psw power inverter

[GotSmart]

You mis understand how a crock pot works. It heats up, then maintains the temperature. It does not constantly run at full power. The pot will mainly be used while traveling. While the alternator is charging the system. So I can stop and have a decent hot meal without blowing my gas money or blood sugar levels.

Sternwake, can I get your feedback on my questions please?

 

[TucsonAZ]

You mis understand how a crock pot works. It heats up, then maintains the temperature. It does not constantly run at full power. The pot will mainly be used while traveling. While the alternator is charging the system. So I can stop and have a decent hot meal without blowing my gas money or blood sugar levels.

Sternwake, can I get your feedback on my questions please?

You have confused a crock pot for a toaster oven or a fridge. A crock pot works like a light bulb or basic space heater, I have had mine on the Kill-O-Watt meter and can assure you the power levels do not change and there is no thermostat in them. You could mod one to turn it into a sous-vide/crock pot to make it more efficient but that isn't how they work out of the box.

 

[SternWake]

I've no experience with crockpots, but the guy with one, AND a kill a watt meter has answered that part as best as can be answered.

GS, your Dodge Van is 2 years newer than mine, but I believe the alternators are the same. Do know that when hot, at idle speed, the alternator is only capable of providing about 32 amps beyond what the ignition and fuel pump require. I have a slightly smaller pulley so mine turns a bit faster than stock. When I am driving at night with a hot engine sitting at a traffic light, lights on and blower motor on high, my battery is having to provide 10 amps on top of what the alternator is making, and the lights will dim as voltage sags to 12.8v or below. Kind of depends on where the batteries were, state of charge wise. Mine Idles at about 525 rpm when hot, A couple hundred more rpm and my alternator can do 50 to 65 amps. So just know, idling to power something, or Idling to recharge are extremely wasteful and not very effective on a Dodge chassis of this era.
108 watts at 12.8 volts is 8.43 amps so it is not a deal breaker, as long as you are driving, but 8.43 amps rounded up to 10 amps for inverter inefficiency, will quickly take a toll on the battery when the engine is not running..

If you are running a dorm fridge on a PSW inverter, you might need one with a very high rating, like 1200 watts/2400 surge, just, to handle the start up surge of the compressor, though it might only pull 90 watts after the compressor gets going. If having to upgrade to a much larger inverter, and add more battery and more charging sources just to make a dorm fridge work, well you can see how getting a 12v compressor fridge actually comes out cheaper in the long run, despite the initial higher cost.

Most laptops today don't pull over 90 watts, though there are exceptions on powerful machines doing intensive tasks.

Going back to the first page, The DC to DC laptop converters ( both 19.5v) I have used on my last two laptops Dell and Sony work perfectly, cost about 22$ and use at a minimum, 15% less juice than using the original power brick on an inverter. The issue with most of these DC to DC adapters, is not the adapter, but the ciggy plug itself, as they are no good for extended use passing more than 6 amps. I hate to think how many bad reviews are caused by poor ciggy plugs, and underwired ciggy plug receptacles. They are more efficient. as long as they can provide the wattage the laptop requires there is no more risk of failure to laptop or battery or adapter itself, and using the original power adapter on an inverter is just warm and fuzzies signifying nothing but that one has battery power to waste.

As an example, I am using my DC to DC adapter typing this right now, and the laptop is using 2.3 amps.

I just turned on my Wagan 400 watt PSW inverter powering only my AC adapter for this laptop, quickly swapped power cords and the inverter is now using 3.4 amps..

That is nearly 50% more electricity consumed for doing the same task.

Inverters are evil. perhaps necessary evil, but they are far too often regarded as easy solution, when the fact is they are inefficient and other methods are available, if one is aware of them.

Ciggy plug receptacles were a junk design before they were cheapened even further

 

[GotSmart]

Something I know that Sternwake does not!!!

The 88 to 91 Dodge vans had two options on the alternator. A 40/90 standard, and a 50/120 upgrade. In testing during my rebuild, mine was producing at 130. My lights do not dim at idle. even under full power usage.

Still I do not want to exceed or max out my power storage sources.

I will be sure to pick up a laptop converter.

