EASY to use 12V usage calculator

[4x4tour]

http://lib.store.yahoo.net/lib/sports-imports/BatterydrainCalc.html<br>

 

[She]

Thanks Tour this is great. I added to my favs. This is so helpful.

 

[4x4tour]

Excellent explanation for the age-old amps/watts/volts question:<br><br>&nbsp;

One ampere hour (AH) of battery capacity means the battery can produce an ampere of current for an hour. One watt of power is one ampere of current at one volt. Watts tell us the power we're getting out of the battery; a watt is a watt whether we use it for one second or 24 hours. Let's say your fully charged battery produces 12 volts. Actually it'll be more like 13+, but 12 is close enough. So you're gonna run a refrigerator that draws 3 amps. <u><b>Volts x amps = watts</b></u>, so 12x3=36. It takes 36 watts of power to run that fridge, whether it's for three minutes or three hours or three days. What we want to know is, "How long can my battery hold out with this thing running?" Okay, that's where the ampere hour (AH) rating of the battery comes in. Say you have a 100 AH battery, and as stated in a post above,<u> it's safe to discharge it to one half of full charge</u>. You've got 50 AH to play with. Your 36 watt fridge draws three amps when running. 50 divided by 3 is 16.66. So the fridge could run over 16 hours before the battery is getting down to the "recharge me quick" point. Add a couple of lights, the water pump, a TV, maybe a fan, and you see why two big batteries are not a bad idea.

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[Suanne]

<P>

http://lib.store.yahoo.net/lib/sports-imports/BatterydrainCalc.html<BR>

</P><P>Thanks AJ,&nbsp; Very timely for me as I'm figuring out the best battery to get for our needs in the trailer.&nbsp; Suanne</P>

 

[Les H]

I saved it on my home screen too, thanks!

 

[yamsack]

@ 4x4tour&nbsp;&nbsp; How many usable amp/hours do your 2 batteries have?&nbsp; Secondly, what electrical devices are using the batteries.&nbsp; Thanks.<br>

 

[4x4tour]

I have 2 house batteries, so I basically divide it in half (see link)<br><br>http://www.powerstridebattery.com/odyssey-65-pc1750t-battery<br><br>The starting battery, which is the 3rd AGM, is used until the Bluse sea 7622 relay shuts down the connection at a pre-set voltage amount.&nbsp; A 2nd fail-safe was installed to make sure i always have juice to start the motor.<br><br>http://www.amazon.com/Battery-Brain-Marine-Type-III/dp/B0019ML5JI<br>&nbsp; <br>I run an Engel freezer, an HP DV-7&nbsp; laptop, direct tv box, and some LED lighting.&nbsp; I use the microwave for 90 second bursts when needed.&nbsp; Cooking &amp; heating are done via propane, although I plan on getting a 12v heated blanket w/30-45 minute timer.&nbsp; <br><br>I found some cheap hand-crank rechargeable LED lights that seem to last all night on just 30 seconds worth of cranking... I dig them...&nbsp; <br><br><br><br>

 

[4x4tour]

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<B><FONT size=1>the battery brain - it is installed under the hood and connected to the starter battery?<BR></FONT></B>&nbsp;<BR><B><FONT size=1>hand-crank rechargeable LED lights -link</FONT></B><BR><B><FONT size=1></FONT></B>&nbsp;<BR>

<BR><BR>Yes, the BB attaches right to the starting battery positve.&nbsp; The remote makes it act like a 2nd alarm system (battery kill).&nbsp; There is a provision to allow bypassing the shut-off for stereo memory wires. <BR><BR><BR>There's no name or numbers on the lights, but I do remember getting them at Kohls for like 15 bucks.&nbsp; They are 2-tone gray, and of a 5-LED lantern style, similar to this one:<BR><BR>&nbsp;<A href="http://www.earthtechproducts.com/ha...;gdftrk=gdfV21172_a_7c1174_a_7c4520_a_7cPPOWL" target=_blank target=_blank>http://www.earthtechproducts.com/ha...;gdftrk=gdfV21172_a_7c1174_a_7c4520_a_7cPPOWL</A><BR></P><A href="http://www.amazon.com/Battery-Free-Crank-Powered-Lantern/dp/B000MYLCHO" target=_blank>http://www.amazon.com/Battery-Free-Crank-Powered-Lantern/dp/B000MYLCHO</A><br><br>The 12 LED one above, would light up a van rather nicely.&nbsp; I may get one.&nbsp; My 5 LED light that lasts forever is the perfect blend of mood lighting/needed light&nbsp;for&nbsp;watching TV, relaxing etc... &nbsp;&nbsp;<br><br><br><br><BR><BR>&nbsp;<br>