Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 


Reply
 
Thread Tools Display Modes
 
Old 01-23-2015, 09:39 PM   #21
Senior Member
 
KTMRIDER's Avatar
 
Join Date: Oct 2009
Posts: 560
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea


Hope this works. Thanks for testing it!
Eric

__________________
2006 Ford E-350 V10 Agile 4x4 SMB EB50

2000 Ford E-350 7.3L Quigley 4x4 hard top with custom interior by Xtreme Fab - Sold
KTMRIDER is offline   Reply With Quote
Old 01-23-2015, 10:33 PM   #22
Senior Member
 
E350's Avatar
 
Join Date: Oct 2010
Location: Sacramento Delta, CA
Posts: 1,024
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

Dude!!! Thanks for showing your homework! I may learn something!
__________________
2002 E350 ext.; 160K; 7.3L; 4R100 (w/4x4 deep pan & filter); 4x4 conv. w/2007 F250/F350 coil frnt axle (oppos. dual Bilstein press. shocks cured DW) diff chg from 3.55 to 3.73 (bad!); BW1356 t.c. (bad!); LT265/70R17/E Michelin LTX M/S2; Engel MT60 Combi Fridge-Freezer; 4 BP 380J pv panels; Auragen 5kw AC gen. in top alt. position; Webasto Dual-Top; Voyager top. 1995 5.8L EB Bronco, bone stock.
E350 is offline   Reply With Quote
Old 01-24-2015, 08:31 AM   #23
Senior Member
 
boywonder's Avatar
 
Join Date: Jul 2013
Location: So Cal
Posts: 4,048
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

....a few other considerations........

a 300W 12V heating element draws 25 amps of current, so a 600W 12V element will draw 50 amps (and heat the water twice as fast).

In either case above, you'll need to provide wiring and fusing large enough to support the load. This means at least 10 AWG wire for 25 amps and 6 or 8 AWG wire for 50 amps.

In my case, there is no way I can support the 50 amp load, so it'll be a 300W heating element or less. There appears to be 200W 12V elements available also.

...and finally, a lower wattage element will be intrinsically safer in a failure mode, since there will be less energy going into the system. For example, let's say the thermostat fails closed (very low probability of this, but we are analyzing failures here) a smaller wattage element will result in a lower "over temperature" condition since the element is adding heat at a slower rate than a larger element and the heat lost through the jacket insulation will be (close to) the same with either element.
__________________
2008 E350 RB passenger 4WD SMB penthouse
2013 KTM 350 EXC
2008 KTM 250 XCF-W
2003 Honda Element
boywonder is offline   Reply With Quote
Old 01-25-2015, 04:51 PM   #24
Senior Member
 
reelchef67's Avatar
 
Join Date: Nov 2014
Location: North Vancouver BC
Posts: 295
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

My dual 12v/120v instant hot I have in my traverse says it takes 15 mins to come up to temp with120 and ½ hour for 12v ..
__________________
2002 E250 5.4 4R70W 2wd 3.5 inch lift Pleasure-Way Traverse on 16x8 with 265/75/16's
reelchef67 is offline   Reply With Quote
Old 01-25-2015, 06:05 PM   #25
Senior Member
 
BrianW's Avatar
 
Join Date: Apr 2012
Location: Philadelphia, PA
Posts: 4,198
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

Quote:
Originally Posted by reelchef67
My dual 12v/120v instant hot I have in my traverse says it takes 15 mins to come up to temp with120 and ½ hour for 12v ..
An "instant" hot water tap that takes up to 30 minutes to get hot? Hmmm...
BrianW is offline   Reply With Quote
Old 01-25-2015, 08:58 PM   #26
Senior Member
 
boywonder's Avatar
 
Join Date: Jul 2013
Location: So Cal
Posts: 4,048
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

Quote:
Originally Posted by BrianW
Quote:
Originally Posted by reelchef67
My dual 12v/120v instant hot I have in my traverse says it takes 15 mins to come up to temp with120 and ½ hour for 12v ..
An "instant" hot water tap that takes up to 30 minutes to get hot? Hmmm...
The label says capacity 1/3 gallon, so it must have a fairly low wattage element if it takes that long to heat up.


......senior moment.......directly above the "1/3 gallon tank capacity" it says 12VDC @ 8.3A...