The dorm fridge is rated at 1.5A, 6A max. I understand wanting to have a safety net in an inverter.

I have installed a cigar lighter from Amazon with 14 gauge wire on a 15A fuse (Trying to do it right!)

http://www.amazon.com/gp/product/B001U4ZZPK/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1


I get worried when things get hot from undersized wires.

So without spending $700 on a 12v fridge, how big of an inverter should I buy? (or is there a different option available?) What wiykd you recommend?

 

[SternWake]

I have seen 110 amps into a pair of depleted group 27 batteries, from my '130 amp' reman'd alternator. The belt was squealing, it probably could have done more

While my lights no longer dim at idle, as I have upgraded the harness to my headlights using 12awg and relays, when my battery is low, and driving at night, sitting at a traffic light still has the voltage drop as the battery has to supply what the alternator cannot.

Don't dismiss this possibility with your Van, no matter how much faith you have in the quality of rebuild. A bench test means little when the alternator is hot, stuffed under the hood, and has a large load on it, and the battery is less than fully charged.

I also added a heat shield between the alternator and the exhaust manifold which is just a few inches away. This was good for an additional 5 amps at hot idle speed.

If the fridge is rated at 1.5 and amps one can assume the 6 amp is the start up surge. 6 amps x 120 volts, so in theory an inverter with a 720 surge watt rating should be able to start the fridge compressor pumping.

1.5 amps at 120 volts is 180 watts. 180 watts at 12.6 volts DC is 14.28 amps. And add another 2.15 amps for inverter inefficiency. So you are looking at a nearly 17 amp load on your battery bank whenever the fridge compressor is running

I don't know how often the compressor will run. Have you measured this?

My 12v compressor fridge draws right about 30 watts for 20 minutes each hour in 75 to 80f ambient temps.

That 700 dollar compressor fridge will ultimately cost less than powering the existing Dorm fridge, when you factor in the larger inverter required, the larger battery bank required, the larger charging sources required, and the fact that the batteries will have to be replaced more often due to having to power a 17 amp load at a 30 to 50% duty cycle, round the clock, day after day.

 

[GotSmart]

OUCH.

Time for more research to see how I can make thing work for me.

 

[SternWake]

If those fridge dorm specs are accurate, and lets assume a 50% duty cycle, the battery bank required just to power the fridge for 24 hours would need to be 410 amp hours, to stay above 50% charged, and that does not factor in Peukert.

Returning 210 amp hours per day to replenish just what the fridge would use would require a minimum of 550 watts of solar and good weather.

This theoretical battery bank cycled to 50% daily and even recharged promptly and fully and properly, would last perhaps 500 cycles before it would not have enough capacity.

4 new t 105's cost ~ 600$

That 12v compressor fridge is looking a whole lot cheaper now, is it not?

Making that 120v dorm fridge "work" for you could very well be an expensive failed experiment.

 

[akrvbob]

I could easily run that crock pot off my solar. If it draws 10 amps for 5 hours that's 50 amps and assuming a 50% inverter waste that's still only 75 amps. I could easily do that once or twice a week.

I have 380 watts and 4 golf carts, but in the summer that is so much more than I need I wouldn't have any problem with a crock pot.

That wouldn't be true in the winter when I add in my Satellite TV receiver and TV for 4-5 hours a day and lose a lot of sun. Then the crock pot wouldn't be possible.

On edit I've decided I probably could do it in the winter. I would use hay box cooking and cut the cook time in half also cutting the amps in half. I have a Wonderbag and almost without exception I can count it to cut the cook time in half.
http://smile.amazon.com/dp/B00ESI97YU

See my review here:
http://www.cheaprvliving.com/blog/hay-box-cooking-wonderbag-nissan-thermos/
Bob

 

[GotSmart]

If those fridge dorm specs are accurate, and lets assume a 50% duty cycle, the battery bank required just to power the fridge for 24 hours would need to be 410 amp hours, to stay above 50% charged, and that does not factor in Peukert.

Returning 210 amp hours per day to replenish just what the fridge would use would require a minimum of 550 watts of solar and good weather.

This theoretical battery bank cycled to 50% daily and even recharged promptly and fully and properly, would last perhaps 500 cycles before it would not have enough capacity.

