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maria_bettina

Auburn, CA

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Posted: 06/20/22 08:36pm Link  |  Quote  |  Print  |  Notify Moderator

shastagary wrote:

this is what it says on the amazon page of that inverter that i also own. it can easily draw more than 10 amps with the heater load
Quote:

If the rated input of any connected AC devices exceed 150W, please use battery clamps to directly connect to your vehicle's battery as most vehicles' 12V cigarette lighter ports are rated for 150W. Do not use to power high power electric devices such as hair dryers, electric heaters, which might blow a fuse.


[emoticon] guess we will count ourselves lucky with a couple blown fuses.

I better relook at the DVD and TV wattage. Thanks for pointing this out.

* This post was edited 06/20/22 08:44pm by maria_bettina *

maria_bettina

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Posted: 06/20/22 08:40pm Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:

Inverter should draw power direct from the battery using #8 wire minimum. 250w is close to 25 amps at 12 volts.


If I bought a new inverter and connected it to the battery directly, I am still looking at 25A. Which is crazy. We have a 200Ah battery, so 4 hours of continual use (before I reach 50% battery charge)? But if that same 250 Watt heater was DC, that's a whole different story. Electricity is like magic. Totally boggles my mind! Haha

maria_bettina

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Posted: 06/20/22 08:47pm Link  |  Quote  |  Print  |  Notify Moderator

stevenal wrote:

Once the fuse blowing issue is solved, I expect you'll be dealing with battery capacity. Heating appliances will draw your battery down very quickly.


Yes, I am bummed. I don't know how to heat ourselves at night. Below 40-degrees and it's downright uncomfortable. We have a Little Buddy heater, but not for sleeping. We have Reflectix around the vinyl (we have a pop-up TC), but that's not enough.

Back to the drawing board.

CA Traveler

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Posted: 06/20/22 09:00pm Link  |  Quote  |  Print  |  Notify Moderator

maria_bettina wrote:

But if that same 250 Watt heater was DC, that's a whole different story. Electricity is like magic. Totally boggles my mind! Haha
Nope a 250W DC heater: 250W/12V = 20A+, ie It will draw 20A+ DC amps.

Plus the cig plug is likely rated for 8A, you need to connect the inverter more directly to the battery. About 4 hours of run time and more with solar cranking.


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pianotuna

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Posted: 06/20/22 09:03pm Link  |  Quote  |  Print  |  Notify Moderator

maria_bettina wrote:



Yes, I am bummed.


How many amp hours is the battery bank?

The rule of thumb is multiply amps by 10 to get the draw at 12 volts. This is due to inverters being at best about 88% efficient.

If the voltage on the battery is low, the inverter may well draw even more amps, causing the fuse to die.

Generally the inverter may be sized to do 125% of the load. 250 x 1.25 = 312.5 watts (so the inverter is busting its heart out trying to run that heater).

There are a couple of solutions.

1. connect the inverter directly to the battery posts. That will eliminate the fuse and amperage issues.

2. Use a 50 heating pad instead. You could run two.

3. There are 12 volt heaters available.

In any event the batteries are not going love running the heater for long periods of time.

My first battery bank was 875 amp-hours. Heaters were not an issue.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

jimh406

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Posted: 06/20/22 09:10pm Link  |  Quote  |  Print  |  Notify Moderator

You can use a Little Buddy or Buddy heater in an RV. To be extra safe, open a window. Most people just use heaver bed covers at night.


'10 Ford F-450, 6.4, 4.30, 4x4, 14,500 GVWR, '06 Host Rainer 950 Dbl Slide, Torklift Talon tiedowns, Glow Steps, and Fastguns. Bilstein 4600s, Firestone Air Bags, Toyo M655 225/19.5 Gs, Curt front hitch, Energy Suspension bump stops.


maria_bettina

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Posted: 06/20/22 09:11pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

maria_bettina wrote:



Yes, I am bummed.


How many amp hours is the battery bank?

The rule of thumb is multiply amps by 10 to get the draw at 12 volts. This is due to inverters being at best about 88% efficient.

If the voltage on the battery is low, the inverter may well draw even more amps, causing the fuse to die.

Generally the inverter may be sized to do 125% of the load. 250 x 1.25 = 312.5 watts (so the inverter is busting its heart out trying to run that heater).

There are a couple of solutions.

1. connect the inverter directly to the battery posts. That will eliminate the fuse and amperage issues.

2. Use a 50 heating pad instead. You could run two.

3. There are 12 volt heaters available.

In any event the batteries are not going love running the heater for long periods of time.

My first battery bank was 875 amp-hours. Heaters were not an issue.


875 Ah? I thought ours was large - 200 Ah...

Yea, those DC heaters don't get good reviews. I looked at a couple. I will keep looking, but the Amps they use have me looking elsewhere. It's the cold air that doesn't allow me to sleep. Maybe I just need to get electrical sites when it's cold. *Sigh*

We will definitely connect the inverter to the battery directly. Now that another post said using over 150 watts needs a direct connection to the battery.

maria_bettina

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Posted: 06/20/22 09:14pm Link  |  Quote  |  Print  |  Notify Moderator

jimh406 wrote:

You can use a Little Buddy or Buddy heater in an RV. To be extra safe, open a window. Most people just use heaver bed covers at night.


I have an uber safety conscious son who won't run the Little Buddy at night. I guess it could be worse. I could have a son who juggles knives or something. [emoticon]

Yes, it's the breathing the frigid air that keeps me up.

maria_bettina

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Posted: 06/20/22 09:18pm Link  |  Quote  |  Print  |  Notify Moderator

CA Traveler wrote:

maria_bettina wrote:

But if that same 250 Watt heater was DC, that's a whole different story. Electricity is like magic. Totally boggles my mind! Haha
Nope a 250W DC heater: 250W/12V = 20A+, ie It will draw 20A+ DC amps.


Right! Math. [emoticon]

I just can't wrap my head around the high Amps.

time2roll

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Posted: 06/20/22 09:57pm Link  |  Quote  |  Print  |  Notify Moderator

Amps x volts = watts. DC or AC works the same.

Always use 12 volts when calculating because that is where the power is coming from.
Otherwise need to plug into a 120v generator.

The 12 Volt Side of Life


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