Batteries

[bugsydog]

I am charging my batteries from an extention cord from n
my house. Does the battery knob by the floor need to be on or off to charge the batteries. I have had differnt opinion on this. Also when we camp at the the rv campgrounds and plug in to there power, does the battery knob need to be off? I know this sounds stupid but electricity and me dont get along.

[mel s]

Originally Posted by bugsydog

I am charging my batteries from an extention cord from n
my house. Does the battery knob by the floor need to be on or off to charge the batteries. I have had differnt opinion on this. Also when we camp at the the rv campgrounds and plug in to there power, does the battery knob need to be off? I know this sounds stupid but electricity and me dont get along.

bugsydog
My house battery switch, (aka: "salesman switch") has not been turned OFF during the 14 years, (109k miles). I've owned my coach.
Mel
'96 Safari, (137k miles)

[wa8yxm]

Does the battery knob near the door need to be on or off.

Depends, 3 answers

1: If your RV has a CONVERTER, (not an INVERTER/Charger) odds are in the high 99s that it does indeed need to be on

2: If you have a big (1000+ watt) inverter/charger Odds are good the state of the switch does not matter.

3: IF you are using an outboard charger, such as a Battery Minder (TM) to maintain the batteries over-winter Then OFF

How to tell...

You will need: Digital volt meter

Turn off switch and Unplug RV/Charger, go to dinner (Breakfast or Lunch will do too, just leave for an hour)

Hook up digital volt meter, NOTE voltage on batteries 12.6? Very good

Plug in

Come back in a few minutes (like 1-5, basically walk around the rig)

Re-read the digital volt meter.. Still 12.6 (no change) turn the switch on

Sudden increase (IE: 13.6) It is now charging (Well floating) but..

if turning on the switch causes a sudden INCREASE then leave it on

NOTE: this test covers all possible configurations save #3 above.. (1 and 2 have different possible confirgurations, #3 does not).

Take all voltage measurements at the battery terminals.

[gabriela]

Dear RVers:

My 30' Class C 2007 FR Sun Seeker is parked outdoors on my lot in Poconos PA, where lately we're averaging 5 degrees during the day. I had it professionally winterized in October, and that RV tech told me "do not leave your house battery just plugged in, it will dry up your battery." So I obeyed that, and come every week and plug it in to the house 110-volt outside plug and leave it that way 24-48 hours, and that gets the house battery charged up. I also start the truck engine, which I've read is NOT getting cross-charged just by plugging in the house battery to the outdoor shore 110-volt shore power.

I am noticing that my house battery is going down to 30% every 4 days or so (unplugged, and with inside-door voltage switch turned "off" to prevent any "parasitic" drain during unplugged period) in the cold, and being as we're in the coldest part of winter, with average this week and next in 5 degree range, I am very tempted to plug the RV into my 110 volt outside electrical outlet, put the voltage switch on again, and leave for warmer climes (NYC, where the apts are overheated) for at next 2 weeks or so. I will leave the RV volt systems turned "on," as I've been instructed, otherwise the charging process is futile (I've been told). I understand that this will charge up my house battery, but not the truck battery. All fine.

What I am worried about is that I'll "fry" dry my house battery by doing this for two weeks. Any ideas, folk? Is this likely in 5 degree average temps? If it's true, that means I have to go back and forth, back to Poconos, coming from NYC, plugging and unplugging, which I am finding unpleasant and is like babysitting hens in a hen house.

Thanks for any advice. I want to plug it in and leave it for 2 weeks.

Sincerely, Gabriela

[milasman]

Top batteries off with distilled water and plug it in.

[mel s]

Originally Posted by gabriela

Dear RVers:

My 30' Class C 2007 FR Sun Seeker is parked outdoors on my lot in Poconos PA, where lately we're averaging 5 degrees during the day. I had it professionally winterized in October, and that RV tech told me "do not leave your house battery just plugged in, it will dry up your battery." So I obeyed that, and come every week and plug it in to the house 110-volt outside plug and leave it that way 24-48 hours, and that gets the house battery charged up. I also start the truck engine, which I've read is NOT getting cross-charged just by plugging in the house battery to the outdoor shore 110-volt shore power.

I am noticing that my house battery is going down to 30% every 4 days or so (unplugged, and with inside-door voltage switch turned "off" to prevent any "parasitic" drain during unplugged period) in the cold, and being as we're in the coldest part of winter, with average this week and next in 5 degree range, I am very tempted to plug the RV into my 110 volt outside electrical outlet, put the voltage switch on again, and leave for warmer climes (NYC, where the apts are overheated) for at next 2 weeks or so. I will leave the RV volt systems turned "on," as I've been instructed, otherwise the charging process is futile (I've been told). I understand that this will charge up my house battery, but not the truck battery. All fine.

