Safe to charge battery while connected to shore power

In my old fiver, if we were boondocking and needed to get a quick charge to the battery, I'd use the battery disconnect switch to isolate the battery from the onboard converter, then directly attach my Sears intelligent battery charger running off the genny. Would move that Group 31 from 40% to 90% in less than an hour. Got a smarter charger in our current rig, so haven't had to go that direction since.

Thanks for all the replies. Since I do have a 2014 TT I will just plug into shore and let the converter charge it up. Was not sure if those converters did a lot but I will check the inside guage to see . tks

kaydeejay wrote:

Bobbo wrote:

kaydeejay wrote:
His CONVERTER should be charging the battery.
An INVERTER will drain it real quick!

Unless it is an Inverter/Charger. ;)
Ain't this fun?

Wouldn't that sorta defeat the object of the exercise?
Lemme think about this, Invert 12V DC to 110V AC so it can run a charger to charge up the battery that the inverter is draining.
Aha - we have perpetual motion (Not!)

Obviously you are not aware that some rigs have an inverter that also functions as a converter/charger as needed.

Will this cause any problems: NO... Unless. (read on)

Will it result in faster recharge of the battery: It might, or might not depending on the charger and the converter.

(Unless) will this faster re-charge damage the battery: Perhaps, if it's too fast it will shorten overall battery life. (greater than 30% c/20)

What is 30% of C/20?
Let's take a rounded battery (G-27/29 and give it a capacity of 100 amp hours at the 20 hour rate. 30% would thus be 30 amps.

On many modern RV's the best way to charge is the on-board converter.. HOWEVER some RV's have older converters like the Magnetek line, Or even a modern one like the Parrallex 7300 In these cases a converter upgarde will benefit but so will an external charger when the battery is low.

Bobbo wrote:

kaydeejay wrote:
His CONVERTER should be charging the battery.
An INVERTER will drain it real quick!

Unless it is an Inverter/Charger. ;)
Ain't this fun?

Wouldn't that sorta defeat the object of the exercise?
Lemme think about this..... Invert 12V DC to 110V AC so it can run a charger to charge up the battery that the inverter is draining.
Aha - we have perpetual motion (Not!)

If you are plugged into shore power, the on board converter/charger will likely confuse the external charger and vise versus. Disconnecting the battery before using the external charger will resolve this. However, the onboard converter may or may not require a battery in the circuit to provide consistent stable 12v power to the lights and more important the various 12v circuit boards in the fridge, AC, water heater, etc. You need to research your converter to determine if you can disconnect the battery. If you can not, you can throw the breaker for the converter, disconnect the battery and charge the battery, but none of the 12v dependent systems will function while doing so.

kaydeejay wrote:

Teamfour wrote:
Your inverter should charge the battery while connected to shore power. Why would you connect an external charger to it?

His CONVERTER should be charging the battery.
An INVERTER will drain it real quick!

Unless it is an Inverter/Charger. ;)
Ain't this fun?

Teamfour wrote:
Your inverter should charge the battery while connected to shore power. Why would you connect an external charger to it?

His CONVERTER should be charging the battery.
An INVERTER will drain it real quick!

beemerphile1 wrote:
It won't harm anything but your 2014 should have a good charger built into the RV.

X2, why do you think the battery needs charging? While you are plugged in you are not actually even using the battery, the converter is providing all power (it's voltage is higher than the battery so the battery isn't contributing anything). Is your battery disconnect connected?

travelnutz wrote:

...To charge an RV battery when the RV is connected to shore power, take the + (red, positive) cable completely off the battery's terminal to be externally charged and at least wrap a dry rag around the cable end to insulate it so it can't short out by bumping into against anything. It will be a very high amperage spark if shorted out and if battery acid gasses are present in dense enough concentration, there could even be an explosion happen and acid thrown all over you....

Particularly true if you follow this advice. You should always remove the negative lead first and install the negative lead last.