EPDM Coatings
rvupgradestore.com Composet Products Custom Yacht Interiors

Author Topic: Battery Power Management, House Battery, Chassis Battery, etc  (Read 18810 times)

Len and Jo

  • ---
  • Posts: 1186
Our 'B' has one group 31 size house battery.  (I ASSUME most of you B'ers out there that one battery is the general rule and more would be the exception.)  That has a listed Ah rating of 115 amp-hours.  On our recent 'Great Northern' trip that battery just seemed to not be really putting out the juice.  It surprised me because we has historically always had enough and we had just switched from a group 27 battery (100 amp-hours) to the 31 just two years ago and if anything we should have had even more available power.  This is what I have found out:

1) The $16 digital voltmeter that I got from Radio Shack several years ago to monitor battery voltage ain't what it used to be.  It now has a 0.15 volt error.  This is very significant when the total voltage range one is looking at is about 0.60 volts.  That is 12.6v for full battery charge (~115 Ah available) to 12.0v for 50% battery charge (~55 Ah consumed and time to recharge for maximum battery life).  So with that voltmeter error we thought we had lost a quarter of useable battery power.  Got a new Radio Shack voltmeter - the price is now $19 but I do like the very small size and have it mounted and hard wired on a wall for easy use - If this second sample doesn't last very long I will look for a different brand.

2)  A battery capacity test when we got home showed that the battery really is in excellent shape.  I load tested the battery:  charged battery over night then 100 watts 1 hour, 1000 watts 10 minutes, 100 watts 1 hour.  Let battery rest for half a day and then measured the battery voltage ( at 12.35v ) and the reading was in the ball park for draining about 50% of the battery usable power.

So, some of the problem was the voltmeter I was using.  I thought we had used up half the battery juice when indeed we still had another 0.15v to go.  But my impression was that the battery had even less life then the voltmeter error allowed for.

3)  The modern age...... :D :D ::) ::)  We were using the laptop computer much more EVERY night then we have ever done in the past :o :o.  I really do not know the exact power it was drawing but its power supply says "60 watts".  Most every night we would download from our digital camera 50-75 pictures.  Review them, delete the bad ones and rename the ones we kept.  Joanne would then do our days trip log.  So, we now have the computer on for 3-5 hours a night plus interior lights ( 40w-60w at computer table and 20w reading light by my bed).

So, it isn't the battery but our "wild" power use.  I have reduced bulb wattage in most light fixtures by 50%.  See how that works on next trip.  Also, next trip we will run the laptop off its own battery when we do not have shore power and recharge it during the day when we have the vans engine running and are charging the house battery.

How do you control power consumption in your 'B' when not plugged in to shore power for several days??  Any tips??  This of course is not a problem that the large RV's have with large battery banks and build in generators.

Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

bar20

  • ---
  • Posts: 15
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #1 on: July 18, 2007, 01:32:06 PM »
We use some of the van battery power through the cigerette lighter socket and the acc. socket. We also hook up a solar battery charger to the house battery, and finally we start up the engine and charge the battery that way. We usually run it for about 15 minutes.

Steve 
« Last Edit: July 18, 2007, 01:33:43 PM by bar20 »

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 61019
  • RVer Emeritus
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #2 on: July 18, 2007, 05:59:34 PM »
Len,
Have you considered carrying a small second battery & one of those 75-100 watt inverters to power the laptop - maybe even a motorcycle battery? Could charge it while driving during the day, even on sight seeing trips.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #3 on: July 18, 2007, 10:55:34 PM »
We do have a 1000w inverter attached to the house battery.  The van has outlets for a/c and DC.  I am exploring adding a second house battery.  Might be able to make a well for my present battery and the second one.  It would not only provide more power but free up some space in the van.  The present house battery is behind the food pantry and I have to remove a panel to expose it for servicing.  A 2nd battery will also put us back in the range of being able to be without shore power or running the van for 2-3 days at a time with this "modern" life style.  It is very unusual for use to go longer than 3 days w/o using the van (and thereby charging batteries).  Also we do have a spare laptop battery that can carry with us.  We have just gotten into the bad habit leaving the computer plugged in to the inverter whether we are on the road or parked.

