What is the most efficient way to charge batteries with a generator? Is using the 12 volt DC charging cord connected directly to the batteries any more efficient than plugging the camper power cord into the generator. Why? Just curious. Thanks in advance.

Probably let the onboard smart charger do it.

I use my 5ers built in charger. May not be as efficient as better charger/converters or a good battery charger but it gets the job done when needed.Been using the gen and built in for 6-7 years.

POLORBR wrote:What is the most efficient way to charge batteries with a generator? Is using the 12 volt DC charging cord connected directly to the batteries any more efficient than plugging the camper power cord into the generator. Why? Just curious. Thanks in advance.Does efficient mean fast? Use both.The converter probably has more amps but may not have a high enough voltage. 12v cord has the voltage but only 8 amps.You can replace your converter to get both voltage and amps. Post the existing converter model number for best answers.The 12 Volt Side of Life

time2roll wrote:Does efficient mean fast?x2

Look at your converter and get make and model. Some newer converters have a higher charge rate then others. Best help cn be given by posting make and model of converter.

Charging batteries with generator? | Good Sam Community

29 Replies

time2roll
Nomad
8 years ago
I prefer separate components. Stand alone charger, separate inverter, separate transfer switch. This primarily because if something fails the rest continues to work. The failure point is easier to bypass, diagnose and repair.

The advantages of the combo units don't do much for me.
Copperhead
Explorer
8 years ago
time2roll wrote:
Xantrex got out of the RV converter market some time ago.
Still have my XADC-40 as a spare.

Maybe as a factory install, but anyone can get a Xantrex any day of the week from a variety of sources to use in a RV or TT. And the Xantrex units are multi phase charging. Some Xantrex units even can be user programmed for LA, AGM, or Lithium Ion batteries to take advantage of the individual charging characteristics of those.

I don't really care for charger/converter only setups. I prefer full blown Inverter/Charger units. Charge batts and pass thru AC when on shore power or generator. When unplugged from shore power, they automatically switch to providing AC from the Batts. Too bad not an option from the factory. But I realize the initial cost of a good inverter / charger can be pretty steep and for it all to work well usually demands more than one battery or going with something like a lithium Ion battery. But you get what you pay for in both functionality and end user satisfaction.
Dirtpig
Explorer
8 years ago
If you do a lot of dry camping, and wish to keep generator run time to a minimum, i would suggest upgrading your stock converter/charger. Many RV's come with the WFCO units which work fine for many people but do not charge batteries very fast. If you are wanting a fast charge, look for 55-75amp models from good brands like progressive dynamics, Iota, powermax. etc. I recently upgraded my converter and I am pleased with it. If you only occasionally battery charge from a generator then it may be a waste of money though.

Example - If your 220 amp battery bank is at 50% charge (110amps missing from batteries) it would take that honda eu2000 with the DC charge cable, at 8amps, over 12 hrs to bring them back up to 90% capacity.

A quality 75amp converter/charger would take 1.5 - 2 hrs to bring to 90% charge.
time2roll
Nomad
8 years ago
Xantrex got out of the RV converter market some time ago.
Still have my XADC-40 as a spare.
Copperhead
Explorer
8 years ago
That is why giving Xantrex a look see is a wise move. They have been at the game for a long, long time, in a lot of applications. It is the only brand I have relied on for better part of 3 decades.
Huntindog
Explorer
8 years ago
trail-explorer wrote:
Mandalay Parr wrote:
Probably let the onboard smart charger do it.

Very few towable RVs have a charger that's "smart" (3 stage)
THey area a dumb, converter.

But, they are far more effective than using the 12v output on the generator to charge your batteries.
This was true many years ago.
In todays world, I have not seen a so called dumb converter listed for ANY towable... I am not sure if there are any on the market any more.
Now one of the most prevalent converters are the WFCOs.... They are supposed to be a smart charger. But they are VERY unreliable in this respect.
trail-explorer
Explorer II
8 years ago
Mandalay Parr wrote:
Probably let the onboard smart charger do it.

Very few towable RVs have a charger that's "smart" (3 stage)
THey area a dumb, converter.

But, they are far more effective than using the 12v output on the generator to charge your batteries.
westend
Explorer
8 years ago
It will be faster and more efficient to use the onboard converter than the 12V output of your generator. An additional battery charger powered by the generator will be faster, still.

The installation of 200+W of solar panels may mean that you never need the generator again, if you don't use it for other things like A/C or other heavy use. Solar does a better job of keeping my batteries charged than I can, manually (with many chargers).
Atlee
Explorer II
8 years ago
It was warm enough today to change out the old WFCO 8955 for the Progressive Dynamics 4655L MBA converter. We'll see how well it does going forward.

Atlee wrote:
Assuming you have an on board smart charger. Some RV's have quality converter/chargers, and some do not. Mine, a Jayco 23RB does not. It's a WFCO 8955 model. I am going to fix that however. Have a Progressive Dynamics 55A unit with Charge Wizard on the way as I type.

Mandalay Parr wrote:
Probably let the onboard smart charger do it.
kevden
Explorer
8 years ago
ADK Camper wrote:
I have a OEM WFCO converter in my camper. It will not go into boost charging mode no mater how discharged my battery. Therefore it can take a VERY long time to recharge a battery because the charger a!ways operates in adsorption mode. As others have said using the 12 VDC output from your genset is not very efficient either. What works best for me is to power the camper with the genset and use an inexpensive 10 amp manual charger plugged into 120 vac and connected directly to the battery. I only need to use it for about an hour every other day to keep the battery 50 to 90% charged.

Same for me, I use a vector/black and decker smart charger and the wfco together.