4 new t 105's cost ~ 600$

That 12v compressor fridge is looking a whole lot cheaper now, is it not?

Making that 120v dorm fridge "work" for you could very well be an expensive failed experiment.

The problem is $. I am working with a limited income, and my $1,500 build money went in a "loan" to my children. It will be a while if ever I see that money. I do not have $700 for a fridge, but I do have a dorm fridge sitting in my van. I have everything set up with the wires run to and from the battery box, a power distribution system set up with safety fuses, 4 guage wiring, a blue seas fuse block that takes the same fuses as my van. A box filled with wire, connectors and a hydraulic tool to make my heavy connections.

I can get a couple t105s a month, order solar panels one at a time~~~ but spending a big chunk is out of the question at this time. I might end up buying used batteries to run my CPAP and go with a small ice chest for now.

That is why I am seeing what kind of inverter I need to buy. Survival and build it a little at a time.

Roof rack and plywood. $130.
Solar panels. $150 each X 3?
Inverter $150 to $700
Fridge 700?
Batteries. $150 each X 4 $600.

Due to my injuring myself a couple times recently, (as well as surgeries) I am not taking on any new jobs. I cant take the chance on paralysis

 

[TucsonAZ]

The problem is $. I am working with a limited income, and my $1,500 build money went in a "loan" to my children. It will be a while if ever I see that money. I do not have $700 for a fridge, but I do have a dorm fridge sitting in my van. I have everything set up with the wires run to and from the battery box, a power distribution system set up with safety fuses, 4 guage wiring, a blue seas fuse block that takes the same fuses as my van. A box filled with wire, connectors and a hydraulic tool to make my heavy connections.

I can get a couple t105s a month, order solar panels one at a time~~~ but spending a big chunk is out of the question at this time. I might end up buying used batteries to run my CPAP and go with a small ice chest for now.

That is why I am seeing what kind of inverter I need to buy. Survival and build it a little at a time.

Roof rack and plywood. $130.
Solar panels. $150 each X 3?
Inverter $150 to $700
Fridge 700?
Batteries. $150 each X 4 $600.

Due to my injuring myself a couple times recently, (as well as surgeries) I am not taking on any new jobs. I cant take the chance on paralysis

Think about a fridge like a fish tank and the energy (or cold air) used to run it like the water. Now think about if you would rather have a fish tank that opens from the top or the front in terms of having to replace the water? In some cases like living in Washington state it may not matter so you choose the one you like more, in other cases like living in Arizona you choose the one that uses less water (or energy).

This is why I'm such a fan of chest freezer conversions, you can get a chest freezer between $150 and $200 with ease, you can get fairly small ones as well and with the addition of a $15 temp controller you can get it to where it's only using 10w per hour.

Here's a photo of the front panel on mine.

---

If you want the Amazon link to this unit let me know.

 

[GotSmart]

So if I get a chest freezer and a thermostat controller I can use less power than a fridge? Not dumping the cool air makes sense when ever it is opened, but ohms law still states that it takes X amount of energy to bring temperatures down to 32, and 2X for every degree below. (I think I remember that from HVAC school) There is no free energy. It takes power to make ice.

There are chest freezers all over the place here for $100. I still would need a 7 to 800 inverter to run the thing. I guess making ice jugs and a small cooler to keep my eggs and drinks in is smarter than a dorm fridge.

 

[TucsonAZ]

So if I get a chest freezer and a thermostat controller I can use less power than a fridge? Not dumping the cool air makes sense when ever it is opened, but ohms law still states that it takes X amount of energy to bring temperatures down to 32, and 2X for every degree below. (I think I remember that from HVAC school) There is no free energy. It takes power to make ice.

There are chest freezers all over the place here for $100. I still would need a 7 to 800 inverter to run the thing. I guess making ice jugs and a small cooler to keep my eggs and drinks in is smarter than a dorm fridge.

In this case you're no longer dealing with ohm's law but entropy or your ability to retain that temperature.

I wouldn't make ice jugs with it, honestly, on solar, you can buy a 20# bag of ice at Costco for $1.79 which you could store in it but I wouldn't try to make the ice in there as it would up the costs a lot.

