Generator owners

[steamboatscott]

To those running your generator all day to “recharge the batteries,” do you ever wonder why other nearby RVs don’t need to do this?

Pro tip: if you don’t dip your deep cycle batteries below 50%, they will last a lot longer and not require that daily gas-powered boost.

Sincerely,

Someone who doesn’t understand how anyone can enjoy sitting around the campfire huffing gasoline fumes while listening to some cheap *** Walmart engine roar less than 20 feet away.

[fjr vfr]

Yeah...generators can be very annoying! Usually it's the weekend warriors. Most of the experienced RV people either have full hook ups or off grid solar.

[NH_Bulldog]

Most people that use a generator to charge their batteries mid-stay also don’t realize that they could do it quicker by directly connecting a stand-alone charger to the batteries instead of running it through the converter if all they really want to accomplish is to top of the battery.

I have a quiet inverter generator, but have rarely had to use it mid-stay when boondocking. We can safely operate for 3-4 days off battery power (no solar) before reaching a point where the batteries need a boost.

[Max23]

There is however the fact of no shore power and the need to run the A/C. Don't need A/C, ya, don't really see the need for generator to be running.

[larryflew]

Wishing we didn't even have one. Rarely boondock at our age and needed to run for an hour a month just becomes a pita. Having it and gas tank at opposite ends of 39 footer would be a pita for removal or at this point I would consider it.

[xrated]

Originally Posted by NH_Bulldog

Most people that use a generator to charge their batteries mid-stay also don’t realize that they could do it quicker by directly connecting a stand-alone charger to the batteries instead of running it through the converter if all they really want to accomplish is to top of the battery.

I have a quiet inverter generator, but have rarely had to use it mid-stay when boondocking. We can safely operate for 3-4 days off battery power (no solar) before reaching a point where the batteries need a boost.

That would depend on the size of the stand alone charger. Many of these RVs have 35 up to 55 amp converter/chargers, and unless you are using a lot of the amperage that the converter/charger is putting out, for other 12V stuff, the converter/charger will probably do it quicker. On the other hand, if you have a giant stand alone charger that puts out 50...60...100 amps, you might have a valid point. I wouldn't even consider hauling that around though or having to run a heavier 120V circuit to feed it.

[NH_Bulldog]

A typical 125-AH RV or Marine battery will take approximately 80 hours to recharge at 13.6 volts off the built-in converter. Add more time to that if you have 2 batteries. Simply stated; even a small plug-in charger the size of a loaf of bread will charge your battery (or batteries) quicker than a converter alone will.

[CedarCreekWoody]

Originally Posted by NH_Bulldog

A typical 125-AH RV or Marine battery will take approximately 80 hours to recharge at 13.6 volts off the built-in converter. Add more time to that if you have 2 batteries. Simply stated; even a small plug-in charger the size of a loaf of bread will charge your battery (or batteries) quicker than a converter alone will.

I'm not really understanding your logic here.

[NH_Bulldog]

Simply, the primary purpose of a battery charger is to charge a battery. The primary purpose of a converter is to convert 120v AC power to 12v DC to operate the 12v DC needs of the coach, while secondarily providing a slow charge to maintain the coach battery or batteries.

In the context of the original post, using a generator to produce shore power to your converter to then in turn provide power to slowly charge your battery or batteries is far less efficient (and more annoying to your neighbors due to the required long running time of the generator) than simply running a generator to power a battery charger which can charge your battery or batteries quicker and more efficiently.

Think of it like comparing a hatchet and a chainsaw. They will both cut a tree down, but one does it quicker and more efficiently than the other.

[CedarCreekWoody]

But when a converter is ONLY charging the battery and not powering other things such as fridge, lights, etc. does it not then provide full amperage to the battery?

[NH_Bulldog]

Unfortunately, unless you pull all the 12v fuses you can’t “force” the converter to channel all it’s energy to battery charging. Even when running on gas, there is still 12v draw on the system.

Most factory supplier converters are limited in function. They bulk charge up to a certain point (usually 70-80% of battery capacity), then they move to a slower (float) charge rate for the remaining 20-30%. If you are drawing from the batteries during this float, the charge rate tends to be VERY slow, and in some cases the float mode can’t keep up with the demand so the converter kicks back into bulk charge mode. This is why it can take up to 80 hours to fully charge your batteries from the converter.

