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Calculating Amp Usage for T@b

jays55jays55 Member Posts: 13
edited July 2015 in Battery/Electrical & Solar
Greetings, I'm moving forward on purchasing a zamp solar system for our T@b, and would like to calculate the amp/hour (ah) usage during our typical day to decide which unit to purchase.  The T@b owners manual contains the following information;

12 Volt DC Amp Ratings
Appliance or Accessory Estimated Amps
• Aisle Light 1 Amp
• CO Detector 1 Amp
• LED Lights <1 Amps
• Furnace 10-12 Amps
• LP Gas Leak Detector 1 Amp
• Overhead lights (Per Bulb) 1 Amp
• Porch Light 1 Amp
• Power Roof Vent 1.5 Amps
• Radio/Stereo 4 Amps
• Range Hood (Fan & Light) 2-3 Amps
• Refrigerator (LP Gas Mode) 1.5- 2 Amps
• Security System 1 Amp
• Television (12 volt) 4-5 Amps
• TV Antenna Booster <1 Amp
• TV Antenna Booster 12 Volt outlet Up to 8 Amps
• Variable Speed Ceiling / Vent Fan 4 Amps
• VCR Recorder / Player 2 Amps
• Water Pump 4 Amp

My question is this; are the Amp figures per hour, or ?.  If per hour, seems easy enough to calculate our usage, based on the appliance and our normal usage during trips.  Zamp units are expensive and I can't see any reason to buy a lot more than we need :)


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    gilbutlergilbutler Member Posts: 169
    Amp (Ampere) is the rate of energy flow, not a quantity.  An Amp-hour would be one Amp flowing for an hour.
    Gil Butler, Folsom, CA, 2015 T@B M@XX CS - White with Yellow tim
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    mash2mash2 Member Posts: 581
    My understanding is that these  are amp hours. To determine the total amps used in a day, you would need to estimate how long the appliance is on for a given day (and drawing against the 12v battery power).  So for instance, if you use the radio for a 4 hour period, the total AMPS used in a day would be 16 AMPs.  When I was sizing my solar, I created a winter and summer budget for use and then calculated yield from the panels in winter and summer -- solar yields in winter are lower, so you have to decide when you will be camping to fully size.  As I recall, I sized for march to october when considering my needs.  For me the 2 way frig, furnace and fan were my largest draws.  I don't use television and swapped my lights for battery driven LED's.  I figure in winter I could survive less than a week (though the frig use would be lower), but could make it for extended periods throughout the rest of the year.  This has generally worked out to be true with a 200 AMP battery system.  
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    jays55jays55 Member Posts: 13
    mash2 said:
    My understanding is that these  are amp hours. To determine the total amps used in a day, you would need to estimate how long the appliance is on for a given day (and drawing against the 12v battery power).  So for instance, if you use the radio for a 4 hour period, the total AMPS used in a day would be 16 AMPs.  When I was sizing my solar, I created a winter and summer budget for use and then calculated yield from the panels in winter and summer -- solar yields in winter are lower, so you have to decide when you will be camping to fully size.  As I recall, I sized for march to october when considering my needs.  For me the 2 way frig, furnace and fan were my largest draws.  I don't use television and swapped my lights for battery driven LED's.  I figure in winter I could survive less than a week (though the frig use would be lower), but could make it for extended periods throughout the rest of the year.  This has generally worked out to be true with a 200 AMP battery system.  
    That's what I was hoping the numbers represented, as that would make it easy to calculate the amp/hours used in an average day.
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    Lisa33Lisa33 Member Posts: 260
    edited July 2015
    Those numbers don't look very accurate to me.  Some don't even apply (security system, range hood?).   I'd say each LED light is about .25 amps (3 watts) at most.  Those numbers are probably old.  There isn't a furnace on the new models either.  And even that number seems really high.  My LP furnace only uses battery power for the fan.  Perhaps someone with a newer model T@B can help you with more accurate numbers.
    Lisa. 2008 T@DA, previously 2012 6x10 SS. Southeastern PA
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    jays55jays55 Member Posts: 13
    Lisa33 said:
    Those numbers don't look very accurate to me.  Some don't even apply (security system, range hood?).   I'd say each LED light is about .25 amps (3 watts) at most.  Those numbers are probably old.  There isn't a furnace on the new models either.  And even that number seems really high.  My LP furnace only uses battery power for the fan.  Perhaps someone with a newer model T@B can help you with more accurate numbers.
    I agree, Lisa33.  According to those numbers, my daily limited usage would be 49ah.  The Zamp website says the average daily usage is around 36ah.......and the tiny T@b hardly seems "average".  Zamp also list Good, Better, Best recommendations for different battery set-ups, with the 80watt unit ZS-80-P being "Better" for a single group 24 battery, which is what we have.  There's a big jump in price to the 120w system, and I don't want to pay for it, if I don't need it :)!  Our needs while boondocking are very basic; refrig (propane), 6hr of heat at 55 degrees, very minimal lights and no gadget charging.  The 80w seems like it would be fine?
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    NomadNomad Member Posts: 7,209
    jays55 - The Alde takes so little (it's a pump vs a fan) that I can hardly tell it's running battery wise. I popped for the 120 because I have several things I need to charge thru an inverter and wanted to make sure I was covered.
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    mash2mash2 Member Posts: 581
    The Alde site indicates that the 3010 uses 1.9 amps max (from their site).  If you are using a 3-way frig, the draw in propane mode is small.  When I estimated my usage, the largest draws I anticipated from three sources.... w-2ay frig, furnace and fan (about 90% of my yield).  In normal weather I planned on a need for about 40 amps (because of the AC/DC frig) and sized from there.  
    There are some solar calculators out there that would allow you to estimate anticipated yield  (for example, http://www.where-rv-now.com/Notes/Solar/index.php?lat=32.63851&month=November&mday=7).

    If you need more amps, you should probably revisit the battery setup first, anyway.  

    I've modified over time and found the battery capacity issue arose as my needs changed.  I added solar, then added additional battery (driven more by the 2-way frig needs than anything).
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    jays55jays55 Member Posts: 13
    Well, after reading more of the forum discussions on solar, visiting manufacturers' websites and googling the various products (until my head was spinning :)), I purchased a Renogy 100watt foldable solar unit on ebay for $265;
    http://www.ebay.com/itm/281556876312?_trksid=p2060353.m1438.l2649&amp;ssPageName=STRK:MEBIDX:IT

    I can't imagine I will need more, but it seems to be a rabbit hole that's hard to avoid going down.......
    Thanks for all the great information!

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    NomadNomad Member Posts: 7,209
    Rabbit Holes - Yep, they're everywhere. Solar seems to be one of the deeper ones. And trying to sort facts, specs and opinion are a lost cause.
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    Lisa33Lisa33 Member Posts: 260
    I'd also suggest the 100w Renogy suitcase as a great starting point.  
    Lisa. 2008 T@DA, previously 2012 6x10 SS. Southeastern PA
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    mash2mash2 Member Posts: 581
    Hadn't looked but penology price is very good.
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