Forums

Using Batteries as a "Buffer" to Stabilize Grid Electricity

Started by Robert Miller November 15, 2017
Robert Miller <rmiller@teledyne.com> wrote in <ouj17l$oau$1@gioia.aioe.org>:

>A friend of mine lives in a remote area. The power grid voltage >fluctuates causing problems with his equipment. He has tried line >filters with no success. > >I suggested using a bank of SLA batteries as a "buffer". > >IOW a grid-connected charger would keep the batteries topped up and >current could be redrawn via a 110V inverter to power appliances. > >In a nutshell, what would be the design criteria and limitations of such >a system? > >To what extent would it be practical to power an entire house? > >Robert Miller
You have to specify min max and duration of disturbances. There are many ways, apart from Tesla for long outrages, for just variations in voltage some of these may or may not work.... https://www.ebay.com/sch/i.html?_nkw=ac+line+voltage+regulator At the top end building your own nuclear plant and making plutonium and developing the bomb and then declaring independence may get you support from the US weapon lobby MIC. At the low end buy a Honda generator and store up on petrol. Price of petrol will go up with republicans in power, so buy long running call options on it too. You cannot go wrong, can always sell the fluid for more. And you can cook on it too, and run a car on it. reps do not care about air pollution, so you will be fine. Sell electrickety to your neighbors and use the money for ura.. OK
On Thursday, November 16, 2017 at 3:21:21 AM UTC-5, Martin Brown wrote:

> > It would make much more sense to protect only the equipment that is > prone to line fluctuations rather than the whole house. > > > Regards, > Martin Brown
+1 Dan
Robert Miller <rmiller@teledyne.com> wrote:
> A friend of mine lives in a remote area. The power grid voltage > fluctuates causing problems with his equipment. He has tried line > filters with no success. > > I suggested using a bank of SLA batteries as a "buffer". > > IOW a grid-connected charger would keep the batteries topped up and > current could be redrawn via a 110V inverter to power appliances. > > In a nutshell, what would be the design criteria and limitations of such > a system?
An Online UPS does exactly what you need. The limitation usually would be the amount of power it can supply (dependent on the electronics) and the time it can supply that (dependent on the batteries).
On Thu, 16 Nov 2017 14:38:31 +1100, Robert Miller
<rmiller@teledyne.com> wrote:

>A friend of mine lives in a remote area. The power grid voltage >fluctuates causing problems with his equipment. He has tried line >filters with no success. > >I suggested using a bank of SLA batteries as a "buffer". > >IOW a grid-connected charger would keep the batteries topped up and >current could be redrawn via a 110V inverter to power appliances.
I had that configuration in my last building, just for the computers. 80amp, 13.8volt Parallax Intellipower supply feeding 4 100amp-hour AGM batteries feeding a 1kW inverter. This was on-line all the time. It worked perfectly but since the input to output efficiency is only about 60%, I paid the cost on my electric bill. It was hidden in the $1000+ restaurant electric bill so I didn't much care. When I retired and moved up here to the mountains, I could not afford that arrangement. Here I have a 2kW standby UPS connected to 2 sets in parallel of 100 amp-hour AGMs to make 24 volts, 200 amp-hours. Next I divided the house into two parts. Using nuclear terminology, the vital bus and balance of plant bus. The vital bus is connected to the UPS and has all my lighting, refrigeration and computer hardware on it. The BOP has everything else. I also installed a 10kW Generac automatic standby generator. If I had it to do over again, I'd install a larger Onan. The Generac is very loud and is a bit undersized. When the line goes out, the Generac controller waits 10 seconds to make sure it's an outage and not just a recloser burping. It starts the engine, waits 5 seconds and throws the automatic transfer switch. The controller has the ability to shed up to 4 loads to prevent overload. I only have one channel connected to the electric water heater. If the central AC and the well pump are running, the water heater will overload the generator. The controller will reconnect the water heater when there is available capacity. My vital bus only has to run on the UPS for about 20 seconds. I keep the large battery bank installed for in case there is a problem with the generator. I have a backup 5.3kW generator that I can roll out and connect manually. No AC on that configuration. If everything else fails, I can drag out my Cordless Battery Charger http://www.neon-john.com/Generator/CBC/CBC_home.htm The page shows the first prototype that used a commercial analog controller. I made and sold several of these things and for them I designed a custom controller capable of 12, 24 and 48 volts. In this instance,the CBC would be used to charge the UPS batteries. This is probably excessive for the city dweller but way up here in the mountains, the power goes off at least every week. The longest it's been off since I've lived here was 9 days.
> >In a nutshell, what would be the design criteria and limitations of such >a system?
See above.
> >To what extent would it be practical to power an entire house?
Only if you have cubic dollars! Depending on how large your house is, you'd need probably a 20kW UPS with 240/120 output. The alternative is something similar to what I have. You'd need to measure the volt-amps drawn by each load and in the case of HVAC, the starting VAs. All them all together and add in a safety factor and you have your generator size. The generators are rated in watts but the reality is they have to supply the VARs for any reactive load. They assume a power factor of 1.0. A 20kW Cummins will cost you about $5k from Norwall. https://www.norwall.com/products/Cummins-Quiet-Connect-20kW-Air-Cooled-Home-Standby-and-200-Amp-SE-Rated-Automatic-Transfer-Switch-RS20AC If you install it yourself, figure a couple hundred bux for supplies. It'll cost you around $4k to get it installed by a contractor. Plus you'll need a propane tank. I recommend a 500 gal buried tank. I recommend buried because increasingly, punks are taking shots at above-ground propane tanks. A few weeks back, a "deer hunter" punctured a 250 gallon tank. There was a good breeze that day so no fire but it was touch and go until the tank emptied itself. John
> >Robert Miller
John DeArmond http://www.neon-john.com http://www.tnduction.com Tellico Plains, Occupied TN See website for email address
On 17/11/17 05:20, Neon John wrote:

