Charging with internal or external charger

[dcf]

We're going to brave some cold this weekend to get a first outing in our new (to us) Keystone Passport, but likely will end up in a campground without AC power.
Realizing we're not going to make it 2 or 3 days without charging the battery, so we'll bring along a small generator and try to run the heat only at night.

Question: Will it be enough to plug the main power cord from the camper into the generator in order to charge the single battery, or should we go ahead and disconnect the battery and bring along a dual purpose automotive/deep cycle charger that can plug into the AC out on the generator.

I'm trying to throw this together from what I have available because we expected to be somewhere with power this weekend but flubbed reservations.

Any thoughts as to which would allow us to run the generator less? Since we're used to being in a pop-up until now, we really have modest power needs. All bulbs in the TT are LED.

[dcf]

Don't know the variables here, but thanks for the comments. New trailer that's pretty much stock means it is what it is.

[horton333]

It depends on the situation, but I get much better results with a 25 amp car charger than the 55 amp (supposedly 3 stage) one built in. Its of the order one third the time to get to a usable charge level with one 80 AH AGM battery. In my case it goes full 25 Amps till over 80 charge. The built in one never got over 15 amps and is below 10 much of the charge cycle. Near total waste of generator time.
Why?
There is 20' plus of number 6 wire between the battery and the built in convertor. That results in a lot of voltage drop and batteries are charged on a small differential voltage so this drop is very important. I don't know how typical my (cheap manufacturers ) installation is, but from general discussions I expect it is fairly common and while it can be helped with thicker wire that would only be worth it if your going to use it dry campng a significant amount.
The car charger can, and in my case does, go to higher voltages than just about any built in unit and in my case will go to 15.2 volts to try to force the 25 amps in.
The car charger connects directly to the battery terminals, there is minimal voltage loss.
The car charger has built in current monitoring, when it gets down to 10 amps or so I turn off the generator as this is in the 95% plus charge range. The built in unit often does not let you know the charging current, so you either start adding shunts and voltage meters and finding a place to put them, or you take a blind guess at when they battery is charged.
Note there are lots of cheap car chargers out there that are single voltage or very low current, I am talking of an intelligent one, but it was still only $115 on sale, simple and cheap.

[time2roll]

Bring the charger. Just slap it on and charge. No need to disconnect.
Start the charger and plug in the RV is not a problem either.

For best response you need to list the model number of the converter and charger.

[valhalla360]

While we can't say it with certainty, the built in converter is most likely going to charge much quicker than an automotive charger.

[MEXICOWANDERER]

It would take a 2,000 watt generator to have a decent chance at connect-it-and-forget-it duty IMHO. With a 12 hour run time capability. Lots of timr between sundown and bedtime with lights and heater.

[Golden_HVAC]

Hi,

Your factory charger is probably rated at 45 - 65 amps, and will charge the battery much faster than a typical portable charger.

That said, without knowing the generator capacity, I would not know if you would overload the generator or not. A typical 'contractor' generator will be well over 2000 watts, and not overloaded by either charger. If the generator is less than 1,500 watts, write back for further information.

If the generator is over 2,000 watts, let everyone know that you will be OK, so we do not have a lot of people answering a question that has already been solved.


While you state "All LED lights" - most of the power you might be using will be actually by the CO meter and propane leak detector. Those loads and the refrigerator add up to about 35 amp hours per day!

The water pump is really insignificant, as it will pump 2 GPM while using 7 amps per hour, or empty a 120 gallon tank with just 7AH of power.

LED lights also are a insignificant load, using just 0.4 amps each. While in years past perhaps the lights in your pop up might have used 1.2 or 0.9 amps each, depending on the bulb size, it would have been important to reduce light usage.

My suggestion is find out the generator hours. You do not want to disturb your neighbors running the generator late into the night, but run the furnace while the generator is on - if you have that need. The furnace fan typically is about 7 amps per hour, and can use 35 AH daily by itself, and really drain the battery.

You might have a smaller group 24 battery with a 'lab' rating of 85 AH or about 60 on a good day, but perhaps only 50 AH on a cold night. Group 27 will have a 105 AH rating, or about 75 on a cold night.

I have a Olympic Catalytic Heater that I run all night long, not consuming any power. I have to leave a roof vent open a bit, and window too. This brings in a constant stream of cold air, but overall I can keep it at 70F inside while it is 30F outside. When colder, I also run the furnace a few minutes every hour, to blow warm air into the basement and keep it warm too. Then my water tanks will not freeze. The furnace has a 1" diameter air duct into my basement compartment, near the tanks, to keep them warm.

Good luck,

Fred.

[tenbear]

All converters will charge the battery. Most OEM converters will only charge very slowly, think many hours if not days. Some newer converters will charge to the 90% point in a couple of hours, depending on how discharged the battery is.

As beemerphile1 said, more info is required.

[beemerphile1]

We have no idea what converter you have nor what portable charger you have so it is impossible to give a quality answer.

Assuming that you have a late model RV, you can just plug it in. More info is needed for a better answer.