Run Whole House on Wimpy Generator?

[redpoint5]

Originally Posted by freebeard

Foundation is five lodgepole pine lashed together at the top, and spread apart to make pilings. Five compound curve hexagonal shells leaned together. Half-hex decks swing up to make shutters over the fenestration. Windmill at the top should be an hyperboloid Ugrinsky turbine.

Start whenever you can.

I'll start with repairing the 2 "extra" holes I put in the ceiling, and 1 in the wall, and build on that momentum.

[cRiPpLe_rOoStEr]

Originally Posted by redpoint5

My dream is to own property along a river that has a small stream sufficient for micro-hydro power generation. 100% electric house, with no dependency or connection to the utility. Saving $200 in gas/electric per month sounds good to me, not to mention the savings of having EV cars and free electricity.

Of course that would be cool, but if I were doing that I would also probably feel tempted to brew some alcohol, both for drinks and for motor fuel. And it would be also nice having a chance to grow some food.

[redpoint5]

Originally Posted by cRiPpLe_rOoStEr

Of course that would be cool, but if I were doing that I would also probably feel tempted to brew some alcohol, both for drinks and for motor fuel. And it would be also nice having a chance to grow some food.

Sounds good, you're invited.

[mort]

From the description, I don't see any mention of capacity measure. I'm not sure how one would extrapolate capacity from an internal impedance measurement. I could be wrong, but I only know to measure the drain on a battery to determine the remaining capacity.

From the blurb:

It measures the actual cold cranking amps(CCA) ,capability of the battery,the State of Health(SOC),the State of Charge(SOH)

It does compute the CCA from the internal resistance. The formula used is
CCA = 3051.85 / R where R is in μΩ. Which you can do in your head.
This meter can measure the internal resistance of the battery, which you can't do with just an ohm-meter. I assume your resistive CCA meter is a smokin' hot load.

If the battery has a stated CCA you enter that and it tells you % of capacity. Which you can do in your head too.
-m

[RedRyder]

The two weak points in you initial experiments are going to be the inverter and the battery plant.

- I tried to run an efficient chest freezer on a good-sized portable inverter during a power failure. The inverter's electronic protection circuit immediately tripped out at every attempt. The inverter could easily have RUN the freezer based on Kill-A-Watt readings, but was incapable of STARTING it. Make sure an inverter is chosen with enough surge capacity to start motor-driven appliances if needed, such as a refrigerator or a well pump.

- Mixing and matching reclaimed batteries is a recipe for disappointment. When connecting batteries in parallel, a strong battery will discharge itself trying to "top up" the charge in a weak mate. That's why it is strongly recommended to always replace batteries in matched sets.

Sure, you could test pallets full of discards to find some equivalent batteries to mate, but do you want to spend the rest of your your life nursing batteries? The only upside is that you are getting them for free.

One cheap source for getting working but used deep cycle batteries for stationary use recommended online has been buying big 6-volt pulls from a golf-cart service vendor. I have not investigated this myself.

- Also, lead-acid batteries are not good for some of these applications. Running LED lighting with a steady resistive draw, OK. Please note that most deep-cycle batteries (not starting batteries) are rated at C/20. This means that a 100 amp-hour deep cycle battery should provide 5 amps for 20 hours to depletion. You cannot expect a 100 AH battery to provide 100 amps for 60 minutes.

Also, lead-acid batteries do not "come back" after repeated deep discharges. I looked at one premium manufacturer's graph for deep-cycle recovery, and if discharged to depletion (defined as about 1.75 volts per cell, or 10.5 volts on a 12 volt, 6 cell battery), the batteries could be expected to recharge only about 3 times! If lightly discharged, they would come back hundreds of times.

Most RVers and off-grid users set personal limits of only discharging deep cycle batteries down to 80% full or at worst 50% full in order to extend cell life. Stopping at 50% full, a 100 AH deep cycle battery provides 5 amps for 10 hours, or 2.5 amps for 20+ hours.

I don't want to discourage you, I myself fully intend to back up a semi-reliable grid connection with generator, battery plant, and inverter. That is 2/3 of a solar system. Just add PV panels and a charge controller. But go into this with your eyes open, and do your research.

