HELP: One lithium battery dead, the other one is fine -- what gives?

[jgree2]

We have a 2021 Caravel with the Solar and Battleborn 2x 100ah Lithium Ion battery upgrade. The trailer sat in a lot for the past few months while I was deployed. I errantly did NOT disconnect the batteries before I left, leaving the parasitic load to constantly draw on both batteries.

I came home to find your standard symptoms of dead batteries (electric jack not turning, lights slow to come on, etc.), which I was not expecting because I expected the output of the installed solar panels to far exceed the draw of the parasitic load. The trailer was located in coastal N. Carolina during the period, with a good amount of solar output even in the winter.

I connected the trailer to shore power overnight and came out the next morning to find the same issue, so I disconnected the batteries and tested both with a voltmeter. One reads between 13-14 volts and the other reads .3 volts.

Yikes.

So I guess I’ve found an answer but also another question. One battery is clearly dead. I’m hoping it’s revivable but I’m waiting on the Victron li-ion battery charger I ordered to arrive to see if it can work its magic. But now I have new questions — how could one battery get completely discharged and the other one is fine, especially when they’re attached to solar, which I understand will continuously charge the batteries (solar output dependent) and is not affected by the on/store switch? My path forward appears to be to see if I can revive the dead battery and then re-install both and see if that fixes the issue, but now I’m concerned there’s a larger issue that’s preventing charge from reaching one of the batteries. Thoughts?

Also, am I wrong in my assessment that the installed solar output should far exceed the draw of the parasitic load, all but preventing complete discharge in the first place?

I've attached a picture of my battery compartment so you can see my battery wiring arrangement. the Battery reading .3 volts is at the bottom of the picture.

Thanks to you all for your help!

[SSquared]

When batteries are installed in parallel, they should either be

1) wired to positive and negative bus bars, using equal-length cables; or
2) wired with all positive connections made to one battery, and all negatives made to the the one on the other end of the string.

The worst thing is to have all the connections on the same battery at one end of the string. That causes the first battery "to do all the work", and that can lead to early failure. There is a thread here on Airforums of someone you ruined a set of four BBs in two or three years with his batteries wired this way.

It looks like you have positive and negative connections on both batteries. Depending on what those connections are, you might have the same problem.

Good luck with the battery charger. I hope your battery gets revived.

[Shiny16]

All the positives should be from the outermost positive terminal. Same for the negatives. Don’t send that picture to Battle Born without correcting it. The two posts in the center negative and positive should only have the jumpers for the parallel setup.

Hopefully one of the batteries just shut down and can be woken up.

[jgree2]

SSquared/Shiny,

Thanks for the quick replies and great information. Unfortunately for me and my relationship with my AirStream dealer, I took that picture before I started messing with any wiring to ensure I knew how to put it back correctly — that’s how it came wired from the dealer. So if there’s an issue with how it’s wired I need to have a hard conversation.

Have either of you seen a simple wiring diagram for how two 100ah batteries should be wired in parallel?

Thanks again.

[Shiny16]

Originally Posted by jgree2

SSquared/Shiny,

Thanks for the quick replies and great information. Unfortunately for me and my relationship with my AirStream dealer, I took that picture before I started messing with any wiring to ensure I knew how to put it back correctly — that’s how it came wired from the dealer. So if there’s an issue with how it’s wired I need to have a hard conversation.

Have either of you seen a simple wiring diagram for how two 100ah batteries should be wired in parallel?

Thanks again.

Talk to battleborn customer service. They may be able to help you wake up the one cell if that’s the issue . If the wiring caused an issue they might back you up in a conversation with the dealer.

If the battery is restored just rearrange the wires. It looks like you have enough slack.

[Shiny16]

Just move the two red wires on the center positive post to the outer positive post and one black to the opposite negative terminal.

[uncle_bob]

Hi

Best guess here:

The same dealer who really didn't know how to route the cables *also* didn't understand how to tighten down the connections to the batteries. One battery "came loose" and the other "did all the work". That's why you have one dead one and one that still is at 13.x volts. The cable routing stuff would not explain this.

Yes, the 0.0 V battery might have been disconnected for a very long time. That also could explain what's going on.

Grab that Victron charger (when it gets there) and try to charge the "dead" battery. See what happens. Once you have that data, you can move on.

Bob

[jgree2]

All,

Thanks for all the follow-up information (and crafty wiring diagram -- why can't all wiring diagrams be that simple? ). I've got some work to do starting tomorrow when the charger comes in. I'll report back with findings, and likely a test wiring diagram of my own to ensure I've got it right before I turn anything on.

-Justin

[3OnOurWay]

Originally Posted by Shiny16

Talk to battleborn customer service. They may be able to help you wake up the one cell if that’s the issue . If the wiring caused an issue they might back you up in a conversation with the dealer.

