minimal, so some of what I share below might not be relevant.

• First, the details of the camper: 2021 5.0, 2 solar panels, 2 lithium batteries, EMS, Invertor, a DC only compressor fridge
• The camper is normally parked in a covered commercial storage area. We have the option to request the storage company to plug it in, and we did. [The storage company parks inside their facility and we do not have access to the camper while it is in storage. So, we could not check if they did it right.] Since we expected it to be plugged in, we did not turn the battery disconnect and left the refrigerator on.
• When we picked the camper up, it looked like that either they had not connected it or the connection was not successful due to some EMS fault. The refrigerator was not cold.
• After we drove it home from storage, the we saw that the battery was at 13% and the refrigerator was starting to cool just a bit. Either the solar panels and/or the tow vehicle had charged the battery up just a bit in the short drive. Although around 4 PM, the sun was out and I figured that the sun will charge the batteries (thought that was too optimistic). So, we left it like that.
• When we checked today (2 days later), there is no current anywhere in the camper. The panel that shows how full the battery is does not even light up.

That’s where things stand.

This evening, I turned the battery disconnect switch on hypothesizing that the batteries just did not have sufficient charge to support the refrigerator and got completely drained. That said, I am not sure if the solar panels are doing their job as it’s been sunny (until today).

I am hoping (but am far from confident) that the solar panels charge the battery tomorrow while the battery disconnect stops the fridge and everything else from drawing power tomorrow. Not sure if this is a valid line of thought as the battery disconnect might prevent the solar panels from charging the battery (if they are working in the first place).

I did buy a multi-meter this evening in case I need to do more troubleshooting tomorrow (after I watch the videos on how to use it!).

I would be very thankful for any advice on how to proceed with troubleshooting this situation.

[oldwave]

First thing I’d do is get shorepower somewhere and fully charge the batteries. It sounds like the soc is so low that the solar panels can’t keep up with the compressor fridge. When your connected to shore power, your fridge shouldn’t run off the batteries anyway, it should run off the converter. I suspect the company either turned off the outlet or never turned it on. It is possible that the outlet was miswired and the ems shut it down. Also was the inverter off ?

[richm]

If the system is not charging the batteries, I'd suggest using a clamp on ammeter. It can measure the current output of the solar controller or the WFCO charger.

Same for the fridge. The ammeter can tell you how many amps it's drawing.

[rubicon327]

Originally Posted by kavm

I am hoping (but am far from confident) that the solar panels charge the battery tomorrow while the battery disconnect stops the fridge and everything else from drawing power tomorrow. Not sure if this is a valid line of thought as the battery disconnect might prevent the solar panels from charging the battery (if they are working in the first place).

Escape typically wires their solar system so that it charges the battery even with the battery disconnect engaged (open).

Sounds like you drove your lithium batteries very low. You need to get some charge in them soon or you risk permanent damage.

Why are you leaving your fridge on in storage even with shore power?

[kavm]

Originally Posted by oldwave

First thing I’d do is get shorepower somewhere and fully charge the batteries. It sounds like the soc is so low that the solar panels can’t keep up with the compressor fridge. When your connected to shore power, your fridge shouldn’t run off the batteries anyway, it should run off the converter. I suspect the company either turned off the outlet or never turned it on. It is possible that the outlet was miswired and the ems shut it down. Also was the inverter off ?

Thank you!

The inverter was definitely off. We only turn it on rarely when we use it.

Unfortunately, I don’t have access to shore power. Can’t bring the camper anywhere near our building. I do have a 7.2 kW generator on the truck. Can I connect that? Would it do the job even while the battery disconnect is on (i.e. engaged)?

The fridge on was a newbie mistake.

[kavm]

Originally Posted by richm

If the system is not charging the batteries, I'd suggest using a clamp on ammeter. It can measure the current output of the solar controller or the WFCO charger.

Same for the fridge. The ammeter can tell you how many amps it's drawing.

I have an idea of how much the fridge is drawing… I am not too clear with where all things are and new at the multimeter. So, my first hope / plan is to see if the batteries were overdrawn and see if they can be charged up.

[kavm]

Originally Posted by rubicon327

Escape typically wires their solar system so that it charges the battery even with the battery disconnect engaged (open).

Sounds like you drove your lithium batteries very low. You need to get some charge in them soon or you risk permanent damage.

Why are you leaving your fridge on in storage even with shore power?

Thank you very much, Dave!