Experiment on the cheap, but be prepared to spend for quality permanent components if you want to sleep peacefully at night. My "on the cheap" experimenting has started with a pair of 2kW portable inverter gennys that can be paired, and converted from gasoline to propane. I need to figure out how to get 240 volts for the well pump, either using a big transformer to step up the voltage, or maybe a smaller transformer to 'trick' the inverter gennies to output opposite phases for the necessary Line 1 and Line 2 hot outputs.

There are also new battery chemistries that are interesting. Lithium Iron Polymer (LiFePO) batteries support high current output and multiple recharges, but are still very $pendy. And the light weight of LiFePO cells is not a factor for stationary battery plants.

[hayden55]

Originally Posted by redpoint5

Well, I raided my dad's battery pile as well as the unused farm equipment and filled the rear hatch area with about 18 or so. Unfortunately all 3 of the large tractor batteries were sitting at ~2v or less. 2 of them had sufficient electrolyte levels though (no exposed plates). Curious if either will take a decent charge.

Half the car batteries were at 11v or more, so some likely have some life to them.

Anyone have a methodology to test capacity that doesn't involve deeply discharging the battery? Perhaps target a 75% voltage as the discharge cutt-off and extrapolate capacity from that?

Know where to get top dollar for the scrap value? I don't see batteries mentioned on the webpage of the local metal scrapyard, but it's also not on the prohibited list.

If a lead acid is below 11V its really not even on the scale anymore. Scrap them for lead for a good price. Its more than the $10/ battery core they give you. The local recycling place will take those batteries, aluminum wheels etc...

[hayden55]

Depends on what you're going to want to run on said generator. But, if you could get a whole home inverter that would start a 240v range or ac plus about 500 watts running at the same time you would have it (typically about 5000-6000w. Then you would just need a string of batteries connected that could handle the peak load, and then probably just charge the batteries from the generator.
Or you could get the 240v appliances figured out. A variable refrigerant flow hvac unit would be able to run in reduced capacity mode all day long depending on programming greatly reducing the compressor starting spikes in load to maybe even just one for a said period of time. A clothes line would solve the dryer issue. a Single burner induction stove top would solve the range oven issue, Then if you have a grill you could bake with it if needed. Gas water heater etc...

With all of the new advancements in technology now i would love to do a $375 homestead credit house out in the woods outside of the city (by say 20 minutes). Stick to 120v appliances, an external intake and exhaust wood stove, a 120v vrf hvac unit, a 2000w honda generator, a heat pump based 120v water heater, a whole home inverter, some batteries to weather a set amount of days without sun, and a small amount of solar panels and you are there.
You would have to figure out rain water and septic systems as the authorities hate you drinking rain water or doing any sort of septic system outside of one on land that passes a perc test and has the inground tanks($$$)
(outhouses are not approved lol)

[redpoint5]

Originally Posted by hayden55

Depends on what you're going to want to run on said generator. But, if you could get a whole home inverter that would start a 240v range or ac plus about 500 watts running at the same time you would have it (typically about 5000-6000w. Then you would just need a string of batteries connected that could handle the peak load, and then probably just charge the batteries from the generator.

The only thing I have that takes 240v is the oven and AC (luxury appliance I rarely use). Even the range is gas (weird they didn't go gas oven). Everything else could be run from a 3,000 watt inverter, and possibly smaller. TV and lights is probably 200 watts. Fridge is a hundred typically. HVAC is 700 watts for the blower.

So, I don't need 240v.

It was nice to have dual energy sources during the power outage. Never really thought about it before, but it builds another layer of resiliency. If I had installed the right carburetor on the genset my dad loaned me, the house could have been 100% powered from the natural gas line.

[RoadRaceJosh]

I have all of the equipment to do what you've said you want to do. I have a 2kw inverter/charger with a support/generate function. It works like this... You program the inverter with the amount of generator/shore power available down to 10 amps. This works perfectly with my 1200 watt Honda. The generator is running and powering everything through the inverter bypass. If you say press start on the microwave and the house requires more than 10 amps the inverter will draw from the battery to support the load and supplement the generator. When the load drops the surplus is then used to charge the battery. This inverter was not an inexpensive piece of equipment like the inverters you cite. Mine is meant for boats and RVs with limited shore power.

In your case I would find a large 12V alternator and engine to charge the batteries as needed. Add some solar if you like to help keep the fuel consumption down. Under normal grid conditions you can use the solar with a zero-export inverter to power household loads.

[hayden55]

What inverter are you using?