Re: Preventative maintenance and possible battery upgrade
Reply #61 –
Hanna and Tyler, I hope this helps. My "guess" to answer your question of how long to charge two 8ds, from 50% to 100% state of charge, with an 80 amp smart charger, is the following, 5 hrs (to 90%). In real life you will only probably go to 80-90% as the topping off would take to long. The topping off will be done when you are plugged in. East Penn is saying 4.8 hrs to take one battery from 0-90%. So let's use round numbers, two 8ds 9.6 hours, from 50-90%, 5hrs.
And so....since in an earlier responce you said,
"As far as electricity consumption, we really don't use all that much because all of our lights are LED and we can run the refrigerator and furnace off of propane if need be. Other than using a laptop during the day for Hanna's job and in the evening for shows we don't use much electricity."
I believe your goal to run the generator ⁷each day less than 2hrs is a real possibility. Especially with the Victron 712, you will easily, on your phone, see the net # of how many amps you are putting in and how many you are using. I learned along time ago, "it is difficult to improve, what you do not measure." This data will help you conserve electricity.
For the most useful information, check out the following Lifeline Technical Manual, "charging" section, page 19, of this Lifeline manual. Although not the brand you are buying, I've used this as my agm bible now for over 10 years. I'd ignore the section on conditioning or equalization as this is specific to Lifeline. The Lifeline manual recommends a 100 amp charger minimum, for two 250 amp lifelines if you plan on going below 50% depth of discharge. I think you will be fine with the 80 amps, as you stated you plan on charging from 50 to 100% charge. I charge my 3 8Ds with 100 amps and I also never go below 50% state of discharge. East Penn even gives data with less than an 80 amp charger to calculate charge times.
Check out page 3, chart B, from East Penn file 0139.pdf below. "For example, to charge an 8G8D (curve H) to 90% in 3.5 hours, 100 amperes are required; at 35 amperes, it would take 10 hours".
Double the times for two batteries.