What I am worried about is that I'll "fry" dry my house battery by doing this for two weeks. Any ideas, folk? Is this likely in 5 degree average temps? If it's true, that means I have to go back and forth, back to Poconos, coming from NYC, plugging and unplugging, which I am finding unpleasant and is like babysitting hens in a hen house.

Thanks for any advice. I want to plug it in and leave it for 2 weeks.

Sincerely, Gabriela

Gabriela
If you are using a 3 stage automatic charger the only danger to the "house batteries" is low electrolyte.
If your inverter/charger, (or an added battery maintainer of some type), also monitors your "chassis battery" there is no danger there either.

I shore my coach, (plugged into 15 amp shore power). for as long as 6 months with no problems.... but I do check the battery electrolyte levels every 3 months, (year 'round), and add distilled water when necessary.

Mel
'96 Safari
Mine for 14 years, (5 through cold Wisconsin winters)
Freedom 20 inverter/3 stage charger

[wanderso]

On my rig, even with the factory master switch in the "off" position and not a true battery disconnect installed, there are still parasitic drains. I confirmed this with the amperage test circuit of a multimeter. You can eliminate those by adding a negative lead battery disconnect switch (many are available on Amazon for example). Flooded wet cell batteries tend to lose up to 10% of their charge per month even if fully disconnected. AGMs are closer to 1-2%.

Most rigs indeed don't charge both the starting battery and house battery. Mine does when plugged in only due to having a factory installed Surepower 1315 battery isolator that is bidirectional. While this sounds like a great feature, I have mixed feelings about the isolator and may swap it out in the future for an isolator such as the 1314 that only allows for a charge to go one direction as I don't want to inadvertently overcharge my house batteries and confuse the charger with the starting battery also in the mix.

If your charge controller is not at least a 3 stage charger, you may consider an inexpensive smart charger option such as the battery tender Jr. or one from CTEK. The CTEK has added features such as compensation for higher charge voltages required when ambient temperatures drop as well as a battery conditioning setting.

I have both and am pleased with them, recently upgrading to a CTEK when installing AGM batteries.

These chargers can be plugged in 7x24 and are very efficient.

[Dynadave]

Plug it in and let it charge. I leave mine plugged in for several weeks at a time with no problems, just check the electrolyte every couple of months.

[mikell]

I leave mine plugged in all the time and have had no issues but I also have 100 watts of solar to keep it going when not plugged in.

[gabriela]

Originally Posted by wanderso

On my rig, even with the factory master switch in the "off" position and not a true battery disconnect installed, there are still parasitic drains. I confirmed this with the amperage test circuit of a multimeter. You can eliminate those by adding a negative lead battery disconnect switch (many are available on Amazon for example). Flooded wet cell batteries tend to lose up to 10% of their charge per month even if fully disconnected. AGMs are closer to 1-2%.

Most rigs indeed don't charge both the starting battery and house battery. Mine does when plugged in only due to having a factory installed Surepower 1315 battery isolator that is bidirectional. While this sounds like a great feature, I have mixed feelings about the isolator and may swap it out in the future for an isolator such as the 1314 that only allows for a charge to go one direction as I don't want to inadvertently overcharge my house batteries and confuse the charger with the starting battery also in the mix.

If your charge controller is not at least a 3 stage charger, you may consider an inexpensive smart charger option such as the battery tender Jr. or one from CTEK. The CTEK has added features such as compensation for higher charge voltages required when ambient temperatures drop as well as a battery conditioning setting.

I have both and am pleased with them, recently upgrading to a CTEK when installing AGM batteries.

These chargers can be plugged in 7x24 and are very efficient.

Hello:

Thanks for the advice. I decided to leave the RV plugged in for at least the next two weeks (unattended) based on a everyone's advice, and based on my experience so far this winter with the RV, which is that its house battery was losing 66% of its charge every 3 or 4 days. The temperatures right now in Poconos are hovering near zero or below on a "real feel" basis, and I just realized in those temperatures, it is unlikely I'd "fry" the battery as I'd been warned against.

The truck battery seems fine, which makes hope there is a little cross-charging going on--there is a "battery" assist button dash board (for assisting truck battery with the house battery), so maybe there's a cross-charge. I sure hope so, because it's so brutally cold up there right now.

Sincerely, Gabriela