If the battery is restored just rearrange the wires. It looks like you have enough slack.

link here from BB about LVD
I rearead you post and now realize from Bb I needed to completely disconnect and wait 30 mins before I measure to see if I have a battery in LVD. If so, then it’s first time to wake it up
( I think I must my SOC mirrors a 100 ah battery bank, not 200 ah. )

I also realize you can jump awake a LiFePo battery from any other battery source including car

Then you can move to charging the battery to full.

[Shiny16]

Like Bob said the wiring probably did not cause the issue. Once you get the batteries going though rewire them so you don’t have other issues down the line.

[3OnOurWay]

Tested battery all 0.0 volts DC
Time to jump it and charge it

Can’t wait to have 2 batteries again. !

[PhilipRay]

Originally Posted by jgree2

Also, am I wrong in my assessment that the installed solar output should far exceed the draw of the parasitic load, all but preventing complete discharge in the first place?

I've attached a picture of my battery compartment so you can see my battery wiring arrangement. the Battery reading .3 volts is at the bottom of the picture.

Thanks to you all for your help!

To answer this part specifically, you are not wrong. LiFePo batteries are actually a collection of smaller batteries in series to get up to the desired voltage. Included in the battle born case is a Batter Management System (BMS) which is intended to protect your batteries from overcharge and overdrain, and protect the battery from charging if it's too cold or too hot an ambient temperature. It can also shut down the battery to protect it before it drains completely.

https://explorist.life and https://www.mobile-solarpower.com/ are two go-to sites I used when setting up my solar.

[mythbuster88]

Assume there are loose connections and miswires everywhere.
Forget the dealer.
Inspect the entire trailer and make everything ship shape.
Also assume the same for the plumbing.

[jgree2]

UPDATE:

Sorry it's been a while since I've provided an update. Thanks again to the entire community here for all the help.

I received my VICTRON Smart Charger and put it to work on the low-voltage battery. Unfortunately, after multiple phone conversations with both VICTON and BattleBorn, it was not able to bring the battery back from the dead. It never got above .6 Volts. However, BattleBorn offered to replace the battery FREE OF CHARGE, as it resulted from what they assessed was faulty wiring set-up from the AirStream dealer as well as imprecise instructions from Airstream on how best to treat the Lithium Ion batteries when they are left for multiple months. WOW. Battleborn was incredible gracious and professional throughout my phone calls, but I was SHOCKED they offered to replace the battery. I am a lifelong customer now.

Anyway, I should get the replacement battery in a few days, but now my attention is focused on ensuring this does NOT happen again. I am going to wire in the attached configuration. Please let me know if this is NOT correct. Additionally, I'm going to ensure I fully charge and physically disconnect and remove the batteries when storing for more than a few months.

How one battery completely discharged while the other remained fully charged remains a mystery, however...

[richard5933]

Your wiring diagram is okay, but I'd suggest taking it up one notch and using bus bars to make the connections instead of putting all those wires directly to the battery terminals.

On my trailer I have one positive cable coming from the positive side of the battery bank which go to a high-quality bus bar, and then all other positive connections are made there.

My negative side works basically the same, except that the single cable leaving the negative side of the battery bank first goes to my shunt for the monitor, and then to the bus bar.

To make all this easy for yourself, get long enough (and thick enough) battery cables between the battery bank and bus bars and then put the bus bars inside the trailer. That makes future upgrades and maintenance an inside job. Hopefully you have a suitable space for all that. Putting them inside also helps keep things cleaner on the bus bar connections.

[uncle_bob]

Originally Posted by jgree2

UPDATE:

Sorry it's been a while since I've provided an update. Thanks again to the entire community here for all the help.

I received my VICTRON Smart Charger and put it to work on the low-voltage battery. Unfortunately, after multiple phone conversations with both VICTON and BattleBorn, it was not able to bring the battery back from the dead. It never got above .6 Volts. However, BattleBorn offered to replace the battery FREE OF CHARGE, as it resulted from what they assessed was faulty wiring set-up from the AirStream dealer as well as imprecise instructions from Airstream on how best to treat the Lithium Ion batteries when they are left for multiple months. WOW. Battleborn was incredible gracious and professional throughout my phone calls, but I was SHOCKED they offered to replace the battery. I am a lifelong customer now.

Anyway, I should get the replacement battery in a few days, but now my attention is focused on ensuring this does NOT happen again. I am going to wire in the attached configuration. Please let me know if this is NOT correct. Additionally, I'm going to ensure I fully charge and physically disconnect and remove the batteries when storing for more than a few months.

How one battery completely discharged while the other remained fully charged remains a mystery, however...

Hi

Ok, we have a pretty wide mix of situations in this thread. That diagram is ok for a trailer. It does not get into the rest of the charging system. That also needs to be checked out.

One gotcha: If you are only getting one of two batteries replaced, that's a bit of an issue. The second battery may not be in the best of shape. I think I'd go ahead and replace the other one if they are only sending out one.

Bob