We also could get a Honda 2000 generator.  A Honda 1000 would be enough exept for winter and the 2000 could cover all our potential needs.  We could then use the van in the winter w/o being forest to camp at electrified state parks.  But I have always been against generators in forest campgrounds and that would be going over to the dark side.  :o :o :o  We would also have issues with secure generator storage.

And of course it is always just fun to play and modify our toys.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 61019
  • RVer Emeritus
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #4 on: July 18, 2007, 11:39:18 PM »
That 1000W inverter may be sucking a fair amount of juice too. It has an overhead (0.5-1.0 amps?) even when idle and is far more than you need to run the laptop. That's why I suggested a small 2nd battery and tiny inverter just for the 'puter.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #5 on: July 19, 2007, 11:12:35 AM »
Good point.  Yes, I believe the efficiency of  invertors goes up with load and the laptop really is a low load.  At low loads a good percentage of the power used is going to the invertor and not the  laptop.  Most every place I have 120v a/c I also have a 12v DC outlet.  So it would be very easy to plug in a small invertor for laptop use when not using shore power.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Ned

  • Former Staff
  • ---
  • Posts: 25574
  • Ned and Lorna are former full time RVers
    • Have you seen Rolling Stock?
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #6 on: July 19, 2007, 11:27:41 AM »
Many laptop computers have 12VDC power adapters available that would let you eliminate the inverter completely.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #7 on: July 19, 2007, 06:09:40 PM »
My Dell Inspiron 1300 does not have that feature, it requires a AC to DC charger.  Can I borrow your laptop for awhile? ;D ;D
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #8 on: July 19, 2007, 06:20:41 PM »
Gary,

The no load power consumption of the Tripp Lite PV 1000HF (bought July 2003) is about 18 watts.  I estimate that the efficiency of the inverter is around 70% when a 60w AC load is attached and that the battery must therefore supply about 84 watts.  Rough numbers.  I note the date on mine because they have newer ones out with the same model number but with more features.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 61019
  • RVer Emeritus
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #9 on: July 19, 2007, 07:18:41 PM »
18 watts is  1.5 amps @ 12V, so it's no small thing if on for long periods.  I used to have a small 120W inverter to use with the laptop and it was hardwired to an outlet by the computer work area in our previous coach.  It is still in the car for use there or to plug into the 12v outlet in this coach when we boondock.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #10 on: July 28, 2007, 03:25:31 PM »
Well I am slowly working my way through the loads on the van.   I am measuring voltage drop on the battery over 2-3 day periods.  The last thing I have just done is measure battery drain with things "turned off".  The result is a 1.5 watt per hour drain on the house battery.  I looked under the van and the watts were not setting there in a puddle.  The next step in isolating where this 1.5 watts might be going, I disconneted everything that runs on 12 volts except the inverter.  Low and behold the drain went away.  No measureable voltage drop to the second decimal place for the last 3 days.  I was sure it was the inverter. :-\ :-\  The next step is to seperate (pull fuses) the interior lighting from the radio and see where the 1.5 watts per hour is going.  I bet on the radio.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

joelmyer

  • ---
  • Posts: 1050
  • Joel (W4JNM) and Camille, GA
    • The Retirement Saga
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #11 on: July 28, 2007, 09:07:57 PM »
Len,

Interesting discussion.

I have a fiver, 2 six volt AGMs, a charge wizard & a 1000i.  It takes me a couple of hours of generator time in the morning to pay for the evening 'puter & TV time.

>1) The $16 digital voltmeter that I got from Radio Shack several years ago to monitor battery voltage ain't what it used to be.  It now has a 0.15 volt error.

How did you determine that?

Joel
Joel (W4JNM) and Camille, GA

John From Detroit

  • ---
  • Posts: 19793
  • ^My New Home^
    • Diabetics Forum
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #12 on: July 29, 2007, 09:38:49 AM »
1.5 watts or 1.5 amps

Common "Always on" include the radio (memory) and Propane detectors, smoke/co detectors may or may not use internal batteries. Air conditioner, furnace and such controllers  You need to de-populate the fuse panel to be sure
Nothing adds excitement like something that is none of your business
My Home is where I park it.