First, the fridge on in storage was a mistake. We will not do that in the future.

Now the battery disconnect is on. So, there is no draw on the batteries. My two choices for charging the battery are:

• Today is a expected to be a sunny day. We can see if the solar panels can charge them.
• I can use the generator to do this. Should I turn the battery disconnect off before using the generator?

What would you advise? How do I confirm that the battery is charging / how charged it is? Currently, the WCFO screen doesn’t even light up. I don’t know if it will with the battery disconnect on.

PS: One more silly question: Does the battery disconnect need to be off during towing?

[rubicon327]

Originally Posted by kavm

Thank you very much, Dave!

First, the fridge on in storage was a mistake. We will not do that in the future.

Now the battery disconnect is on. So, there is no draw on the batteries. My two choices for charging the battery are:

• Today is a expected to be a sunny day. We can see if the solar panels can charge them.
• I can use the generator to do this. Should I turn the battery disconnect off before using the generator?

What would you advise? How do I confirm that the battery is charging / how charged it is? Currently, the WCFO screen doesn’t even light up. I don’t know if it will with the battery disconnect on.

PS: One more silly question: Does the battery disconnect need to be off during towing?

I think you have my number. Give me a call and I’ll talk through all this with you.

[oldwave]

Originally Posted by kavm

Thank you very much, Dave!

First, the fridge on in storage was a mistake. We will not do that in the future.

Now the battery disconnect is on. So, there is no draw on the batteries. My two choices for charging the battery are:

• Today is a expected to be a sunny day. We can see if the solar panels can charge them.
• I can use the generator to do this. Should I turn the battery disconnect off before using the generator?

What would you advise? How do I confirm that the battery is charging / how charged it is? Currently, the WCFO screen doesn’t even light up. I don’t know if it will with the battery disconnect on.

PS: One more silly question: Does the battery disconnect need to be off during towing?

You need to disengage the battery disconnect switch to charge from shore power or a generator. Perhaps that was to case in storage. The solar panels should charge with the battery disconnect switch engaged. Does that make sense ? I don’t know why you would disengaged the battery while towing, with the lithium package you should have gotten a dc to dc device that allows the trucjk to safely charge the batteries. The only time i disengage the batteries is when my trailer is in storage for a while. You can check is the battteries are engaged by looking at the propane detector, it will light up in the batteries are angaged and not when they are disenaged. Your onboard generator can be used to charge up the batteries. Also, if you have an adaptor for the 30 amp cord to a regular plug, (cheap), that’s plenty of power to charge the batteries, just not the air usually.

[kavm]

Thank you, oldwave! This clarifies our confusion with the disconnect switch! Very helpful!

[kavm]

Status Update: Dave very kindly took the time to speak with my wife and me to clarify a number of our confusions.

We successfully used the Pro Power generator from the F150. Once we figured out that we needed to bypass the EMS, it worked smoothly. We charged it for about an hour. The camper will be outside for the next couple of days, so the solar panels will add further charge. Since nothing (except the propane monitor) is using the power - it ought to be fully charged up.

We don't have a reliable way to see how charged the lithium batteries are. The SeeLevel II panel just shows the voltage rather than percent full (as stated on the label). Dave helped us figure that out.

On Dave's recommendation, we will look into installing the Victron BMV-712 as soon as we can find someone who can do this for us.

So, the issue is resolved - and thanks to Dave's generosity, we understand things a bit better.

Many thanks, Dave!

[oldwave]

Good luck , a simple 15 amp plug will be enough to charge the batteries. As far as the lithium batteries there should be an internal battery management system that protects the battery from deep discharge, so I doubt you have damaged the batteries. One word of caution for winter storage with lithium , charge them to 100 percent and disconnect them from the trailer to avoid cold damage . The battery disconnect switch should be sufficient. Let us know what your solution is.

[oldwave]

Originally Posted by kavm

Status Update: Dave very kindly took the time to speak with my wife and me to clarify a number of our confusions.

We successfully used the Pro Power generator from the F150. Once we figured out that we needed to bypass the EMS, it worked smoothly. We charged it for about an hour. The camper will be outside for the next couple of days, so the solar panels will add further charge. Since nothing (except the propane monitor) is using the power - it ought to be fully charged up.

We don't have a reliable way to see how charged the lithium batteries are. The SeeLevel II panel just shows the voltage rather than percent full (as stated on the label). Dave helped us figure that out.

