Built in inverter and other electrical queries

[Queen]

So, new van has 12v plugs all over the place, and it came with an entertainment package we didn't care about (told them to find us a van elsewhere without it cuz we weren't paying for it... they threw it in).  Anyhoo, part of that package is an inverter that can handle 150 watts/volts/amps/magic electric stuff, since that means nothing to me does it mean something to you folks?  I can't think of anything to plug into it but guess I could plug in a fridge or maybe an electric blanket?

Also, the thing has a DVD player in it, if we wanted to watch something some rainy evening while camping, does that sort of thing drain the battery quickly?

[tx2sturgis]

Congrats on the new van....

150w is fine for charging up most normal laptops, phones, tablets, cameras...etc.

It will run small items like an electric can opener, hair trimmer, cordless drill charger, small LED TV, soldering iron, florescent desk lamp, etc. 

It MIGHT run a 26" TV, desktop computer, stick blender, hot glue gun, etc. 

It won't operate items like space heaters or hair dryers, large kitchen blenders, microwave ovens, refrigerators, or A/C units. 

Most of these factory 120v outlets shut off when the ignition is off, OR, they will shut off after a certain time period, OR, they will shut off when the battery voltage drops to a preset level.

All of them have built-in protection against overloading.

The built-in DVD player most likely also has some built-in battery saver protections. Most new vehicles have some sort of LVD (low voltage disconnect) inline with things like headlights, radio, dome lights, etc.

[Queen]

Thanks for the great info! The owners manual mentioned the inverter shuts itself off if you put too much of a load on it, I honestly think it's there to plug in a gaming system since it has color coded round plugs just above the 120 plug.

It's been fun trying, with my tremendously limited knowledge, to explain how this stuff works to my honey.  She thought we could pull into a campsite and run a drop cord to the inverter and power the AC.  Electrical stuff is hard.  

[tx2sturgis]

Gaming system....DOH!

I try to think of several examples but since gaming systems aren't something I own, I forget about those....

Most all electrical items that plug into that outlet will have a wattage rating printed on a label somewhere.

Laptops typically use 60-100 watts, for example, and that will be printed on the charging brick. 

Window A/C units typically pull 500-1000 watts or more. 

A toaster or convection oven might pull 1000-1500 watts.

So it's all in the 'fine print'!

[Queen]

Thanks. I've never actually seen a gaming system, but the sales guy mentioned it. LOL

[tx2sturgis]

He was probably in that 20-34 year old demographic...

[Queen]

He was actually in his 60's, he said his grandkids wanted him to buy the van for that express purpose.  

[rvpopeye]

TX pretty much covered everything I was gonna post.

You probably should try to use things that need 100 watts (Around 9 amps) AC or less as inverter mfg's usually show the peak power rating which it typically will only supply for a very short time .

I loved the line find us another one without it cuz we won't pay for that POS !
(My paraphrasing , I forgot the exact wording already)

[tx2sturgis]

You probably should try to use things that need 100 watts (Around 9 amps) AC or less...

You forgot a decimal point, me thinks. 



9 amps at 120v would be almost 1100 watts.

[sternwake]

A hundred watt load at 12.2v DC is 8.9 amps. With 80% inverter efficiency this load then becomes 9.82 amps, on the battery.

A group 27 battery, which is likely larger than that which came in a Minivan, is usually around 100Ah.

Somple math would have the healthy new fully charged group27 battery, under a 100 watt load powered by an 80% efficient inverter, depleted to 50% in ~ 5 hours.

But simple math does not account for the peukert effect, which basically says the bigger the load the lass capacity the battery has.

The 100Ah battery earned this rating by supplying a 5 amp load for 20 hours until voltage fell to 10.5v, which is considered 100% discharged. The 100 watt load on an inverter almost doubles this load on the battery , and according to this Peukert calculator, the 100 Ah battery under a 5 amp load becomes a 70Ah battery under a 9.82 amp load. That peukert number used is that of a high quality AGM battery like odysey or Northstar, so on a OEm starting battery that capacity is likely around 63AH.

http://www.csgnetwork.com/batterylifecalc.html

So that 100 watt load powered by the inverter, can deplete the healthy fully charged starting battery( which do not like to be deep cycled) to 50%, in about 3.5 hours.

And this is likely also generous, as as the battery depletes, its voltage drops, but the inverter is demanding the same wattage, so it draws more amperage, as volts times amps equals watts.

The point of this?

Inverters are excellent battery depleters.

Secondary point, is that vehicle charging systems are not magic. While an alternator can indeed provide large amperage when it is asked to by its voltage regulation and there are suffieient loads to consume those ampheres, it cannot force a battery to recharge to full quickly.

One can easily drain a 100% battery to 80% charged in 10 minutes with enough load. One Cannot recharge that 80% battery to full in less than 3.5 hours, and that assumes a fairly high amperage charging source that is seeking then holding ~ 14.5 for those 3.5 hours.

Which NO Vehicle will allow.

Except mine, as I am the voltage Nazi, and 13.7v when the battery is still less than 100% charged, was not tolerable.

But the rest of you are up shit creek in a barbed wire canoe.

Consider the parade, rained upon.



Just kidding, congrats on the new minivan