Power Question

[WMDunkin]

Okay, I am first stating I new to automotive electrical/camping mods. That being said; I am looking at running a few things for my light/medium duty expedition set up I am planning out for my 2010 WRX. I plan on having a fridge/freezer, electric grill, air pump, small electronics, driving lights, etc that need to be powered. So my question is how should it all be powered? My first thoughts are to get a power pack/backup and run a cigarette lighter plug inverter to keep that charged and run everything off the power pack. But I am not sure if that is the best way to keep everything running? would that even work? I have found some high out put alternators online ranging from 180amp all the way up to 270amp. So in theory I could just get a yellow top and an upgraded alternator and run a simple inverter, right? How much power am I really needed to provide also? Would I even need to change anything?

 

[dwh]

Well, first of all you've lumped in electric grill and driving lights and these are two different things.

So first you need to distinguish which loads you need to supply while the engine is running, and determine if your alternator can handle however many amps that is. Keeping in mind that alternators really should not be run at their full rated load for very long. So if you determined that you needed say 100a continuous, then you'd likely want a 140a or larger rated alternator.

Then, you have to figure out what sort of loads you'll need to supply when the engine is off, and how you will supply them. That's generally done with a deep cycle battery. So let's say the electric grill. A quick search on the net shows me that most are either 1500w or 1750w. Well then 1500w / 12v = 125a. So if you had a battery with a rated capacity of 125 amp*hours, it could run a 1500w grill for 1 hour.

Except it couldn't because you would also need a giant (at least 1500w) inverter and that inverter would itself draw some power. Also, the heavier the load you put on the battery, the lower capacity it has. For example a battery might supply a 10a load for 10 hours, but if you put a 20a load on it, it would last less than 5 hours. Conversely, it would supply a 5a load for more than 20 hours.

So, figure an Optima rated at 65ah with inverter might run a 1500w electric grill for oh...maybe 1/2 hour. More likely it would be less than that. Then it would be completely dead.

The next part is figuring out how you will recharge the battery. You might run your engine for 6 or 8 hours (or more) to get it done, or you might have some solar to help out a little, or you'll probably do what anyone else in that situation does - fire up a generator to run a high capacity battery charger. But if you were gonna do that, then you didn't need to kill your battery or buy a giant inverter.


But yea, you could just get a high output alternator and a giant inverter and use your truck's engine as the generator. Be a bit wasteful of fuel, but it would work.

The most common thing to do is to figure out how much auxiliary battery you can fit, then figure out how much you can recharge it in a day - say by solar or driving a few hours - then cut back on your loads so you don't destroy the (usually expensive) battery by running it dead repeatedly.

 

[Dan Grec]

Excellent post dwh.

To summarize, in case it's not clear, cooking with an electric grill with a 12v setup is not really feasible. It's just too much power to cook with electricity.

Bring some kind of propane/alcohol/white gas/gasoline/diesel stove for your cooking needs.

-Dan

 

[WMDunkin]

Well, first of all you've lumped in electric grill and driving lights and these are two different things.

So first you need to distinguish which loads you need to supply while the engine is running, and determine if your alternator can handle however many amps that is. Keeping in mind that alternators really should not be run at their full rated load for very long. So if you determined that you needed say 100a continuous, then you'd likely want a 140a or larger rated alternator.

Then, you have to figure out what sort of loads you'll need to supply when the engine is off, and how you will supply them. That's generally done with a deep cycle battery. So let's say the electric grill. A quick search on the net shows me that most are either 1500w or 1750w. Well then 1500w / 12v = 125a. So if you had a battery with a rated capacity of 125 amp*hours, it could run a 1500w grill for 1 hour.

Except it couldn't because you would also need a giant (at least 1500w) inverter and that inverter would itself draw some power. Also, the heavier the load you put on the battery, the lower capacity it has. For example a battery might supply a 10a load for 10 hours, but if you put a 20a load on it, it would last less than 5 hours. Conversely, it would supply a 5a load for more than 20 hours.

So, figure an Optima rated at 65ah with inverter might run a 1500w electric grill for oh...maybe 1/2 hour. More likely it would be less than that. Then it would be completely dead.

The next part is figuring out how you will recharge the battery. You might run your engine for 6 or 8 hours (or more) to get it done, or you might have some solar to help out a little, or you'll probably do what anyone else in that situation does - fire up a generator to run a high capacity battery charger. But if you were gonna do that, then you didn't need to kill your battery or buy a giant inverter.


But yea, you could just get a high output alternator and a giant inverter and use your truck's engine as the generator. Be a bit wasteful of fuel, but it would work.

The most common thing to do is to figure out how much auxiliary battery you can fit, then figure out how much you can recharge it in a day - say by solar or driving a few hours - then cut back on your loads so you don't destroy the (usually expensive) battery by running it dead repeatedly.

Thanks for the reply. I guess it is time for me to do some math. My main question is still on if a simple inverter and a deep cycle battery (with solar help) could handle "standard" camping/expedition loads? Or would having a power pack with inverter/solar/generator/whatever be a better route for the same loads. I know I need to find out my loads so that is the first step I guess.

 

[sixbennetts]

For grilling, get a $30 hibachi available almost anywhere, a bag of Kingsford charcoal, and a bottle of charcoal starter fluid. I know it's not an answer to your power questions, but it's cheap, you can find a bag or box to put it all in for storage, which is small, and your food will taste 10X better.

A cheap Yankee told ya that.

 

[CaliMobber]

So everything except the electric grill lol, you will be fine with just the stock alternator and what ever battery you pick as long as you drive at leased once every other day. I would probably go with sears battery( largest one that will fit) as they seem to have longer Amp Hours.

just plan on almost everything running on 12v's, Inverter is nice to have and will come in handy when needed. i use my 1000w inverter for my coffee maker and 120v florescent work light but everything else is 12v.

