Reply
 
Thread Tools Display Modes
Old 02-03-2020, 08:43 PM   #1
Senior Member
 
Bayoudave's Avatar
 
Join Date: Jan 2018
Location: Central Louisiana
Posts: 13
Charging my battery with generator and 25 amp charger

I have camped a few times where there was no electricity. Using my cpap runs the battery down in a few days. When I plug the trailer into the generator it takes all day to get the battery back up. I was wondering if I could hook my 25 amp charger up to the battery and charge it much faster. Would this hurt anything or should I disconnect the battery before charging? Don't want to mess up anything in the trailer with the charger.
__________________
2017 Forest River Wildwood X-Lite 254RLXL
2006 Ford F150 XLT
2002 Honda Goldwing 1800 MotorTrike

Bayoudave is offline   Reply With Quote
Old 02-03-2020, 08:50 PM   #2
Site Team
 
bikendan's Avatar
 
Join Date: Jan 2007
Location: Camano Island, Washington
Posts: 22,537
Your trailer's converter should keep the battery charged. Have you tested the battery with a hydrometer, to see if there's a dead cell?
If you plan on doing more dry camping or boondocking, you need to have at least two deep cycle batteries.
__________________
Dan-Retired California Firefighter/EMT
Shawn-Musician/Entrepreneur/Wine Expert
and Zoe the Wonder Dog(R.I.P.)
2016 PrimeTime TracerAIR 255, pushing a 2014 Ford F150 SCREW XTR 4x4 3.5 Ecoboost w/Max Tow Package
Equalizer WDH
bikendan is offline   Reply With Quote
Old 02-03-2020, 08:58 PM   #3
Junior Member
 
Join Date: Aug 2019
Posts: 15
Charging with a generator

I use a 25 amp automotive charger for the same reason. I always hook it up directly to the battery post, but I don't disconnect anything. It shouldn't hurt anything in your electrical system as long as the charger is functioning correctly. Of course, a better quality charger will protect your batteries by backing down the charge rate over time. I am using traditional deep cycle batteries. If it makes you feel better, you can use your battery disconnect if you don't need any power in the RV while charging.
__________________
Brent
2017 Flagstaff 30WIKSS
2018 Ram 2500 CC LB Cummins
Bdcothran is offline   Reply With Quote
Old 02-03-2020, 10:26 PM   #4
Senior Member
 
NMWildcat's Avatar
 
Join Date: Jun 2012
Location: Southern NM
Posts: 6,122
Using a separate battery charger plugged into your generator usually won't charge your battery any faster or better than your converter, especially since your converter is one of the newer ones.
And yes, if boondocking, you definitely need two batteries and run your generator a few hours every day. Don't wait until the batteries are almost dead.
__________________
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder
NMWildcat is online now   Reply With Quote
Old 02-04-2020, 02:55 PM   #5
Senior Member
 
Bluepill's Avatar
 
Join Date: Jun 2015
Location: Pensacola, FL
Posts: 1,645
It has been established that in many cases the WFCO converters supplied by FR do not go into fast charge mode unless the batteries are below half charged. For this reason, I use an automotive charger to maintain my batteries.
__________________
2019 Coachmen Freedom Express 192RBS
2015 T12RBST Flagstaff Hardside

Disclaimer: The actual value of my "Two Cents" of advice varies just like a bitcoin.
Bluepill is offline   Reply With Quote
Old 02-04-2020, 03:26 PM   #6
Senior Member
 
NMWildcat's Avatar
 
Join Date: Jun 2012
Location: Southern NM
Posts: 6,122
I don't know that that rumor about WFCO converters is an established fact, but even your separate car charger will charge at a higher rate the more the battery is discharged, then gradually taper down to a trickle charge. So no real gain there, but everybody does things differently.
Quote:
Originally Posted by Bluepill View Post
It has been established that in many cases the WFCO converters supplied by FR do not go into fast charge mode unless the batteries are below half charged. For this reason, I use an automotive charger to maintain my batteries.
__________________
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder
NMWildcat is online now   Reply With Quote
Old 02-04-2020, 03:32 PM   #7
Site Team
 
Flybob's Avatar
 
Join Date: Oct 2014
Posts: 11,692
Your converter should charge the battery faster than a 25 amp charger will as it is likely a 55amp converter. Be careful with the CPAP especially if you use heat as they can drain the battery quickly. You should be recharging the battery when it gets to around 50% See chart below.
Attached Thumbnails
Click image for larger version

Name:	Battery Voltage.jpg
Views:	31
Size:	223.6 KB
ID:	222864  
__________________

2015 Freedom Express 248RBS
TV 2015 Silverado HD2500 Duramax
TST Tire Monitors
Honda 2000I + Companion
2 100W solar panels
Flybob is online now   Reply With Quote
Old 02-04-2020, 03:54 PM   #8
Senior Member
 
Scubanut's Avatar
 
Join Date: Mar 2013
Location: Canada
Posts: 414
Quote:
Originally Posted by Bayoudave View Post
I have camped a few times where there was no electricity. Using my cpap runs the battery down in a few days. When I plug the trailer into the generator it takes all day to get the battery back up. I was wondering if I could hook my 25 amp charger up to the battery and charge it much faster. Would this hurt anything or should I disconnect the battery before charging? Don't want to mess up anything in the trailer with the charger.


