valhalla360
No paticular place.
Senior Member
Joined: 08/19/2009
View Profile
Good Sam RV Club Member
|
pianotuna wrote:Properly set up is not possible unless you wish to buy a special purpose alternator. Or add a diode type device to the existing alternator.
The computer in the engine "looks" at the starter battery voltage. When the starter battery has recovered--charging is scaled back. Once that happens there is little or no charging of the house bank.
A dc to DC takes the incoming voltage and boosts it to an acceptable voltage for charging the house bank.
My dc to DC charger does a maximum of 20 amps. That works out to less than 5 amps per battery.
Because I have a larger than usual bank, I chose to set the output voltage of the dc to DC at 14.7 volts. Don't do this unless you have researched what the ideal charging voltage is for the house bank.
Except the house bank is connected to the starting bank when running, so the engine computer sees a lower voltage and keeps the amps up...not 100-200amps but if properly set up, it's still sending maybe 20 amps back which will largely negate the draw from the fridge.
If you want to fast charge, you need to upgrade the pathway to the house bank and make sure the alternator is one designed for continuous high output. Used to be quite popular with boats to upgrade to a 300amp alternator...now it would be simpler to add 400w of solar since most people drive during the day when the sun s out.
Tammy & Mike
Ford F250 V10
2021 Gray Wolf
Gemini Catamaran 34'
Full Time spliting time between boat and RV
|
Blaster Man
USA
Senior Member
Joined: 08/01/2007
View Profile
 Offline
|
One often forgot about fact is that the 12v are very much lighter than the 6 volts. I went from 8 six volts to three 12 volts (all AGM) and my total weight went down a bit over 300 lbs.
2014 American Eagle
|
Campinfan
Washtenaw County, Michigan
Senior Member
Joined: 05/18/2005
View Profile
Good Sam RV Club Member
Offline
|
It looks like the motorhome I may buy has 2 12volts in it now and they are 2 years old. I will keep an eye on them and when it comes time to replace them, I most likely will go for 6 volts.
______________________
2016 F 350 FX4 4WD,Lariat, 6.7 Diesel
41' 2018 Sandpiper 369 SAQB
Lovely wife and three children
|
SJ-Chris
San Jose, Ca
Senior Member
Joined: 09/24/2017
View Profile
Good Sam RV Club Member
Offline
|
Blaster Man wrote:One often forgot about fact is that the 12v are very much lighter than the 6 volts. I went from 8 six volts to three 12 volts (all AGM) and my total weight went down a bit over 300 lbs.
12v AGM battery weighs ~63lbs (google)
6v GC battery weights ~60lbs (google)
Two 12v AGM batteries (~100AH + ~100AH = ~200AH) weigh ~126lbs
Two 6v GC batteries (~210-220AH) weigh ~120lbs
Eight 6v GC batteries provides ~840AHs capacity and weighs ~480lbs.
Three 12v AGM batteries provide ~300AHs capacity and weighs ~189lbs.
Yes, your weight dropped ~300lbs, but your battery bank capacity dropped ~540AHs. Your weight didn't go down because you switched from 6v batteries to 12v AGMs, it went down because you cut your battery bank capacity down ~540AHs (which is certainly the right thing to do if you don't need that much battery bank).
-Chris
San Jose, CA
Own two 2015 Thor Majestic 28a Class C RVs
|
Blaster Man
USA
Senior Member
Joined: 08/01/2007
View Profile
Offline
|
Call it what you like, my three 12 volt AGMs do fine on an all electric 45' coach if you do very little dry camping...we do virtually none.
|
|
|
Bruce Brown
Northern NY
Moderator
Joined: 06/01/2001
View Profile
Good Sam RV Club Member
|
^^^ I've been thinking about this - if you never do any dry camping wouldn't it make sense to buy the cheapest battery you could buy? You're not looking for quality, you're looking for something to take the voltage, and nothing else.
I do this at our hunting camp - I don't need a good battery, I just need something that will take a charge, it doesn't even need to hold it for more than a few minutes.
There are 24 hours in every day - it all depends on how you choose to use them.
Bruce & Jill Brown
2008 Kountry Star Pusher 3910
|
valhalla360
No paticular place.
Senior Member
Joined: 08/19/2009
View Profile
Good Sam RV Club Member
|
Blaster Man wrote:Call it what you like, my three 12 volt AGMs do fine on an all electric 45' coach if you do very little dry camping...we do virtually none.
If you never dry camp, buy a single flooded 12v as cheap as you can (around $100) and it will do fine.
There saved you an extra 120lb and probably $500-800 over AGMs which make zero sense in an RV unless you are doing barrel rolls on a regular basis with it.
Now back to your thread talking about actual apples to apples comparisons....
|
Blaster Man
USA
Senior Member
Joined: 08/01/2007
View Profile
Offline
|
I tried two 12 volts, but that was not enough juice to run the inverter...the third one fixed that.
|
pianotuna
Regina, SK, Canada
Senior Member
Joined: 12/18/2004
View Profile
Offline
|
Blaster Man wrote:I tried two 12 volts, but that was not enough juice to run the inverter...the third one fixed that.
How large was the inverter?
What type of battery bank?
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.
|
