Jackery 500 versus my RV battery
My Casita trailer has one Duracell AGM group 27 battery with 92 amp hour capacity. If I can use about 40% before needing to charge it, that's about 40 amp hours I can use. I paid about $200 includin...
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Your numbers are off. The 40 AH @12 v is conservative but correct for your current battery. To compare the Jackery you need to convert 500 Watt hour divided by 12 v = 41.6 AH. They have close to identical useable power.
You laptop charger will pull 90 watts divided by 12 v = 7.5 amps. That seems excessive. I would check that number. That is only roughly 5 hours of charging for either the house battery or the Jackery. Of course, 5 hours of charging is not 5 hours of laptop use. Charging should take well less than an hour and should give you many hours of use off of the laptop battery.
Clearly buying conventional batteries costs much less. Battery banks work best when all of the batteries are identical and of the same age. If you want more capacity and your existing battery is a few years old, then it makes sense to buy at least 2 new batteries. There is another common misconception that 6 v batteries will give you more amp hours. Remember to equate the AH of a 6 v battery to 12v, you need to divide the 6 v AH by 2. You will pay roughly the same and have batteries of equivalent size and weight when buying either 6 v or 12 v batteries. 6 v batteries, especially "golf cart" batteries are built for deep discharge. You can also buy deep discharge 12 v batteries. The typical car battery is optimized for quick cranking power. They work in an RV. They are not ideal but are readily available and often relatively low cost.
You laptop charger will pull 90 watts divided by 12 v = 7.5 amps. That seems excessive. I would check that number. That is only roughly 5 hours of charging for either the house battery or the Jackery. Of course, 5 hours of charging is not 5 hours of laptop use. Charging should take well less than an hour and should give you many hours of use off of the laptop battery.
Clearly buying conventional batteries costs much less. Battery banks work best when all of the batteries are identical and of the same age. If you want more capacity and your existing battery is a few years old, then it makes sense to buy at least 2 new batteries. There is another common misconception that 6 v batteries will give you more amp hours. Remember to equate the AH of a 6 v battery to 12v, you need to divide the 6 v AH by 2. You will pay roughly the same and have batteries of equivalent size and weight when buying either 6 v or 12 v batteries. 6 v batteries, especially "golf cart" batteries are built for deep discharge. You can also buy deep discharge 12 v batteries. The typical car battery is optimized for quick cranking power. They work in an RV. They are not ideal but are readily available and often relatively low cost.
