Adding more batteries
Good Afternoon all! Fully charged my 2 x 6v batteries in my class A work well and provide me 208AH (104 usable). I have 300 watts of solar that works great in the summer to keep me going however in...
Forum Discussion
Same as a year ago: (And do note the last para--reduce your capacity as entered into the Trimetric as necessary to confirm your SOC percentages. Compare your resting voltage, SG, and AH count.)
Posted: 11/30/15 07:00am Link | Quote | Edit | Print | Notify Moderator
If you bench test the Boondocker converter with only a voltmeter in its terminals, no loads, it should kick off at 14.6 and stay there for 15 minutes, then drop to 13.6.
It should do that with the batteries connected as well no matter what the SOC is. But if it "sees" above about 14.3 at that 15 minute mark, it will assume the voltage is about to hit 14.6 and it will drop to 13.6. If the voltage is below that it will assume the batteries have a ways to go and it will stay in boost until it actually sees the 14.6.
Of course with 0.4v voltage drop, that 14.3 will be "seen" when the battery is only at 13.9v.
At 50% SOC on the two 6s, the 60a Boondocker will do 14.6v and 60 to 63ish amps steady, for about half an hour to raise the battery voltage from 12.1v to 14.6v. it will then drop to 13.6 and amps will drop to about half what they were and then taper from there. Other forum members with that converter are seeing that.
So it is obvious that your wiring from the converter to battery bank has too much resistance, making the converter "think" it is at a higher SOC than it is. (you need #4 and good connections at that distance) You should note the voltage soon after you start the charge. I expect it "spikes" to 14.6 very quickly and then the voltage drops to 13.6 as programmed.
In addition, I suspect the battery bank capacity is less than "as new" from too much undercharging since this trouble has been going on.( A smaller bank has higher resistance) adding to the wiring resistance problem, making it spike to 14.6 even sooner
Posted: 11/30/15 07:00am Link | Quote | Edit | Print | Notify Moderator
If you bench test the Boondocker converter with only a voltmeter in its terminals, no loads, it should kick off at 14.6 and stay there for 15 minutes, then drop to 13.6.
It should do that with the batteries connected as well no matter what the SOC is. But if it "sees" above about 14.3 at that 15 minute mark, it will assume the voltage is about to hit 14.6 and it will drop to 13.6. If the voltage is below that it will assume the batteries have a ways to go and it will stay in boost until it actually sees the 14.6.
Of course with 0.4v voltage drop, that 14.3 will be "seen" when the battery is only at 13.9v.
At 50% SOC on the two 6s, the 60a Boondocker will do 14.6v and 60 to 63ish amps steady, for about half an hour to raise the battery voltage from 12.1v to 14.6v. it will then drop to 13.6 and amps will drop to about half what they were and then taper from there. Other forum members with that converter are seeing that.
So it is obvious that your wiring from the converter to battery bank has too much resistance, making the converter "think" it is at a higher SOC than it is. (you need #4 and good connections at that distance) You should note the voltage soon after you start the charge. I expect it "spikes" to 14.6 very quickly and then the voltage drops to 13.6 as programmed.
In addition, I suspect the battery bank capacity is less than "as new" from too much undercharging since this trouble has been going on.( A smaller bank has higher resistance) adding to the wiring resistance problem, making it spike to 14.6 even sooner
