Originally Posted by vinmaker
Is that how the math works?
If I have a 100 Amp/h battery then I can expect to get 50 Amp/h out of it?
If I have a phantom draw of 2amp then after 24 hours I have used up 48 of the 50 amp/h?
Sure makes you want to carry a small inverter genny to charge up during the day. How long would it take to charge up? At home I put a slow 2amp charge on my battery and will run that overnight. But most CG's restrict the genny to certain hours right?
If your total amp draw is a constant 5 amps you will discharge a 100 AH battery to its 50% discharge point (where it must be recharged to avoid permanent damage to the battery) in 10 hours
It gets more complicated if you are drawing more or less than that due to something call the Peukert Effect. (see graph)
As you demand more amps from a storage battery (as opposed to a starting battery), the ability of the battery to generate amps decreases due to plate design. As you can see from this graph, just demanding 10 amps will reduce the available capacity by 25% to 75 AH. At 20 amps of demand, the capacity available is reduced to 62.5 AH.
This is with a FULLY CHARGED 100 AH battery to start with. That is why adding multiple batteries is critical (to spread the demand across several battery suppliers) if you even THINK you might want to add an inverter to your camper.
Lou and Laura with Bella - German Short Hair Pointer
2008 GMC Sierra 2500HD Crewcab SB Allison Duramax
2010 Flagstaff 8526RLWS - Superglide 3300
HAM CALLSIGN - KC3FFW