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Messages - GeoffHammond

#1
Bob: Thanks for your time and the response.

The battery is 12x2V cells (Raylite M-Solar series - just a shade under 600kg total weight) and the proprietary interconnects between the cells have a waterproof seal that helps to inhibit corrosion of the terminal and the connector. I can replace one of them with something more accessible, but would prefer not to.

I understand your point about taking a 12V field current from the centre tap of the battery bank versus a sense voltage. My thinking was to use 24V for the field to avoid taking too much current from the small engine's electrical system in case it couldn't cope; in essence, everything would operate at 24V, but with an alternator that has 12V written on the side. Is there anything stopping me from exciting the field with 24V?

I purchased the battery (as a replacement to the pre-existing battery that had died) with the intent of very shallow daily discharge to allow for several days without solar/wind input. Assuming a fully charged battery, we tend to see SOC drop to 90-93% before the sun comes up most of the time. Our major power draw is an excessive number of fridge compressors. In the majority of cases, my solar/wind system brings the battery through a 4-stage charge to float each day. But, in the depths of winter there is an occasional need to ensure absorb and equalise charging happens. I've got too much invested in the battery bank to mistreat it and the current petrol-based charger is simply inappropriate.
#2
My house is powered by a stand-alone energy system: 1kw wind turbine, ~2kw solar, 1050AH 24V battery and an inefficient 240V generator/battery charger. I originally thought I would buy a 24V alternator and baby-sit it (or cobble something via the control circuits of my inverter) through bulk charge and let the solar deal with equalisation charge, but have been convinced otherwise.

I've read mobile_bob's paper on using a 12V alternator to charge a 24V battery and understand enough of it to get excited. It will probably be read several times in the near future.

I have purchased a cheap electric start engine and am now considering my alternator and regulator options. Here in Australia, I can get a second-hand 12V alternator for much, much less than a 24V equivalent. The cell-cell interconnects on my battery would get in the way of using it as a voltage divider as described in mobile_bob's paper and while I could change that, it is my preference not to.

I'm looking at the 24V Sterling regulators and wonder if I could discard the alternator's regulator and replace it with just the Sterling so that the entire thing is operating at 24V rather than the alternator's designed-for 12V. I figure that there will be double the current flow in the rotor field of what it was designed for and this might generate excessive heat and/or annoy the regulator, but will this be excessively annoying?

Imagine that it were doable - with a dual-voltage regulator such as the Sterling, both 12 and 24 volt batteries could be charged with the same unit and just a small amount of fettling, making both my house and my LandCruiser chargeable from the one unit.