Help choosing the right converter/charger?
Hi My TT has a Parallax 7345 converter. For the past year I have been using 550 watts of Solar and a MPPT controller charging my batteries. We have a 12V system at the moment. And I am using (4) 6V...
Forum Discussion
Just leave it on till it gets the job done, however long it takes.
The 90% business is bogus. They are assuming maybe a 10% charging rate. The truth is that the batteries will go from bulk (when they reach near 14.4v) to absorption (still at now fixed 14.4 but with tapering amps) at a SOC percentage depending on the charging rate (initial charging amps /AH of battery bank.)
A higher charging rate will get the batts to Vabs sooner at a lower SOC, while a lower charging rate will get them to Vabs (14.4 for a standard PD) at a higher SOC.
You have 55 amps on 4 batts so say 55/440 = 12.5% charging rate. That is quite low, and should get you to about 85% SOC before amps taper.
OK so how long at bulk? That depends at what SOC you start the recharge. Calculations! :)
4 hrs at 55 = 220AH
85% of 440 = 374AH
So to end at 374 with four hours of 55 means you started at 374-220= 154 and 154/440 = 35% SOC
So I think your batts are down even more than that, and that is why it is taking longer than four hours,
Or else you are suffering from PDitus where the 55 doesn't do 55, but something less for the four hours, which means you are doing a lower charging rate than at 55, which will mean tapering doesn't start until later, after you pass 85%.
Another thing is without using the CW it will stay at 14.4 for so long, depending on what the battery SOC gets to, but if you hit the CW it will go into Timer Mode and stay at 14.4 for four hours regardless of battery SOC.
The 90% business is bogus. They are assuming maybe a 10% charging rate. The truth is that the batteries will go from bulk (when they reach near 14.4v) to absorption (still at now fixed 14.4 but with tapering amps) at a SOC percentage depending on the charging rate (initial charging amps /AH of battery bank.)
A higher charging rate will get the batts to Vabs sooner at a lower SOC, while a lower charging rate will get them to Vabs (14.4 for a standard PD) at a higher SOC.
You have 55 amps on 4 batts so say 55/440 = 12.5% charging rate. That is quite low, and should get you to about 85% SOC before amps taper.
OK so how long at bulk? That depends at what SOC you start the recharge. Calculations! :)
4 hrs at 55 = 220AH
85% of 440 = 374AH
So to end at 374 with four hours of 55 means you started at 374-220= 154 and 154/440 = 35% SOC
So I think your batts are down even more than that, and that is why it is taking longer than four hours,
Or else you are suffering from PDitus where the 55 doesn't do 55, but something less for the four hours, which means you are doing a lower charging rate than at 55, which will mean tapering doesn't start until later, after you pass 85%.
Another thing is without using the CW it will stay at 14.4 for so long, depending on what the battery SOC gets to, but if you hit the CW it will go into Timer Mode and stay at 14.4 for four hours regardless of battery SOC.
