Battery Water level / Charging with Solar

[Gerry]

We are planning a summer camping trip doing 90% boondocking and today I hooked up my 100W Solar panel for the first time this year.
My battery is full of water and it's location under the dinette seat is a pain in the Butt to get in there to check water levels.
Battery at 8:00 am was 12.4 and when I shut it down at 5:00 pm battery was at 13 so it is charging no problem with just 50% sunshine here in Maine.

Wondering how often others check the water level in the battery using the same type of charging system?

I may have to invest in a remote battery watering system.

All advise will be welcome.

[jgilliam1955]

Get a AGM Maintenance free battery.

[Mike_L]

I'm almost exclusively a boondocker and I've been using flooded lead acid deep cycle batteries for over 30 years. For quite a few years I would charge my batteries at home. I'd use each battery for about 2 days by which time it would be 50% discharged and then I'd switch it out with a fresh battery. This usually gave me a 6 - 8 year battery life span. I'd add water (always distilled) up to the bottom of the fill tube AFTER charging unless the tops of the plates were visible above the fluid level before charging.
It's the charging process (electrolysis and heating) that consumes the water. I'd top up my batteries at the beginning of the season (April, May) and at the end of the season (Sept, Oct) and sometimes mid season if I was camping a lot.

About 5 years ago I installed 150 watts of solar power with a charge controller.
Solar appears to be a much better way of maintaining charge in a battery. It maintains the battery at a much higher level of charge as the solar panels keep the battery topped up. My battery never drops between 85% - 90% full charge. This greatly extends battery life and minimizes water consumption as the batteries require much less charging to keep them full and it is the charging process that consumes water. I added water twice in 5 years of solar panel use.
I have the option of installing a battery inside my unit but was reluctant to use a flooded lead acid battery due to the production of flammable hydrogen gas as the battery charges. This year I will be installing an AGM battery inside my trailer as these have minimal off gassing.
Last season we opened up an AGM that had been in service with solar panels for 5 years. The cells were down about an ounce of water but the plates were still covered and the battery showed full charge.
The charge controller is all important. It starts the charging process as soon as the battery is used which minimizes the depth of discharge. This prevents heating the battery as may occur when it has been more deeply discharged which can also cause fluid loss. It also prevents over charging, a major cause of elecrolysis and fluid loss.
Install your new battery and watch the fluid levels. Then you'll be able to determine how often you need to check it going forward.

[ARVZ]

There are special battery cell caps designed to reduce water loss,
like these: https://www.ebay.com/itm/Water-Miser...sAAOxy1VlREz5U


Like Mike says, you have to watch the water level long enough to get a sense of how fast you are losing water, and be sure your solar charge controller is configured for the correct battery type charging algorithm.

[ehoepner]

I have an 80 watt solar panel on my Casita 17 ft. SD. We have had the solar system for about ten years now. Long enough to have replaced one charge controller. I bought a more expensive charge controller, one that goes into the disulfate mode about once a month. The end result is the battery lasts about five years and I add a little bit of water to the cells once a year. I could probably go two years without adding water. In Colorado sunshine, it takes about 4 hours to recharge the battery after a night with reading lights and the furnace running.

[Gerry]

All great replies and now I am going to rethink getting the AGM battery and just opt for a new battery. The one I now run is 6 years old. Another problem of the tight space the battery is in, under dinette is that I can only get a group 24 battery to fit in.
I do have it in a vented box so gas out is not a problem.
I think a new battery will work.
The only thing I will be running full time is a small computer fan in the back of the fridge and LED lights for reading at night.
I do have a max-fan but probably wont run this unless we have shore power.
Hot water / fridge are both LP gas and we will run the water pump only when we know we have a full battery.
Battery will charge off Tow Vehicle while driving and when stopped the solar panel will work fine.
Thanks for all the comments.

[Darwin Maring]

Charging a battery inside the camper is dangerous because they off gas and that can explode. ME, I would move the battery to the tong.

[Wayne Collins]

As far as I know, what you use to charge a battery, makes no difference to the water (acid) level. Just be sure to not "boil" the electrolyte as that will lower the fluid level.
A battery monitor. or simple voltmeter is an easy way to keep track.

[Glenn Baglo]

Originally Posted by Darwin Maring

Charging a battery inside the camper is dangerous because they off gas and that can explode. ME, I would move the battery to the tong.

Unless the battery is in a properly sealed, vented battery box.

[GaryM]

Originally Posted by jgilliam1955

Get a AGM Maintenance free battery.

Lithium rocks!

[redbarron55]

Originally Posted by GaryM

Lithium rocks!

And burns good, too!

[GaryM]

Outdated information.

[Raspy]

Originally Posted by redbarron55

And burns good, too!

With lithium iron phosphate batteries and the proper charger (not a lead acid battery charger), there should be no problems from either moisture caused fires or runaway heat caused fires.

I'm really looking forward to getting setup with lithium bats after my (4) T-105 6 volt bats give up. But I have no idea what it will cost, or the cost of the charger.

The difference lithium batteries have made with power tools really tells the story. Such a small and light battery can do so much work.

