Announcement

Collapse
No announcement yet.

Calculating hours of backup correctly

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Calculating hours of backup correctly

    Due to lack of local stock I've had to buy some ****ty off brand batteries.

    Correct me if I'm wrong but is the following the correct way to calculate how long my battery should last:

    Let's say I have 200Ah battery at 12 V, allowing 70% discharge and 80% inverter efficiency with a constant load of 100W

    200*12*.7*.8/100 = 13.44 hours of battery?


    Is my math correct?
    Last edited by choob; 06-11-2018, 05:31 AM.

  • #2
    Your math may be correct but your batteries will die an early death due to being discharged 70%.

    A safer calculation to get as many "cycles" as possible out of the batteries is to never discharge them more than 25% on a daily basis.

    That 200Ah battery should safely provide you about 600 watt hours a day (200Ah x 12v x .25 = 600wh) so a 100 watt load will use that up in 6 hours or less depending on the equipment efficiency and losses.

    Comment


    • #3
      Hi there,


      This question has got me stumped so I was hoping there

      Moderator note: RickyD, try it again, your message was truncated, possibly because you copied and pasted it from another application, or used something other than a computer (like an iphone). After posting, your message might not show up right away since you haven't been fully approved for posting yet, that might take a day or two. --Steve
      Last edited by sdold; 06-16-2018, 11:01 PM.

      Comment


      • #4
        Thanks so much for letting me know what the problem was. I have never posted before, old school and to be honest I

        Comment

        Working...
        X