Battery storage and charging

[Jeffr75]

Hello,

I will be storing my new Airstream 23FB for the first time this winter. It gets quite cold in Quebec but I'm fortunate to have a heated garage. The dealer is recommending that I disconnect the batteries and use a smart charger or trickle charger, not sure what it's officially called.

I have 2 Interstate DCL-75U deep cycle batteries. I have 2 questions below.

The smart chargers I found have a few single and dual bank models, but there are also different options when it comes to amps. I see a dual bank 4 amp model (2-amps each) I see a single 10 AMP model. I also see "Onboard chargers" that have a 2-bank 20 amp model (10 amps each)

Here are the links to the models I'm referring to.

https://www.amazon.ca/stores/page/72...3&ref_=ast_bln

https://www.amazon.ca/stores/page/72...3&ref_=ast_bln

I'm really not knowledgeable when it comes this kind of stuff, so here are the questions

1. How many AMPS do I need?

2. Do I really need to disconnect everything or can I just clamp on the smart charger once I find the right model?

Inside the battery storage compartment looks complicated to me. Lots of wires, looks like my solar stuff is also connected, I'm afraid to disconnect it all and mess it up.



Thank you in advance for any help or guidance!

Jeff

[uncle_bob]

Hi

Batteries can and do freeze. It does get cold in the winter in Quebec. (we spent a lot of time skiing up there ....). A fully charged lead acid battery will freeze somewhere below -60C. I don't ever recall it getting that cold up there. Even if the heat fails in your storage area, the batteries should be safe.

You should disconnect your batteries when in storage. There may or may not be a full disconnect switch already on your trailer. They usually are red with a big knob on them. If you don't have one already, it's a very good idea to install one. The alternative is to pull the negative wires off of the battery when in storage.

Why disconnect? The trailer has all sorts of very small loads that drain the battery. You do not want the battery to discharge while in storage. You can kill the batteries this way. Some trailers will only make it about a month if stored "hooked up".

If the batteries are in good shape, you do not need a charger on them in storage. If they are many years old and have been abused .... replace them instead of playing with a charger.

Bob

[ITSNO60]

You're probably going to get a lot of replies on this but the short answer to disconnecting everything is no, just clamp it on. Even if you have small parasitic loads the smart charger will keep things charged. Much easier than disconnecting or removing batteries too. On mine I bought a 6' extension and fastened it to the batteries and zip tied it along underneath to the outer edge of the frame, then I just reach down and plug in my charger, easy peasy. For maintenance you do NOT need a lot of amps but nice to have if you are ever in a situation with a deep discharge, although your converter will take care of the trailer in that case.

Check out the Victron Smart Chargers, you can get a better product for the same money as NOCO. With NOCO you have to pay for their huge advertising campaign.

Some people like to disconnect the batteries and leave them without a charger, I find it far easier to leave them connected and use a smart charger. Owning multiple vehicles for decades, many that sit for extended periods, the charging method has proven to be a smart decision for me. I have seen the options for charging/maintaining improve to the point where now you can pretty much trust the good ones not to boil your battery. On the older ones there was always the need to be checking up on them all the time.

[Jeffr75]

Originally Posted by uncle_bob

Hi

Batteries can and do freeze. It does get cold in the winter in Quebec. (we spent a lot of time skiing up there ....). A fully charged lead acid battery will freeze somewhere below -60C. I don't ever recall it getting that cold up there. Even if the heat fails in your storage area, the batteries should be safe.

You should disconnect your batteries when in storage. There may or may not be a full disconnect switch already on your trailer. They usually are red with a big knob on them. If you don't have one already, it's a very good idea to install one. The alternative is to pull the negative wires off of the battery when in storage.

Why disconnect? The trailer has all sorts of very small loads that drain the battery. You do not want the battery to discharge while in storage. You can kill the batteries this way. Some trailers will only make it about a month if stored "hooked up".

If the batteries are in good shape, you do not need a charger on them in storage. If they are many years old and have been abused .... replace them instead of playing with a charger.

Bob

Hi Bob,

Thanks for the reply. I do have a kill switch in my trailer. I believe that eliminates the worry of small loads killing the batteries. So if that is off, then I prefer to not undo all the wires from the batteries themselves and connect a trickle charge for good measure. The trailer and batteries are new.

Thanks again!

[uncle_bob]

Hi

The trickle charger thing is very much a tradeoff between the damage the device does to the batteries and the help it provides. There is a *lot* of debate about them providing any benefit on new batteries.

Bob

[Jeffr75]

Originally Posted by ITSNO60

You're probably going to get a lot of replies on this but the short answer to disconnecting everything is no, just clamp it on. Even if you have small parasitic loads the smart charger will keep things charged. Much easier than disconnecting or removing batteries too. On mine I bought a 6' extension and fastened it to the batteries and zip tied it along underneath to the outer edge of the frame, then I just reach down and plug in my charger, easy peasy. For maintenance you do NOT need a lot of amps but nice to have if you are ever in a situation with a deep discharge, although your converter will take care of the trailer in that case.

Check out the Victron Smart Chargers, you can get a better product for the same money as NOCO. With NOCO you have to pay for their huge advertising campaign.

Some people like to disconnect the batteries and leave them without a charger, I find it far easier to leave them connected and use a smart charger. Owning multiple vehicles for decades, many that sit for extended periods, the charging method has proven to be a smart decision for me. I have seen the options for charging/maintaining improve to the point where now you can pretty much trust the good ones not to boil your battery. On the older ones there was always the need to be checking up on them all the time.

Hi Brian,

If I don't disconnect anything and just clamp on which is what I want to do, do I need a single smart charger or dual? If the batteries are ganged together I was thinking 1 charger on 1 battery would do both or do I need a dual?

