Seal the battery boxes?

[Randalf]

I did a check on the two 31DCM batteries yesterday morning and found they were both dry and the plates looked like swollen blobs. That sort of surprised me, since we just bought the trailer four months ago, and have only exercised the slides three or four times. I ran to Autozone and bought two wet cell 29 DC marine/rv batteries as replacements.
The battery boxes were sealed like crazy with black silicone. I didn't have the time or inclination to reseal the boxes so the holes in the sides of them where the wires run through are still open. The boxes have vents/drains in the bottom and I reconnected to vent hoses on the top.

A couple of questions:
Are bad things going to happen to good people if I don't reseal those boxes? Auto, truck and boat batteries run in unsealed boxes & are in close proximity to wires and hydraulic lines, and nothing bad happens. Is there something unique about RVs I'm missing?

Checking the water in sealed battery boxes jammed inside a tiny compartment is absolutely agonizing! The front compartment is partitioned & pre-wired for a generator (on the to-do list), so the battery area only has space for two batteries. What batteries should I install next time so I don't have to check them? AGM?

[mhs4771]

The Sky will fall if you don't put the batteries in sealed boxes, NOT!
Our 2010 Montana was delivered with the battery just strapped to the floor of the front compartment, not even in any type of box.
I have removed the factory boxes on our MB, added two more batteries for a total of four, boxed them in and fab'd a cover with the two vents attached, is it sealed, NO, and we haven't died yet and we live in it 9 to 10 months of the year. And as Alfred E. Newman would say "What me worry".
When it comes time to replace, AGMs will go in. The price of AGMs have come down a long way and if you look around can be found for not much more than standard Lead/Acid.
Others can disagree with my setup, but they're not living it in, we are.

[travelin' texans]

Other than flimsy foam gasket mine aren't sealed & we've lived in it for 4 3/4 years. I also agree checking the water is a royal PITA, fortunately I only do it twice a year & mine doesn't have the gen box in the way.

[Randalf]

Thanks, folks. I couldn't imagine how it could be an issue. So far that seems to be the only area on our Redwood where they got carried away and did TOO good a job when they built it!

Now I'm fussing with the Trailair pin box. It was only filled to 30 pounds, so I jacked it up to 68 pounds. Next I'm going to look for my grease gun. If they didn't check batteries or pin box pressure when they prepped the trailer, they probably didn't grease it up, either.

[Shane Wood]

My batteries lasted 2 weeks after we bought the trailer. Put in Interstate AGMs. They have been great for 2 yrs so far. No checking and adding water

[ted 95]

i would verify the charging voltage. your charger could be boiling the batteries if it is not set to the correct type you have. to have a toasted battery in 4 months is not normal.

[spindrift]

Originally Posted by ted 95

i would verify the charging voltage. your charger could be boiling the batteries if it is not set to the correct type you have. to have a toasted battery in 4 months is not normal.

Agree, something is definitely wrong.

[johnboytoo]

The 3 batteries delivered with our new 38gk were junk and were replaced by the dealer.

I agree, bet your charger is not set up for the proper charge rate for your batteries. Every time batteries are changed that should be checked and adjusted.

I too fought the battery fill nightmare - you can get a flow rite system to make it a piece o cake !

That is what is on our motorhome now, makes battery checking a thing of the past because you just hook it up and pump a few times to fill with distilled water.

[Ford truck guy]

After 2 years, I had 1 dead battery, and 1 very weak battery.. I replaced my no-name sealed batteries after 2 years.. I just dropped in 2 of the Lifeline Group 31 AGM's . .

[Grizzby]

My battery covers lay loose on top of the battery box. With the vent hose hooked up, they vent fine...been that way for 4 years.

Bob

[atom ant]

Batteries generate hydrogen, especially batteries that are overcharged to the point they boil off all the electrolyte in a short time. Hydrogen explodes when the mixture with air is within the lower and upper explosive limit.

The underhood of your car or truck is a well ventilated space with the ability to naturally ventilate through the grill and down to ground. Boats are allowed open batteries because they have both prestart mechanical ventilation and natural ventilation while underway for any trapped gases in the bilge area. The hydrogen vents out along with any fuel vapor collected in there.

The case on your batteries forms an enclosure with natural ventilation (hose to atmosphere out the top and hole below to atmosphere). Compromising that enclosure allows hydrogen to build up in your compartment without any form of mechanical or natural ventilation. Even if you leave the lids off but the vent hose hooked on, hydrogen is still allowed to migrate into the rest of the compartment because you have altered the designed draft.

Hydrogen buildup is a risk, the battery box mitigates that. I'm not saying a hydrogen explosion in that compartment would blow you to bits, but it could blow the door off the front and burn whoever might be in the path. What you do with it is up to you. Don't base your decision on the testimony of those that are lucky. The codes are typically based on incidents that already occurred.

[excapt1259]

I have had AGM's since Jan 2017 and all is well with mine.

[bergeman]

Atom Ant is correct. If you stay with the lead acid batteries, keep them in the box. Or switch to AGM and eliminate the box. Even with AGM, some will insist that they are kept in a ventilated box. For myself, AGM and no box.

The first time I went to check my batteries and saw that mess, I was fortunate to be able to replace them with AGM's. The boxes that came with my unit did have a big hole in the side so they where useless from the beginning.

[atom ant]

Originally Posted by bergeman

The first time I went to check my batteries and saw that mess, I was fortunate to be able to replace them with AGM's. The boxes that came with my unit did have a big hole in the side so they where useless from the beginning.

Scott, did your boxes have a 2" hole out the bottom? My factory boxes had 2" out the bottom and top on the Redwood. If I remember right, the boxes had ridges to keep the battery off the bottom a bit so they could vent.

AGMs are nice! I have 6 31 series now and the are a little more tolerant to cycling down in power than a standard lead acid, but they are pricey. Replaced mine and it costs $1,470

[Randalf]

Thanks everyone for your input.

I considered the fact that it is a sealed space, but I still felt safe with the holes in the sides of the boxes because it has the top & bottom vent hoses installed. I was assuming that everything is operating normally and I just have crappy factory batteries, so hydrogen gas build-up wouldn't be a big issue. After all, our trailer is a year-end close out model, so the no-name batteries are two years old, and I have no idea how many times they've been cycled, or if they've ever been checked. But then Atom Ant just had to bring up overcharging & boiling batteries & hydrogen gas build up, and bergeman just had to go and concur with him.

I will install AGMs as soon as we get back to Texas and we recuperate financially from this trip to Colorado. Without the need for battery boxes, I'll have enough room for three batteries. Best of all, without the boxes I'll be able to check the water in the.... oh wait, I'll never have to do THAT again!

But how do I know if my charger is boiling the batteries? Whenever I've looked at the gauge in the trailer it indicates that the batteries are on float, and voltage is somewhere between 13.2 to 13.8. How much is too much?

[atom ant]

My Redwood factory battery died before we finished the PDI so they replaced it. Before we even got home I stopped and got two 27 series deep cycle lead acid batteries at CW and they held up through the duration of our ownership.

Check your inverter - we had a PD4500 (manual attached). The Charge Wizard can be set to automatic or several manual modes including boost which could cause overcharge if continuous. Ultimately it should be on automatic for normal use.
I suspect however the batteries are faulty.

Also, the PD4500 did have a jumper wire that needed removed to go to gel cell, you might ask the manufacturer about AGM batteries because I'm not sure. They may ask you what brand of AGM, as there is a difference between Trojan and the others in how they like to charge and minimum voltages. Our MH has multiple settings based on the brand and type of battery.