|
07-01-2021, 09:51 PM
|
#1
|
Senior Member
Join Date: May 2014
Location: Pioneer, CA 95666
Posts: 501
|
Inverter Question
I have some basic questions regarding my coach that I’ve never asked anyone. First, when set up in a no shore power situation, I run the generator until I reach 100% charge on house batteries. This is at bedtime. Then I switch on the inverter to get me through the night using minimal lights. At 7am I am at 34%. Seems normal. What if I was to run the house batteries down to 0 %? I’m assuming the generator would bring them back up to 100% in a couple hours. If I was to just go off batteries without the inverter would it drain the house batteries quicker? Also am I correct in assuming the generator uses the chassis batteries to start? I don’t boon dock very often, but want to know the best procedure.
__________________
2004 Monaco Camelot 38PST 400ISL
2001 Jeep Cherokee Larado toad
Blue OX tow bar, Patriot brake box, 4" drop receiver
|
|
|
|
Join the #1 RV Forum Today - It's Totally Free!
iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!
You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!
|
07-01-2021, 10:34 PM
|
#2
|
Senior Member
Join Date: May 2014
Location: Pioneer, CA 95666
Posts: 501
|
I’m thinking running the inverter will drain house bats quicker than just using battery power for evening lights.
__________________
2004 Monaco Camelot 38PST 400ISL
2001 Jeep Cherokee Larado toad
Blue OX tow bar, Patriot brake box, 4" drop receiver
|
|
|
07-01-2021, 10:37 PM
|
#3
|
Senior Member
Monaco Owners Club Workhorse Chassis Owner
Join Date: Aug 2002
Location: Clovis, CA, USA
Posts: 13,103
|
Quote:
Originally Posted by DaveBunker
I’m thinking running the inverter will drain house bats quicker than just using battery power for evening lights.
|
You are correct.
An inverter draws power even if nothing is being used.
__________________
2004 Monaco La Palma 36DBD, W22, 8.1, 7.1 MPG
2000 LEXUS RX300 FWD 22MPG 4020 LBS
Criticism is easier than Craftsmanship
|
|
|
07-02-2021, 06:52 AM
|
#4
|
Senior Member
Monaco Owners Club
Join Date: Jun 2011
Location: CA
Posts: 4,456
|
Quote:
Originally Posted by DaveBunker
I have some basic questions regarding my coach that I’ve never asked anyone. First, when set up in a no shore power situation, I run the generator until I reach 100% charge on house batteries. This is at bedtime. Then I switch on the inverter to get me through the night using minimal lights. At 7am I am at 34%. Seems normal. What if I was to run the house batteries down to 0 %? I’m assuming the generator would bring them back up to 100% in a couple hours. If I was to just go off batteries without the inverter would it drain the house batteries quicker? Also am I correct in assuming the generator uses the chassis batteries to start? I don’t boon dock very often, but want to know the best procedure.
|
As mentioned, just having your inverter on, with nothing else, will deplete your batteries. So if boondocking, leave the inverter off unless it's energizing something you need.
You didn't mention what type of house batteries you have. It's best not to deplete wet cell batteries below 50%. How are you reading the 34%? What is the voltage reading?
You mention running the batteries down to 0%. What voltage are you thinking/seeing? Quick rule of thumb is not to run the voltage below 12 volts very often.
__________________
Bill & Brigitte
06 Windsor PEQ, Cummins 400 ISL
2014 Honda CRV or 2012 Jeep
|
|
|
07-02-2021, 07:13 AM
|
#5
|
Senior Member
Join Date: Oct 2014
Posts: 7,870
|
First, running the generator to bring batteries to 100% is a waste of fuel (unless running the generator for A/C or other reasons).
Running below 50% materially shortens battery life.
If an overnight with conservative use takes them down to 34% you either need a larger battery bank, or the current batteries have diminished capacity. Identify and fix this.
If running a generator just to charge batteries, most efficient use of the generator is to discharge the batteries to 50%, then recharge to around 85%. Above 85%, you are putting very few amps into the batteries. Perhaps once a week, yes, you need to charge them all the way up so that they don't loose capacity.
__________________
Brett Wolfe
Ex: 2003 Alpine 38FDDS. Ex: 1997 Safari Sahara. Ex: 1993 Foretravel U240
|
|
|
07-02-2021, 07:22 AM
|
#6
|
Senior Member
Join Date: Nov 2018
Location: Beaver Dam, Wisconsin
Posts: 5,085
|
"What if I was to run the house batteries down to 0 %? I’m assuming the generator would bring them back up to 100% in a couple hours."
