Power Inverter

xxxbadfishxxx · #1 12/15/2007, 04:28 PM

Just picked up a Black & Decker 750 watt Power Inverter as a back up plan to run my tanks during a power outage. I will need to run an MJ900 & 50 watt Heater on the nano, and a MJ1200 & 150 watt heater on the 50 gallon.

My question is, how long can i run it off the car battery without the car running, or does the car always need to be running? In the event of a power outage, i dont think i want my car running overnight if it doesnt need to be.

http://www.safehomeproducts.com/shp2....asp?id=159192

Konadog · #2 12/15/2007, 05:44 PM

The problem with inverters are that they don't work well with heaters. Small heaters are a constant drain, and most don't work at all. Now with just a few powerheads, you should get quite a few hours depending on the battery.

xxxbadfishxxx · #3 12/15/2007, 07:12 PM

even with the car on will the heaters drain it? From what i understand Water Movement is the most important thing during a power outage, correct?

Snowboarda42 · #4 12/15/2007, 07:34 PM

Even with the car on, the battery will still drain. Unfortunately, car alternators only work if the car is above 1100 rpm (average), anything below that and it is not charging, just running off the battery. Again, it all depends on the car and the alternator's amperage. You might be better off with a generator.

xxxbadfishxxx · #5 12/15/2007, 08:43 PM

So is the inverter not really worth it? It was $65 and if its not really going to work, i would rather return it. Can't really afford a generator. We have been living in the house for just over a year now, and the power only went out twice for two hours. We have underground powerlines, so we might not get as many power outages as others.

usmc121581 · #6 12/15/2007, 09:03 PM

If you were to do that you would blow the diode's. think of it has having a car stereo system. If you run a amp that big without the car on it will drain that battery in less then 30 mins. If you keep the car running with it plugged in the inverter will run off the alternator not the battery. The only time the battery is used in a car is to start it. When you start your car it takes so much out of the battery. Once the car turns over the alternater kicks in, to keep a charge on the battery. You can get away with it. But just think your alternator will work twice as hard, meaning you will eventually blow it and have to replace it.

iairj84 · #7 12/15/2007, 09:20 PM

I dabble quite a bit in car audio and I can say without a doubt that unless you've upgraded your alternator when running under load like a large inverter you WILL be using your battery, not a ton and it won't drain more than likely but you will be using it... Which is fine. Have you ever seen a car with a loud system driving by? more than likely you will notice their headlights dimming as the bass hits same goes with an inverter as opposed to an amplifier... Very similar concepts. 750 watt running at it's full voltage probably will not cause the battery to be needed but much more than that and you better believe it.... You're right about it working twice as hard though. I wouldn't say a power outtage every couple weeks max would kill his alternator. I have the stock alternator and about 1500 watts total (MAX about 1000 RMS) and haven't had to replace the alternator in the two years I've had it, and it's the original alternator as the owner had all the previous records.

You also need to think about safety when using inverters or any other high powered Amp. You will need to hook that directly up to the battery or you won't get anywhere near 750 watts out of it. I've seen 1200 watt inverters that give you a cigarette lighter plug and it won't work. Anything over about 3-400 watt will easily be overloading a cigarette lighter circuit. It's only running probably 16 maybe even 18 gauge wire to the plug and probably a 20 amp fuse which is not anywhere near sufficient for that kind of power. Get at the very least 4 gauge wire to connect to the battery and be sure to get an inline fuse for it as well. Put the fuse within 12'' of the battery and you should be alright. If you want to pursue doing this get an amp wiring kit (cheapest place probably local is wally world, $25-30 for a 4 gauge kit.)

I would say that the inverter is 100% better than nothing but ideally a generator is what you'd want. The inverters will get you through and keep powerheads running for a couple hours. As long as you aren't going to have long term power outage you can probably get by without the heaters. You can always put hot water bottles in the tank to warm it up and keep it stable (Assuming you have a gas stove or access to a gas stove)

I am lucky enough to be in an area where we don't lose power too much and even when we do it comes on quickly as I'm on the same power grid as the hospital.

xxxbadfishxxx · #8 12/15/2007, 09:27 PM

yeah the inverter i got hooks directly into the battery, it has two of the alligator clips to go directly onto the battery. I was under the impression that i could run my powerheads directly off the battery (only like 10 watts each - 20 watts total). I probably will be better off with battery operated air pumps. I think i will return it, just doesnt seem to be what i expected.

rsw686 · #9 12/15/2007, 09:33 PM

Quote:

Originally posted by Snowboarda42
Even with the car on, the battery will still drain. Unfortunately, car alternators only work if the car is above 1100 rpm (average), anything below that and it is not charging, just running off the battery. Again, it all depends on the car and the alternator's amperage. You might be better off with a generator.

I advise you to hook a multimeter up and test your theory. I know for a fact that the alternator charges the battery when the vehicle is idling. The battery normally reads around 12.4. With the vehicle on it reads 14.1 or so. Thus the battery is charging. Sure at idle the alternator can't reach full capacity, but its still charging and powering the electronics.

