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electrical:severe_battery_use

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Intentionally severe battery use

Lead-acid chemistries prefer light cycling and full recharge between those cycles. Lead-acid batteries are traditional cycled to 50% depth of discharge because it offers a balance between duty life (years between failure) and bank size.1) Pulling the bank below 50% DoD in emergnecies will not automatically cause damage assuming a full charge is accomplished ASAP.

This article is about the intentional and chronic depletion of lead-acid banks below the 50% mark, followed by vigorous recharging.

how low can we go?

For folks willing to trade battery longevity for some amount of increased capacity, common low-end targets for low voltage disconnect are:

  • 60% DoD / 40% SoC, ~12.0 rested volts
  • 75% DoD / 25% SoC, ~11.7 rested volts
  • 80% DoD / 20% SoC, ~11.6 rested volts

limiting the damage

Deep cycles generally extend the amount of time for a battery to complete Absorption.

  • get power back into the battery ASAP after deep discharge; drive for alternator charging or run a generator to get bulk stage going. Solar alone might be sufficient but it might require meaningful overpaneling.
  • increase Absorption time, or even set Vfloat == Vabs.
  • if flooded, keep a close watch on water levels
1)
“dead lead”
electrical/severe_battery_use.1589384243.txt.gz · Last modified: 2020/10/11 19:48 (external edit)