Grid Tie Battery Bank - AGM sealed or deep cell?

[russ]

I may look into the Generac but seriously, peak oil planning is really not feasible. We have it good here.

You got it right - this other garbage is loony.

[MrEnergyCzar]

I may look into the Generac but seriously, peak oil planning is really not feasible. We have it good here. The USA will be fine. Our grand-children may have issues, but those who came before us had it much worse. If you don't have children, you have it even better. I have two so I do have some concerns over how they will live. But they'll be fine.

A Generac is a cheap investment for the very rare grid outage. You could always be hit by a storm like in recent years and be out for 10 days, sure. But that's no reason to do the expensive batteries. Use that money and invest it. Your bug-out bag should be a trusted growing investment, not tied up in hardware.

One of the best ways to prepare for peak oil is to make friends with neighbors, attend community functions and to go to church.

Hi Bonaire, how's the Volt running. I'm at 325 mpg, give or take 20 mpg, 17,500 miles.... as a generator, it looks like the Volt only uses about .14 gallons per hour to give 1,000 watts continuous, that may have to be my "generator". The discussion about it is on the front page of the volt forum showing the calculation for gallons used.

[Sunking]

I was talking about the batteries you leave plugged into the AC outlet to keep charged until the power goes out, not sure what you're referring to. My mistake.

One in which can supply a C/8 charge current. They make chargers that go up to 18000 amps @ 48 volts battery. I know because I have built a many of them. Well actually the are Telco Battery Plants

[MrEnergyCzar]

One in which can supply a C/8 charge current. They make chargers that go up to 18000 amps @ 48 volts battery. I know because I have built a many of them. Well actually the are Telco Battery Plants

Can you put a link to what you are talking about? Are you talking about UPS battery back-ups for computer server type stuff? I'm trying to figure out what no one seems to know, where do you get a back-up battery that you have "in" your home plugged into a regular 120v outlet (or 240 dryer outlet would work since my dryer is detached) with it's own built in inverter that is bigger than the 1,800 watt ones? I've searched far and wide. Even Sneiderelectric today told me they only have a ups up to about 1,800 watts, same with Northern Tool. Maybe there is a law banning them being any bigger. It's hard to believe no one has a nice 3,000 watt battery with 100 + amp hours for this purpose.....

Thanks,
MrEnegyCzar

[Sunking]

You can buy a 2 MW UPS if you can afford it, built a many of them. APC Toshiba Emerson Networks, makes them in any size you want.

[MrEnergyCzar]

You can buy a 2 MW UPS if you can afford it, built a many of them. APC Toshiba Emerson Networks, makes them in any size you want.

Wow. Thank you. Ironically, I called the first APC link earlier today and they said they only go up to like 1,500 watts but I'll re-ask tomorrow. So it looks like I'd need a server back-up type once you get above 1,800 watts. This is why I always missed these. Can I back charge this with my volt/generator directly? There would be a normal 10 gauge ac cord with 1,000 watts continuous coming from the Volt into the home where it would be located. Since you built them, I assume you would know that answer better. I guess another way to ask is if they have a normal ac 120 volt plug cord coming out of the back of them? Another impossible question no one has ever been able to answer, can the batteries be continually backcharged while I'm using the unit? Every time I ask they say that's not what it's meant for and that's it. That would determine if I'd have to get two of them and just keep rotating them etc... That's how the battery on wheels (1,800w) works. Why I don't know.

Thanks,
MrEnergyczar

[MrEnergyCzar]

Sunking: After looking at those sites, I'm confused because they don't say the watts or KWH of the battery. The huge ones talk about 5 minutes of coverage. I know I'm going to get slammed when I inquire because I won't understand "VA", I understand watt hours or KWH. Don't bother telling me the formula because it won't help, I just read it. I will call and ask all 3 links you sent, "Do you have a battery system that plugs into the 120v wall that contains 3KW or more of power?". and "can it be charged while being used?" heck, "can it be plugged in to a live 120v outlet while being used?". Any advice on the phrasing language, please let me know. Only you know what type I want.

Thanks,
MrEnergyczar

[inetdog]

Sunking: After looking at those sites, I'm confused because they don't say the watts or KWH of the battery. The huge ones talk about 5 minutes of coverage. I know I'm going to get slammed when I inquire because I won't understand "VA", I understand watt hours or KWH. Don't bother telling me the formula because it won't help, I just read it. I will call and ask all 3 links you sent, "Do you have a battery system that plugs into the 120v wall that contains 3KW or more of power?". and "can it be charged while being used?" heck, "can it be plugged in to a live 120v outlet while being used?". Any advice on the phrasing language, please let me know. Only you know what type I want.

Thanks,
MrEnergyczar

The company will characterize their systems by two parameters:
1. The maximum load they can supply for the length of time that the batteries will allow. Usually in KW, but maybe in Watts for a very small UPS.
2. The length of time that they can supply that load before the batteries are drained to the point that they shut off. May be either in minutes or in hours and fractions. If stated in minutes, convert to fractions of an hour. So 5 minutes = 1/12 hour.

When you multiply the two (KW and H) you get KWH.

Since the loads on a UPS often are not pure resistive loads, they have what is called a low power factor (PF) , a number less than one. If PF = 1 then VA = watts and VA times hours = watt hours or kilowatt hours. Simple arithmetic.
Usually a UPS will also indicate their Watt hour capability as well as their VA-hour capability, but as a first approximation you can consider them to be the same within say 30%.

