Well, I did my homework.
Calculated my energy needs and came up with 2 basic scenarios, with and without a 12v fridge.
In all scenarios - Electric water pump runs sparingly and a 12v fan running all night. We currently do not have a 12v fridge, but use an Engel ice chest and it serves our needs for now. All our lights are now LEDs, and our iPhones, tablets can be charged about every 3rd day. We carry enough camera rechargeable batteries to last 2 weeks until we hook up to 110v. No inverter needed at this time. No microwave, no TV, no stereo running all the time.
Without refrigeration - 10 AH/day
With (future) refrigeration - 30AH/day
I assumed a 2.5A 12v fridge like a Truckfridge with a duty cycle of 8 hours per day.
Other assumptions / guesses
I don’t want to rip the entire back out. So the existing battery box stays for now. Current battery is 13”x7”x9+” high (could fit 10”)
If i am going to spend money it will be a high quality battery. Several Lifeline AGMs fit this space but I am thinking of the GPL-31XT with a 20 hours rate of 125AH. Might as get get most AH I can.
I think this will be fine for the Without Refrigeration scenario. We generally stay only 2-3 days at one place, driving around during the day and then on to the next place, so I figure that should be enough charging, if we don’t plug in. Obviously, with a fridge, the load really means I need to plug in more often or I might get solar for additional energy input. OR bigger battery bank. Fridge is off a bit for now, $ wise.
GPL-31XT Charging Instructions and Voltages:
Bulk Charge Voltages: 14.20 - 14.60v
Absorption Charge Voltages: 14.20 - 14.60volts
Float Charge Voltages: 13.10 - 13.40v
The GPL-31XT is designed for charging amperages up to 312.5 amps or 250% of the rated Amp Hour Capacity due to low battery internal resistance.
So which charger?
I was looking at the Prosport Gen3 chargers and the PDI 9200 series, that others have put into their EVC and been happy with. Also within budget. However, I noticed they have 2 very different charging profiles:
Prosport (profile for Flooded and AGM the same)
ProSport Charging: During this mode the “Charging” indicator will be red. ProSport will use all of its available charging amps (as controlled by temperature) until the battery voltage is raised to 14.6VDC (Flooded lead-acid factory setting).
ProSport Conditioning: During this mode the “Conditioning” status indicator will be amber. Batteries will hold at 14.6 VDC (factory set for Flooded lead-acid batteries) to complete charging while conditioning each battery connected. Upon completion the ProSport will go into its maintain mode.
ProSport Ready / Maintain: During this mode the “Ready/Maintain” status indicator will be green and remain on with the blue “power” LED indicating that your batteries are fully charged while being maintained at a precision 13.4 volts (factory set for Flooded lead-acid batteries) and are ready to go when you are.
ProSport Storage Recondition Mode: During this mode the ProSport “Recondition Mode” green indicator will illuminate with a slow fade in and out pulse indicating that while your batteries/boat are in storage the ProSport will automatically recondition all batteries for up to 3 hours once a month extending battery life and maximizing on the water battery power performance.
PDI 9200 Series
14.4 Volts (Boost Mode) – Returned the battery to 90% of full charge in approximately 8 hours. The battery reached full charge in approximately 11 hours.
13.6 Volts (Normal Mode) – Required 40 hours to return the battery to 90% of full charge and 78 hours to reach full charge.
13.2 Volts (Storage Mode) – Required 60 hours to return the battery to 90% of full charge and 100 hours to reach full charge.
EQUALIZATION MODE: When in storage mode the microprocessor automatically increases the output voltage to 14.4 volts for 15 minutes every 21 hours. This will help to reduce the buildup of sulfation on the battery plates.
Is PDI “Normal” the same as Prosport “Conditioning”? If so, how will the lower PDI "normal" charge of 13.6 affect the batteries?
Any advice will be appreciated.