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 61019
  • RVer Emeritus
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #13 on: July 29, 2007, 11:06:28 AM »
1.5 watts over a couple days is a really tiny drain and quite normal. We are talking milli-amps of current.  That sort of load comes from electronics in idle (stand-by) mode, the sorts of things that John mentioned.  Your van probably has less of that sort of stuff than a Class A, but just about anything with digital controls, remote controls or membrane-type switches will have a tiny circuit board monitoring for button pushes and/or remembering settings in its tiny memory.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #14 on: July 29, 2007, 12:29:00 PM »
Gary,

That is why I think it is the radio.  The importance depends on how many amp-hrs or watts one can use from the house batteries.  In my case battery.  In approximate numbers I figure my fairly new schedule 31 battery has ABOUT 600 watts available for consumption.  So over a two day ( 48 hour) period when boondocking the 1.5 watt per hour drain would consume about 12% of my usable power.  It would be fine if we had need for the radio.  In reality we mostly use it while going down the road.  So, if the drain is the radio then it is a simple matter to add an on-off switch to the 12 volt radio feed and basically increase my battery size by 12%  :P :P :P

The down side is the radio (aftermarket Jenson AM/FM radio, CD/cassette player) would need to be reprogrammed when we get to home (like we do now when we get the van out of storage).

Yes, my 'B' is very simple no propane, no refrig., battery operated CO/smoke detector.....

I am ESTIMATING power drain by using a 0.60 voltgage drop as representing the battery half power point (about 600 watts consumed).  So, each 0.10v drop represents 60 watts used, each 0.01v drop repesents 6 watts used, etc.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #15 on: July 29, 2007, 04:07:08 PM »
Joel,

I am using my Greenlee 93-606 multi meter as base of reference.  No, I have not compared that to anyone elses voltmeter.  The new Radio Shack meter I installed in the van reads 0.10 volts higher then the one I replaced (still 0.05 volts lower then the Greenlee).  The old Radio Shack multi meter dial was also wearing out.  Touching or lightly pushing on the dial could change the displayed reading.

I am toying with the idea of getting a Honda 1000 watt unit but I do have storage issues with things in the van.  I really like the size and weight of the Honda 1000 BUT on the other hand like the power of the Honda 2000 but not its size or weight.    :-[ :-\ :-[ :-\ :'(    Because they hold gasoline I would want to store them outside of the van but do not any secure storage or "out of sight" locations.

Life is hard.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

joelmyer

  • ---
  • Posts: 1050
  • Joel (W4JNM) and Camille, GA
    • The Retirement Saga
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #16 on: July 30, 2007, 05:46:56 AM »
I am toying with the idea of getting a Honda 1000 watt unit but I do have storage issues with things in the van.  I really like the size and weight of the Honda 1000 BUT on the other hand like the power of the Honda 2000 but not its size or weight.    :-[ :-\ :-[ :-\ :'(    Because they hold gasoline I would want to store them outside of the van but do not any secure storage or "out of sight" locations.

A couple of thoughts:
1. It seems like a run to town for groceries, sightseeing, going out for dinner would at least partially get your batter(ies) back up.  How long do you sit without moving?

2. When I was planning, it seemed to me that even if you have solar, you're gonna need a generator for the long cloudy day stretch.  If you have a generator, do you need solar?

3. The 1000i is fine for the things you talk about - really it just gets the batteries back up.

4. Mine rides in a tool box in the truck,  When we're in a dry camping mode it sits on the ground with a bicycle chain (really a plastic coated steel wire cable) attaching it to the fiver.  That wouldn't stop a determined thief, but avoiding tempting an honest man.  You might be able to do something similar (the chain I mean).

Joel
Joel (W4JNM) and Camille, GA

Karl

  • Former Staff
  • ---
  • Posts: 5154
  • No Brett; no sweat. A QB's not the whole team.
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #17 on: July 30, 2007, 08:54:18 AM »
I find it difficult to believe that the 'keep alive' current for the radio is anywhere near 1.5A. A hundred milliamperes - maybe. Keep looking. ;)
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

Ned

  • Former Staff
  • ---
  • Posts: 25574
  • Ned and Lorna are former full time RVers
    • Have you seen Rolling Stock?
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #18 on: July 30, 2007, 09:19:34 AM »
Len did say 1.5W which would be on the order of ~125mA.  Others inquired about W or A.  That drain is insignificant and is probably on the order of the self discharge.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #19 on: July 30, 2007, 11:25:41 AM »
Yes, I am talking in termss of watts.  Doesn't matter if one is using a 12 volt DC device or 110v AC device.

