Solar power - length of solar day - does this make sense

[StuM]

Originally Posted by onestepcsy37

For us, we keep our power requirements low and then put up all the solar and batteries we have room for. Biggest draw is the fridge, maybe 40 amps hrs a day. 40 more amps hrs will run everything else. Our six golf cart batteries have 675 amp hours, so maybe 320 is usable, enough for four days of no charging.

[sailinglegend]

Originally Posted by onestepcsy37

What Utahsailor says. Don't obsess over 100% charges, they aren't necessary......

Utahasailor says fully recharge overnight once a week. This is good advice if you can do it, if not sulfation (Lead Sulfate Crystals) begins to build up on the plates. So you should worry about not getting to 100% charges otherwise the batteries will die prematurely. This is one of Maine Sail's main messages. PSOC or Partial State of Charge will prematurely kill batteries. An overnight shorepower charge with a suitable sized charger is the best way to guarantee a 100% charge. A heavily depleted large bank may take 24 hrs or more.

Lead Sulfate crystals are produced every time a battery is even partially discharged. It's part of a chemical formula that, among other things, produces water which reduces the SG of the electrolyte and results tin the Lead and the Sulfuric Acid combining to form Lead Sulfate. Charging reverses the process, but if not fully re-charged the Lead Sulfate Crystals that build up on the plates over a week or more start to harden. The longer they are left the harder the crystals become and a high Equalization voltage will be needed for several hours to remove them. When fully charged regularly all the Lead Sulfate Crystals are converted back to Lead and Sulfuric Acid with its maximum SG value.