More battery/converter/inverter questions
As many of you know I have been asking many questions and greatly appreciate all of your inputs. It seems the more I read the more questions I have. I have ordered a Mega Watt PS to Top Charge and EQ ...
Forum Discussion
Say you know your daily AH usage is about 70AH and you want a fast recharge off generator. So you want to operate in the 50-80% SOC zone where the batts can accept full amps.
To recharge every day, that means 50-80=30% is 70AH so 100% is 233AH
Great. Grab a pair of Interstate 6s (232AH) Now say you only want to do your recharge every second day. So you will run 140AH in two days but still want that to be a 50-80. So grab a second pair of 6s and now your bank is 464AH.
Now how long do you want that 50-80 recharge to take? My ugly graph posted here and there shows doing a 50-80 on 220AH with smart chargers will take 60min with a 70a charger, 79 min with a 55a, and 117 min with a 35 amper.
Double those times for the same amps on four batts for the 50-80. Or you can double the amps on the four that you used on the pair and get the same times as with two batts. Ie to do a 50-80 on four in an hour you need a 140a charger
Now you need enough generator to run that many amps that you need for the time you want the 50-80 to take. Here is where you have a fixed limit and may already have that generator, so you might have to work back from that to see what you can do.
Say you have a Honda 2000 and it will run a 70a charger but no more. So you can see that if you want to do your 50-80 in an hour you must recharge every day and only have the two 6s. If you choose to recharge every second day with the 70amper on four batts it will now take you two hours.
So you have to juggle battery bank size, generator size, charger size, and fit that all within your generator running time, which may not be up to you. EG here the provincial parks allow two hours of gen time 9-11am and 6-8pm.
If you want to do your 50-80 in the morning (it is dark out 6-8pm in the "winter" here, so who wants to go out there in the dark and maybe rain to play with chargers and generators?) then you are working with a two hour limit.
So going back to your choices, you can see that to get your 50-80 done in two hours you have to have that 70 amper and the 2000 gen. BUT--bad news! In winter your 70AH a day just went to 140AH day now that you need 70AH for the furnace and keep doing everything else the same as in summer. Drat! Now you need 140a charger, four batts, and a gen that can run 140a recharging.
Of course you must always have enough of everything so you can at least do one day before recharging so you don't run out of battery at 3am on a winter night.
EG camping here in February, we use nearly 200AH a day, so on four batts that means a recharge every day, and the Honda 3000 can do 130a.
I do 50-90s so that adds time (doubles it!) over a 50-80 but gives us another 10% of 460 or 46AH to be part of that 200AH we used. 40% of 460 is 184AH so close enough to our daily usage.
With 140a it will take about 130minutes to do that 50-90 so we have to cheat and run over the time by 10 minutes. Except we only have 130a so we need to cheat for longer. (No sweat--at that time of year we would usually be the only ones camping in the whole park and nobody cares about the two-hour generator times. :)
To recharge every day, that means 50-80=30% is 70AH so 100% is 233AH
Great. Grab a pair of Interstate 6s (232AH) Now say you only want to do your recharge every second day. So you will run 140AH in two days but still want that to be a 50-80. So grab a second pair of 6s and now your bank is 464AH.
Now how long do you want that 50-80 recharge to take? My ugly graph posted here and there shows doing a 50-80 on 220AH with smart chargers will take 60min with a 70a charger, 79 min with a 55a, and 117 min with a 35 amper.
Double those times for the same amps on four batts for the 50-80. Or you can double the amps on the four that you used on the pair and get the same times as with two batts. Ie to do a 50-80 on four in an hour you need a 140a charger
Now you need enough generator to run that many amps that you need for the time you want the 50-80 to take. Here is where you have a fixed limit and may already have that generator, so you might have to work back from that to see what you can do.
Say you have a Honda 2000 and it will run a 70a charger but no more. So you can see that if you want to do your 50-80 in an hour you must recharge every day and only have the two 6s. If you choose to recharge every second day with the 70amper on four batts it will now take you two hours.
So you have to juggle battery bank size, generator size, charger size, and fit that all within your generator running time, which may not be up to you. EG here the provincial parks allow two hours of gen time 9-11am and 6-8pm.
If you want to do your 50-80 in the morning (it is dark out 6-8pm in the "winter" here, so who wants to go out there in the dark and maybe rain to play with chargers and generators?) then you are working with a two hour limit.
So going back to your choices, you can see that to get your 50-80 done in two hours you have to have that 70 amper and the 2000 gen. BUT--bad news! In winter your 70AH a day just went to 140AH day now that you need 70AH for the furnace and keep doing everything else the same as in summer. Drat! Now you need 140a charger, four batts, and a gen that can run 140a recharging.
Of course you must always have enough of everything so you can at least do one day before recharging so you don't run out of battery at 3am on a winter night.
EG camping here in February, we use nearly 200AH a day, so on four batts that means a recharge every day, and the Honda 3000 can do 130a.
I do 50-90s so that adds time (doubles it!) over a 50-80 but gives us another 10% of 460 or 46AH to be part of that 200AH we used. 40% of 460 is 184AH so close enough to our daily usage.
With 140a it will take about 130minutes to do that 50-90 so we have to cheat and run over the time by 10 minutes. Except we only have 130a so we need to cheat for longer. (No sweat--at that time of year we would usually be the only ones camping in the whole park and nobody cares about the two-hour generator times. :)
