Advice on charging Lithium Batteries

[Halfstar]

Looking at Buying a 2025 Flying Cloud with Solar and Lithium Batteries, it will be stored under our covered port next to our house and hooked up to electricity, a little confused on charging the batteries,
what are people using to keep the charge up since the solar panels will not be able to receive sun while under the covered port? Do we need to use a Trickle charger?

[AlbertF]

Yes, a 1 or 2 amp trickle charger that automatically detects lithium batteries would be logical. Try to find one that will connect to the Zamp solar port or other 2 pole SAE connector in the way that you connect a portable solar panel. You can buy adapters to reverse polarity if needed. I had to do that with our trailer.

[thiel]

Just charge to about 70% and then disconnect the batteries when stored. Lithium will hold a charge for months and months. Lithium actually prefers to NOT be fully topped off all the time.

[Wazbro]

Since you said it will be "hooked up to electricity," the stock converter should keep the batteries charged.

[vanderwielen]

Originally Posted by Wazbro

Since you said it will be "hooked up to electricity," the stock converter should keep the batteries charged.

This ^

[BGClassic]

Originally Posted by thiel

Just charge to about 70% and then disconnect the batteries when stored. Lithium will hold a charge for months and months. Lithium actually prefers to NOT be fully topped off all the time.

Exactly. I would not have shorepower running to an unattended trailer, even on my property. Just check the SOC once per week, since the stock setup does not totally disconnect all loads.

[PaulBristol]

Originally Posted by vanderwielen

This ^

^
I agree with this as well.

The built in lithium compatible charger will keep the lithium batteries fully charged and ready to go.

Battle Born BBCG3 batteries can be stored fully charged. They do not need to be discharged to 70% for storage.

You may have to keep the main disconnect switch "ON" for the charger to work. Ask the dealer to tell you best practice for your situation when you buy the AS Flying Cloud.

I have a 2025 AS Trade Wind. It has three Battle Born BBCG3H 270 amp lithium batteries and a 3000 watt Victron Multiplus II inverter/charger. The Victron keeps the batteries charged just fine as long as the main power disconnect is "ON".

I plug the Trade Wind into a 20 amp 120 volt garage outlet.

This works really well for Northern climates because you also need battery heat when ambient temperature drops below -14 degrees F. This is the low limit for storing Battle Born batteries. Turn the battery heat "ON" when temperature is forecast to be below -14 degrees F.

[thiel]

Originally Posted by BGClassic

Exactly. I would not have shorepower running to an unattended trailer, even on my property. Just check the SOC once per week, since the stock setup does not totally disconnect all loads.

After many years of avoiding the task, I have found it really worth it to install a hard-switch battery disconnect in the battery box itself. About $40 for the switch and the cables and about 10 minutes to install.

[BGClassic]

Originally Posted by thiel

After many years of avoiding the task, I have found it really worth it to install a hard-switch battery disconnect in the battery box itself. About $40 for the switch and the cables and about 10 minutes to install.

I did the same, when I moved the batteries inside. Added a Blue Sea switch. We store at a site seven miles away, and check on it weekly. Easy.

[Airkeeper]

We use the CTEK battery conditioning system for lithium. We keep our in heat/air conditioned garage next to our house. We also attach the CTEK unit with a 7 pin receptacle so we don’t need to connect directly with the battery.

[Airkeeper]

https://share.icloud.com/photos/04aM...KR89gbyZu5YgYQ

[AlbertF]

Originally Posted by vanderwielen

This ^

I missed that!

Yes, obviously the onboard system will keep the batteries charged. Our trailer is stored in our backyard, and I decided to buy a trickle charger rather than leave the converter plugged in all year round. I can't help but think that lifespan of the unit will be affected. Also, the GC2s are heavy batteries, and I'm happy to leave them on the trailer while connected to the trickle charger.

[gypsydad]

Install a mechanical disconnect switch as some noted above. I leave my coach plugged in when in storage. I also will flip the disconnect switch when leaving for extended periods and flip back on, a week before leaving. I always check status using my Bluetooth, BMS on my phone when I visit. Your converter in the newer AS's will charge/maintain your Li batteries while plugged in; you don't need to use an additional trickle charger.

[Trons4u]

You should have a battery disconnect. I'm not sure on the new one's if it cuts ALL power or not. In the past there were ancillary items that would draw power even when the switch was in disconnect mode.

Enable the 'Disconnect' switch, Charge them up and disconnect the power from the pedestal and check it periodically and see if power is dropping.
If it is, you can disconnect the pos lead of the battery. That will prevent anything from having power. Ensure that lead doesn't touch metal.

