No Power from Battery System

[kgpuzio]

Hi folks,

We own a 26' 2018 Flying Cloud. We winterized it about 6 weeks ago, but left the Lithium batteries (2 - 100amp batteries) in it fully charged. During the winter, I like to go out into the AS everyone once in a while and relax.

It was cold today (20F), and I thought I would go out to the Airstream, throw the furnace on, and read. I opened the door and clicked the battery disconnect button but nothing happened. No "click" noise. No power. No lights.

Our batteries (Aolithium) have a direct bluetooth app, and both batteries are showing plenty of power (see attached images). This level of power is what I would expect considering what the batteries were at 2 week ago.

At that point, I plugged the Airstream into power from my house, and things started working -- lights, furnace, etc. I am heating it up now as I write this note.

It seems like the entire DC power system isn't engaging or connected. My first reaction was that it could be a problem with the battery disconnect switch, but I really have no idea.

Any thoughts on what could be wrong or how to approach this?

[Tyler2you]

At 11.1 V and 11.52 V your batteries are pretty close to 0% state of charge. Not sure how your BMS calculates SOC, but it sure doesn't seem right.

I'd also be very careful hooking up external power at 20 degrees F if your batteries don't have low temperature charge protection.

[kgpuzio]

@Tyler2you

Thanks for that idea. What you're suggesting is that I could have left something on, the batteries could be low/dead, and the app reading (showing state of charge) is wrong. So, not having any power in the DC power is because the batteries are just dead.

The batteries do have low temperature charge protection, but I will remove them now.

[Tyler2you]

Originally Posted by kgpuzio

@Tyler2you

Thanks for that idea. What you're suggesting is that I could have left something on, the batteries could be low/dead, and the app reading (showing state of charge) is wrong. So, not having any power in the DC power is because the batteries are just dead.

The batteries do have low temperature charge protection, but I will remove them now.

kgpuzio,

I'm just looking at the shots from the app that you posted. In the voltage box, it says the batteries are at 11.1 and 11.52 volts. Not sure why the state of charge meter is showing they're at 68% and 73%.

Here's a pretty typical SOC table for LifePo4 batteries:

[kgpuzio]

Tyler2you,

Thanks again. I just removed them and have them inside warming up. I will attach them to a battery charger and see if that fixes the issue. Will update with progress. Again, thank you for your help!

Kelly

[kscherzi]

With another brand of battery the instructions to configure the bluetooth properly upon first use is to completely discharge the battery (ie to the point where the BMS turns the battery off). Then charge back full to the point where the BMS stops accepting a charge.

[kgpuzio]

@tylertoyou

You were right. The bluetooth app information was not correct. The batteries were low and went into a "protection state" due to low voltage (in the pictures above, protection state = open). Due to the protection state being activated, I'm guessing that the app was providing SOC information from the last time that I actually checked instead of pulling/calculating real-time information.

One of the batteries was completely dead. I pulled the batteries inside, charged them up, and then hooked them up again. Everything worked fine.

In our current AS battery setup, the carbon monoxide detector continues to draw on the batteries even while the AS is in storage mode. I think that (combined with snow on top of our solar panels) just emptied one of the batteries in the low temperature environment. Or, I might have left the AS in USE mode. Not 100% sure.

[Tyler2you]

Originally Posted by kgpuzio

@tylertoyou

You were right. The bluetooth app information was not correct. The batteries were low and went into a "protection state" due to low voltage (in the pictures above, protection state = open). Due to the protection state being activated, I'm guessing that the app was providing SOC information from the last time that I actually checked instead of pulling/calculating real-time information.

One of the batteries was completely dead. I pulled the batteries inside, charged them up, and then hooked them up again. Everything worked fine.

In our current AS battery setup, the carbon monoxide detector continues to draw on the batteries even while the AS is in storage mode. I think that (combined with snow on top of our solar panels) just emptied one of the batteries in the low temperature environment. Or, I might have left the AS in USE mode. Not 100% sure.

Glad you got it figured out and working.

At some point, you may want to install a battery disconnect switch to completely isolate the batteries and prevent future no power incidents.

[Wazbro]

Do your batteries have heaters so you can charge them in cold weather?

[BayouBiker]

In addition to the CO monitor, the inverter electronics, solar charger electronics and battery monitor electronics draw a bit of power as well unless completely disconnected, generally on the order of .1-.2 amps total. These devices are not disconnected by the factory "Store/Run" switch and solenoid.

This would give you perhaps 30-60 days capacity unless one or more of these devices are out of spec and drawing more power than designed.

[kgpuzio]

@tylertoyou
Yes, I would like to install the battery disconnect. If you know of good sites or threads that explain how to do this in an AS I would appreciate any guidance.

@wazbro
No, sadly no heaters. Though I thought about using an electric blanket and a small fire. Decided just to bring them inside.

@biyoubiker
I get the CO monitor and solar charge controller would draw power, but why would the inverter draw power if it wasn’t on???

[Tyler2you]

Originally Posted by kgpuzio

@tylertoyou
Yes, I would like to install the battery disconnect. If you know of good sites or threads that explain how to do this in an AS I would appreciate any guidance.

I get the CO monitor and solar charge controller would draw power, but why would the inverter draw power if it wasn’t on???

If your batteries are still outside in the box, this thread has some good pictures/diagrams. Probably the most difficult part of the install will be finding a way to mount the switch.

https://www.airforums.com/forums/f37...ll-201499.html


As far as the the inverter drawing power, a portion of the circuit needs to be powered to be able to respond to the remote switch.

[BayouBiker]

In addition, the inverter is wired in passthrough mode. The electronics required for the logic and the solid state relays to pass power if/when shore power is available draws a bit. This is by design so pass through will function even if the inverter is "turned off".