If you plan to use the inverter for extended periods I suggest you invest in a multimeter. You can tell when you are draining the battery, instead of just using the alternator by the voltage. You can also determine how long you can go between starting the vehicle.

I have a 700watt inverter hardwired in with an 80 amp fuse. It draws around 60-70 amps max and the alternator provides 110 amps max. You can figure out the approx load by taking the house wattage and diving by 12. For a 200 watts of heaters that is around 17 amps give or take some loss from the conversion process.

Anyway those heaters aren't going to run all the time. You could check the car battery every hour and when it hits around 11.5 or so start the car, run it for 10-15 minutes, raising the rpm just above idle will help out.

rickh · #10 12/15/2007, 10:42 PM

Several years ago, before generator, I idled a Civic for 24 hours running my tank with a 400 watt $25 inverter from Mejiers. You have to run the car, a standard battery will be damaged if you discharge it. No problems with idling the car.
Get a Generator. R

xxxbadfishxxx · #11 12/17/2007, 05:03 PM

i was reading other threads on power inverters. First let me say that our power does not go out all that often, and cant rememver the last time its been out for more then 5 hours (other then that blackout a couple years ago). We have underground power cables in our neighborhood, and since we brought our house 2 years ago, its gone out 2-3 times, longest form maybe 2-3 hours.

That being said, i still want to have a backup plan. A Generator would be nice, but cant afford one right now, but i also want to protect my investment. From the threads i have read it seams that oxegination/water movement is the most important thing, Thus, i think running 2 powerheads (1 for each tank) woul be good enough, totalling under 20 watts. I have gas heat so i can always put in hot water bottles if temp becomes a concern.

I would say that i would never be using more then 100 watts while using this, most likely under 50. Some people say it would be fine and with the car off, some say to start the car every couple hours for like 20 minutes, others say to keep the car on idle. Others Recommend getting a Deep Cell Marine Battery, they say that they are meant to be sitting for long periods of times without being used, and should be able to run powerheads for days at a time without needing to be replaced. What does everyone think about this? I dont want to ruin my car or my tank.

rsw686 · #12 12/17/2007, 06:08 PM

Quote:

Originally posted by xxxbadfishxxx
I would say that i would never be using more then 100 watts while using this, most likely under 50. Some people say it would be fine and with the car off, some say to start the car every couple hours for like 20 minutes, others say to keep the car on idle. Others Recommend getting a Deep Cell Marine Battery, they say that they are meant to be sitting for long periods of times without being used, and should be able to run powerheads for days at a time without needing to be replaced. What does everyone think about this? I dont want to ruin my car or my tank.

If you deep discharge the car battery you will take away its life. Although its not going to hurt the car, just the battery and they are $50-80. You could buy 5+ batteries for the price of a generator or to replace your tank.

Lets say your power goes out once a year for a couple of hours. That is not going to impact the life of your battery that much. I would not leave the car running the entire time. Idling a car for extended periods isn't the best thing you can do for it.

I would use the inverter and every half-hour to an hour check the battery voltage. When it drops in the 11.7-12 range you should start the car and run it for 10-15 minutes to recharge the battery.

Deep discharging is when you take the battery down to 10 volts. The car should still start with the battery at 11 volts. So staying about this range will not impact the battery life that much and still give you a decent amount of run time.

Who knows you may find that you can go for 2-3 hours before the battery voltage drops to 12 volts.

rickh · #13 12/17/2007, 08:14 PM

Quote:

Originally posted by rickh
Several years ago, before generator, I idled a Civic for 24 hours running my tank with a 400 watt $25 inverter from Mejiers. You have to run the car, a standard battery will be damaged if you discharge it. No problems with idling the car.
Get a Generator. R

Another thing to consider about buying a generator is----
If you do the inverter,start the car every hour, let the food in you refrigerator spoil thing---you have to stay home from work. My refrigerator probably has hundreds of dollars worth of stuff in it. If I stay home a couple days babysitting an inverter I lose more pay then the cost of a generator.

sundancer · #14 12/17/2007, 10:33 PM

Home depot carries 2000 watt gas generators for $400. This is not a lot of money compared to what you have spent on your tank. I think it's an insurance policy worth considering. NOt only will this generator save your tank in a crisis it will also power other household essentials as well. I have a Honda generator 2000watt generator. I have a female 3 prong branching off of the 15 am circuit that feeds my tank. When the power goes off I plug the generator into that tag and start her up. The whole neighborhood is pitch dark except for this really bright window..

rsw686 · #15 12/17/2007, 10:38 PM

The only generator I would buy is one of the Honda inverter generators. You can't get a nicer generator. They are quiet, consume little gasoline, produce pure power save for use with electronics, and did I mention quiet. Downside is it runs $1000 for the 1000 watt unit.