On Dave's recommendation, we will look into installing the Victron BMV-712 as soon as we can find someone who can do this for us.

So, the issue is resolved - and thanks to Dave's generosity, we understand things a bit better.

Many thanks, Dave!

Nice, I’m installing that same victron smart shunt next week, it will give me Bluetooth connectivity to monitor the soc. I’ll look into lithium next year maybe

[Brian B-P]

Originally Posted by oldwave

As far as the lithium batteries there should be an internal battery management system that protects the battery from deep discharge, so I doubt you have damaged the batteries.

Not yet, but if discharged to the protective shutdown level and then just left, they will eventually self-discharge to destruction. That would take a long time, though, so it's not a concern at this point.

Originally Posted by oldwave

One word of caution for winter storage with lithium , charge them to 100 percent and disconnect them from the trailer to avoid cold damage .

Or to significantly less than 100%, according to best practices for lithium-ion batteries... but yes, disconnected from any load and even from a charger that's not smart enough to handle storage.

[alanmalk]

Originally Posted by kavm

...

• When we checked today (2 days later), there is no current anywhere in the camper. The panel that shows how full the battery is does not even light up.

...

If your battery is near zero State-of-Charge ("dead") then the BMS should have disconnected internally.


From another thread on keeping Lithium batteries cozy and warm:
https://www.solacity.com/how-to-keep...tteries-happy/

"Jump-Starting The BMS

For most conditions (over-current, over-Voltage, under-temperature, or over-temperature) the BMS will automatically switch back on again, either after a set amount of time has passed, or once the conditions are safe. However, there is one case where the BMS will NOT switch on by itself, the battery will stay off: When any cell within a LFP battery falls below the lower safe Voltage limit the BMS will switch off to protect the cells from over-discharge. It does this with still a little charge left in the cells, so the battery can sit for a while and self-discharge before damage to the cells occurs. The important part is that the BMS will not switch the battery back on by itself! When this happens the battery simply “goes away” and produces 0 Volt.
To make the BMS switch on again after a low-Voltage disconnect event the battery needs to see a charging Voltage. How much exactly varies from brand-to-brand, but generally this means 14.0 Volt or up (for a 12V battery). Keep in mind that inverter-chargers won’t work without a battery, nor will solar charge controllers. They need to see regular battery Voltage to function. That means you cannot switch the battery BMS back on by charging from a generator (via your inverter-charger) or your solar panels. To make the BMS switch on again you either need a 120V AC charger that can do “dead battery charging” as it is usually called in the brochure, meaning it puts out a charging Voltage even if it does not sense a battery. Alternatively you can “jump start” the switched-off battery by taking another battery of the same nominal Voltage, even a lead-acid battery, and connect it in parallel with the dead battery, and then charge via solar or your inverter-charger. As soon as the Voltage reaches high enough the BMS will sense it and switch the battery back on again. At that point you can disconnect the extra battery, but please keep charging so the empty battery does not immediately switch off again with the slightest load."


To summarize, the Lithium battery has a protective circuit that completely disconnects the battery - to protect it from serious damage - when the voltage drops too low. It is called a BMS and it will not reconnect the battery until 14 volts (varies a bit with manufacture) is applied. Your conventional charger may, or may not, provide this voltage when connected - because it thinks there is no battery! A simple 14V battery charger with no "smarts", and only an amp or 2 of power, will do the trick.

This is something that varies a lot from the old days of lead-acid. A dead lead-acid battery is a big load, while a dead LFP battery may not "exist".

[rubicon327]

Originally Posted by kavm

We don't have a reliable way to see how charged the lithium batteries are. The SeeLevel II panel just shows the voltage rather than percent full (as stated on the label). Dave helped us figure that out.

On Dave's recommendation, we will look into installing the Victron BMV-712 as soon as we can find someone who can do this for us.

For those with the optional SeeLevel II monitor it is important to note that despite the permanent “level in percent” label that is not for the battery but rather only for the tanks. When BATT is pressed you are reading voltage not % state of charge (SOC). For the most accurate SOC of any battery it cannot be based on voltage but rather the amps entering and leaving the battery. Thus the recommendation for the Victron BMV-712 or equivalent. Once you enter the size of the battery bank, enter some parameters and are synced to a fully charged battery you can trust the % SOC. I was able to compare the readings on the Victron to the built-in monitor on my Bestgo lithium battery and they were very close in the full range from 95-30% SOC when I tested my mini-split on battery for 5 hours.