If you plan on staying parked for a few days then invest in a few solar panels to throw out when your not driving. Solarblvd.com has a 45w panel for $45 that about as cheap as you will find in a smaller panel size.

Personally I find charcoal more expensive and its harder to gauge how much is needed for cooking vs propane you have full control of how much is being used but cooking is a personal preference

 

[WMDunkin]

So everything except the electric grill lol, you will be fine with just the stock alternator and what ever battery you pick as long as you drive at leased once every other day. I would probably go with sears battery( largest one that will fit) as they seem to have longer Amp Hours.

just plan on almost everything running on 12v's, Inverter is nice to have and will come in handy when needed. i use my 1000w inverter for my coffee maker and 120v florescent work light but everything else is 12v.

If you plan on staying parked for a few days then invest in a few solar panels to throw out when your not driving. Solarblvd.com has a 45w panel for $45 that about as cheap as you will find in a smaller panel size.

Personally I find charcoal more expensive and its harder to gauge how much is needed for cooking vs propane you have full control of how much is being used but cooking is a personal preference

Thanks for the reply, I will look into that. yeah my thought was to use the factory "set up" for as much as I can. But I didn't know how long or what to keep the battery/alternator alive and happy.

 

[madmax718]

If this is the 5 door, you'd be in better shape. (size wise for the cooler)
It will still be a little cramped. you'll have to pack smartly.

Try to keep things 12v- inverters waste a decent amount of power doing the inverting process, so unless you have a special need for something, you can usually find it in 12v (even blenders and toasters).

1 20 dollar butane single burner will be cheaper and easier to deal with. BEen using the same one for like 9 years. Cartriges are cheap, about 1.25 to 1.50. I usually get about 2-3 days cooking for 2, for 3 meals a day on one cartridge.

Im not certain the WRX comes with a constant power lighter. Probably worth putting one in somewhere, for your fridge, and also for things like charging up your phone at night. Its also useful for solar charging your battery. I use a 5w panel to keep the main battery trickle charged.

I have no fridge yet. Im not so "far" away from civilization that I can't get resupplied with ice and food every 3 days.

 

[lysol]

I'm in the same predicament as you right now Dunkin. I figure I'll get as much battery as I can fit and as I am moving the full size spare tire in my Jeep to outside, I'll have as much room as I need.

I plan on getting the Oddysey PC1800 battery. It has over 200ah. That should be more than enough for what I want it for (50L ARB fridge and various small things). The way I see it is I don't want to have to buy a second battery and wire it in parallel. I just want 1 battery for my Aux needs. The only problem which really is more of something to be aware of is that this battery weighs about 130 lbs. Though, I would have the same weight with say 2 100ah batteries anyway.

If I start draining the 200ah battery quickly (I won't lol), I would need to bring more input power to offset the discharge. Eventually, I'll start with a 100 watt solar panel mounted on the roof rack to help with the aux battery but for now, I won't be using the full potential of the battery so I don't find it necessary. I'm only going a little overboard on the battery to future proof my overall plan.

Plus, I'm an electricity fanatic. I love power. lol. The longer I can run my stuff without gas or generators, the more fun I have.

 

[dwh]

The longer I can run my stuff without gas or generators, the more fun I have.

I'm the opposite. I buy cheap deep cycle batteries for my aux, run them dead over and over (abuse the hell out of them) and then replace them every couple of years. I absolutely love my little generator, which I only use for recharging the aux battery. It'll run 14 hours on 1.2 gallons of gas running nothing but the charger, which is just about right to do a full recharge on a dead 100ah battery with the cheez-whiz charger I have.

I'm an electro-freak myself. I just can't be bothered babysitting some crappy chemistry experiment in a plastic box - which is all any lead-acid battery is anyway. By the time you figure the cost of the cheapo generator and the gas used, I spend less than a good solar setup, get a lot more amp*hours to use for whatever I want and get to park in the shade.

 

[madmax718]

What do you guys do with all this power? All I ever do with it is keep a fan, charge a few phones, some AA and AAA batteries. Am I missing something? (other than a fridge)

 

[dwh]

I run my fridge on propane. But I like to stay at a site I like for days (or weeks when I can), without having to drive at all if I can away with it, so I tend to run my aux battery into the ground then fire up the genny and charge the battery once or twice a week. I run a 12v DVD player, a couple of netbook computers, a few fans, some LEDs, phone, charge AA batteries (for the Mini-Mag, electric toothbrush and Braun electric shaver) and an 18v Ryobi battery for the big flashlight. I have a couple of inverters, but I almost never use them.

Since I do a lot of writing, it's the computers that eat the most power.

 

[madmax718]

I would think you'd be a perfect candidate for a little solar power.

 

[dwh]

I would think you'd be a perfect candidate for a little solar power.

It would seem so, but nah. When I can, I like to park in the shade. When I can't (which happens quite a bit, as I love the desert), I have a parachute that I use to cover the truck. I stretch it out and tie it off to stakes, to make a nice shady awning all around the truck. Kinda like this, but with a truck in the middle instead of a center pole:




I used to do the "unpack all the crap and pile it around the truck" camping style. I decided it was too much like work, and I was camping because I was trying to avoid work. If I still did that sort of thing, I might consider a solar panel that I could put out in the sun and move around, but I'm trying to stick with the "pull up and park and kick back" style of camping. Yea, staking out the chute is a bit like work, but what the hell...shade rocks.

EDIT: I also like being able to just lock up the truck and wander off without having to worry (much) about having people eyeball or grab my stuff.

 

[lysol]

I like the idea of the surplus chute. Found this online

Do you just 550 cord it to various trees? is there a particular shape you go for each time?