Thor Forums

[Beau388]

Originally Posted by Bob Denman

When you plug in to re-charge the batteries: at what voltage reading do you plug them in, and how long do you let them charge?

If flooded batteries then, the more time you keep them fully charged the longer they will last. During bulk charging, the voltage will vary from 13.7 to 14.2 volts depending on how deeply the batteries are discharged. Absorption stage charging voltage will be 14.2 to 14.4 volts (the same as the engine's alternator). When the charger switch to float charging, the voltage will vary slightly from 13.4 to 13.6 volts showing the batteries are fully charged. If a 100 AH battery is 50% discharged it can take as long as 5 hours to bring it up to fully charged (assuming you have a 50 amp three stage charger). The battery will be 80% charged is about 1.5 hours but the absorption stage will usually take another 3 hours or so depending on battery temperature. If you have a bigger charger the the bulk charging will be shorter but the absorption stage will be take the same time. If you have a larger battery bank the bulk charging will take more time but the absorption stage will be the time. Remember converter controlling several chemical reaction, so temperature is a big factor as the condition of the chemicals (lead, lead oxide, lead sulfate, sulfuric acid and water).