Now the way I figure it for NEW batteries (and its all downhill from there):

1 Battery.......about 600 watts usable   (B's, travel trailers, pop ups, pickup campers ???)
2 Batteries.....about 1200 watts usable  (large travel trailers, C's, 5th wheels, some A's??)
4 Batteries.....about 2400 watts usable  (bigger A's??)
6 Batteries.....about 3600 watts usable  The number can go on for ever...any A's...bus conversions carry 6 or more???

So the watts available (no. of batteries carried) to consume and of course the length of time you are consuming the power.  My point being that a couple of watts of "wasted" power in an RV that carries a single battery is far more significant then a couple of watts in an RV that has multiple batteries.

The longest we stay in one place w/o moving (ie: starting and running the van) is about 3 days.  Our present limit is the ice in the chest.  It is very easy for us to be 15-20 miles from a town w a store and supplies.  Also these travels are usually along 1.5 lane dusty, washboard, gravel country roads.  So under those conditons the fewer the trips the better.

So that is why I'm chasing after the watts and trying to make sure that I use them for what I really want.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Karl

  • Former Staff
  • ---
  • Posts: 5154
  • No Brett; no sweat. A QB's not the whole team.
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #20 on: July 31, 2007, 07:51:52 AM »
Quote
Len did say 1.5W which would be on the order of ~125mA.
OOPS!
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #21 on: July 31, 2007, 09:19:46 AM »
It will take about a week to get test results from my radio.  1.5w seems a little high just for that but we will see.

I recharged the battery, let it set 24 hours, measured 12.80v, removed 123 watts from the battery [ 92 watts worth of interior lighting on for 1hr 20minutes] and measured a battery voltate of 12.50v.  I will check the voltage again this evening and if the battery is stablized I will start a 3-4 radio "off" current drain test.  I will pull all 12 volt fuses to EVERYTHING except the radio.

 After the radio "off" test I think I will do a radio "on" power drain test with a few hours of Vivaldi "The Four Seasons" at a reasonable inside sound level and get a handle on what the cost is to use the radio while we are w/o shore power.  My radio limit is usually not power used but Joanne.  "Can't we turn that thing off" usually comes just as I am really just starting to get into it.  It wounds me deeply.  As a retired engineer you would think she would want me to widen my horizons beyond flannel shirts and dirty blue jeans?

So I will post again in the this thread in a week or two.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Ned

  • Former Staff
  • ---
  • Posts: 25574
  • Ned and Lorna are former full time RVers
    • Have you seen Rolling Stock?
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #22 on: July 31, 2007, 09:37:33 AM »
You're assuming that the voltage/SOC curve is linear, which may not be true.  Also, the time to discharge to any given level isn't necessarily a linear function of the load.  And, again, 1.5W is on the order of self discharge of the battery.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Karl

  • Former Staff
  • ---
  • Posts: 5154
  • No Brett; no sweat. A QB's not the whole team.
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #23 on: August 01, 2007, 08:52:00 AM »
Quote
Also, the time to discharge to any given level isn't necessarily a linear function of the load.
You're correct - it isn't. A 10 ohm load at a battery voltage of 12.6 volts would draw 1.26 amps, but when the voltage drops to, let's say 11.5 volts, that same 10 ohm load would only draw 1.15 amps; the change of the state of charge is definitely time dependent.
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #24 on: August 04, 2007, 09:36:50 AM »
After recharging and discharging the battery back into the 12.4v range again I have removed all 12v fuses except for the circuit that has the radio on it.  I have watched  the voltage drop for about 64 hours so far.  For what ever reason the radio does appear to be consuming 1.0w to 1.5w per hour in the "off" mode.  Thinks thats high but that is what it is.  We have had some problems w the radio lately.

As far as battery self discharge rate.  The single battery in my RV is a Delco M30HMF marine/RV battery w lead-cad.  I don't think its self discharge rate in rough numbers would be much different than any other lead acid battery of its size.  I do fugure the self discharge rate should be on the order of 0.05watts/hr.  That is less then what Ned is referring to.  As far as I can tell self discharge rate for a lead-acid battery should be on the order of 3% of power per month at least for the first several months of storage.  This would be consistant with my July 28th post were I did not get a measureable voltage drop over a three day period of having the battery disconnected (to 1/100th of a volt).

