Wednesday, July 06, 2005

Using an inverter for emergency power is by far the most common use. The Hurricane season is here for those of you in the east and down south. I hope that this article will help all of you to be more prepared in the likely event that power failure occurs. Here are some helpful tips about running an inverter during a power outage.


Before you purchase an inverter you will want to take a piece of paper and a pen and write down all of the appliances that you feel are necessary to have during a power outage. After you write down all that you need to run go to each one of the appliances and look on the back or bottom for what is called the service tag. This tag will show you a few important specs that help with picking the correct size of the inverter. The first spec that you will most likely come across is the voltage this will either be 110,115, or 120vac.

In some cases you may find that the voltage is between 205vac and 240vac. You will need a special inverter to run this appliance. We will get to that later.

The next spec you will find will be the Amps. For example this should read like this 6.0a or 6.0 amps. What you will do now is take the volts lets say 115 and multiply by amps 6.0 and this will give you 690 watts. The equation should look like this Volts x Amps = Watts or in this example 115 x 6.0 = 690. Ok, Now that we got that out of the way we can start sizing an inverter that is going to work well during a power outage.

The most common inverter sold for emergency home back-up power is a 2000 watt. The reason for this is that most people want to hook them up to there car and the 2000 is perfect for most vehicles and will run most appliance's. When you hook the inverter up to your vehicle to run the inverter you will want to try to keep the inverter close to the battery and out of any weather. I get a lot of calls about why inverters sometimes won't work when they are hooked to the vehicle this way. Most people hook these up with jumper cables. This is not the best way to do this. Jumper cables do not give a proper connection to the inverter. The best way to hook them up is with a ring terminal that fits properly over the inverter post.

Next we have to cover how the battery will hold a charge. You will want to keep the vehicle running while the inverter is hooked up. This will allow the vehicles charging system to keep a charge on the battery while the inverter is in use. If the car is off the inverter will still work. However, for prolonged use the inverter will work best if the vehicle is running. This just about covers using an inverter for emergencies with a vehicle.

When using an inverter for emergency back-up power in a home without a vehicle there are a number of ways to accomplish this. First you can have say two 12 volt batteries and hook them in parallel and one inverter. This will give you enough power to run say a reproduction off and on for two days or so depending on the size of the batteries. If you decide to do this you may want to have at least one back-up battery for the system in case power failure exceeds your battery time.

The next option is for complete home back-up. This is the best option but one of the most expensive. The system will require a large bank of batteries at a higher voltage say 24 volt or 48 volt. However, they do make 12 volt systems but they are less efficient. The best batteries to use in a large bank like this are the 6 volt batteries either made for solar or golf carts. They have a much higher reserve time and are cost effective. The next component is an inverter/charger. These are great for home back-up they have three key components. The components are an inverter, a charger, and a transfer switch. They come in sizes ranging from 1500 watts to 5500 watts. The battery chargers that are included range from 70 amps to 150 amps and will charge the input DC voltage of the inverter. This system is a lot more complex then that of a inverter and battery. Most of the inverter/chargers do not have built in AC outlets and require an electrician or professional solar installer to hook them up.

The way that the inverter/charger will work is that the inverter will work when the power is off and the battery charge will charge and maintain the batteries while the power is on. Since the battery charger that is included is a three stage battery charger with smart charging capabilities it is safe to leave the batteries hooked up to this at all times. The internal transfer switch will allow for automatic switching. This means that you will not have to do anything when the power goes out. The inverter/charger will start running all of the appliances you have selected all by itself. Even though the inverter/chargers are more expensive they are much more convenient and you won't even know that the power went out.

Now that we covered the home back-up without a vehicle lets talk about 240vac appliances. Even though there are inverters that will work for this you may want to consider not running them during a power outage because of the large draw from the batteries that they have. If you must run a 240 vac appliance you will want to have a complete separate system from the 110vac inverter system that is running the common household appliances such as the refrigerator or lights.

I hope that this entry will help those of you who are faced with hurricanes and other sources of power outages. You can find a great selection of power inverters at www.donrowe.com. Any questions or comments would be appreciated.

14 comments:

johneyharolds86086918 said...
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room air conditioners said...
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Anonymous said...

Question about power inverters. I purchased a 400 Watt inverter today. My purpose in purchasing it was to be able to power up a 12" color (portable) TV at a tailgate. I plan to run the inverter through the cigarette lighter on my car. My question is ... does the car have to be running continually in order for the TV to operate thru the inverter? When I simply turned the ignition to on, the inverter would not come on ... am I doing something wrong? I can't imagine trying to watch scores and maybe even a few games at a tailgate with the car engine running continually. Talk about fumes and carbon monoxide! Please let e-mail me and let me know if you have any suggestions on how I might operate the TV safely without leaving the engine running the entire time. (P.S. My car is a 2003 Lexus ES300 .... does that make a difference on connecting power inverters to the cigarette lighter??) My e-mail address is vickigalloway2004@yahoo.com

mohawk-griffiss squadron said...

Can we charge the battery bank from a high out put alternator while the external AC is connected to an inverter/charger?
Also is there an inverter/charger available that has hard wired dual 110V outputs that can feed a typical home type distribution panel?
Thanks

jon said...

Can we charge the battery bank from a high out put alternator while the external AC is connected to an inverter/charger?
Also is there an inverter/charger available that has hard wired dual 110V outputs that can feed a typical home type distribution panel?

Yes, The Batteries are able to accept a charger while the inverter/charger is drawing Dc current off of them. There are inverter's available that can be hooked up to the main panel in a home. You will need an inverter that has dual AC voltage capability 120/240vac. There is also another option available by Xantrex and this is to use two Trace DR series inverters connected in series and the Ac output wired through the Trace t240 auto transformer. This will allow the two inverters to supply the main panel in your home with 240vac and it will split the voltage to dual 110vac in the panel. You can find more information about the Trace DR series inverter/charger's at http://www.donrowe.com/inverters/dr_series.html. Please let me know if you have any further questions. Thank you for looking at my blog. have a great day.

Jon

Joseph said...

Your site explains things very clearly. I have a 230 volt submersible pump (my water source) that I would like to operate in power failures, along with my freezer and a few other essentials. You suggest trying to leave the 230 volt equipment out of my strategy, but these two are pretty basic. What would you recommend? If I set up a 230 volt system, can it more simply be used to run 115 volts? Where can I find inverter info of that type? I have found ones at 50 hertz and suspect that they are European.
Thanks for taking the trouble. It is very helpful.

Paul said...

Question: I have a portable generator w/ 12v DC receptacle...can I operate a 5000W inverter from the 12v DC receptacle on the generator? Responses appreciated to plepard@navenewell.net

Anonymous said...

how long can I charge two batteries of 12v connected together to an inverter of 700w and a hydro mains supply of 220-250v

paulseny said...

Is there a minimum or maximum time for recharging a 2-battery bank (12v each or 6v each)connected to an inverter. NB I recharge using a hydro mains source of 220-250v.

paulseny said...

My 2 batteries(12v)cannot last the inverter power supply for more than 3 hours when they could do so for more than 7 hours just 3 weeks ago when I had just bought them. Please, what could be the reason.

paulseny said...

Jon, before you answer the question on the 2 12v-batteries that last less than 3hrs where they lasted 7hrs just 3 weeks ago when they had just been bought, I forgot to tell you the load is just a 20" colour tv, a decorder, satelite dish and 2 bulbs totaling 20w. The load as not changed.

Anonymous said...

I jon i have a 5000watts wagan inverter,can i connect a ten 10amps charger to the inverter to give the battery a continues charge while it is running.

Robby,