pianotuna wrote:
Chip,
How much will you have saved when the aims inverter fails?
For the best pricing on Magnum look at iMarine.
Why are you only doing 2000 watts for the inverter?
Look for used telecom batteries. 100 pounds each and 139 amp-hours @ 12 volts. Mine cost $120 Cdn with no core charge. They are a variant on AGM in that they are not an acid starved design.
Is the heat pump 48 volts or would you be running it via the inverter? If via the inverter then the wattage probably needs to be a bit higher--3000 watts.
Thanks for your reply, Pianotuna, and the imarine lead. WOW, you are correct about their low prices. They sell the $2,700, 48v, 4,400 watt Magnum for only $1,529! That sure makes it a horse of a different color. It has the advantage of a built in 60 amp charger vs the Aims meager 15 amp charger or the Outback's 35 amp charger. It also has lower idling (no load) parasitic draw, which is important - 25 watts vs 60 watts for the AIMS (the Outback draws 23 watts, but it is a lower output too). This makes me consider the Magnum over the Outback, as it is a little cheaper and more feature packed, despite it's slightly shorter warranty. I've heard nothing bad to say about the Magnum. I hadn't looked at this model because 4400 watts is clearly overkill for my needs. The 100 amps required to produce a full 4400 watts it is more than my 48v battery bank (8 GC-2s) could provide for more than a few minutes, hence the desire to go with a smaller converter/charger.
Where does one shop for used telecom batteries, and do they come with any guarantee? If I went with 8, 139ah 100lb telecom batteries (wired series and parallel as I assume they are 12v) that would still be 800 lbs of batteries for 278 AH (.35ah/lb), vs 8, S-550s at 984lbs for 428ah (.43ah/lb) though at higher cost. How long can I expect used Telecom batteries to last? I'm sure they are replacing them because they are old and have lost much of their life and capacity, right?
The heat pump runs on native 48v DC drawing 11.5 amps to make 12,000 BTUs of cooling and 12.1 amps for 12,500 BTUs of heating. http://www.geinnovations.net/HSAC_Productline.html I'm looking at the HSAC-12H/C model. This type of AC uses a low-head rotary compressor that scales back its output and current draw based on need. It doesn't cycle like a normal piston compressor so no high current surges are required for start-up. Assuming it runs at full power continually, (an unlikely occurrence) and does not scale back current draw a 200ah bank of golf cart batteries would allow it to run over 8 hours (all night) before the batteries drained to 50% capacity. However with an inverter using considerable battery power, the larger 428ah Rolls bank would be ideal, especially in bouts of bad weather when there is incomplete solar charging. During the day, an elevated 1740 watt solar bank (25+ amps) should be enough to power the AC for several hours during the day as well as at night, without too much power management (reduction of consumption) in other areas.
Like your valid argument against the AIMs inverter, favoring the more durable Magnum - I'd rather pay 3 times as much for new 10 yr Rolls batteries than for ones with 35% less capacity and uncertain life expectancy.
Chip
