How Long can I expect my Inverter Batteries to Last?

By Neil Vorster

generators, loadshedding, Office off the Grid, ups, UPS Inverters

The Enertec Deep Cycle Heavy duty sealed lead acid batteries that we use are designed to last 1000 cycles if you look after them properly. 

BUT only if handled properly.

If you overload your batteries by “red-lining” them ie  discharging it too deeply, or drawing a very heavy load continuously,  they will only last a few months, no matter what brand of deep cycle batteries one uses.

Make sure that the inverter or UPS you use has automatic  low voltage cutoff set properly to switch off automatically before your batteries discharge too deeply. Too deep a discharge of you battery will ruin any lead acid battery very quickly. In my experience battery brand is not the main cause of failure, normally unwitting battery abuse is the culprit!!!

Another tip that nobody speaks about is the continuous  amperage that your inverter will pull from the battery.

A very experienced battery supply that I have come to rely heavily on recommends that your continuous design load does not draw more than 15 Amps from a 12 V deep cycle battery. This 15 Amp target  is guesswork, but experience counts in this industry!

Divide your normal inverter load ( in Watts) by the voltage of your battery ( probably 12 or 24 Volts) to obtain the current draw on your batteries.


A 240 Watt load on a 12 V system would draw 240W/12V = 20 Amps – which is a bit too high !!!

But on a 24 V system, the same load would only be drawing 240W/24 V = 10 Amps which is very low and consequently you can expect excellent endurance from your battery - as long as you do not discharge it to deeply!

About the author

Property Investment Coach
Off The Grid Power consultant
BSc Eng - (Wits) 1985

Neil Vorster

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