When Iím out hunting I use a combination of generator, solar and car battery charger. Some times all at the same time. I havenít notice any negative effects doing this. I have never disconnected the battery or turned off the battery switch.
Scubanut is offline   Reply With Quote
Old 02-04-2020, 06:06 PM   #9
Senior Member
 
Join Date: Jul 2017
Location: North of Seattle, WA
Posts: 8,999
Quote:
Originally Posted by NMWildcat View Post
Using a separate battery charger plugged into your generator usually won't charge your battery any faster or better than your converter, especially since your converter is one of the newer ones.
And yes, if boondocking, you definitely need two batteries and run your generator a few hours every day. Don't wait until the batteries are almost dead.

First off, unless your converter is smaller than the separate battery charger nothing is to be gained. Most RV's have 40 amp or larger converters (small RV's may be less) and are capable of charging one or two batteries as fast as they can be charged without boiling.

Where most people go wrong with lead/acid batteries is that they don't charge them long enough when they do run the generator. The bulk, or initial high rate of charge, will replace a fair amount of discharged power in a few hours but the remainder of the used energy takes many more hours to replace. Often as much as three times that of the time it took for the bulk charge.

Lead/Acid batteries, unlike Lithium, rely on an electro-chemical process within the battery and even though the voltage may show "Fully Charged" after a few hours the specific gravity hasn't reached the level of full charge.

Failure to fully charge a battery merely leads to reduced capacity. Unless you have a battery monitor that measures amp hours used versus amp hours replaced, and utilizes the Peukert factor in it's calculations you really don't know if your lead acid battery is fully charged without first letting it rest for a few hours and then checking voltage, or better yet, specific gravity of electrolyte in each cell.
__________________
"A wise man can change his mind. A fool never will."

"Sometimes you're the dog, sometimes you're the tree"

2018 Flagstaff Micro Lite 25BDS
2004 Nissan Titan
TitanMike is online now   Reply With Quote
Old 02-04-2020, 06:23 PM   #10
Junior Member
 
Join Date: Sep 2019
Posts: 4
I was under the impression even a 55 amp converter still only reserves 4 to 5 amps for charging the batteries. The rest is used to power the trailer fridge , hot water heater , furnace blower etc. So wouldn’t a dedicated charger be faster ? Please enlighten me.
Rob
Rob Darrah is offline   Reply With Quote
Old 02-04-2020, 06:34 PM   #11
Senior Member
 
Join Date: Jul 2017
Location: North of Seattle, WA
Posts: 8,999
Quote:
Originally Posted by Rob Darrah View Post
I was under the impression even a 55 amp converter still only reserves 4 to 5 amps for charging the batteries. The rest is used to power the trailer fridge , hot water heater , furnace blower etc. So wouldn’t a dedicated charger be faster ? Please enlighten me.
Rob
Converters do not "reserve" any output power. Voltage is regulated to Bulk, Absorbtion, and Float voltages. As voltage hits max for each step they switch to the next, remaining on the float setting to take care of internal losses and 12V draws as they switch on.. Current flow is only limited by the max output of the converter.

There is no separate "Charging Circuit" in a modern converter.

In a sense the converter in an RV operates much like the alternator does in your motor vehicle. Power is supplied to run all the 12 volt equipment and charge the battery. All happens at the same time until the battery is fully charged and current output from the alternator just continues to flow to equipment at a steady voltage.
__________________
"A wise man can change his mind. A fool never will."

"Sometimes you're the dog, sometimes you're the tree"

2018 Flagstaff Micro Lite 25BDS
2004 Nissan Titan
TitanMike is online now   Reply With Quote
Old 02-05-2020, 08:49 AM   #12
Trailer Park Supervisor
 
NJKris's Avatar
 
Join Date: Sep 2018
Location: Northern NJ
Posts: 3,283
BayouDave, make sure you turn off humidification AND heated hose if you have it, dry air is not a problem in LA I'm sure! I bought an expensive 25 amp smart charger (CTEK) before I got trailer, not realizing the modern converter would be more than adequate to quickly restore charge to my batts when using generator. I have not boondocked yet, but when I do, I'll be using generator to do bulk charging, which as mentioned takes place in less time than final absorption charging (the last 20%), then let solar take over for that final 20%, instead of running generator for hours.

I now use the 25 amp charger when parked at home to maintain batteries, as it has special features to prevent over-charging, and I don't have big plug sticking out of side of trailer under the cover, just the charger on a couple boards beneath the battery box (charger is water resistant).
__________________
2019 Rockwood Geo Pro G19FD w/off road package
2015 Ford F150 XLT Super Cab 4x4 V8
NJKris is offline   Reply With Quote
Reply

Tags
battery, charging, generator

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by Forest River, Inc. or any of its affiliates. This is an independent, unofficial site.



All times are GMT -5. The time now is 12:50 PM.