It is interesting that a day to night temperature swing of 20+ degrees F can be picked up with a voltmeter on the battery.




Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Ned

  • Former Staff
  • ---
  • Posts: 25574
  • Ned and Lorna are former full time RVers
    • Have you seen Rolling Stock?
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #25 on: August 04, 2007, 09:44:16 AM »
I still think you're in the range of self discharge.  A 220AH battery has 2640W of power at full charge.  If it self discharges at 3%/month that's 2.64W/day, more than you're seeing.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Ron

  • Former Staff
  • ---
  • Posts: 18087
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #26 on: August 04, 2007, 09:54:01 AM »
I still think you're in the range of self discharge.  A 220AH battery has 2640W of power at full charge.  If it self discharges at 3%/month that's 2.64W/day, more than you're seeing.

Just as I was thinking.  Why not just insure the batteries are fully charged then disconnect the batteries and measure the voltage drop over several days.
Ron & Sam-home is where we park it. Currently located   HERE

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #27 on: August 04, 2007, 11:52:51 AM »
Fat fingered the keys and sent message before being done.

Apples and oranges Ned.  We are saying the same thing it turns out.  I am using watts per hour not watts per day.

My Delco M30HMF battery is a 115Ah battery.  So fully charged it would have 1380 watts and 3% per month self discharge would be:  1.40 watts per day OR 0.058 watts per hour.  Same thing after adjusting for units. 

So when I say I am lossing 1.5 watts per hour that is for me a big loss and is about 24 times the battery self discharge rate.
« Last Edit: August 04, 2007, 02:08:41 PM by Len and Jo »
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Tom

  • Administrator
  • ---
  • *
  • Posts: 44710
    • RV Forum web site
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #28 on: August 04, 2007, 01:02:10 PM »
I removed the "fat fingered post" Len. FYI you can edit your posts by clicking the Modify button near the top right of each message (next to the subject line). If you don't see the button, let me know. Thanks.

I get to use that button a lot  :-[
« Last Edit: August 04, 2007, 01:04:14 PM by Tom »
Tom.  Need help? Click the Help button in the toolbar above.

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #29 on: August 04, 2007, 02:01:24 PM »
Thanks Tom,

Assuming my search does not turn up any other significant power losses, I think I will rewire the radio power. 

If I remember correctly the radio has two 12v sources of power (a red wire and a yellow wire)r.  Normally one 12v source is the chassis battery directly so that radio memory is not lost when the radio is turned "off".  The second 12v source is through ignition switch.  So if the radio is inadvertently  left on when the ignition is turned off the radio will be turned off to prevent battery drain.  Wanting to be able to use the radio while camped I directly wired both wires to my house battery.  So, while stopped and the engine turned off we can use the radio w/o being concerned about draining the chassis battery.

I think I will pull the my center console (to get at the wiring) and my radio and rewire it.  I will put the 12v memory wire back on the engine battery.  The wire that normally is ignition switched (and I ASSUME at this point is source of my 1.0-1.5w per hour power loss) and that I have hard wired into my house battery I will dual power source it.  I will power the radio with an 12v of chassis power via an ignition switched wire AND power the radio from the house battery through a mechanical timer mounted in the dash.  On the road the radio will play normally off of the engine battery.  Stopped the radio can play for as many hours as I set on the timer off of the house battery.  When the timer times out no house battery drain.  I think this will stop that power drain.

Yep..... right there in plain sight is the "modify" button. :D :D 
« Last Edit: August 04, 2007, 02:05:04 PM by Len and Jo »
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Tom

  • Administrator
  • ---
  • *
  • Posts: 44710
    • RV Forum web site
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #30 on: August 04, 2007, 02:11:45 PM »
Yep..... right there in plain sight is the "modify" button.

The story of my life Len - right in front of my nose all the time. Glad you found it.
Tom.  Need help? Click the Help button in the toolbar above.

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 61019
  • RVer Emeritus
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #31 on: August 04, 2007, 06:16:18 PM »
Quote
I have removed all 12v fuses except for the circuit that has the radio on it.  I have watched  the voltage drop for about 64 hours so far.  For what ever reason the radio does appear to be consuming 1.0w to 1.5w per hour in the "off" mode.  Thinks thats high but that is what it is.

