Solar Battery Charge Issue

Boon Docker wrote:

Gdetrailer wrote:

KenS999 wrote:
The two lead acid Duralast batteries that I charge with the Renogy 100W solar suitcase are rated at 65 amp hours each.

100W "suitcase is not "rated 65Ahr", more like 6.5A hr and that would be in full sun at noon during the summer solstice with the panel pointed directly at the sun with no clouds in the sky. That max only lasts at best 4hr-5hrs a day.

If it was 65Ahr, that would be on the order of 57.1A!

To get the 65Ahr you would need 10 of those panels.

I think you misunderstood what KenS999 was saying. his batteries are 65 AH each.

Granted, yeah I missed that was the batteries at 65Ahr..

However,

Draw half of that from each battery would be 65Ahr for TWO batteries PLUS more for losses that needs to be put back in..

Call it say 70Ahr that needs to go back in..

100W panel can only give you 5.71 Amps PER HR for max of 4-5hrs..

So on a GOOD day with full sunlight in the middle of summer the OP has the potential of 28.55Ahr of max charging provided they kept moving the panel with the sun..

Might get a few amphrs the rest of the day so we will call it 35 Ahr total for a 24 hr period..

That is a 35Ahr DEFICIT each day..

In other words they will never, ever get the batteries fully charged with only one 100W panel..

They need about 10A of constant charge current per battery for 8-10hrs just to fully recharge both batteries..

Not gonna happen with 100W of panel, as it is each battery is only getting 50W at max sun and at 50W they could even connect the panel directly to both batteries without the charge controller.. There is not enough wattage to over charge the batteries if they are drawing them down halfway.. 2.5A per battery for 5 hrs is not much more than a trickle charger..

Think back to the days when the ONLY charger you may have had was a 2A trickle charger and attempted to charge a flat battery.. that could take days before your battery had enough charge to turn the engine over if you were lucky..