Coach Batteries

[Randy Perry]

So I just installed (4) new 6-volt coach batteries and my question is, while I'm parked in my Beaver Barn, I have her plugged into shore power, do I hit my "Coach Power Disconnect" switch? The guy I bought the batteries from said not to have them charging (even tricking charging) while the coach is in storage mode! Do they charge when it's in Coach Disconnect mode? I will put a meter on them to check, but just wanted to know what ya'll were doing! I would to get the maximum life out of these guys!

Thanks fer yer input!
Randy

[Richard And Babs Ames]

Get a second opinion about charging at a float charge. Disconnect allows a float charge for a reason but to stop you turn off the inverter.

[Karl Welhart]

I would leave them on a float charge when in storage.  Check the voltage to see if they are around 13.5 in float charge mode.  This should also keep your chassis batteries charged as well.

[Dick Simonis]

Just a random thought.  Can you put a skylight in your Beaver barn above the solar panel???  I find my solar panel keeps everything topped of nicely when the coach power is turned off.

Alternatively, if you're concerned about the constant trickle charging, just plug it into a timer and have it come on for an hour/day or therabouts.

[Joel Ashley]

Even in the NW winters my solar panel does a good job keeping my batteries up, as long as the main switches are off to mitigate minor drainage sources.  During extended periods of dark weather I do plug into our 30 amp RV outlet and let it float.  I'm at 5 years on original batteries, and going strong.

Our old coach didn't have solar, but I learned to extend battery life on it by using a Battery Minder device that did a superb job of float charging, and added several years.  Part of that was due to The device's equalizing charge feature;  not all charge maintainers can do that.  I now use the Battery Minder to keep my infrequently used pickup truck's battery top notch.

Joel

[Gerald Farris]

Randy,
Your batteries will be better off if you leave the inverter charging circuit on.  If the house batteries are on float charge when in storage, the Echo Charger will keep the chassis batteries fully charged. Otherwise the chassis batteries will be completely discharged by the engine computer (ECM). The ECM (engine control module) is powered up at all times, and will kill your chassis batteries in a week or so if they are not recharged in some way.

The only other option if the coach is stored inside is to be certain that the coach and chassis batteries are completely disconnected ( most factory installed battery disconnects do not do this) when in storage. The batteries will self-discharge and need to be recharged if the coach is stored more than a month or two, if you decide to use this method, because the batteries will self-discharge enough to possibly cause alternator failure if not recharged.

Gerald

[Gil_Johnson]

Gerald,

On my 09 Contessa there seems to be a fair load on the house bank even with The battery switch off.  I know the Magnum charger/inverter remote panel is powered, so I assume the charger/inverter is not islolated by the cut off switch.  I'm considering installing cut off devices on both he house and chasiss banks.  Is there any risk to taking power away from the ECM?  Any other risks?

Thanks,
Gil

[Gerald Farris]

Gil,
The only risk that I know of is the self-discharge problem that you get with any battery that is stored without a float or maintenance charge.

If you have access to a power outlet, it is much simpler to just leave the batteries on float charge. This will keep all of the batteries in good shape, and remove the risk of starting the coach with discharged batteries and overheating the engine alternator.

Gerald

[Randy Perry]

Plugged in and battery disconnect switch open, I'm reading 14.4 volts. Is that a "Float" charge? If it sits plugged in for 2 or 3 months will it boil the water out?

[Mary and Mike Boone]

I have the same question.  If we have our RV plugged into 110 v for a trickle charge, will the batteries charge even if the coach power button by the door has been used to turn off coach power?  

[Keith Cooper]

When charging, batteries there are three charging stages. The first stage is the constant current charge, and typically takes about half of the total time required to reach a fully charged state.  A battery is typically charged to 70% of the fully charged state during the constant current charge.  During this state, voltage is typically increasing while current remains constant.  The second stage is the  topping charge.  The voltage is relatively constant, typically between 2.4V and 2.45V per cell.  This is very likely the 14.4v you are seeing.  During the topping charge, voltage peaks and current decreases.  The battery remains in this state, until the remaining 30% of charging is completed.  Frequently, this is referred to as saturation.  Once the batteries reach saturation or full charge, the third stage of charging (float charging) is entered. During float charging, both voltage and current are reduced. Float voltages vary depending on the type of cell (Gel 13.05V, Flooded 13.4V and AGM 13.6V).

[Keith Oliver]

All the Coach Power button does is turn off the loads.  It doesn't affect the charging.  that is controlled by the Inverter/charger, which ought to be connected directly to the + terminals, so ON all the time.
Charging with a "smart" charger will give you battery health.  In the old days (I think 20 years have passed since the last "dumb" charger was used in this sort of application) a ferro-resonant charger was as good as it got.  those would boil the batteries if not turned off when done.  If you have an Inverter/charger, is is undoubtedly "smart" and will have 3 stages, so will keep your batteries in perfect health if connected and turned on at all times that you are near shore power.

[Gerald Farris]

Randy,
Like Keith said above your inverter will drop the charge voltage down to float voltage of 13.4 to 13.6 volts as soon as the batteries are fully recharged (usually about a hour or so unless the batteries are badly discharged).

Float charge voltage will not boil the water in your batteries. The water level in your batteries will need to be checked and toped-off monthly to once every three months, depending on the temperature and humidity where the coach is stored. Battery quality and condition will also affect how often you need to water them. Also always use distilled water when watering your batteries.

Gerald

[LEAH DRAPER]

Gerald
Am a little confused about all this battery charge chatter.  I have my coach plugged into 50 amp power at home, with a battery minder on the chassis batteries, when plugged into shore power.  I leave the inverter OFF.  My question is:  Am I to understand that I should also have the inverter turned ON, rather than OFF, to ensure proper battery charging of the house batteries??

The only issue I have faced with these Interstate batteries is corrosion in the tray (not on the cables etc).  I cannot understand why this is, or where it is coming from, but it does keep building up, and I have to constantly keep cleaning it off.   I don't detect that they are boiling over, perhaps a small leak somewhere in one of the cases??

Would once again appreciate your insight.

Leah

[Gil_Johnson]

Leah,

Why do you have a battery minder?  My '08 Contessa has a Magnum charger/inverter, that charges both battery banks.  The Magnum charger is also a smart charger, so it goes to float charging after the batteries are charged.  So, if your coach is wired like mine, the inverter should be off and the charger on.  I think Gerald was just saying the charger/inverter should be energized.

Gil