Costco GC2 spec
I decided to replace the old GC2 batteries (4 years old). Costco's GC2's are now labeled Interstate Batteries. There isn't much data on the battery, just RC = 107. A "real" Interstate battery that ...
Forum Discussion
Two 6s can take around 70-80 amps as initial charging rate for a fast recharge. You only get a few minutes faster by going higher in amps than that.
The problem now is to find the right charger to do that at 14.8v which is as high as you want to go. (Except to equivalent of 14.8 in cold weather, which will be a bit higher voltage, but that isn't the same thing)
Now you need a generator that can run the chosen charger. Eg, the PD 80 amp charger is not PF corrected and will max out a Honda 2000. But you could run the PD 70 amper with a Honda 2000 at sea level.
So now you have to worry about how high up is your campground.
If you fall asleep with the gen running you are not concerned about limiting its running time to do the recharge, so why are you worrying about fast charging?
If you are going to stay awake, then you can also deal with a manual adjustable voltage charger like the PowerMax 75ADJ (you might need the 60 amper with a Honda 2000 above sea level) which does not even need adjusting to do a "50-90" recharge. You just leave it at 14.8v. That stops when you shut off the generator at 90% SOC.
BTW, a 50-90 on two 6s with 14.8 and 70Amps initial, will take about 130 minutes with the first 30 minutes at 70 amps to 65% SOC when amps will begin to taper while voltage stays at 14.8 for another 100 minutes to reach 90% SOC
You can't do it faster than that. You can do it slower. There are trade-offs you must make, such as how big a gen can your rig carry? Cost of things, etc.
The problem now is to find the right charger to do that at 14.8v which is as high as you want to go. (Except to equivalent of 14.8 in cold weather, which will be a bit higher voltage, but that isn't the same thing)
Now you need a generator that can run the chosen charger. Eg, the PD 80 amp charger is not PF corrected and will max out a Honda 2000. But you could run the PD 70 amper with a Honda 2000 at sea level.
So now you have to worry about how high up is your campground.
If you fall asleep with the gen running you are not concerned about limiting its running time to do the recharge, so why are you worrying about fast charging?
If you are going to stay awake, then you can also deal with a manual adjustable voltage charger like the PowerMax 75ADJ (you might need the 60 amper with a Honda 2000 above sea level) which does not even need adjusting to do a "50-90" recharge. You just leave it at 14.8v. That stops when you shut off the generator at 90% SOC.
BTW, a 50-90 on two 6s with 14.8 and 70Amps initial, will take about 130 minutes with the first 30 minutes at 70 amps to 65% SOC when amps will begin to taper while voltage stays at 14.8 for another 100 minutes to reach 90% SOC
You can't do it faster than that. You can do it slower. There are trade-offs you must make, such as how big a gen can your rig carry? Cost of things, etc.
