Help for an electrical know-nothing!

[EarthboundBob]

Hey all,

I have a 2015 4x4 F-150. I am planning on having a shop wire a 110-volt connection from my alternator to my truck bed (always covered by a camper shell). The purpose of this is so that I can plug in a portable power station that charges while the truck is running, and stops drawing power when the truck is off. The main thing I'll have plugged into the power station is a 45 qt fridge, probably an IceCo.

The thing is, the guy at the shop told me to pick up an inverter (I think he may have meant converter?) for this, but I have no idea what I need. Any help you can offer? I know basically nothing about electrical systems! Thanks!

 

[EarthboundBob]

I don't have it yet, but I am looking to pick up a Bluetti AC200Max. I believe it can charge from the truck's 12V system, but it can take upwards of 20 hours to get a full charge. Is there any way to safely draw more power from the vehicle while it's running?

 

[NatersXJ6]

Depending on your budget, it can make a lot more sense to list all of your expected loads, and time between charges, to size an appropriate battery / power station. If you are talking fridge only, and driving or charging at least once every other day, there are far cheaper options than power stations. You sound like you are on the verge of a $2k project, when just isolated charging a 12V battery could end up more in the $250-600 range and would probably cover your fridge plus LED camp lights and a few other things. Will you also add solar?

Is the goal to:

1) Have power for your needs at the truck?

2) Buy a power station or have portable power?

3) Collect brand-name gear?

4) All of the above?

By coming here and asking questions, you will get on the right / best path for you. Have fun!

 

[rruff]

I don't have it yet, but I am looking to pick up a Bluetti AC200Max. I believe it can charge from the truck's 12V system, but it can take upwards of 20 hours to get a full charge. Is there any way to safely draw more power from the vehicle while it's running?

It looks like the DC input is limited to 10A then, so only 120W at 12v. It will however accept 500W from an AC outlet.

Something like a Renogy 40a DC-DC charger ($130) would probably be the safest way to get juice from your alternator-battery. That will get you ~480W, which you can put through an inverter to give you 120V AC to charge your Bluetti.

It would be more efficient though and cheaper to use your solar input, though. Specs for that are: 900W Max., VOC 10-145VDC, 15A... which I think means 15A is the max current. You can get a boost converter to take the output of your Renogy charger (12V, 40A) and convert it to 48V ... and plug that into the solar input.

I've never tried this and don't know for certain how well it will work.

Renogy charger:
12v to 48V 8A converter. Need 2 of them in parallel.

 

[EarthboundBob]

Is the goal to:

1) Have power for your needs at the truck?

2) Buy a power station or have portable power?

3) Collect brand-name gear?

4) All of the above?

Good question. My goal is really just to be able to have a fridge for the family that does not run the risk of losing power. (I'm not that into the idea of running a fridge myself, but it's pretty much a non-negotiable for the wife.) We will be out for at least a month at time, sometimes staying near shore power but more often boondocking. I plan to use a portable solar panel when we're camped, there will be times we will be driving long stretches and I'd like to ensure the fridge power source stays topped up.

 

[rruff]

I don't know if any power stations will accept more alternator input. Maybe not. But if the only draw on it is the refrigerator while driving, 100W will be more than sufficient, as typically the fridge will need 30W or less on average. Just make sure your power station is charged when you leave home.

 

[rruff]

This seems redundant.
Why not connect inverter directly to battery?

You need something to keep from draining the starter battery when it's not being charged. There is probably a simpler device to do that, but I don't know. Plus I personally don't like going from DC-AC-DC due to contraptions and inefficiency, which is why I suggested trying the Renogy charger to the solar input instead.

But like I said above, I don't think he needs more than 100W while driving, so none of it is necessary.

 

[EarthboundBob]

So it turns out my truck actually has an inverter already. (It's a new vehicle to me and I'm still making these discoveries!) From what I've read on F-150 forums, it's not all that powerful or reliable, but I imagine all I would need to do is wire an outlet from the inverter to the bed and have a relay put in to stop any power draw when the truck isn't running. Are there any other pieces to this puzzle I'm missing?

 

[rruff]

Are there any other pieces to this puzzle I'm missing?

Your 100W DC input is more than enough to run your fridge, and would be simpler and more efficient than DC-AC-DC conversion.

