Battery water top up

[DrBob7762]

I'm about to install a battery watering system. It will be a Flo-Rite manual system, so system will need my intervention on a scheduled basis.

I need to determine that schedule. Of course, I can figure that out by looking at water levels frequently, but I am looking for some general guidelines before I start.

I know that charging causes the water level to rise. What causes it to go down?

Is it just evaporation? Or does usage/cycling have an affect?

Put another way - will I expect to need to top up more often in the months we use the RV and less in the non-use months? Or is it a "lots of evaporation in hot weather" phenonminon. Or both?

If it matters - we're using four Trojan T105.

Thanks in advance,
B

[Skip426]

I'd put this right beside a two month weather forecast ; subject to change without notice .

Charging , causes off gassing of the electrolyte , rapid charging and discharging causes faster off gassing .Heat above 80f evaporation , and so on.
Battery condition will effect rate of charge and discharge and a single cell in any battery can require more water than others due to it's condition.

Any info you receive is going to be a guess , if the RV is in constant use , driving & plugged in , my best guess is start with a two week schedule and adjust accordingly.

[Old-Biscuit]

YEP^^^^

You need to monitor weekly, then monthly then 3 months to determine frequency to add water based on your DC System

[TonyDi]

I used to check mine every two months.

[bddadles]

I didn't pay any attention to mine and was plugged in all the time. When the batteries started to smell I discovered a sticker that said to check the water every 2 weeks when plugged it.

I put new batteries in and now my yahoo sends me an email every 2 weeks to check the batteries. Only takes 30 seconds.

[hamm2018]

At least first of every month, until you determine how much water you need. Then you will need to adjust your time to check based on that information.

[153stars]

Two 8D and four GC2 about same capacity with 4 stage charger inverter. I use about 1.5 gallons per year. Probably top off 3-4 months. You'll use much more in very hot and or dry climate.

[rffowler55]

I can add only 1 other factor to the equation: the age of the battery will often impact the frequency of water input. I have an off-grid solar power system at home with (4) strings of 8 trojan T105's and the newest string of batteries can go weeks without needing water but a 2 year old string may need a minimal addition of water bi-weekly. Your usage and other factors will dictate your frequency so don't rely on outside information only, check your batteries and it will soon become evident how often you need to add water.

The main concern from a battery maintenance perspective is to maintain an adequate level of water. An adequate level of water translates into never letting the water level drop to a point the lead plates are exposed and not adding excessive water that boils out during charging diluting the battery acid level.

[Bobertgoes]

Only the water off-gasses, not the electrolyte, so you only need to add water back, the electrolyte is always in the battery. Use only distilled water. Rain water and tap water is very contaminated.

The battery lead plates need to be submerged is all, check monthly if you have easy access to battery. Every two months might be enough after you learn your battery off-gas rate.
You might only need to add water twice per year.

It is the charging that boils off the water and some chargers will put too much voltage and boil the water faster (boil in this case does not mean 212 degrees - just evaporation).
Over charging boils it faster.
Lots of driving/alternator power on a morothome can boil faster than if using only a smart charger.
Trailer batteries are farther from the battery and possibly have too thin of wire so the alternator might not be able to put much of a charge on the battery to matter.