How To Make a Car Power Inverter - 800W

[DIYSwede]

The inverter may say 800W but you're not pulling that much from a car cigarette lighter. At least not for very long.

I guess most lighter outlets are fused at 20 A, giving max 280W out at 14V battery voltage.

But if you hook the inverter up the proper way - with starter jump cables straight to the battery poles,
the battery will provide just as much as it states: Voltage X Capacity. 12V times (say) 75 Amp-hours, equals 900 Watt-hours.

-Your all with me this far? So the 800W gadget will run comfortably at max for 1hr 7 minutes and 30 secs, you think??
WRONG: Batterys age slowly (starting even before leaving their factory) -
losing capacity, and then if you wanna have some lifetime out of it -
perhaps reaching some 300 charge-discharge cycles? - you shouldn't tap out more than 60% before charging.
I.e. 540W-hours total - giving only max 40 minutes run time as of above.

Then starter batteries are (as they're called) built for high amp outtakes for short bursts,
not for constant loads and deep cycles.
For those, they'll inevitably suffer - offering less capacity for each cycle and a shorted life spans in return.
For fork lifts, RVs, boats and the like there are Deep-Cycle batteries around (at a Premium price of course),
designed for long constant outtakes and deep cycle discharges.

So - what might look like a really good idea in theory, on paper and in ads, is unfortunately simply not possible in the physical world.
-Leibniz was simply wrong - we're NOT living in the best of all possible worlds!
(Off-topic Detour: He also stated that Monads didn't have any windows, but not why they're lacking them.)

2 cents
Johan
"-This might seem simple - but just wait 'til I've explained"


Links: https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery
https://batteryuniversity.com/learn/...n_modern_times
(https://en.wikipedia.org/wiki/Monadology)