Is there a DC battery charger in my coach?

wolfe10 wrote:
With the standard alternator/regulator, yes, your batteries will be slightly overcharged while driving.

There are (rather expensive) smart regulators that can reduce voltage (goes through the same bulk, absorption and float as a smart charger). Have them on our sailboat. Not sure it would be cost-effective on a motorhome.

Said another way, keeping a fully charged battery at 14 VDC all day while driving is slightly excessive voltage. But cost of cure would exceed any likely damage to the batteries.

Brett,
In your last statement here, are you insinuating that any/all/most alternators consistently keep charging at 14VDC even after quite some time at driving? If so, I'm not sure what you mean. All I've ever known is the standard charging system in an auto/truck/Motorhome/Motorcycle etc. will charge, after the engine starts, at a higher rate of amps/volts, to replenish what was used to start the engine , i.e. 14+ volts and, corresponding amperage.

Then, when that initial "re-supply" of higher volts/amps has been accomplished, and the main starting battery (normally the only battery in anything but an RV) is back up to peak voltage, usually not very long, the alternator/voltage regulator will auto-sense what's needed to keep the system at normal system voltage for the rest of the time that the engine is running. And, that usually hovers around 13.0-13.5 plus or minus.

Now, if there's additional loads being used while driving, i.e. heater, A/C, headlights and running lights, and maybe some other form of semi-high amp draw, then the voltage regulator will sense that and, will respond by allowing the alternator to ramp up output to compensate for those additional loads.

Now, that's my pretty much basic understanding of how the average system works.

To the OP,
Based on your signature, you have a Newmar King Aire 4599. Well, I have no idea what that is, 5th wheel, Gas, diesel or what? But the only Newmars I'm aware of are diesel pushers. If that's the case, you should (I always hesitate to group all diesel pushers because there are some differences) have what's called an "Inverter/charger" on board.

And, if that's the case, you've noted that your "battery charger" will handle the house batteries with a three stage output to correspond with what's needed by the house batteries. Well, I'm assuming that you know that the "battery charger" is in fact, the second half of your Inverter/Charger and not an independent battery charger. That is of course unless your coach has been equipped with other forms of house battery charging.

And, as has been stated, on some coaches, the Inverter/Charger does NOT charge the chassis batteries while on shore power. Some do. It all depends on how your coach was setup and, the type of equipment that was installed during the build process or, possibly what was added aftermarket.

If your coach is a Gas coach, 99.999999% of those, were or, are equipped with what's called a Converter/charger. The process of charging the house batteries is close to that of an Inverter/charger, depending on how intricate the charger side of the Converter/charger is built and or, if it has a circuit board in the system to mitigate just how much voltage is applied to the house batteries at any given time.

As for the engine alternator charging both, well there's a few variations of those systems too. In our coach, an '04 Itasca Horizon 36GD with the C-7 330HP CAT, the engine alternator does charge both sets of batteries. But, the voltage IS NOT regulated by anything but the voltage regulator in the engines alternator. The two sets of batteries are connected by a large, mechanical, dual duty solenoid, AFTER the engine is started.

It IS NOT part of the BULK/ACCEPTANCE/FLOAT system that is utilized by the charging section of the Magnum 2012ME Inverter/Charger. That system is built within that Inverter/charger and DOES NOT come into play, when the engine is running.


So, to answer your question, your engines alternator and, it's own voltage regulator are the main players in replenishing voltage to both your chassis and, coach batteries. Now, again, not all diesels and RVs are the same so, it's quite possible that, your Newmar could have some alternate system that helps regulate what kind of voltage is replaced into your house batteries when the engine is running.

On some gas and, even some diesel coaches, there's what's known as a "BIRD" system. That system utilizes a Bi-directional-relay-delay system that basically THINKS to determine, just what kind of voltage goes to both systems and, when they are deserving of it. But, there are many on here that think that system is in every RV ever built. Well, not quite so.
Scott