sundancer · #16 12/17/2007, 11:19 PM

Yes,the Honda 'quiet'generators are real nice. I have the 2000si. It's about the size of a carry-on. But you can't recommend that to someone on a budget. There are a lot of decent sericeable generators for under $400. IMO, back up power supplies are a necessity for anyone who has a sizable amount of $ invested in a tank. For apartment or shared housing dwellers where a noisy,carbon monoside spewing machine may not be convenient, one could easily purchase a set of 3 or more 12 volt batteries and a trickle charger wired parallel with an inverter. This arrangement should power your tanks vital organs long enough through any outage until the utility people get things back on track. This setup cost a little bit more money(around $800) but you don't have to deal with the gas and noise of a generator. I use this set up on my boat. It powers my microwave,water heater,TV/DVD player,lights,stereo and much more for a loong weekend out on the water. When I get home I just hook up the trickle charger fora couple of days and it's ready for the next trip. This same set up can easily be installed in your closet until needed.

Konadog · #17 12/17/2007, 11:31 PM

Quote:

Originally posted by rsw686
The only generator I would buy is one of the Honda inverter generators. You can't get a nicer generator. They are quiet, consume little gasoline, produce pure power save for use with electronics, and did I mention quiet. Downside is it runs $1000 for the 1000 watt unit.

Yamaha also makes a very nice generator the EF2400iS, and its 2400 watts. It will actually start a 2400 btu AC unit where the honda won't. Either manufacturer make great "quiet" generators. If my neighbor had a HomeDepot generator running in the night, I think I would "tune it up" with a sledge hammer! Cheaper generators are "OK" for day use, but if you think you'll need it at night, the quieter the better.

smcdonn · #18 12/17/2007, 11:48 PM

http://cgi.ebay.com/Contractor-Line-...QQcmdZViewItem

I bought one of these just to put in my garage in case of an emergency. Nothing like a little piece of mind for $250. And it will run quite a bit of stuff, including the fridge and the fan on the furnace. And trust me, I have ran the crap out of this thing and it hasn't missed a beat. I hooked two 1500w heaters to it and ran two tanks of gas through it to give it a good break in and it never gave me any problems. It's also fairly quiet. Not as quiet as the Honda's or Yamaha's, but hey, I don't have $3k for the yamaha equivalent.

sundancer · #19 12/18/2007, 12:08 AM

Keep in mind,fellas,that no decent human being should complain about a running generator during a power outage,no matter how loud the unit. Now if you were to run it on a regular basis,like a tailgate party or camping trip, that's an entirely differnt matter. Another downside of a geneator is that it should be run every couple of months because the gas inside will go bad or something will seize up when you need it most. Just something to keep in mind...are we getting away from the main topic?

badpacket · #20 12/18/2007, 03:44 AM

OK, so you got a 750w inverter, why is everyone worried about that?
You aren't drawing but ~250 watts with the pumps and heaters, nowhere near the capacity of that inverter.
If you really want to save some money, return it and get something like a 250 watt inverter, a decent car battery and a trickle charger.
I'd suggest a marine one if you can afford it, as they take deep discharges much better than car batteries which are all about cranking amps.
Down size the 150 watt heater maybe for emergency use to 50 watt? And, not sure what sort of output you get off of these inverters nowadays, but years ago they used to be hell on motors and inductive loads.

Actually, found one of my old links, this one only requires a decent UPS from BB and a battery.
Check Best Buy for their loss leader UPS, or Craigslist for a 'dead' one. Most people trash them because the batterys are expensive or they don't know they are replaceable.
You can go with a marine battery or a nice gell cell, though the marine should last much longer.

http://www.youtube.com/watch?v=ViXHWTw0P7E

nybyrne · #21 12/18/2007, 06:22 AM

Go with a genarator.

reggiepe · #22 12/18/2007, 08:58 AM

I have a marine deep cycle battery that I bring in the house of the winter months. Most all power outages take place over the winter too. So I was thinking of getting a 400 watt inverter to run a couple of Korolias for water movement. is there a calculator to see what kind of runtime hours that I would get wrom this setup? I would like to be able to use a pair of 100 watt heatersas well of the battery could handle it. Any thoughts?

daven · #23 12/18/2007, 10:27 AM

Yes. go to http://www.lifelinebatteries.com/marinesizing.php

Deep cycle batteries is what you would want to use instead of starting batteries (like car batteries). They are designed to deep cycle. A starting battery will not ever fully recharge if it has been discharged under 80%.

Another option for people is to get a solar charger and charge the battery during an outage. They don't cost that much.

badpacket · #24 12/19/2007, 09:41 PM

If you're drawing 75-100 watts off of the battery, then you need at least that size solar panel to charge it. You're talking $200-300 for panel alone.

twiggyman · #25 12/20/2007, 01:09 AM

Well a inverter will work just fine of any car that is on the road. The heater portion will more than likely cause the inverter to clip or shut of. All cars and trucks idle at 14.4 to 14.2 volts and can with stand a amprage draw of about 30amps before having to draw from the battery. For what you are trying to do with the inverter is ok. If you are wondering I am in the custom car audio business and have been for 15 years.