inverter question

[Dale M.]

I was having a major brain fart in my last post...120vac to 12vdc does indeed increase amperage by a factor of 10.......

....120vac FROM 12vdc......

Dale

[madjack]

I was having a major brain fart in my last post...120vac to 12vdc does indeed increase amperage by a factor of 10.......

....120vac FROM 12vdc......

Dale

OKOKOKOKOK my excuse this morning is a late night last nite and I haven't finished my first cuppa joe
madjack

[Dale M.]

Its coffee FIRST and computer SECOND....Try to remember that!



Dale

[luluyug]

hello friends, just to put a little oil on the fire. is the mini fridge you are thinking a compressor type! be careful some of them are now thermoelectric and i think you are way better whit the compressor type
it is a real fridge that can actually cool your drinks before the leafs fall of the trees... i use a thermoelectric cooler because i already had it but in my next build i will use a real fridge (4.3cu ft is ok).

[Shomeyrwit]

real fridge, but those numbers sound a little more like i thought

however I still have a thought

do y'all (yes I'm from Texas) think that the ice pack idea might work

It's my understanding that the freezer on the small friges is what cools the whole frige, so if you packed it full of the hard shell gel ice packs plugged it in at the house ran it till they froze you would in effect have a giant ice block (think origional "ICE" Box) that would not need a drain, then when you unplugged it should stay cool for hours, maybe even a day or two if opened sparingly, since my camping usually includes a generator or other shore power this should get me through the transit times at the expense of being able to use the freezer


take that one more step, even with the power consumption increased by a factor of 10, the frige would probably run very little with such an ice bank, kind of an energy saver on the other end of the system, might make it feasible to run on an inverter during transit since the demand would be miniscule,,,,,,,, stop me if I'm off track

[madjack]

...if talking about running during transit time with 120vac available at your camping location, then yes that would work just fiine...a couple of my buddies who are duck hunters have a small class "c" motorhome with a dorm style fridge in it and that is what they do...fire it up a couple of days before leaving and get everything cold/frozen...upon arrival at their camping spot, they run a gennie as needed to keep things fresh and cool...during transit (about an hour or so) they dont run it at all.....
madjack

[Steve Frederick]

Maybe a Hijack!! But, I'm wondering if it's OK to place the inverter in the same space as the battery? Spark issues?
I'm planning on a vented compartment for the battery. Was thinking of placing the inverter with it?? If not with the battery, in another compartment, vented also. Any thoughts from the collective mind???

[Chuck Craven]

Hi Steve.
Well the only time that an inverter would generate a spark is if a failure occurred.
Or you used a relay or switch to turn “on / off” the 12 V DC power. If you run the inverter close to full power they will get hot and may need a fan to keep air flowing around it. I would put it in a compartment separate from the battery. Actually I would keep the battery away form all the electrical circuits if possible.

Chuck

[asianflava]

Not saying it's correct but My inverter is in the same compartment as the battery. I used an Optima because they don't outgas as much.

[bdosborn]

I dont understand the complexities of this and cant decipher any other threads to answer this questin so


Say I have a nice mid level inverter, about 1500 watt continuous, and a nice optima deep cycle, and the only load is a device that draws .9 amp while running and say 5amps to start, said device runs maybe half of every hour, say it kicks on and off,,, 5 times,,,

1. How long will the battery run this before it's dead?

2. How much would a small solar panel help?

3. Will a twelve volt lead from the tow vehicle straight to the towed vehicle battery charge both batteries (i.e. a second pigtail)

4. the little 12v halogen lamps dont seem to draw much power but the idea of running one for even an hour seems like it would considerably drain a battery, am I overly concerned about that?


Your answers, patience and opinions are appreciated?

Thanks
S

1. 0.9AX120V=108W. 108W/12V=9amps@12V. Inverter is maybe 70% efficient so lightly loaded so 9/.7~12A load on battery.
Group 27 deep cycle battery = 120amp-hour capacity but you should never use more than 50% battery capacity.
60amp-hr/12amps=5 hours. But, it only runs 1/2 hour every hour so 10 hours for a typical group 27 battery.

2. Well, what's small? Its a 144W load (12A*12v=144W) so your extended runtime will be proportional to the size of the solar panel. For a 45w panel, the run time would be extended 144/45~3 times, as long as the sun is shining on the panel. Won't help a bit at night. This is assuming you really get 45 watts out of the panel (which you probably won't ever get more than 90% of rated capacity) but you get the idea. Plan on spending $6-7/watt for a solar panel big enough to power the fridge.

3. Yup, that's how I charge my battery.

4. A typical small halogen is 10W or about an amp of load. So you could run the light for 60 hours on a group 27 battery. An LED light will draw about half that amount or less of current.

Hope this helps,
Bruce

[bdosborn]

Maybe a Hijack!! But, I'm wondering if it's OK to place the inverter in the same space as the battery? Spark issues?
I'm planning on a vented compartment for the battery. Was thinking of placing the inverter with it?? If not with the battery, in another compartment, vented also. Any thoughts from the collective mind???

Steve,

The instructions that came with my xantrex 1000 prowatt inverter says it should not be installed in the same compartment as the battery. It also says that the inverter emits sparks by design, which seems very weird to me but oh well. Here's a quote from their installation manual:
Bruce

Explosive Explosive Gas Precautions
1. Batteries generate explosive gases during normal operation. Be sure
you read this guide and all battery documentation and follow all
instructions exactly before installing or using your inverter.
2. This equipment contains components which tend to produce arcs or
sparks. To prevent fire or explosion, do not install the inverter in
compartments containing batteries or flammable materials or in
locations that require ignition-protected equipment. These locations
include any space containing gasoline-powered machinery, fuel
tanks, as well as joints, fittings, or other connections between
components of the fuel system.

[bobhenry]

All most makes you want to go back to candles. It may burn down but you could at least enjoy the fire. Explosions are just over way to quick to really enjoy !!!!

[bledsoe3]

Explosions are just over way to quick to really enjoy !!!!

That depends on how big they are and your proximity to them.

[Dale M.]

Maybe a Hijack!! But, I'm wondering if it's OK to place the inverter in the same space as the battery? Spark issues?
I'm planning on a vented compartment for the battery. Was thinking of placing the inverter with it?? If not with the battery, in another compartment, vented also. Any thoughts from the collective mind???

Steve,

The instructions that came with my xantrex 1000 prowatt inverter says it should not be installed in the same compartment as the battery. It also says that the inverter emits sparks by design, which seems very weird to me but oh well. Here's a quote from their installation manual:
Bruce

Explosive Explosive Gas Precautions
1. Batteries generate explosive gases during normal operation. Be sure
you read this guide and all battery documentation and follow all
instructions exactly before installing or using your inverter.
2. This equipment contains components which tend to produce arcs or
sparks. To prevent fire or explosion, do not install the inverter in
compartments containing batteries or flammable materials or in
locations that require ignition-protected equipment. These locations
include any space containing gasoline-powered machinery, fuel
tanks, as well as joints, fittings, or other connections between
components of the fuel system.

All they are saying is that unit probably has relays or switches that are not sealed in explosion proof enclosure and the opening and closing of contacts may produce sparks....

Dale