What's the difference between a "Converter" and a "Battery Charger"?

[TheHandyDan]

I'm confused...

In the world of boats, I used to have an on-board battery charger that you'd plug into shore power and it would charge the trolling motor battery, etc.

As a newbie in the trailer world, there are "converters" that appear to do the same thing... or do they?

[Al and Missy]

Just my opinion and understanding, but a battery charger is optimized for one purpose, charging batteries. A converter, in addition to charging attached batteries, provides power to operate devices on the boat, trailer, whatever. Now a battery charger will do this, but may not provide sufficient power without potentially overcharging the attached batteries. A smarter converter will have the capability to sense whether the power drain is due to a discharged battery or an appliance like the furnace and act accordingly.

Again, just my understanding, may not be completely accurate.

Al

[Jammer]

Hi Dan

The only difference is historical.

Some early RVs used a 120v to 12v converter with a transfer switch that isolated the converter from the battery, so that the battery did not charge from the converter. Designs varied, some (including those used by Airstream for a brief time) produced 12 volts AC, with in many cases a 16v or 18v AV output for fan motors. Others, including the one in my Cayo C-11, do in fact produce DC, but at a poorly controlled voltage that is not suitable for battery charging. Since these devices weren't capable of charging batteries, they came to be known as a "converter" since they were used to convert the 120v shore power to something that the lights and fans could use.

RV converters are electrically similar to marine "battery chargers" with some devices being sold for both purposes. The marine ones often have support for multiple battery banks, and in some cases will run on 220v 50hz power found outside the U.S., and better environmental specifications (temperature, humidity).

[cwf]

Converter = AC to DC (input to output)
Inverter = DC to AC. (Input to Output)

In U.S. 120VAC / 60Hz(cycles per second) is the "standard" many of us can relate to in our homes for powering lights and being available at our "wall outlets), washing machines, toasters, can opener, TV(televisions).

The "appliances" like stove, water heater, electric clothes dryer, use 220-240VAC/60Hz. (Most if not all U.S. Electricity is 60 Hz. ) because these generally perform better on the higher voltage.

In an AS(as in most RVs), the 120VAC/60Hz runs the "appliances", microwave, TV, AIr Conditioning and Converter.

The 12VDC runs lights, water pump, fans, , sensors and "control circuits" for Air Conditioning (heat and cool), Fridge, water Heater.

With the 12VDC you may "boondock" or operate your 12VDC items as long as you have sufficient "battery" power. Now, I can pull off the road and have lights and fan while I eat a snack in my AS. This frees me from being "plugged in" to the grid. (Commercial power)

The Converter in modern AS or upgraded ones, should be capable of providing all the 12VDC power your AS can consume at one time... This means all lighting up, running on full, with a bit of "reserve" for startup loads and for charging of batteries.

Our new Converter is capable of providing all the 12VDC we consume and it is "smart" meaning it can adjust output so that it does not over charge batteries. This ensures all consumable needs are met, with a margin of 10%.

Certain battery chemistry and construction requires proper "charge capability" which a Converter should be chosen to provide, such as AGM batteries.

[jcanavera]

Keep in mind that in many Airstreams the charging function is not smart and my 2004 Classic's converter will ruin a set of batteries if the trailer is stored while constantly connected to power supply. Someday I will break down and modernize my converter with an intelligent unit. As of now, I just minimize plugging it into my home power outlets if it isn't necessary.

Jack

[DaveFL]

Mine is one of the dumb converters so I disconnect the house batteries when parked at home, I installed a 120v outlet near the batteries and can plug in a trickle charger and a battery minder to keep the batteries up, the more I hear about batteries being fried by the converter, I will start getting used to disconnecting the batteries when camping with electric.

[SteveH]

The original question was, What's the difference between a "Converter" and a "Battery Charger"?

A battery charger is designed to charge a battery, period, and usually does not have a filtered DC output, and so is not good for powering electronic devices such as radios, and TV's.

A converter is designed to power all these items with a filtered output, and charge the battery at the same time.

So, in actual practice in your trailer, you can use a converter with, or without a battery in the circuit, but to use a battery charger you need to have the battery in place also to help filter the charger's output.

If on the road, and your converter fails, you can get by with using a battery charger in it's place, provided the charger is of suitable capacity.

[NWRVR]

I'm new at this and after reading the threads on overcharging batteries I now switch my battery to "Store" thus disconnecting it from the trailer when I am on shore power. Also, the solar panels keep the batteries up when I am not using the AS.

[MelGoddard]

Originally Posted by jcanavera

Keep in mind that in many Airstreams the charging function is not smart and my 2004 Classic's converter will ruin a set of batteries if the trailer is stored while constantly connected to power supply. Someday I will break down and modernize my converter with an intelligent unit. As of now, I just minimize plugging it into my home power outlets if it isn't necessary.

Jack

I just use a 'Noma' block heater timer, and set it for one hour a day, to keep the batteries up, when in storage. (any 15 amp. rated timer will work.)
When activating the AS for a trip, then the power is on full time, to keep the 'fridge going.

[MelGoddard]

Originally Posted by jcanavera

Keep in mind that in many Airstreams the charging function is not smart and my 2004 Classic's converter will ruin a set of batteries if the trailer is stored while constantly connected to power supply. Someday I will break down and modernize my converter with an intelligent unit. As of now, I just minimize plugging it into my home power outlets if it isn't necessary.

Jack

I just use a 'Noma' block heater timer, and set it for one hour a day, to keep the batteries up, when in storage. (any 15 amp. rated timer will work.)
When activating the AS for a trip, then the power is on full time, to keep the 'fridge going.
The question just came up, tho; should I shut off the battery while doing this, and just let the TV charge it up on the road?

[DaveFL]

Originally Posted by MelGoddard

I just use a 'Noma' block heater timer, and set it for one hour a day, to keep the batteries up, when in storage. (any 15 amp. rated timer will work.)
When activating the AS for a trip, then the power is on full time, to keep the 'fridge going.

I checked my voltage problems after replacing batteries, converter plugged in as you said charges to house batteries at a constant high voltage, used a disconnect switch at the house batteries and a trickle charger directly on batteries, sort of solved the problem prior to investing in new converter. Unplugging converter also worked but make sure you plug it back in when using the mh camping after three days house batteries will be very low causing water pump to overheat and to stop running;(
I like the idea of a timer on the electric supply, using one right now to run the dehumidifers for a few hours in the morning to solve the moisture buildup, will have to find a way to add converter circuit to the dehumidifier circuit