Recipe for manual battery charging
So from start to finish, what is the recipe for charging a battery up (when charging time is to be minimized) from 50% SOC? Here's a 100 AH battery as an example. Please correct my errors and omissio...
Forum Discussion
Two thoughts / your decision. Money for wasted gasoline, or slight reduction in battery lifespan. Choose one. It takes thirty three gallons of gasoline to purchase your battery.
At 20C I insert enough amperage to raise the voltage to 14.8 but no higher. Throttling the voltage is not easy, but do the best you can. With a standard TRANSFORMER TYPE battery charger you can connect the battery charger AC lead through a VARIAC and then twist the dial on the variac to whatever you want. With a group 27 cyclable battery you should be seeing 42+ amperes.
At 14.8 volts at 20C when the electrolyte starts to bubble more than two bubbles per second per cell, I'll back the voltage down to 14.4. It'll stay there for an hour and a half or so. Again I manage to struggle out of my easy chair and peer into the cells with a flashlight. Same recipe for bubbling. The amperage will have spanned from around 38 to mid to high twenties. Let the damned thing CHARGE until you can count those bubbles. This is where manual charging kicks-butt as far as time is concerned.
Feel the battery case. A whole side. If one or all areas feel warm, say thirty degrees above ambient but LESS than 50C or 122F, stop the charging. The voltage will start to rise if you do not twist the dial on the VARIAC down. Let the voltage rise to 14.8 again. Amperage should now be in the teens.
Voltage limited charging will reduce the lifespan of the battery perhaps ten percent over an absolutely perfectly "recommended show charged" battery that sees the same kWh transaction.
Those extremely expensive smart chargers with all the bells and whistles are doing a -better- job than they used to, but as far as plug in and forget for regularly cycled off grid (boondock) camping. The manual method listed above will save about 30% of the time and actually get the battery to 100% full specific gravity. Chargers that are connected mostly to the grid and batteries that do not see regular and prolonged deep cycling make this black and white with various shades of gray.
Paying sixteen dollars and thirty cents for 5 gallons of gasoline on the other hand makes me see everything -red-
How many gallons of fuel equals a battery..............not enough...
At 20C I insert enough amperage to raise the voltage to 14.8 but no higher. Throttling the voltage is not easy, but do the best you can. With a standard TRANSFORMER TYPE battery charger you can connect the battery charger AC lead through a VARIAC and then twist the dial on the variac to whatever you want. With a group 27 cyclable battery you should be seeing 42+ amperes.
At 14.8 volts at 20C when the electrolyte starts to bubble more than two bubbles per second per cell, I'll back the voltage down to 14.4. It'll stay there for an hour and a half or so. Again I manage to struggle out of my easy chair and peer into the cells with a flashlight. Same recipe for bubbling. The amperage will have spanned from around 38 to mid to high twenties. Let the damned thing CHARGE until you can count those bubbles. This is where manual charging kicks-butt as far as time is concerned.
Feel the battery case. A whole side. If one or all areas feel warm, say thirty degrees above ambient but LESS than 50C or 122F, stop the charging. The voltage will start to rise if you do not twist the dial on the VARIAC down. Let the voltage rise to 14.8 again. Amperage should now be in the teens.
Voltage limited charging will reduce the lifespan of the battery perhaps ten percent over an absolutely perfectly "recommended show charged" battery that sees the same kWh transaction.
Those extremely expensive smart chargers with all the bells and whistles are doing a -better- job than they used to, but as far as plug in and forget for regularly cycled off grid (boondock) camping. The manual method listed above will save about 30% of the time and actually get the battery to 100% full specific gravity. Chargers that are connected mostly to the grid and batteries that do not see regular and prolonged deep cycling make this black and white with various shades of gray.
Paying sixteen dollars and thirty cents for 5 gallons of gasoline on the other hand makes me see everything -red-
How many gallons of fuel equals a battery..............not enough...
