Diane Maldonado wrote:20 amp charge controller-that I still have to buy!
I don't know if it has been covered yet or not, but last time I did any checking on chg-ctrls, there were two basic types.
1 - Standard Analog
2 - MPPT
As I understand it, the MPPT tech takes any voltage over and above the 13.8 - 14.2vDC that your batteries are being charged at and converts it into added amperage instead of wasting it in heat energy loss from the charging components, so the voltage output of your panels comes into play there. I'm not sure of the conversion algorithms used or their actual efficiency ratings.
Depending of the Vo and Io of you panels it might behoove you to wire them in series/parallel rather than straight parallel, depending on the Vi capabilities of your controller.
If you've already plugged these factors into your design plan, I apologize for being redundant.
If you double the voltage of the storage medium, connecting the batteries in series @ 24vDC, you can use smaller gauge cables from the PV array to the controller, IF your controller is designed to also charge at that voltage (24vDC) as well.
I didn't notice if you were using any kind of 'Inverter' to get up to 110vAC for your control circuits/igniters, etc, or if you are staying at 12vDC for those devices. Any time you can bring the Voltage up through the cables from PV to Controller, the amperage drops relatively, and you can get away with smaller gauge cables - as long as your controller can handle the Voltage input.
And if you can double AGAIN the voltage of the storage to 48vDC, and have an inverter designed for that input, you'll notice a much better conversion efficiency.
I would also agree with Mr.Baker and Mr.Baillie re: the heavier cables. They both have some other great ideas also.
I would suggest as close as you could get to 'ought' (0#) gauge interconnecting the batteries AND going to the inverter. Max out on the size accepted by the terminal blocks of each device.
I realize you already have your DeepCycle storage at this point, but with the price of top end 12v DeepCycle batteries, you can probably pick up a couple flooded acid 'RE' grade 6vDC devices and bump your amperage reserve up quite a bit (380AH/device, 380AH-20%efficiency=~300AH@12v=3.6kw-50%rule=1800W usable), I doubt you'll get much better than 100AH each out of those 12v deeps with the same (or less)efficient ratings being calculated, and the 6vDC units are much more forgiving of excess discharging. IMHO
I seriously doubt you'll get the amperage capacity you think out of those Marine Batteries.
I use one 280w panel though an old Xantrex CC into two flooded 6v@380Ah rated batteries to power the control circuits (water heater, propane fridge, central furnace) in my 5th Wheel, and take care of keeping the laptop and cell phone charged, plus a minimum number of 12v automotive LED lights, and a 12vDC ceiling fan in the Summer. My goal is to add 3 more panels in the near future for a total of 1kw/h (5kw/d), and add another 6-6v batteries for a total capacity of 14.4kw (so I can bring my HF Transceiver back into Ops), of course that will NOT give me the 3-day reserve one should design into their system.
Thanks for reading my Ramble,
Bruce