If it's still using power in disconnect, I would install a manual switch, that will for sure cut power.

[uncle_bob]

Hi

There are a number of "parasitic loads" built into the trailer. The only way to get them "off" the battery is with a full disconnect switch. The "use/store" switch does *not* disconnect them.

You are far better off disconnecting the batteries, shutting off the solar, and not attaching to shore power. This significantly reduces the risk of something bad happening while you are away from the trailer. Yes, it's unlikely something will happen. Still there is indeed a risk. Having the trailer burn down to ashes is not something you want happening anywhere, let alone in your back yard.

Bob

[jasoneg77]

Originally Posted by PaulBristol

^
I agree with this as well.

The built in lithium compatible charger will keep the lithium batteries fully charged and ready to go.

Battle Born BBCG3 batteries can be stored fully charged. They do not need to be discharged to 70% for storage.

You may have to keep the main disconnect switch "ON" for the charger to work. Ask the dealer to tell you best practice for your situation when you buy the AS Flying Cloud.

I have a 2025 AS Trade Wind. It has three Battle Born BBCG3H 270 amp lithium batteries and a 3000 watt Victron Multiplus II inverter/charger. The Victron keeps the batteries charged just fine as long as the main power disconnect is "ON".

I plug the Trade Wind into a 20 amp 120 volt garage outlet.

This works really well for Northern climates because you also need battery heat when ambient temperature drops below -14 degrees F. This is the low limit for storing Battle Born batteries. Turn the battery heat "ON" when temperature is forecast to be below -14 degrees F.

Question on the Battery heat switch: Does that switch not need to be turned on, when below freezing at 32 degrees? Thank you.

[ROBERT CROSS]

Originally Posted by Halfstar

Looking at Buying a 2025 Flying Cloud with Solar and Lithium Batteries, it will be stored under our covered port next to our house and hooked up to electricity, a little confused on charging the batteries,
what are people using to keep the charge up since the solar panels will not be able to receive sun while under the covered port? Do we need to use a Trickle charger?

I DO NOT SHORE POWER AN UNATTENDED TRAILER.

I just charge the BB batteries when they need charging.
I see no need to keep them on a charger 24/7.

I charged them last fall when put into storage, and they were still at 13.2v this Spring.
If you install an isolation switch, you will have no problems.

Bob
🇺🇸

[HendoJD]

With a 2024 Basecamp, on advice from the dealer, I just turn the power switch to off, and the lithium battery does just fine. We use that approach in the winter and the rest of year, too, as our trailer is stored in a covered parking area with no access to power, and where the solar panels can't charge. The battery gets a good charge every outing.

[Wazbro]

Originally Posted by jasoneg77

Question on the Battery heat switch: Does that switch not need to be turned on, when below freezing at 32 degrees? Thank you.

Only if you need to charge them and it might be higher then 32° depending on which batteries you have. NOTE: Quoting a requirement on one brand may not apply/be accurate on another brand.

The heat is only needed when approaching or passing -14°F when stored due to Battle Born's minimum storage temp (stored=not charging or discharging).

[Air2Trout]

Originally Posted by PaulBristol

^
I agree with this as well.

The built in lithium compatible charger will keep the lithium batteries fully charged and ready to go.

Battle Born BBCG3 batteries can be stored fully charged. They do not need to be discharged to 70% for storage.

You may have to keep the main disconnect switch "ON" for the charger to work. Ask the dealer to tell you best practice for your situation when you buy the AS Flying Cloud.

I have a 2025 AS Trade Wind. It has three Battle Born BBCG3H 270 amp lithium batteries and a 3000 watt Victron Multiplus II inverter/charger. The Victron keeps the batteries charged just fine as long as the main power disconnect is "ON".

I plug the Trade Wind into a 20 amp 120 volt garage outlet.

This works really well for Northern climates because you also need battery heat when ambient temperature drops below -14 degrees F. This is the low limit for storing Battle Born batteries. Turn the battery heat "ON" when temperature is forecast to be below -14 degrees F.

On our 2025 Trade Wind the Solar charges whether the battery disconnect is on or off. Agreed you should ask the dealer about the setup on the Flying Cloud, or better yet just try a few things when you get her home. There are several ways to address the concerns.

Letting them discharge is OK, too, but not ever below 20% or more importantly whatever that voltage is for your particular battery setup. Also agree with battery heat on if you are charging at or below 32 degrees.

We plugged into our house only once after we tested the Heat and other electrical devices in December when we took possession and to monitor capacity % and voltage. Went down to 20%. Matched specs.

Ran the AC yesterday just to test it but now just letting solar charge her up. Love having her next to my house.