Battery Life and Low Temps
I have been having a ball up at Iris Meadow off of Rock Creek Road, Close to Mammoth Lakes, CA. It's the steeper side of the Sierras just East of Yosemite. It's a little known area comparably, but v...
Forum Discussion
PNICHOLS wrote:
Quote: “You do realize that a higher voltage charger delivering 45 amps for 2 hours will use about the same fuel from a generator as a lower voltage charger delivering 15 amps for 6 hours from a generator?”
… It's not that simple. It depends on how much waste is involved. In your case, yes, the 650 is only producing about 4.6a, (550w / 120v = 4.6a), while your charger is using about 2.2a. (13.8v x 15a, / 80% eff., /120v = 2.2a). Add another amp to that for t.v., etc, and you are using about 3.2 out of 4.6a. So, not too much waste. Well done…But a 550w gennie also has its limitations. Try running the microwave, for example, on that 550 watter. If the OP uses a microwave occasionally, the 650 just won’t cut it.
Moreover, any generator, (but especially one with eco mode, like the honda eu20001), will always run at no lower than its normal (or minimum in the eu2000i's case) idle. Therefore, it will be producing at least its minimum amount of available power at any given time. If that gennie is producing say 9a (minimum)of 120v power, it would be very wasteful to only use 3.2a of that 9a. But a 45 amp charger at 14.6v and 80% eff. would draw about 7a. Add the 1a for t.v., etc., for a total of 8a out of the 9.
Now here’s the kicker…My eu2000i, on eco mode, uses about 1/4 of a gallon of gas in 2 hours, so about 88 cents U.S. So, it actually uses 1/2 the gas to power the 45 amper for 2 hours with the 2000i than it does to power a 15 amper for 5 hours with the 650. It's all about efficiency vs. waste.
Quote: “For my case I didn't have to buy another charger to get the higher voltages because I already had the ultra-quiet economical generator ... so why not run it for 5-6 hours at only the 15 amps that the batteries will accept at the stock converter's (that was already in the RV) lower voltage.”
… I believe I just answered that. And you could always use an 85% eff. 25 amper with that ex650, set at 14.4v, and replace the same Ah’s in 1/2 the time, at 1/2 the cost.
Quote: “I think the issue here might be the usual one ... the OP might be in a non-hookup campground (state or federal) that has generator run-time windows maybe only 2-3 hours long ... so a higher voltage charger may be needed to get more amps into the batteries in a shorter time.”
… Thank you for acknowledging that.
Quote: “I don't always drycamp in places like that with generator run-time restrictions, so running an already-owned generator with an already-owned stock 13.8 volt converter for 5-6 hours makes sense”
… NOPE!
“ ... especially since I have faster charging AGM batteries anyway.”
…Numbers don’t lie, but assumptions do in this case…. 5-6 hrs at 15 amps vs. 2 1/2 - 3 hrs at 25 amps with the same ex650.
Quote “If I was to do extended drycamping in a run-time restricted campground, I'd have to supplement my little generator's time with some big engine idling time to speed up the charging during the run-time window.”
… Exactly my point!!! Your method just gets less and less efficient as you try to speed up the process. It’s like using a 10 ton fork lift to move a 10 pound box!
Quote: “The whole point I'm making is that 14.XX charging voltages are not always needed to achieve adequate recharging cycles”
… IF, AND ONLY IF, you are either plugged in to the grid, or enjoy burning money.
“… while at the same time not necessarily slowly ruining one's batteries.”
… But you are ruining your batteries if you never get them truly full. And at 13.8v, that’s gonna take 168 hours of continuous generator run time at an additional fuel cost of $59.00, every two or three weeks!
Sorry, but stock converters just do not cut it when it comes to efficient battery maintenance while dry camping.
Quote: “You do realize that a higher voltage charger delivering 45 amps for 2 hours will use about the same fuel from a generator as a lower voltage charger delivering 15 amps for 6 hours from a generator?”
… It's not that simple. It depends on how much waste is involved. In your case, yes, the 650 is only producing about 4.6a, (550w / 120v = 4.6a), while your charger is using about 2.2a. (13.8v x 15a, / 80% eff., /120v = 2.2a). Add another amp to that for t.v., etc, and you are using about 3.2 out of 4.6a. So, not too much waste. Well done…But a 550w gennie also has its limitations. Try running the microwave, for example, on that 550 watter. If the OP uses a microwave occasionally, the 650 just won’t cut it.
Moreover, any generator, (but especially one with eco mode, like the honda eu20001), will always run at no lower than its normal (or minimum in the eu2000i's case) idle. Therefore, it will be producing at least its minimum amount of available power at any given time. If that gennie is producing say 9a (minimum)of 120v power, it would be very wasteful to only use 3.2a of that 9a. But a 45 amp charger at 14.6v and 80% eff. would draw about 7a. Add the 1a for t.v., etc., for a total of 8a out of the 9.
Now here’s the kicker…My eu2000i, on eco mode, uses about 1/4 of a gallon of gas in 2 hours, so about 88 cents U.S. So, it actually uses 1/2 the gas to power the 45 amper for 2 hours with the 2000i than it does to power a 15 amper for 5 hours with the 650. It's all about efficiency vs. waste.
Quote: “For my case I didn't have to buy another charger to get the higher voltages because I already had the ultra-quiet economical generator ... so why not run it for 5-6 hours at only the 15 amps that the batteries will accept at the stock converter's (that was already in the RV) lower voltage.”
… I believe I just answered that. And you could always use an 85% eff. 25 amper with that ex650, set at 14.4v, and replace the same Ah’s in 1/2 the time, at 1/2 the cost.
Quote: “I think the issue here might be the usual one ... the OP might be in a non-hookup campground (state or federal) that has generator run-time windows maybe only 2-3 hours long ... so a higher voltage charger may be needed to get more amps into the batteries in a shorter time.”
… Thank you for acknowledging that.
Quote: “I don't always drycamp in places like that with generator run-time restrictions, so running an already-owned generator with an already-owned stock 13.8 volt converter for 5-6 hours makes sense”
… NOPE!
“ ... especially since I have faster charging AGM batteries anyway.”
…Numbers don’t lie, but assumptions do in this case…. 5-6 hrs at 15 amps vs. 2 1/2 - 3 hrs at 25 amps with the same ex650.
Quote “If I was to do extended drycamping in a run-time restricted campground, I'd have to supplement my little generator's time with some big engine idling time to speed up the charging during the run-time window.”
… Exactly my point!!! Your method just gets less and less efficient as you try to speed up the process. It’s like using a 10 ton fork lift to move a 10 pound box!
Quote: “The whole point I'm making is that 14.XX charging voltages are not always needed to achieve adequate recharging cycles”
… IF, AND ONLY IF, you are either plugged in to the grid, or enjoy burning money.
“… while at the same time not necessarily slowly ruining one's batteries.”
… But you are ruining your batteries if you never get them truly full. And at 13.8v, that’s gonna take 168 hours of continuous generator run time at an additional fuel cost of $59.00, every two or three weeks!
Sorry, but stock converters just do not cut it when it comes to efficient battery maintenance while dry camping.
