Replacing 12V Deep Cycle with AGM or Lithium

[M and M]

Greetings,

I just tried to post a lengthy thread about our considerable woes with battery charging and retention in our last two NEW Airstreams, but the website timed out before I could finish. That is probably to your benefit. So, now, I’ll cut to the chase.

2019 AS Globetrotter 27FB
Interstate 12V Marine/RV Deep Cycle Batteries
100 watt flexible photovoltaic solar panel
Go Power 40 amp MPPT Solar Charge Controller w/ Remote Display

After only 2 overnight outings, one of which was in full hook-ups, our batteries are dead and irreparable.

QUESTION: Can I replace the 12V lead-acid batteries with either AGM or Lithium batteries, while still utilizing the existing electrical wiring, charge controller, inverter, converter/charger, and solar panel?

We need to significantly improve/upgrade our existing battery power, as we really enjoy boon-docking (Yes. We have two Honda 2000 watt generators).

Any helpful input would be appreciated.

Thank you. M & M

[pteck]

Originally Posted by M and M

QUESTION: Can I replace the 12V lead-acid batteries with either AGM or Lithium batteries, while still utilizing the existing electrical wiring, charge controller, inverter, converter/charger, and solar panel?

The simple answer is no at least in regards to the two components that's charge profile need to match the battery technology: solar charge controller and converter/charger.

There is a chance that these components depending on the model, can be configured to support one or both of the battery chemistries you're proposing.

That said, the failure of your current batts is not due to the technology they use. Many a new trailer has been delivered with batts that have sat in a depleted state for long periods. A sure way to kill them dead.

Personally, I'd just drop two 6V batteries into the box and give it a whirl. No need to worry about changing anything else.

[kenfconnor]

Originally Posted by pteck

The simple answer is no at least in regards to the two components that's charge profile need to match the battery technology: solar charge controller and converter/charger.

There is a chance that these components depending on the model, can be configured to support one or both of the battery chemistries you're proposing.

That said, the failure of your current batts is not due to the technology they use. Many a new trailer has been delivered with batts that have sat in a depleted state for long periods. A sure way to kill them dead.

Personally, I'd just drop two 6V batteries into the box and give it a whirl. No need to worry about changing anything else.

With all due respect I don't think the response is correct. If you have 2 12 volt batteries that are wired in parallel you cannot just drop in 2 6v batteries. You would need to connect the 2 6v in series. The comment about the likely cause of the dead batteries is valid and you should try to get interstate to replace. Finally if you use lithiums with a built in BMS such as Battleborne you should be able to drop in 2 12v lithiums and be fine. There are ways to get an overall better optimization with other changes but what you have should be ok. There are tons of threads on the subject and many options you can consider.

[pteck]

Fair point. I don't generally consider this to be a wiring change of any significance. I will offer amends:

[kenfconnor]

Originally Posted by pteck

Fair point. I don't generally consider this to be a wiring change of any significance. I will offer amends:

Attachment 340092

Thanks pteck. I agree but not knowing the background on the OP feared something mught smoke :-) The images you posted should be very helpful.

[Omnial]

I've just gone through an upgrade to my Factory solar in my 2019 Globetrotter. In case you wish to go down this path it's worth noting that the factory pre-wire for solar is 8 gauge, not 10 gauge as commonly believed.

Be sure to verify by checking the green and yellow wires located under the front bed.

Just thought this might be useful info when determining options.

[JCWDCW]

Just a note on getting timed out
That has happened to me a few times. Just do your message in word or a text program and copy and paste it into the AS forum message.
JCW

[Skycar]

I just switched to three Battleborn 100 amp hour lithium’s on my 2014 19 feet flying cloud. The batteries should not go outside in the front box. They do not perform well in the cold. They will shut themselves down before any damage can be done and therefore won’t be able to be used in freezing temperatures. Mine are now under my bed, which is in the back of the trailer next to the back of the water heater. I also have a 2000 W Go power inverter under my dinette in the front of my trailer along with a TriStar PWM solar controller for my 300 w solar panels on my roof. I know that you’re going to say that I need a MPPT unit, but with the changing of the dip switches it is adequate for now. What I’ve come to find out is that the distance between everything will not allow the inverter to work properly. Go says that I need 2 0 wire, rather than the 2 gauge I currently have. So now, I’m going to have another company move the inverter to the back of the trailer as the least expensive method. So far I really like the batteries and have not gone under 82%. I would also install a Victron battery monitoring system, because just looking at the volts will not give you an accurate reading of how much you have left. I’ve installed all of this because I fulltime and like to boondock as much as possible. This is just my experience. I’m not an expert, but I’ve learned quite a bit the hard way!

[chicagoair]

Originally Posted by Skycar

The batteries should not go outside in the front box. They do not perform well in the cold. They will shut themselves down before any damage can be done and therefore won’t be able to be used in freezing temperatures.

Some more detail is needed here, for most practical purposes they are fine in the cold.

The batteries will discharge down to -4 degrees F. They will not accept a charge below 24 degrees F.

We keep our two Battleborns in our outside (slightly modified for size) battery box and the temperatures have never been an issue. Even if it drops below 24 at night, we’re not getting solar then anyways to charge. If daytime temps are below 24 for multiple days, we’re moving.

The batteries are the best upgrade we’ve made on our trailer. With 2 100Ah Battleborn batteries we can easily get a week of use out of them without hooking up our external panel. We can go indefinitely with the panel.

[Keithkleinmd]

I've had considerable experience with this. First your problem is either a defective battery or a short circuit/con't load that is draining your batteries. I would turn off everything, disconnect a fully charged battery and see if it holds its charge. If it does, then the battery is not your problem

Put it back in place and turn on the loads one at a time every 24-48 hrs until you find the culprit .

