profdant139 wrote:
2oldman, I did not realize that your question about hooking "directly" to the panel was really about the controller -- yes, there is a controller. I would not bypass a controller -- too much risk of boiling the battery.
And red, I measured the 14 volts by putting a multimeter onto the battery terminals. The panels are 120 watt "no name" Chinese panels -- very much like the Renogy suitcase unit.
And mexicowanderer, I should add that my purpose in wanting to charge the panels fully is not "instant gratification" -- it is delayed gratification! I am hoping that the batteries will last longer than three days till they reach 12.1 volts and have to be swapped out. (This assumes, of course, three very cloudy days. If there is sun on this trip, the batteries will be hooked to the panel, and we will have more juice than we can use.)
Your assumption is incorrect. You do need to babysit and"boil" the battery with 16.0V at the battery terminals, to equalize charge and desulphate. You should briefly do this both when you return from a trip to equalize the battery charge, and do it briefly again shortly before you leave on your next trip.
Batteries used on trips like this require maintenance, there is no such thing as plug and play with generators, smart chargers, or solar panels and charge controllers. You will need to tinker and fine tune, and learn as you go. Might cost you a deep cycle battery in the process, but we learn from our mistakes, or at least some of us do.
Do a search in the technical section here on how to equalize charge your battery. Then go to the manufacturer of your battery and ask them how to do an equalize charge on their brand and particular model of battery.
Disconnect your battery from the trailer every time you finish a trip when you get home or to the storage yard, then do an equalize charge. Only connect the travel trailer battery terminals again when you are ready to leave on your next trip.
If you have a flooded lead acid battery, you need to get a instrument grade hydrometer to measure the Specific Gravity of your battery cells, one, by one. Log the readings, compare them, and get back to us with what you find. A SG of 1.275 or better per cell, tells you your battery is fully charged. Voltage and amps are helpful, but the specific gravity per cell is the acid test of telling you each cell is fully charged.