[kavm]

Originally Posted by oldwave

Good luck , a simple 15 amp plug will be enough to charge the batteries. As far as the lithium batteries there should be an internal battery management system that protects the battery from deep discharge, so I doubt you have damaged the batteries. One word of caution for winter storage with lithium , charge them to 100 percent and disconnect them from the trailer to avoid cold damage . The battery disconnect switch should be sufficient. Let us know what your solution is.

Does battery disconnect serves as disconnect from the trailer? Or, do you mean to take them out of the camper?

Our camper is stored indoors in a large commercial warehouse facility. It’s not climate controlled but offers some moderation in temperature. I mention it in case that is relevant.

[kavm]

Originally Posted by alanmalk

If your battery is near zero State-of-Charge ("dead") then the BMS should have disconnected internally.


From another thread on keeping Lithium batteries cozy and warm:
https://www.solacity.com/how-to-keep...tteries-happy/

"Jump-Starting The BMS

For most conditions (over-current, over-Voltage, under-temperature, or over-temperature) the BMS will automatically switch back on again, either after a set amount of time has passed, or once the conditions are safe. However, there is one case where the BMS will NOT switch on by itself, the battery will stay off: When any cell within a LFP battery falls below the lower safe Voltage limit the BMS will switch off to protect the cells from over-discharge. It does this with still a little charge left in the cells, so the battery can sit for a while and self-discharge before damage to the cells occurs. The important part is that the BMS will not switch the battery back on by itself! When this happens the battery simply “goes away” and produces 0 Volt.
To make the BMS switch on again after a low-Voltage disconnect event the battery needs to see a charging Voltage. How much exactly varies from brand-to-brand, but generally this means 14.0 Volt or up (for a 12V battery). Keep in mind that inverter-chargers won’t work without a battery, nor will solar charge controllers. They need to see regular battery Voltage to function. That means you cannot switch the battery BMS back on by charging from a generator (via your inverter-charger) or your solar panels. To make the BMS switch on again you either need a 120V AC charger that can do “dead battery charging” as it is usually called in the brochure, meaning it puts out a charging Voltage even if it does not sense a battery. Alternatively you can “jump start” the switched-off battery by taking another battery of the same nominal Voltage, even a lead-acid battery, and connect it in parallel with the dead battery, and then charge via solar or your inverter-charger. As soon as the Voltage reaches high enough the BMS will sense it and switch the battery back on again. At that point you can disconnect the extra battery, but please keep charging so the empty battery does not immediately switch off again with the slightest load."


To summarize, the Lithium battery has a protective circuit that completely disconnects the battery - to protect it from serious damage - when the voltage drops too low. It is called a BMS and it will not reconnect the battery until 14 volts (varies a bit with manufacture) is applied. Your conventional charger may, or may not, provide this voltage when connected - because it thinks there is no battery! A simple 14V battery charger with no "smarts", and only an amp or 2 of power, will do the trick.

This is something that varies a lot from the old days of lead-acid. A dead lead-acid battery is a big load, while a dead LFP battery may not "exist".

Thank you very much, Alan! That’s very helpful. We are somewhat unclear about what cause our issue. But, it is possible that our BMS had switched the battery off. Once helped by the generator, everything seemed to come back to normal.

[oldwave]

Originally Posted by kavm

Does battery disconnect serves as disconnect from the trailer? Or, do you mean to take them out of the camper?

Our camper is stored indoors in a large commercial warehouse facility. It’s not climate controlled but offers some moderation in temperature. I mention it in case that is relevant.

Disconnect switch should be fine. The danger is trying to charge when the batteries are very cold, a good bms will prevent that though. I don’t know if you have a solar charger disconnect switch, but would recommend that also, they are cheap and don’t take much to install:


https://www.explorist.life/how-to-wi...trical-system/

[kavm]

Thank you, OldWave! We aren’t handy, so it’s probably not easy for us. But, we are going to find someone to install the Victron BMV-712. We will ask that person to also look into installing a solar disconnect. So, I have now added this item to our list.

Question: We are planning on a winter trip from SLC to Big Bend NP in December. While we are traveling South precisely to get to above freezing temperatures, we will definitely come across sub-zero temperatures for some of that trip. What precautions do we need to take with the lithium batteries and solar panels? Even if we have a solar disconnect switch, wouldn’t the tow vehicle try to charge the batteries if we are driving in below zero temperatures.