Regarding replacing, 6V golf cart batteries in series are the best. I have used them in the boating for the past 20 years.
Whether you go to that, lithium, AGM etc should not matter as almost all charge controllers and chargers in the past fifteen years allow you to configure them for the battery type. The only issue is the size of the battery compartment.

[cazual6]

You can replace the two 12v Deep Cycle with two 12v AGMs, I just did that and nothing else changed.

However, anything beyond that, then you will have to consider other factors.

[Bill M.]

I think the batteries are bad. If they went down while under full hookups something else is bad also. I think trouble shooting is in order. Probably by starting with fresh batteries. Then check the converter to see if the output is correct. Even if I was going to AGM's I think I would put a set of flooded in until I got the real issue fixed. Sounds a lot like the converter was turned off or defective. Did you run an inverter the night without shore power? Or the furnace?

[waninae39]

if you have 2 or more 12V battery and need to put them in parallel be careful

ensure that you use a very heavy gauge like 0 or a buss bar.

the issue deals with where the +ve and -ve cables go. if the same guage cables are used between batteries and the two load-side are on one battery, the other battery(s)could get a lower charge or not be used as much load

since you want to use both equally, you need to ensure that the supply cables use all batteries equally

this has been posted elsewhere many times

[Skycar]

As far as temperatures go, I’m Canadian. So it can get well below 0 F for extended periods of time. I would not want my batteries exposed to cold like that. Therefore, I will keep them where they can be protected and kept at a reasonable temperature. As well, with three of them, there is no way they could fit in the front box.

[Bradley G]

My brand new 23' FB International had 2 bad Interstate 12v batteries. After our first trip i noticed they were not holding a charge. Couldn't even make it a hour with the furnace running before they were at 40%. My 2017 19' FC had AGM's and could run the furnace all night while winter camping. So i took them out had them tested and both were bad. They gave me new ones BUT i am installing two new Fullriver group 27 6v golf cart batteries and changing out the charge controller as well.

[gypsydad]

There are several, (and I mean several) posts on this battery issue with Interstate batteries being/going bad just after delivery of new AS's...probably the most common problem I see on the Forum!

If your within the 2 year period, call Interstate first, and let them verify cell issues. They will likely keep overnight and verify, and offer you new batteries or a credit toward other batteries they carry; 6V Golf Cart or AGM's, as an example...perhaps even Lithium If you don't want what they offer, take the free exchange they are willing to give you, and sell them on Craigs list...they actually should go pretty fast if you price them right..mine went in 10 min! I got $125 for the pair...then bought 2 6V batteries.

[slackerchef]

I replaced the battery on my 2018 Sport16 to lithium (125AH), shortly after picking it up. In addition, I installed 130watts of solar on the roof, and a Victron MPPT 20A solar controller (bluetooth version). The system works GREAT! I never have to worry about keeping the battery charged or running out of power, so boondocking is a dream. When I get my full time AS (likely a 27ft GT like you have), I'll quickly switch to lithium and solar as well.

Happy Travels!

[Changing Itinerary]

Originally Posted by chicagoair

Some more detail is needed here, for most practical purposes they are fine in the cold.

The batteries will discharge down to -4 degrees F. They will not accept a charge below 24 degrees F.

We keep our two Battleborns in our outside (slightly modified for size) battery box and the temperatures have never been an issue. Even if it drops below 24 at night, we’re not getting solar then anyways to charge. If daytime temps are below 24 for multiple days, we’re moving.

The batteries are the best upgrade we’ve made on our trailer. With 2 100Ah Battleborn batteries we can easily get a week of use out of them without hooking up our external panel. We can go indefinitely with the panel.

Hello Chicagoair,

Can you tell me more about your portable panel kit? Do you connect it via the Zamp Solar Port on the Battery Box?

I am looking at the Zamp 230W portable kit to pair with 200 Ah of Lithium but see that other brands are less expensive. I went with two Lion Energy’s Safari UT 100 Ah batteries as dealer drop in replacements for the Interstates on a 2019 Flying Cloud 30. They are also installing a few 12V outlets for us.

We will be watching our power consumption as we hope to boondock five to seven days at a time.

Thanks,
Scott

[chicagoair]

Originally Posted by Changing Itinerary

Hello Chicagoair,

Can you tell me more about your portable panel kit? Do you connect it via the Zamp Solar Port on the Battery Box?

I am looking at the Zamp 230W portable kit to pair with 200 Ah of Lithium but see that other brands are less expensive. I went with two Lion Energy’s Safari UT 100 Ah batteries as dealer drop in replacements for the Interstates on a 2019 Flying Cloud 30. They are also installing a few 12V outlets for us.

We use the external Zamp port. Any brand would work, we happened to get Zamp because it’s what our dealer sold and I negotiated the panel into the purchase of our trailer.

If you use a non-Zamp panel Airstream Life sells an adapter to make it work: https://store.airstreamlife.com/coll...olar-panel-kit

In the past when I mentioned the adapter folks also mentioned you can “just reverse the wires” on the Zamp port. 🤷🏽*♂️

We just had our setup in Santa Fe National Forest with mostly rainy days and heavy tree cover, and low temps that required the power hungry furnace blower all night. Even with horrible solar output we left after 4 nights with 43% charge on the 200Ah setup.

[ROBERT CROSS]

We are currently on the road...8 days, no hook-ups, no generator, two days of good sun, 6 of cloudy, rain.

Two 180w Zamp suitcase's, charging thru the 7pin.
We have seen 38% SOC as our low, 45% would be close to our average.
Had a very nice AM today and are now back to 52% at noon.
Screen shots...👍

Bob
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