question

jct250 avatar image
jct250 asked

Setting absorption time for battery that specifies time in relation to capacity used

Hi all,

Setting up a solar system for a teardrop caravan I'm building. At the moment I have a MPPT 75/15 charging a single 12v 104ah battery from a single 170w panel. The caravan only has 6 LED lights, a water pump and couple of USB chargers. Max draw when all lights are on is on is only ~2A, the pump adds another ~3A draw

Currently working through the battery configuration in the Victron app, the spec sheet on the battery has the following specified for absorption.

"Absorption Time, 1 hour for every 200 amp hour capacity used per cycle"

Given I anticipate drawing only 10ah max from the battery each day, (periodic pump use plus lights at night) does that mean that I should set the max absorption time to only 3 minutes? That doesn't sound right based on what other people suggest (although not sure if that is a reflection of the difference in bank size).

MPPT Controllers
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1 Answer
snoobler avatar image
snoobler answered ·

While it may not achieve the stated results the MPPT "adaptive" absorption algorithm follows the same philosophy: shallow discharges = short absorption. Deep discharges = longer absorption.

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