Telecom Backup Battery Life Estimator

At the datasheet rating point, VRLA/AGM lead-acid cells of this class are typically rated around the default shown (to 80% remaining capacity). Cycle at a shallower depth of discharge and the count rises steeply — that is the (DoD_rated/DoD)^k term. Heat, fast charging and storage at full charge all shorten it.

Often yes, twice over: a modest solar + controller takes daily shallow grid-outage cycles off the battery (it becomes genuine backup again rather than a daily-cycled bank), and reduces cabinet heat load at the same time. Where outages are long and frequent, hybrid LFP retrofits with solar typically pay back in 2–3 battery replacement cycles avoided. Run both scenarios in this estimator — VRLA at your real cadence vs LFP at the same duty — and compare cost per service-year.

Count equivalent full cycles: two 50% discharges ≈ one full cycle of energy throughput. If your charger or BMS reports total Ah or kWh throughput, divide by the pack's rated capacity to get equivalent full cycles — that is the number to enter as cycles completed.

Industry convention is 80% of original capacity — beyond that, fade accelerates and runtime becomes unpredictable. Fleets usually retire packs at 80% for the duty they were bought for, then cascade them to lighter duty rather than scrapping immediately.

Yes — it is the single biggest lever you control. Lead-acid cycled to 50% instead of 80% roughly doubles cycle count; lithium chemistries gain similarly with the exponent k shown in the formula. Sizing a pack so daily use is a shallower fraction of capacity is usually cheaper than replacing packs early.