Mr Ohm says P=VI so 12V*8.3A=100W element.
__________________
2008 E350 RB passenger 4WD SMB penthouse
2013 KTM 350 EXC
2008 KTM 250 XCF-W
2003 Honda Element
boywonder is offline   Reply With Quote
Old 01-26-2015, 12:45 PM   #27
Senior Member
 
reelchef67's Avatar
 
Join Date: Nov 2014
Location: North Vancouver BC
Posts: 295
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

Quote:
Originally Posted by BrianW
Quote:
Originally Posted by reelchef67
My dual 12v/120v instant hot I have in my traverse says it takes 15 mins to come up to temp with120 and ½ hour for 12v ..
An "instant" hot water tap that takes up to 30 minutes to get hot? Hmmm...
T
Yes they have start up period .once that is over it is more less "instant"
__________________
2002 E250 5.4 4R70W 2wd 3.5 inch lift Pleasure-Way Traverse on 16x8 with 265/75/16's
reelchef67 is offline   Reply With Quote
Old 01-26-2015, 03:54 PM   #28
Senior Member
 
E350's Avatar
 
Join Date: Oct 2010
Location: Sacramento Delta, CA
Posts: 1,024
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

reelchef67 and boywonder: To me it comes down to capacity. I will likely drive more than 30 minutes to a camp spot so both units will be adequately heated upon arrival. The storage tank type will have 2.5 gallons of usable hot water while the instant on variety will have 1/3 gallon of usable hot water. So, unless I am missing something, the storage tank type hot water heater makes more sense in our mini-rv applications.

In fact, I believe they make more sense in a real property home application as well. I have never understood how an instant on water heater could be more efficient for anything but quick showers never in a bath tub or soaker bath tub application - and never, ever, ever if you let your house dip below freezing when you are not there.)

boywonder: I have no doubt that you are truly a "boywonder." While I just wonder (about alot of stuff actually...) So, would you please provide one instance of the full word (i.e., "xxx") for your abbreviations in your formulas above? Actually, I see that you have done that, thanks, except for what Mr. Ohm says - what is P = VI?
__________________
2002 E350 ext.; 160K; 7.3L; 4R100 (w/4x4 deep pan & filter); 4x4 conv. w/2007 F250/F350 coil frnt axle (oppos. dual Bilstein press. shocks cured DW) diff chg from 3.55 to 3.73 (bad!); BW1356 t.c. (bad!); LT265/70R17/E Michelin LTX M/S2; Engel MT60 Combi Fridge-Freezer; 4 BP 380J pv panels; Auragen 5kw AC gen. in top alt. position; Webasto Dual-Top; Voyager top. 1995 5.8L EB Bronco, bone stock.
E350 is offline   Reply With Quote
Old 01-26-2015, 06:22 PM   #29
Site Team
 
daveb's Avatar
 
Join Date: May 2007
Location: Turlock Ca
Posts: 10,407
Garage
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

350 you never heard of pie or a PIE chart? He just used V for E or are you just funnin?


Ohm's Law Defined, Ohm's Law Pie Chart
Ohm's Law defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the resistance value through which one volt will maintain a current of one ampere.

( I ) Current is what flows on a wire or conductor like water flowing down a river. Current flows from negative to positive on the surface of a conductor. Current is measured in (A) amperes or amps.

( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.

( R ) Resistance determines how much current will flow through a component. Resistors are used to control voltage and current levels. A very high resistance allows a small amount of current to flow. A very low resistance allows a large amount of current to flow. Resistance is measured in ohms.

( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.




I'd better not say how we learned the resistance color code (BBROYGBVGW) but maybe you've been there schoolin wise?
Attached Thumbnails
Ohms_Law_Pie_Chart.jpg  
__________________
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer

Sportsmobile 4X4 Adventures..........On and off road adventures
daveb is offline   Reply With Quote
Old 01-26-2015, 07:41 PM   #30
Senior Member
 
reelchef67's Avatar
 
Join Date: Nov 2014
Location: North Vancouver BC
Posts: 295
Re: Dual Voltage (12v dc / 120v ac) Small Electric Water Hea

[quote="E350"]reelchef67 and boywonder: To me it comes down to capacity. I will likely drive more than 30 minutes to a camp spot so both units will be adequately heated upon arrival. The storage tank type will have 2.5 gallons of usable hot water while the instant on variety will have 1/3 gallon of usable hot water. So, unless I am missing something, the storage tank type hot water heater makes more sense in our mini-rv applications. "

I agree with you completely however the one that is my van was designed for producing water for beverages(tea coffee etc) ie 190" not for showering etc.. Ypu don't need more than 120 water for that purpose. I would rather have a larger tanked system but no room in my van so this is what I am stuck with. The tanks is 1/3 gallon but once it heats up it keeps producing hot water fairly steadily when mixed with some cold makes enough for a impromptu rubbermaid bin "shower".
for me it is what it is..
__________________
2002 E250 5.4 4R70W 2wd 3.5 inch lift Pleasure-Way Traverse on 16x8 with 265/75/16's
reelchef67 is offline   Reply With Quote
Reply

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

Powered by vBadvanced CMPS v3.2.3
Disclaimer:

This website is not affiliated with or endorsed by Sportsmobile SIP or any of its affiliates. This is an independent, unofficial site.


All times are GMT -6. The time now is 09:57 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.