Thanks,

Jeff

[ITSNO60]

Originally Posted by Jeffr75

Hi Brian,

If I don't disconnect anything and just clamp on which is what I want to do, do I need a single smart charger or dual? If the batteries are ganged together I was thinking 1 charger on 1 battery would do both or do I need a dual?

Thanks,

Jeff

Yes, a single 12 volt charger connected the same way the batteries connect to your trailer, don't connect anything in the middle where the jumper is.

[ITSNO60]

Sorry I just looked at your picture and realized your batteries are connected in parallel so yes connecting to one would charge both but the way I've always connected parallel batteries, and the way it was recommended by Deltran when I used to use their stuff is to connect to the positive of one battery and the negative of the other.
My rig has 6 volt batteries connected in series to make 12 so my jumper is only 6 volts and you wouldn't want to connect a charger there.

[Jeffr75]

Originally Posted by ITSNO60

Sorry I just looked at your picture and realized your batteries are connected in parallel so yes connecting to one would charge both but the way I've always connected parallel batteries, and the way it was recommended by Deltran when I used to use their stuff is to connect to the positive of one battery and the negative of the other.
My rig has 6 volt batteries connected in series to make 12 so my jumper is only 6 volts and you wouldn't want to connect a charger there.

Hi again, so do you think I should connect it that way as well? Positive to 1 battery and negative to the other? I really appreciate the help!

[Jeffr75]

Originally Posted by Jeffr75

Hi again, so do you think I should connect it that way as well? Positive to 1 battery and negative to the other? I really appreciate the help!

Hey, so you are absolutely correct, just did a quick search and found this quick video.

https://www.youtube.com/watch?v=bfvLcTxgvzo

[JCWDCW]

Canadian Tire sells one for $50 give or take. It can be adjusted for 3 6 or 10 amps and it shuts off automatically and holds the battery on float charge. Have used this on for years....
JCW

[greenflag]

Welcome to the Forums.

The first thing I did was take a picture of the batteries hooked up with my cell phone. I don't trust my memory. Since my trailer is stored at a storage facility, I pull the batteries and bring them home. I purchased a "Battery Tender" dual bank battery maintainer. It is rated at 1.25 amps per circuit. With the COVID pandemic going on, my batteries have been on the maintainer for a full year. Last week I installed my batteries in my AI. They were perfectly charged at 13.1 volts. All that was required was a water level check every few months.
I have no experience with Noco products. Although I am considering purchasing one of their Jump starters.

[ITSNO60]

The latest smart chargers enter a "storage" mode after float. My old Deltran chargers stayed at "float" indefinitely which can cause problems with water consumption and dendrite growth. If you are floating for long periods you should check water levels and periodically load the battery with enough load to break the dendrite growth off the plates. The Victron Smart Chargers I now use enter "storage" mode after float and will only charge when needed instead of all the time. I looked at NOCO but it is impossible to find much technical information on their site and there is no way to log into the charger to see exactly what it is doing. I couldn't even find a spec for their storage mode and it is unclear whether or not they go into a true storage mode. They seem to concentrate on advertisement and mass marketing, and target the general user who has no desire to know the details. Kind of like Bose.

I decided to go with Victron for about the same money but far superior products and I am very happy with them.

[Buckless]

Just adding my two cents of experience worth exactly that.
I would disconnect batteries with a full charge and top off charge in three months or when preferred.

I have had good success with that approach.

I have left batteries on a trickle charge and totally ruined the battery in six months.
others may well have different results.
That is what happened to mine.

[Wazbro]

I hook my charger up to a WIFI switched outlet set to come on for 2 hours once a week.

[uncle_bob]

Originally Posted by Wazbro

I hook my charger up to a WIFI switched outlet set to come on for 2 hours once a week.

Hi

You can get a dirt cheap timer without the WiFi to do the same sort of thing. If power goes out or there is some sort of spike, the mechanical ones are *very* hard to kill. It is becoming harder to find those .....

Bob

[ROBERT CROSS]

Originally Posted by uncle_bob

Hi

You can get a dirt cheap timer without the WiFi to do the same sort of thing. If power goes out or there is some sort of spike, the mechanical ones are *very* hard to kill. It is becoming harder to find those .....

Bob

I use a 12v version of this on the Burb.

Bob
🇺🇸

[panamerican]

For my cars I use a battery tender and it works well, however, if you are in your own garage and it's heated already, you most likely have 120v already in the garage. IIRC Airstream stop putting in battery cooking converters, if so, why not just keep it plugged in and let the 3 stage converter (if installed) manage it? No need to disconnect anything since it's in a heated garage and the factory converter does the work.

I pull my batteries and keep them on a batter tender over the winter not placing the batteries directly on the floor, but in my case, I don't have a heated garage to park my coach, nor do I have 120v at the pole barn I store at for the winter....if I had what you had, knowing I have a 3 stage converter I would be doing exactly as I suggest.

[Paul Dobbin]

Our Airstream has a built in inverter and charging system. All 4 batteries are charged to full automatically when it's plugged in to shore power. I also have
heated storage and still leave it plugged in 24/7/365, when parked.
My batteries last a lot longer that way and it's always ready for a road trip.
It's a 35' Airstream DP Land Yacht. Annually I top off the distilled water in all
4 batteries. (2 house, 2 coach)

[uncle_bob]

Hi

If you dig into data from folks who do a lot of A/B testing on this stuff. Having a battery on charge all the time shortens it's life rather than extends it ....

The gotcha is that we rarely have a group of RV's and the ability to do it this way on 20 of them another way on a different set of 20 and directly compare the actual result by capacity testing the batteries a couple years later. There are settings where folks do indeed have those sorts of setups ....

Bob