> I had that configuration in my last building, just for the computers. > 80amp, 13.8volt Parallax Intellipower supply feeding 4 100amp-hour AGM > batteries feeding a 1kW inverter. This was on-line all the time. It > worked perfectly but since the input to output efficiency is only > about 60%, I paid the cost on my electric bill. It was hidden in the > $1000+ restaurant electric bill so I didn't much care. >
Yep, that was about what I had in mind. A scalable UPS. Thanks for your detailed explanation.
> Plus you'll need a propane tank. I recommend a 500 gal buried tank. I > recommend buried because increasingly, punks are taking shots at > above-ground propane tanks. A few weeks back, a "deer hunter" > punctured a 250 gallon tank. There was a good breeze that day so no > fire but it was touch and go until the tank emptied itself. >
More like "torch and go" I would say. Robert Miller
On 11/16/2017 01:20 PM, Neon John wrote:
> On Thu, 16 Nov 2017 14:38:31 +1100, Robert Miller > <rmiller@teledyne.com> wrote: > >> A friend of mine lives in a remote area. The power grid voltage >> fluctuates causing problems with his equipment. He has tried line >> filters with no success. >> >> I suggested using a bank of SLA batteries as a "buffer". >> >> IOW a grid-connected charger would keep the batteries topped up and >> current could be redrawn via a 110V inverter to power appliances. > > I had that configuration in my last building, just for the computers. > 80amp, 13.8volt Parallax Intellipower supply feeding 4 100amp-hour AGM > batteries feeding a 1kW inverter. This was on-line all the time. It > worked perfectly but since the input to output efficiency is only > about 60%, I paid the cost on my electric bill. It was hidden in the > $1000+ restaurant electric bill so I didn't much care. > > When I retired and moved up here to the mountains, I could not afford > that arrangement. Here I have a 2kW standby UPS connected to 2 sets > in parallel of 100 amp-hour AGMs to make 24 volts, 200 amp-hours. > > Next I divided the house into two parts. Using nuclear terminology, > the vital bus and balance of plant bus. The vital bus is connected to > the UPS and has all my lighting, refrigeration and computer hardware > on it. The BOP has everything else. > > I also installed a 10kW Generac automatic standby generator. If I had > it to do over again, I'd install a larger Onan. The Generac is very > loud and is a bit undersized. > > When the line goes out, the Generac controller waits 10 seconds to > make sure it's an outage and not just a recloser burping. It starts > the engine, waits 5 seconds and throws the automatic transfer switch. > > The controller has the ability to shed up to 4 loads to prevent > overload. I only have one channel connected to the electric water > heater. If the central AC and the well pump are running, the water > heater will overload the generator. The controller will reconnect the > water heater when there is available capacity. > > My vital bus only has to run on the UPS for about 20 seconds. I keep > the large battery bank installed for in case there is a problem with > the generator. I have a backup 5.3kW generator that I can roll out > and connect manually. No AC on that configuration. > > If everything else fails, I can drag out my Cordless Battery Charger > http://www.neon-john.com/Generator/CBC/CBC_home.htm > > The page shows the first prototype that used a commercial analog > controller. I made and sold several of these things and for them I > designed a custom controller capable of 12, 24 and 48 volts. > > In this instance,the CBC would be used to charge the UPS batteries. > > This is probably excessive for the city dweller but way up here in the > mountains, the power goes off at least every week. The longest it's > been off since I've lived here was 9 days.
The Chevy Volt makes a handy portable genset with 15kWH backup battery capacity. Plus you can also drive it!
On Thursday, November 16, 2017 at 12:46:51 AM UTC-8, mike wrote:
> On 11/16/2017 12:20 AM, Martin Brown wrote:
> > ... The way we did it for > > big telescopes was to have a reinforced flywheel going at a fair lick > > driven by an electric motor driving a dynamo. If the mains fails the > > clutch decouples the motor and the stored energy in the flywheel is used > > to stow the scopes and shut down the computers gracefully.
> About 30 years ago, I attended a trade show where they > exhibited flywheel systems. > I never understood how it was possible, and they sure didn't want to > tell me, > but they claimed that they wrote magnetic domains on the "flywheel" > in real time so that the output frequency was RPM independent as the > energy was extracted as a PM AC generator.
Yep, it's a printed-pole generator. Those used to be standard for big computer rooms; I knew an architect who had to reinforce a concrete room in a new building, to hold one. Not a spectacularly bad idea, but you don't want to miss the bearing maintenance schedule. Even older systems used an AC motor to drive a DC generator, with field winding modulation at the generator, to regulate computers' DC power. Half a century ago, that made sense.
On 2017-11-16, Robert Miller <rmiller@teledyne.com> wrote:
> A friend of mine lives in a remote area. The power grid voltage > fluctuates causing problems with his equipment. He has tried line > filters with no success.
he nees an AVR -- This email has not been checked by half-arsed antivirus software