Whether you draw down to 80% or 0% it takes 10 to 14 hours to fully charge lead acid batteries. That strange behavior applies to most lead acid batteries.
On the other hand, you can put lots of power in very fast with a big charger at low SoC levels. The first 4 hours of charging a fully discharged lead acid battery can put 80% charge in. It depends on battery design and charger capacity.
Power absorption decreases with SoC level. It decreases to almost nothing as SoC level reaches nearly 100%
"If I was to just go off batteries without the inverter would it drain the house batteries quicker?"
Turn the inverter "off" to maximize battery capacity.
As posted above. Inverters consume power whenever turned on. Even when nothing is connected to the output they still consume power. Small inverters consume a little. Large inverters consume a lot.
RV inverters do not power 12 volt appliances. They convert 12 volt DC battery power into 120 volts AC. You may use the inverter to power a 120 volt coffee maker or microwave.
An inverter is usually not needed for lights, furnace, or water pump.
"Also am I correct in assuming the generator uses the chassis batteries to start?"
Different RV's are designed differently. Many start the generator from the house batteries and allow using a "boost" button to start from the chassis battery.
I wish you good luck and happy trails ahead!
__________________
Paul Bristol
Kodiak Cub 176RD
Nissan Pathfinder 2015
|
|
|
07-02-2021, 07:28 AM
|
#7
|
Senior Member
Monaco Owners Club
Join Date: Jun 2014
Posts: 14,495
|
I installed a residential refrigerator so I have to run the inverter to keep it powered.
I had checked all my batteries ~7 weeks ago before a trip and they seemed find. I am now on an extended trip out west. I was starting to see some strange readings on the inverter for % charge so I checked the house batteries again and found one with lower voltage and one of the cells had lower Specific gravity on they hydrometer.
Luckily I was near a Sam's Club in Rapid City SD and they had 4 new batteries that they installed for me. That solved the problem
Now after driving all day the batteries will be +95% and at the state of charge will last all night long running my fridge and still be ~70% when I wake up.
If I am just parked leaving the inverter on all day my batteries will deplete to ~65% (I have 325 watt of solar and on a sunny day will actually gain).
Last night when I got back from a day of sightseeing the coach was ~90F inside so I started the generator at ~7PM and ran it for 2 hours with both AC running at which point it was dusk and cooled down to ~75F outside so I shut off the generator and opened windows. The batteries were charged to 93%. This morning when I got up they were at 70%.
If your inverter is no on your batteries should last a long time just using lights. If inverter is on it will draw power even without a load but you do have parasitic type loads anyway.
I'd check your batteries to confirm condition. If in doubt change them.
__________________
Jim J
2002 Monaco Windsor 38 PKD Cummins ISC 350 8.3L
2005 Jeep Grand Cherokee w/5.7 Hemi
|
|
|
07-02-2021, 07:43 AM
|
#8
|
Senior Member
Join Date: Nov 2018
Location: Beaver Dam, Wisconsin
Posts: 5,085
|
"Running below 50% materially shortens battery life."
This is not true. Many lead acid deep draw battery designs can get 300 or so deep discharges as long as they are fully charged 10 to 14 hours before storage. Discharging to 50% gets you 600 or so discharges.
However, putting a given amount of power back into a 50% SoC battery takes longer than putting the same amount of power back in to a 30% SoC battery. Power absorption decreases as SoC increases.
"If an overnight with conservative use takes them down to 34% you either need a larger battery bank, or the current batteries have diminished capacity. Identify and fix this."
Don't worry. No "fix" is required. 34% is well within battery design capability.
You could get twice as many recharge cycles but you need twice as much battery capacity to do it. That means twice as much weight and space used for batteries and twice as much upfront cost to install.
__________________
Paul Bristol
Kodiak Cub 176RD
Nissan Pathfinder 2015
|
|
|
07-02-2021, 08:30 PM
|
#9
|
Senior Member
Join Date: May 2014
Location: Pioneer, CA 95666
Posts: 501
|
Thank you everyone for clearing up a few questions.
__________________
2004 Monaco Camelot 38PST 400ISL
2001 Jeep Cherokee Larado toad
Blue OX tow bar, Patriot brake box, 4" drop receiver
|
|
|
|
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
|
|
Thread Tools |
Search this Thread |
|
|
Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
|
» Recent Discussions |
|
|
|
|
|
|
|
|
|
|
|
|
|