You would want to run it like a fridge, the point of the mod is to control the temps outside of what the stock unit will accommodate. So you could run it at 30 degrees instead of 0 degrees, the chest freezer will do a better job of maintaining that temp and even more if you open it a few times a day. The duty cycle for the compressor will also be less which will equate to less power consumption. If you have condensation issues or the top of the unit is too warm, you could add a small 80mm case fan to the top of the unit to help with that.

You will still get a 1,500-2,000 watt surge each time the compressor kicks on and will need an inverter that can accommodate that 1-3 second surge.

 

[GotSmart]

http://www.amazon.com/Power-Bright-...3147&sr=1-3&keywords=power+inverter+2000+watt

Inverter, $185. used small freezer unit, $100. Thermostat control $15. (Need link please)

So for $300 I have solved the inverter problem and the refrigeration problem. A savings of $1,100, which will pay for two battery replacements. I can upgrade to a better inverter as I can afford it.

Finding cheap ice will be a problem, as there are not many places that use it as a loss leader. Cosco is only on large urban areas.

So when my check comes in, I need to order inverter and thermostat control as my next step toward almost freedom from the grid.

 

[TucsonAZ]

http://www.amazon.com/Power-Bright-...3147&sr=1-3&keywords=power+inverter+2000+watt

Inverter, $185. used small freezer unit, $100. Thermostat control $15. (Need link please)

So for $300 I have solved the inverter problem and the refrigeration problem. A savings of $1,100, which will pay for two battery replacements. I can upgrade to a better inverter as I can afford it.

Finding cheap ice will be a problem, as there are not many places that use it as a loss leader. Cosco is only on large urban areas.

So when my check comes in, I need to order inverter and thermostat control as my next step toward almost freedom from the grid.

http://www.amazon.com/gp/product/B00EZIEU3Q/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I used this on the GE 5cuft from HD and can tell you the temp probe fits in the stock location with a little work, brand new it was $185 I think after getting them to give me 10% off. A newer one may be far more energy efficient than a used one so look into that.

And not to toss a wrench in your plan but your chest freezer will draw more current, start longer, and won't last as long with that modified square wave inverter. I know it sucks a lot but you may have to bite the bullet on this and get PSW, I just bought one from ABC Electronics in Minneapolis for an amazing price and they were a joy to work with. I would google and give them a call. If you go MSW I actually have a new one floating around I would cut you a hell of a deal on as I wouldn't use one for anything in the world.

 

[GotSmart]

The budget can not handle the $800 for a new unit and PSW at this time. In a couple months I can get the good ones, but for now I do not have any other option. Used freezer and MSW for now. Once I am able to work again I will upgrade.

Please send me a PM with price and address to send the payment.

John

 

[Willy]

You could also keep your eyes on Craigslist. I bought all three of my 12v compressor fridges/freezers off of there and saved real big bux. ..Willy.

 

[akrvbob]

I think the freezer conversion is a very good idea! However, do you have room in the van for it?

I know nothing abut their power draw, but I once had a very small Haeir Freezer from Walmart than ran great for a very long time. They are still cheap.

I'd want to add at least an inch of polyiso to the sides and top to super-insulate it. Just be sure to not affect the ventilation or you'll burn up the compressor.

You can buy a Whytner 45 qt 12 volt compressor fridge for $500 and I think by the time you buy a big PSW inverter and a freezer you are going to be very near that. I think I'd use an ice chest till you can afford to get what will work the best.

My Whytner is an outstanding piece of equipment far better than my Dometic/Waeco and burns an incredibly small amount of juice.
http://www.amazon.com/Whynter-FM-45G-45-Quart-Portable-Refrigerator/dp/B002W8BLUG/
Bob

 

[05kas05]

quick question, one of my battery chargers is a little plastic square box with the plug made into the back of it so i don't think it would plug into the front of a power inverter due to clearance issues so what are your thoughts on using a power strip or small extension cord to connect the two is there any reasons or problems i might run into doing it this way?

 

[Zil]

You want to use your battery to charge your battery?

 

[Optimistic Paranoid]

I think he's talking about a little wall wart to charge camera batteries, or something like that.

There's no reason not to plug a power strip into an inverter that I'm aware of.

Regards
John