theoldwizard1 wrote:
Likely your 12V batteries are NOT true deep cycle batteries and do not like being discharged at such a high rate. "Marine" batteries are "dual purpose", but really aimed at high starting currents. True deep cycle batteries alomost never advertise Cold Cranking Amps (CCA) or Marine Cranking Amps (MCA).
Are all 3 batteries the exact same make and model and purchased at the same time ? If not one of them may be pulling down the others. As soon as is reasonable after your load test, disconnect the batteries from one another and check the voltage at each battery post. More than a 0.10V difference is not good.
IDK. My theory is , and what I get from statements here, is that the 75ah 12 volt duracells with a CCA rating and 75ah rating are best at high amp draw. Just like car starting batts.
But I have nothing to compare it with. I really will not know until I get 6 volters and try it.
The other issue is two batts are 75 ah, and the truck batt is a 70 ah.. But the truck one is 20 feet away..Truck batt is a starting batt with a 70 ah rating.
CCA770
CA950
RC (25A)120
Ah Capacity (20hr)70
http://www2.exide.com/us/en/product-solutions/transportation/findabattery-trans-ext.aspx?culture=us%2fen&culture=us%2fen&culture=us%2fen&culture=us%2fen&culture=us%2fen&culture=us%2fen&culture=us%2fen&page=product-solutions%2ftransportation%2ffindabattery-trans-ext&page=product-solutions%2ftransportation%2ffindabattery-trans-ext&page=product-solutions%2ftransportation%2ffindabattery-trans-ext&page=product-solutions%2ftransportation%2ffindabattery-trans-ext&page=product-solutions%2ftransportation%2ffindabattery-trans-ext&page=product-solutions%2ftransportation%2ffindabattery-trans-ext&page=product-solutions%2ftransportation%2ffindabattery-trans-extBut regardless they are parallel so its their voltage that will equalize and amp draw or charge AFAIK will get and take what the batteries want. One or the others will not overcharge or discharge.
So on my test with the micro @ 100% soc I dropped to 12volts from say 12.8 volts.
@ 75% soc what can I expect will be my next test.
Then if 6 volts what can I expect with the same scenario.
Its all a mute point though. As I can do away with my high draw loads.Coffee with a peculators, Pizza for kids in oven instead of Toaster oven. And not use the micro at all.
What I do need is a box fan on low through the night in summer. 25 watts @ 120. 2 amps @ 12
Or heat on cold nights. Furnace 7 amps max when on. @ 12 volts I believe 80 watts.
And my c pap machine. 5 amps @ 120, 25 watts or 2 amps 12 volts
Misc 2- TV's on until bed x 2 @ 25 watts each. 4 amps @ 12 volt
And inverter losses and misc cell phones charging. Plus .5 amps for CO?propane detector
Total. Lets just say 75 ah a night and call it good.. or 10 amps an hour.
Last summer I had trouble with this. But had not a good charging capabilities. Now I have 560 watts 40 amps solar, and a generator with a Wizard converter incase.
I dont want to go 6 volt only to find out @ 80% SOC I have a bigger issue with voltage drop and have my converter keep shutting down.
I shouldn't worry and just get out there with what I got and try it out.
