expected normal voltage drop from load?
Is there a rule of thumb or guidance for an expected voltage drop based on amp load on a pair of 6V GC batteries? I was tinkering in my trailer this weekend and ran a 750 watt AC electric heater off ...
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What gauge is the series interconnect on those GC's?
In my experience, the more abused a battery is the longer the EQ cycle needed.
I was rather timid in my EQ charging, but ultimately found that 16v could do in 45 minutes what took 15.5v 4 hours to accomplish.
Any charging source produces only enough amps to reach/maintain the desired voltage once it gets battery terminal voltage in the absorption voltage range or higher.
If it only takes 2 amps to hold 15.5v, then 2.5 amps would push voltage up beyond 15.5v. One can perhaps limit amps to say 5 and see how high that amperage can push battery voltage, but one cannot say I want 10 amps at 16 volts if the battery only needs 6.2 amps to be brought upto and held at 16v.
My single flooded group 31 would require about 1.4 amps to be held at 14.9v after 3 to 4 hoursat 14.9v, and then ~ 6.2 amps would be required to push the battery to 16v. When amps had tapered to about 4.2 at 16v, SG was usually maxed out. This generally took 45 minutes to 2 hours, depending on the ambient temp, and the amount of abuse the battery endured since the last EQ charge.
Right before I removed this battery from RV service, more than 6.2 amps was required to attain 16v, and amps would taper only to 5.5, then start increasing again as battery temperature started increasing rapidly.
This behavior, along with the bottom of one cell closest to the (-) getting much hotter than the rest of the battery when charging at a ~8 to 9% rate, were the indicators of the end of its cycle life.
This battery has survived 6 more months so far of fairly shallow cycles and no maintenance and no EQ charging in a stationary duty. I estimate its total capacity to be 45 to 50% of what it had when new.
Voltage sag under load is pretty extreme, as is its self discharge. My hydrometer is covered in dust, As the battery I do care about and cycle is an AGM, that continues to impress me, as long as it is high amp recharged and fully recharged each cycle. Low and slow solar only recharging and achieving only 95%SOC and it is not impressive in terms of voltage held under load for AH removed.
In my experience, the more abused a battery is the longer the EQ cycle needed.
I was rather timid in my EQ charging, but ultimately found that 16v could do in 45 minutes what took 15.5v 4 hours to accomplish.
Any charging source produces only enough amps to reach/maintain the desired voltage once it gets battery terminal voltage in the absorption voltage range or higher.
If it only takes 2 amps to hold 15.5v, then 2.5 amps would push voltage up beyond 15.5v. One can perhaps limit amps to say 5 and see how high that amperage can push battery voltage, but one cannot say I want 10 amps at 16 volts if the battery only needs 6.2 amps to be brought upto and held at 16v.
My single flooded group 31 would require about 1.4 amps to be held at 14.9v after 3 to 4 hoursat 14.9v, and then ~ 6.2 amps would be required to push the battery to 16v. When amps had tapered to about 4.2 at 16v, SG was usually maxed out. This generally took 45 minutes to 2 hours, depending on the ambient temp, and the amount of abuse the battery endured since the last EQ charge.
Right before I removed this battery from RV service, more than 6.2 amps was required to attain 16v, and amps would taper only to 5.5, then start increasing again as battery temperature started increasing rapidly.
This behavior, along with the bottom of one cell closest to the (-) getting much hotter than the rest of the battery when charging at a ~8 to 9% rate, were the indicators of the end of its cycle life.
This battery has survived 6 more months so far of fairly shallow cycles and no maintenance and no EQ charging in a stationary duty. I estimate its total capacity to be 45 to 50% of what it had when new.
Voltage sag under load is pretty extreme, as is its self discharge. My hydrometer is covered in dust, As the battery I do care about and cycle is an AGM, that continues to impress me, as long as it is high amp recharged and fully recharged each cycle. Low and slow solar only recharging and achieving only 95%SOC and it is not impressive in terms of voltage held under load for AH removed.