That wattage equates to about 0.1 amp (100 milliamp) and is in the range of what automotive radios use to keep the memory alive and to sense its electronic switches (i.e so you can turn it on again). It probably also has a digital clock it keeps alive.  They ought to be able to do with less power, but saving on batteries is not a big design issue in automotive electronics - they expect you to drive it every day or at worst 2-3 days.

I think your solution to move the "keep alive" wire back to the chassis battery is a good one.
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #32 on: August 05, 2007, 08:07:45 PM »
FYI

I took the direct path and got into the wiring under the dash.  With my multimeter I measured the radio "off" current 95 milliamp and the battery voltage at the time was at 13.1 volts for a power drain of 1.24 watts.  Think I will just add a radio 'kill' switch for multi day boondocking.  Wish I had a similar reading off of the 'old' Delco radio I took out of there 5 years ago to compare to the Jensen radio.

The attached picture is of the modified dash with a 20A toggle switch added below and to the left of the radio.  If we use it, it will save us 30 watts per day of battery power while boondocking.
« Last Edit: August 07, 2007, 08:24:06 PM by Len and Jo »
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #33 on: August 13, 2007, 06:45:43 PM »
Follow-up............

External house battery drain is now not measureable (aka: battery voltage) to two decimal places over a 4 day period.  The radio was source of the battery drain.  Now when everthing is off it really IS OFF.    :)

Think I will start looking at LED lighting options since lights are are largest use.  I'm also going to add a timer in the bathroom for the Fantastic Fan so that it will shut off 1-2 hours after we go to sleep at night.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Ron

  • Former Staff
  • ---
  • Posts: 18087
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #34 on: August 13, 2007, 06:53:21 PM »
Thanks for the followup.  Sounds like you have found the battery drains.
Ron & Sam-home is where we park it. Currently located   HERE

Ned

  • Former Staff
  • ---
  • Posts: 25574
  • Ned and Lorna are former full time RVers
    • Have you seen Rolling Stock?
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #35 on: August 13, 2007, 07:25:31 PM »
Why not use a temperature controller on the Fantastic fan rather than a timer?  Check the web site for a replacement controller.  Ours has a thermostat and it's 10 years old.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #36 on: August 13, 2007, 07:46:57 PM »
For boondocking with finite power I think a timer is best for us.  The thermostat does look like a nice feature though.

Thanks for the idea.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Karl

  • Former Staff
  • ---
  • Posts: 5154
  • No Brett; no sweat. A QB's not the whole team.
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #37 on: August 14, 2007, 10:41:01 AM »
Not sure where you'll find a 12VDC timer readily. If you use a 120ac timer, you'll need the inverter to power it; cuts down on the savings. Yes, 12 volt timers are available, but most are manually operated and don't have a 24-hour clock for day-to-day use.
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #38 on: August 14, 2007, 04:15:42 PM »
No power needed.  The timer I am going to use is a mechanical device.  HD has a 1 hour max. and a 12 hour max. versions.  We have one in our home bathroom wired to the shower exhaust fan to remove mosture and not have to think about turning the fan off.  Have also used several in our church kitchen for exhaust fans, point of use water heaters, coffee makers and thermostats (prior to110v  programable thermostats being available).  Do not have to worry about people turning things off because eventually they will shut themselves off anyway. ;D

Well Ned have to thank you again ;) ;)

After looking at the Fantastic Fans available I am going to remove the one I have and install the one with a variable speed fan and re-install my old one behind the front seats (need to measure things a little first).  We have a VERY NOISY 12v fan mounted inside pn a side wall for hot days that I will pitch.  It's an 8" chrome wire cage thing that I got at Camping World and I have never liked it and as a result never really used it.

The two Fantastic Fans will really move the air on warm days and nights.  Being able to set a very low (AND I ASSUME QUITE) speed on the new one when we go to bed will really be nice.  Thanks again my $20 job just had job scope change and large budget increase. ;D  When done I think I will be very happy with the dual fans.
« Last Edit: August 14, 2007, 04:18:42 PM by Len and Jo »
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Karl

  • Former Staff
  • ---
  • Posts: 5154
  • No Brett; no sweat. A QB's not the whole team.
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #39 on: August 14, 2007, 04:19:48 PM »
Ah, yes. I guess we did have gears and springs before we had electricity :)
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

Tom

  • Administrator
  • ---
  • *
  • Posts: 44710
    • RV Forum web site
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #40 on: August 14, 2007, 05:35:02 PM »
Ah, yes. I guess we did have gears and springs before we had electricity :)

LOL Karl, don't pretend you're too young to remember  ;D
Tom.  Need help? Click the Help button in the toolbar above.