If you want to use AC, check the power/amp specs for that and see if it already has a switch that requires the truck to be running.

 

[Alloy]

all I would need to do is wire an outlet from the inverter to the bed and have a relay put in to stop any power draw when the truck isn't running.

On my FORD trucks the inverter turns off when the battery level drops which isn't very long.

You're better off adding a battery and an isolator.

How to make a cheap isolated dual-battery setup for $50

So there are a lot of kits you can buy to have truly isolated dual-battery setups. Those are VERY NICE kits. They are also very expensive. I try and replicate those kits without spending as much money, while still having a similar level of quality and/or reliability. There are constantly...

expeditionportal.com

 

[Dave in AZ]

Running a fridge in the bed of a truck, is the #1 most answered mobile electrical question I'd bet. There are hundreds of threads describing all the ways to do it, if you search a bit. I'm not dissing you, just saying there is lots of good reading material for you on this, already typed

Various f150 models have different inverter 12v outputs, but it looks like 400w is minimum, and it is already in the bed of truck. You can plug your ac200 in there, and plug fridge into ac200, OR, just plug the fridge aC charger directly into the supplied pickup bed socket. As rruf said, you only need 30w or maybe 60w worst case, to cool the fridge. Once cool it only uses 15 to 30w.

There are hundreds of Youtube videos on setting up a 2nd battery system for a truck. These all involve how to take power from alternator while running, to properly power up a 2nd "house" battery, without risking your starter battery and 40 minicomputers in your car. That thread linked above on a simple battery isolator is one such setup... i love that thread!

The problem comes when folks start mixing batteries. AGM starter, then a lithium house battery...with its own battery mgt system, BMS. Now they charge at different voltages, the bms can chop off lithium charging suddenly with issues, smart alternators can vary output, etc.
I myself would not use a simple relay or isolator either. They were OK with old alternators, but many cars have smart alternators that vary themselves and can cause issues with a simple relay looking for a set voltage. The more "approved" and safer method now, for the well-chippified computer enhanced car, is to use a dc to dc charger like the Renogy one that I think rruff mentioned. Redarc has one they call bcdc too.

 

[Dave in AZ]

RV Solar Power Blue Prints

Building a vehicle mounted solar power system? Let me help.

www.mobile-solarpower.com

Look at the link in there to renogy all in one dc dc unit. It does solar charging, alternator charging, battery isolati9n, smart alternators, charges both start and house batteries, and all types of barreries. Everythi g you need.

 

[EarthboundBob]

Your 100W DC input is more than enough to run your fridge, and would be simpler and more efficient than DC-AC-DC conversion.

If you want to use AC, check the power/amp specs for that and see if it already has a switch that requires the truck to be running.

Apologies if I come off as being tedious, but I genuinely know almost nothing about electrical stuff. Can you help me understand this a little bit better? What/where exactly is my 100W DC input?

I just tested the truck's inverter today charging a cordless drill battery, and it seems to work fine. What I'm wanting to find out is if there's any reason not to just plug a power station (such as Bluetti) into the inverter, with the fridge in turn plugged into the power station. Between this setup charging the power station while driving and a portable solar panel charging it while camped, I think my needs would be covered.

One drawback I've heard is that some power stations don't charge very quickly when plugged into a vehicle's inverter. Does anyone know of a way to overcome this?

 

[NatersXJ6]

You would probably get better answers if you could tell us how long you need the power station to last between driving cycles. No matter how fast your charging, you probably won’t tip off your power station during normal daily drive / commuting.

 

[Alloy]

Apologies if I come off as being tedious, but I genuinely know almost nothing about electrical stuff. Can you help me understand this a little bit better? What/where exactly is my 100W DC input?

I just tested the truck's inverter today charging a cordless drill battery, and it seems to work fine. What I'm wanting to find out is if there's any reason not to just plug a power station (such as Bluetti) into the inverter, with the fridge in turn plugged into the power station. Between this setup charging the power station while driving and a portable solar panel charging it while camped, I think my needs would be covered.

One drawback I've heard is that some power stations don't charge very quickly when plugged into a vehicle's inverter. Does anyone know of a way to overcome this?

When I see portable panels they are in the shade most of the time.