Because the amount of power you can get from a given battery will be lower at high discharge rates than a low discharge rates. (Called Peukert's Law in the case of Lead-Acid batteries.)
That means that if the manufacturer rates their power output at 5 minutes, you will get significant more power out if you reduce your loads enough to get an hour of runtime or 20 hours of runtime.

When you ask the question, be very clear that you are interested in the KWH capability rather than the KW figure that you mentioned in your example.

... contains 3KW or more of power...

What you want to ask is more like "stores 3KWH of energy". Power is the rate at which energy is delivered. Energy = Power times Time.

[MrEnergyCzar]

OK, after several hours on the phone with APC and another company, here's about the only option. Due to needing certain odd nema plug receptacles, APC has nothing beyond 1.5KW battery. They are out. It appears the best UPS that requires a normal outlet plug and can be charged using a normal power cord from generator is the "Network Extreme Rack Tower Series NXRT-1500." It's main single piece is 1,050watts plus you add on multiple units to expand larger yet it still recharges with normal connections. With these 3 additional add on battery packs, it can provide a constant 350watts (pellet stove & Fridge) for about 6 hours before needed to be re-charged by my Volt. It can still work while being re-charged as well which is key. Thanks for all those that helped with this battery back-up issue. I can probably get the set-up for about $3,000, depends on how many add on packs I get. There's also a great sizing calculator website at Xpcc.com, once there you hit the UPS selector tool. No one talks in terms of stored KWH of energy. They say using Amps and VA is how it's done.

Thanks,
MrEnergyCzar

[Sunking]

Well here is the easy way and less expensive way.

Battery Charger > Batteries > Inverter

Done. It is not rocket science.

[MrEnergyCzar]

Well here is the easy way and less expensive way.

Battery Charger > Batteries > Inverter

Done. It is not rocket science.

Can you tell me what you think of these numbers for my Fridge and Pellet stove and whether or not they can both be run off a pure sine wave 1,000w inverter with 2,000 surge? One of the people said I may not need a battery bank for them.

Fridge: It says Max Load 6.5 amps, 115 volts 60 hz What is the Fridges total highest demand in watts when surging?

Pellet stove: The only info given is it has a 5 amp fuse and runs on 120v ac.

When running normally, on the watt meter, they show about 100 watts each. I've read everywhere Fridges alone need around 2,000 watts typically to handle the surge. Any thoughts?

Thanks,
MrEnergyCzar

[Naptown]

Can you tell me what you think of these numbers for my Fridge and Pellet stove and whether or not they can both be run off a pure sine wave 1,000w inverter with 2,000 surge? One of the people said I may not need a battery bank for them.

Fridge: It says Max Load 6.5 amps, 115 volts 60 hz What is the Fridges total highest demand in watts when surging?

Pellet stove: The only info given is it has a 5 amp fuse and runs on 120v ac.

When running normally, on the watt meter, they show about 100 watts each. I've read everywhere Fridges alone need around 2,000 watts typically to handle the surge. Any thoughts?

Thanks,
MrEnergyCzar

What or who told you that in the big red print.
Count on about 5-10 times the power for starting. If you can find a plate on the compressor that says LRA = ?
That would be the starting current of the compressor.
Finally since we do not work in watts consumed but in watt hours plug the kill a watt into the refrigerator for a week or a few days and same thing for the pellet stove. Divide by number of days to get daily watt hour consumption which is what everything is based on.

[MrEnergyCzar]

What or who told you that in the big red print.
Count on about 5-10 times the power for starting. If you can find a plate on the compressor that says LRA = ?
That would be the starting current of the compressor.
Finally since we do not work in watts consumed but in watt hours plug the kill a watt into the refrigerator for a week or a few days and same thing for the pellet stove. Divide by number of days to get daily watt hour consumption which is what everything is based on.

Oh, yes, I did those long term measurements when I cut my homes electric use 75% before the solar came in. Here are those numbers:

Fridge: Avg. watts per hour: 33, Avg. watts per day used: 792,

Pellet Stove: Avg. watts per hour: 63, Avg. watts per day used: 1,512.

Of course the back of the Fridge is sealed, no exposed compressor, and the manual mentions nothing in terms of electrical. The silver sticker inside says "Full Load Amp 6.5". If that's not the highest amp of the fridge then what does full load mean? If I have to, I'll take apart the back of the fridge and find the compressor, I'm assuming it's behind the steel face guard in back.

Some person on the phone for one of the battery ups companies said I may not need a battery because I told her my max surge was 800 watts. I guess now that's in question.

Thanks,
MrEnergyCzar

[Naptown]

Plug the fridge back into the kill a watt and get a reading with just the compressor and fan running (no door open and not in defrost) Multiply that by 5 and you will get a pretty good indication of what the starting amperage is. Also use the VA function not the watt function so power correction for true watts needed can be calculated.

[MrEnergyCzar]

Plug the fridge back into the kill a watt and get a reading with just the compressor and fan running (no door open and not in defrost) Multiply that by 5 and you will get a pretty good indication of what the starting amperage is. Also use the VA function not the watt function so power correction for true watts needed can be calculated.

That was interesting. The door was closed but running, then something else came on (maybe defrost, clicking sound) and the amp reading went from .3 to 6.4 while the VA reading went from 11 to 740. Then back down to .3 amp and 11 VA respectively. So what exactly do I multiply by 5 to get the starting Amps?

Thanks,
MrEnergyCzar