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #41 on: August 14, 2007, 09:18:37 PM »
I have found a Fantistic Vent 6000r at Adohen Supply Co.  I got to their web site via www.fantasticvent.com.  They have the 6000r for $269 and that includes shipping. 

Did see it on E-bay for $251 but the seller only had a one star rating.

I do like the low amp draw.  0.2-1.9 amps

The Fantastic Vent company says the 6000r has been in production since summer of 2006.  Does anyone own this fan model and how do you like its performance and how quite is it??  Any feedback would be helpful.

Thanks
« Last Edit: August 14, 2007, 09:32:04 PM by Len and Jo »
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

King

  • ---
  • Posts: 355
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #42 on: August 15, 2007, 07:47:54 AM »
Please...
Watts have nothing to do with a battery's capacity.  Current times voltage equals watts.  What you are talking about is Watt-hours.
Art

Ned

  • Former Staff
  • ---
  • Posts: 25574
  • Ned and Lorna are former full time RVers
    • Have you seen Rolling Stock?
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #43 on: August 15, 2007, 08:29:13 AM »
When discussing RV DC systems, it's customary and easier to refer to Ampere-Hours (AH) as the systems are almost universally 12V.  Deep cycle batteries are rated in AH and not watt-hours and loads are usually rated in amperes, not watts.
-- Ned -- Fulltimer 1997-2013
1997 Holiday Rambler Endeavor LE
2007 GMC Canyon

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 61019
  • RVer Emeritus
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #44 on: August 15, 2007, 12:14:47 PM »
Quote
Being able to set a very low (AND I ASSUME QUITE) speed on the new one when we go to bed will really be nice.

Karl, have you abandoned your project  to produce a variable speed control to convert Fantastic Vents that have the fixed 3 speed? The prototype you made for me is still working fine in our coach.  Len is looking for a low and variable speed for the same reasons that led me to ask you about the project to begin with. You might have another customer!
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Len and Jo

  • ---
  • Posts: 1186
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #45 on: August 16, 2007, 09:42:21 AM »
A very pleasent experience .... so far.

I ordered a 6600r from Adohen Supply Co. last night at midnight via the internet.  This morning at 10am they called me.  Wanted some more detailed information about my application.  When I told him I was replacing a 4000r with the new one he suggested that I should consider buying an upgrade kit and save some money ( I didn't want an upgrade because I am going to relocate the 4000r to the front of the van).  That was nice of him though to ask and try to save me money.  He then asked several more question (some about my 4000r) to make sure the new fan would install without any modifications.  The new 6600r fans manual open knob will protrude 5/8th of an inch father down and other such good details to know.

Very nice to talk to a person who clearly knew the product he was selling.

On a seperate note:  It would appear to me that the 6600r fan design could be using a PWM (pulse width modulated) speed control for the fans variable speed.  I think that would explain the reduced current draw.  The 4000r and others probably used resistors (power consumers) to control the fans 3 speeds.  Maybe to several of you others this is old hat.
Len & Jo
The Green Tardis
We 'B' RVing   Berkley, Michigan
Van Development:   https://youtu.be/5Xqk_G6k95M
12 Years of Travels:  https://youtu.be/UMIf17CzdZo

Karl

  • Former Staff
  • ---
  • Posts: 5154
  • No Brett; no sweat. A QB's not the whole team.
Re: Battery Power Management, House Battery, Chassis Battery, etc
« Reply #46 on: August 16, 2007, 10:56:33 AM »
Gary,
No, I have not abandoned the project. I've finalized the design and component selection, and just need to do the actual board layout and etching. The only thing I've been lacking is time, and plan to have a number of them ready for Quartzsite.

Len, That's exactly what I built for Gary - a PWM controller to replace the resistor/switch combination. Features 0-100% variable speed control AND is reversible to take air in; not just exhaust it. Adaptable to almost any vent fan except those with remote control.
« Last Edit: August 16, 2007, 10:58:17 AM by Karl »
Karl (Cheesehead) Kolbus   Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting "...holy cow ...what a ride!"

 

Hosted by Over The Network