[GaryM]

Originally Posted by Raspy

With lithium iron phosphate batteries and the proper charger (not a lead acid battery charger), there should be no problems from either moisture caused fires or runaway heat caused fires.

I'm really looking forward to getting setup with lithium bats after my (4) T-105 6 volt bats give up. But I have no idea what it will cost, or the cost of the charger.

The difference lithium batteries have made with power tools really tells the story. Such a small and light battery can do so much work.

FYI: I just bought a new Battle Born 100Ah 12V LiFePO4 Deep Cycle Battery, which, while not the cheapest out there, is considered by many to be one of the best in the industry. The price is $949.00 with free shipping. Don't know about the charger because I didn't have to replace mine. Having 100Ah lithium is virtually the same as having 2 100Ah lead acid batteries because you can draw them down to 10% of capacity thousands of times without damage. The Battle Born has a full 10 year warranty and weighs 30 lbs.

[redbarron55]

The new Lithium batteries are much much less likely to catch on fire while in normal use, but it is not unheard of (see Tesla new technology battery fires).
Lithium will burn very "virtuously" and water will not put it out.
Personally I would worry less about a lead acid battery in the camper with people than I would any lithium batteries.
IF I installed lithium batteries I would at least install them in a contained space with a hatch for service from the outside where the weak point and "Blow out" relief will vent outside, giving the occupants a chance to escape.
As a matter of fact I plan to install two golf cart batteries in my much modified Scamp and as s part of that mod I plan on making a draw out battery bay with a hatch for access. Currently my battery is under a bed with a vent from the battery caps to the outside.

[Raspy]

Originally Posted by redbarron55

The new Lithium batteries are much much less likely to catch on fire while in normal use, but it is not unheard of (see Tesla new technology battery fires).
Lithium will burn very "virtuously" and water will not put it out.
Personally I would worry less about a lead acid battery in the camper with people than I would any lithium batteries.
IF I installed lithium batteries I would at least install them in a contained space with a hatch for service from the outside where the weak point and "Blow out" relief will vent outside, giving the occupants a chance to escape.
As a matter of fact I plan to install two golf cart batteries in my much modified Scamp and as s part of that mod I plan on making a draw out battery bay with a hatch for access. Currently my battery is under a bed with a vent from the battery caps to the outside.

My boat came with four Lithium iron phosphate batteries as main propulsion batteries that ran an electric drive motor. At first I did not want the boat for that reason. But after some research, I went ahead, as the lithium iron bats were designed to be safer. With lithium, it's not that water won't put the fire out, it's water that reacts to start it. A cracked case guarantees a fire from humidity. The last thing one would want on a boat! I think this is what was happening with the Chevy Volt fires in the beginning. A minor accident would crack the case, and later a fire would happen. With the Tesla battery system, as I understand it, a major design consideration was how to remove the heat from fast charging in an array of thousands of small batteries, all confined in a small space.

So it seems if you put them in a tight box to deprive them of moisture, you can't get rid of heat, but out in the open, you can't keep moisture away. On the tongue seems bad because they will get bumped an jostled around. Inside seems bad too. Oliver's have a battery compartment over the axles with an outside access door and a slide-out shelf, but a fire there would ruin the trailer.

[Raspy]

Originally Posted by GaryM

The price is $949.00 with free shipping. Don't know about the charger because I didn't have to replace mine. Having 100Ah lithium is virtually the same as having 2 100Ah lead acid batteries because you can draw them down to 10% of capacity thousands of times without damage. The Battle Born has a full 10 year warranty and weighs 30 lbs.

Gary, Just curious. Why didn't you have to replace your charger when going to lithium?

With lead acid bats, compared to lithium, the absorption phase is different, the float voltage is different and the equalization function cannot be used. It seems the battery full charge voltage is close enough, but the charger must be shut off once the battery reaches that number, instead of left on float.

Am I missing something?

[ZachO]

I've had similar experiences with my battery, almost exclusively charged with solar. I should check the water levels more often, but I've only checked them twice in the 3 years I've had my trailer. I didn't need to add water either time.

I'm thinking of upgrading my solar and battery sometime soon, but for now, around 100W of solar and one 12V lead acid battery work fine for me.

[Perryb67]

Originally Posted by Gerry

All great replies and now I am going to rethink getting the AGM battery and just opt for a new battery. The one I now run is 6 years old. Another problem of the tight space the battery is in, under dinette is that I can only get a group 24 battery to fit in.

By cutting the unneeded battery post off that goes in first we were able to install a group 31 battery in our 2007 Casita.

We also have AGM batteries in our Escape 5.0 fifth wheel. The batteries are located underneath the rear dinette. This is a poor location to monitor battery water levels, one reason why we chose AGM's. Another reason is AGM's charge slightly faster.

Food for thought.

Perry

[Gerry]

Well after weighing all the options I have decided to go with a new "no maintenance" batter. The best price I could get for the AMG battery didn't really make sense for what I got.
I went to my RV dealer and when they take in trailers on trade they replace the battery and sell the one that was in the trailer for $45 and I got a group 24 with 100AH that has manufactures date of 9 / 18. So battery is only 6 months old.
Guess I can live with that.