The power center labels on most units read “POWER CONVERTER with battery charger” not the other way around. Meaning the primary purpose is to be a converter with the secondary purpose being a charger.

Anyway, back to my original point; if you are boondocking and absolutely need to run a generator to recharge your batteries, consider using a battery charger because it will charge your batteries quicker and you have to run your generator less which means your forrest neighbors will appreciate you

[fjr vfr]

The only difference I see in your logic would be if the external battery charger provided more amps. Otherwise it's 6 of one and 1/2 dozen of the other.
The battery charger located in the converter feeds directly to the battery and then the 12v fuses connect to the battery. That's the same circuit either way.

[fjr vfr]

My trailer has 1000 watts of solar on the roof which feeds 2 charge controllers, which are connected to a lithium battery bank.
I completely disconnected the battery charger inside of my converter, so I know it was connected directly to the batteries. The same wire also connected to the 12v fuses.
My 120v system is completely separate from the 12v panel.

[travelin texans]

IIRC my last converter was rated at 55 amps whereas the external battery charger I carry has 3 settings; 5 amp, 10 amp & 50 amp so I'm guessing the converter would charge faster.

[Ramtop]

Originally Posted by travelin texans

IIRC my last converter was rated at 55 amps whereas the external battery charger I carry has 3 settings; 5 amp, 10 amp & 50 amp so I'm guessing the converter would charge faster.

Only if the converter is designed to put out full 55amps from zero battery charge to full 100% charge. Most have a built feature that slows down the charging rate when the battery reaches 75-80% charge.

[travelin texans]

Originally Posted by Ramtop

Only if the converter is designed to put out full 55amps from zero battery charge to full 100% charge. Most have a built feature that slows down the charging rate when the battery reaches 75-80% charge.

That's so it doesn't boil the batteries & properly maintains the SOC as it was designed to do! I've never had issues keeping batteries charged with the converter.
If I leave my stand alone battery charger on full charge it will boil the batteries if I don't watch it very closely.
The charger for my golf cart is also smart enough to shut itself off before boiling the batteries.
With that you do you, I'll do me & others can do whatever works best for them!

[CampNBrew2]

Is there a good resource to figure out charging time to full when at X SOC? Some sort of calculator or formula?

Ex. If I have 200Ah total batteries and my SOC is 12.6V and my converter charger is 55A then it will take approximately X time to top them off. (Assuming charging only and not running the furnace blower, etc.)

[JRTJH]

Originally Posted by Ramtop

Only if the converter is designed to put out full 55amps from zero battery charge to full 100% charge. Most have a built feature that slows down the charging rate when the battery reaches 75-80% charge.

Way back when I was in the Air Force, an NCO was recharging the battery in his bass boat that was parked in the carport of his on-base residence. The battery charger failed to "step down the charge" (that's what the fire department determined was the cause of the fire that destroyed the boat, house and two neighboring homes).

When a battery charger "keeps pumping max amps" into a battery, the FLA battery will overheat, start evaporating the electrolyte and flood the area around the battery with hydrogen gas. If there is an open space around the battery, you'll only suffer the effects of corrosive acid damage to anything in the area (unless you have a spark "too close" to the battery)....

In a closed space, like the battery compartment on many fifth wheels and some travel trailers, you risk making that entire end of the trailer a "ticking time bomb".....

There's a "application of the principles of safe battery charging" that goes alone with the prudent use of a "mega-watt rapid charger" in any RV application. Safety to the occupants is primary, but also protection from "early failure of the battery" also affects your wallet.

The "tried and true WFCO or Progressive battery charger reduced charge rate" is not "a product limitation" but rather is a proven charge regimen that protects the battery bank as well as efficiently charges the batteries in a safe manner.

Of course, if you choose to connect a 50 amp "rapid charge device" to your battery, that's your choice, but pay close attention to all the "associated risks".....

ADDED: While I'm "on a roll here", also consider that installing a battery cutoff switch "in the lid of a battery box" may be really convenient, but the "guts of that switch" are sitting in a cloud of potential hydrogen gas. Turn off the switch after charging the battery and you may find the battery box lid "embedded in your upper body".... Any "spark in a hydrogen gas concentration" can lead to disaster....

OK, rant off ..... YMMV