New batteries, leave charger on all the time or not?

[Letsgoagain]

Good evening,
Just installed four new 6 volt house batteries and set the charger. The charger is part of the xantrex invertor and has a three stage charging process as well as a temp. compensation for optimum charging.
My question is after they have been charged should I leave the charger on all the time? Some of the documentation says so but I'm concerned about to much charging and boiling the water out. Don't want to ruin new batteries if you know what I mean. $$
Like to know what some of you do and logic behind your decision.
The motorhome sits in the driveway most of the winter and stays plugged up and this has worked for the last 4 and a half years but still want to do this the right way.
Thanks for any responses.
Letsgoagain

[paz]

If your inverter (or converter) has a 3-phase charger, you should be OK leaving it plugged in. You do, however, need to check the water level periodically.

We are full-timers, and we have an inverter with 3-phase charger. Since we rarely, if ever, dry camp, the only time we are not plugged in is when we are on the road. I check the house batteries every couple of weeks, and end up adding water about once every 6 weeks or so.

[Letsgoagain]

paz,
Thanks for the reply. Reassures me that this is the right thing to do.
Since the third stage is a trickle or float charge I'm thinking it will be okay but when I shell out that much money for batteries I want to be sure.
We've had the motorhome for 4 1/2 years and it sat on the dealer's lot for a year before we bought it so that made the batteries I replaced at least six years old. I guess the routine that I was following must have been right to get that much life out of them.
Thanks again for the reply. Good to get the experience of a full timer.
Best regards,
Letsgogagain

[BryanL]

Battery charging and battery maintaining are two different tasks.

To maintain a battery when it is not in use, it needs to be kept near full charge with appropriate attention to plate corrosion and sulfation. Converters like the Progressive Dynamics with Charge Wizard or WFCO do very well at both charging and maintenance. They work by using a low float voltage with periodic short bulk level charges.

The BatteryMINDer uses another maintenance technique that seems to work well for battery maintenance. It was first published in Home Power magazine about ten years ago and uses a frequency imposed on the charge voltage as its method.

If you are not familiar with how your equipment maintains batteries, keep an eye on the voltage and the water level. If the voltage gets below 13.0 volts, it is probably not maintaining a good charge. If you have to keep adding water, the battery is being overcharged

[RV Wizard]

First I would recommend getting a good temperature compensated hydrometer and testing each cell of the new batteries. This will assure that each cell is good and they should all be the same specific gravity within 1/100th of a point. If you find that you have a battery with a weak cell, have the place you bought it from exchange it for one that has been tested this way and is in compliance to having all good cells.
Be sure that all cable connections are clean and tight.
Make certain that the temperature sensor for the inverter/charger is connected to a central battery post.
Now you can leave your inverter/charger on charge mode 24/7 if you like. Check the water level once a month but you will probably not have to add water as these three stage chargers are as good as they get at charging and maintaining a battery bank when all else is good.
My house batteries are 9 years old. I have had to add water three times. and they are just now starting to show that they are not as strong as original. I might be able to equalize the battery bank and still get another year out of them. Good luck and keep us posted.

[Letsgoagain]

paz, BryanL and RV Wizard,
Thanks for the replies. I'll purchase a hydrometer to check each individual cell now that the batteries are charged fully. Liking what I see on the freedom remote display so I'll see if the hydrometer confirms it.
Also when I removed the old batteries I noticed that one of them must have boiled some water out cause behind the batteries the wall paint was flaking and had built up some corrosion where the electrolyte had touched. I used my drill and rotary wire brush attached to it to remove the corrosion down to the metal and then I used a paint brush to coat the battery compartment with a mixture of baking soda and water. Must have been some acid cause you could hear the fizz as it was neutralizing it. Washed it down with water after that and painted the walls with rustoleum paint, cleaned the battery cable connectors so they where shiney and sprayed them down with electrical cleaner. I feel good about the compartment and connections so hopefully with some diligent attention I'll get good life out of the new batteries.
Thanks for the help.

[Luv2go]

Letsgoagain:

We also have the coach plugged in in the driveway whenever it is not being used. I have had no problems with boiling batteries (in my case, venting AGM batteries, which is worse) with either the Freedom inverter/charger I had on the old coach or the Trace SW inverter/charger on the present coach.

Regarding your corrosion issue, some people have had success stopping corrosion by using replacement caps, others have had good success adding mineral oil to the cells of the batteries. I have not done this myself as I haven't had a corrosion problem on my starting battery (a flooded battery which is connected to the coach batteries during charging) or the two flooded coach batteries which are in parallel with the AGM coach batteries, but that is probably because I have had the inverter set up for AGM batteries, which uses lower bulk/acceptance and float voltages.

If you believe you may be overcharging your batteries, you can try the AGM settings on your charger (Freedom, for example, lowers both bulk/absorption and float voltages by 0.1V for AGM vs flooded). I would definitely routinely check the specific gravity to insure the lower voltages completely charge the batteries.

I have to add water only once a year to the flooded batteries, but again this is probably due to the lower float voltage the AGM setting uses.

Stewart

[LLonearth]

On our Xantrex inverter/charger (2000 watt) you can change the "Charge Rate" from 100% to 10%. When we are plugged in to shore power for long periods I drop the rate down to 10 or 20% because the batteries do not discharge to need bulk charge cycles. Seems to help prevent boiling out the water in the batteries.