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Where to put the power inverter...

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  • Where to put the power inverter...

    So I just got a new vehicle; 2005 suburban. (2000 - 2005 body style tahoe/suburban/yukon/yukonxl)
    I am now trying to figure out where to wire my power inverter. hmmmm....
    In my previous vehicle (acura RL) I had it wired underneath the spare. Unfortunately the run made it difficult to run adequate wire and I could only get enough wire for a 300w inverter. I would like to run a 2000w inverter this time around so that I can run tools off of the inverter (that was part of the original goal with the acura, the 300w inverter fell short by a long shot.) Running a large enough cable to the back of the suburban (longer distance) would require a much larger cable and be much more difficult.
    Im interested in running it in the engine bay then running 120v back into the truck where I need.
    I have the immediate issue of where to put the power inverter in the engine bay (does anyone know of a good spot?).
    But once I get it there, am I going to run into issues with heat and such?
    Can anyone think of a better spot for the power inverter?

    The power inverter wont work under the seat (i know this is the first option =p). The front are power seats, mid are captain that would end up folding down onto the inverter, and the rear seats are removeable. Wherever the inverter goes, the suburban needs to be able to obtain its ability to be a suburban (fold seats down for storage, etc.)

  • #2
    Alas it's pretty much up to you.

    Ideally all electronics and batteries etc should be in the cabin because that's generally the cleanest, driest and coolest else most moderated environment.

    For an inverter, the engine bay (ie, near the alternator) is good because of the shorter heavy gauge requirement. But it means higher ambient temperatures (generally each 10C/15F else 15C increase doubles electronic failure rate) and a contaminating environment. It might require a longer AC run thru firewalls etc, tho unlike domestic AC it should not be a hazard for a single sided fault (ie - inverters should have isolated outputs that are floating aka independent of input DC +ve & -ve), but an RCD (Residual Current Device) can be used on the inverter output.

    The boot/trunk is usually the 2nd preference after the cabin depending on cable requirements, but they can be the hottest location on average in hot climates (solar heating; no ventilation).


    • #3
      I realize the heat failure rate issue. But I thought it was heat failure while the device was running.
      You said average temperatures (and italicized it, so I image you're making a point there, lol). Are you speaking of when the device is running or over the lifetime of the device.
      IE, if I put the inverter in the trunk (cargo area, bed, boot, w/e you call it) of the suburban it will have a higher lifetime average, but when its actually running the ambient should cool off relatively quickly. However, if I put in the engine bay, the reverse is true; lower lifetime (more air circulation when the truck isnt running) but its going to get a lot warmer when the engine is on.


      • #4
        My 1500w inverter is on the rear cab wall of my crew cab so long runs certainly are feasible. I ran the heavy guage down from the battery to the frame rail then along the frame rail and up through the floor right below the inverter. I have done this on 4 of my trucks from back in 99 all the way up to my current 07, all high mile applications in harsh winter weather and suffered no ill effects. Maybe you could find a spot on one of the side panels in the rear cargo area?
        My 2007 Ford F350 Work Log located HERE


        • #5
          I was thinking about that, the passenger panel is taken up by the rear HVAC system (blower stuffs) but the drivers side is mostly clear. Unfortunately that leaves me running the length of the whole suburban (22ft) and across.... conservatively were calling that 25ft-30ft of run. For 2000w thats going to be a large cable.
          What cable did you end up using when you ran the 1500w inverter? and How long was the run?


          • #6
            I personally would not put in engine bay unless you put the inverter in an enclosure. Most inverters I have seen or used are not element tight. You risk having the unit get splashed with water/snow/salt/grease/oil/ect. Then there is the extra heat element produced by the engine in the enclosed space under the hood. I would run 2 or 4 gauge wire directly from the battery to where ever you put the unit. You should also be aware that 2000watt inverter will draw big time on your battery, if an older battery it will definately shorten it's lifespan. If you want to power tools from your vehicle depending on how many or what tools you will be using I think you best bet would be a portable generator, much more dependable and won't leave you stranded on site should you deplete your battery. Putting the inverter in an enclosure will require some thought as to size for ventalation, ease of access to plug in your tools ect. Good luck and only my personal opinion SNO


            • #7
              I figured out the issue with tools and battery drain.
              Realistically I won't be using the truck as an on-site generator (we have a generator for that) its more of the on-site "I need to plug this in for a short time" generator. Like when you're building something out of wood then realize "crap I need to cut this metal bracket and my only metal cutting blade is on the 110v saw". Instead of having to leave, go to the barn and get the generator, come back, start it up, figure out its out of gas, send someone to barn to get gas, realize they got diesel and send them back for "no not that gas can", etc. etc. etc. Then you can just turn the truck on, plug the saw in, make the cut and keep it rolling.
              In terms of the battery; the suburban has a secondary battery install location; going to utilize that with a deep cycle to run things. I also have a loose plan for an extra set of 12v lights on the rear and capability to hook the radio up to the secondary battery. But all that is small gauge compared to the inverter. The point being, the inverter will pull from a seperate battery than the truck's start up battery. So it should not leave me stranded in the middle of nowhere. (The batteris will be seperated via isolator).
              I have a smalll roll of 2 gauge wire (like 25-30ft) but I'm not sure that will be enough. As you said 2000w its a chunk of power to be pulling through the cable for that distance.
              Its the reason I'm looking for opinions before I start chopping everything up ^_^.

              It sounds as if I'm going to end up running the wire to the back of the car =/


              • #8
                Do you have the center console in your truck? Your truck has the same chasis as my Avalanche and if you have a center console there is a lot of room inside the console. Assuming you have the console pull up the drink holder and you will see the console has a large open area under it. This might be an option. My truck has the bose sound system and I guess the console is part of that package since the sub is in the front of the console and the amplifier is under the storage compartment. But there is a "hidden" area under the drink holder.

                I am moving my BOSE amplifier to the area in front of the compartment so I can put my PC where the BOSE amplifier is. In my setup I am considering putting a fan in the rear of the console to get air moving through the console. It has HVAC piping as well so I am considering cutting a hole in this piping to allow for an air source to cool the PC off. Even if I have the heater on the air is cooler than the air off the PC so it would cool it. I would assume the same for an inverter.

                An issue of mounting the inverter in a sealed container is that it needs air movement and a sealed container will likely not provide that. There are weather proof inverters available that you could use. You can also pick up the 2nd battery tray from GM if you don't already have one. Might be a decent place to mount your inverter if you do it under the hood. This would put a tray on the rear of the passenger fender.

                One thing to be aware of. Inverters do a poor job with inductive loads such as power tools. Especially things like drills and saws when they are under load. We have a 1500W and 2000W inverter in work trucks. They were installed to power our ventilation systems for confined space entry but they tried to size them bigger than needed so they could use powered tools. What they have found is they just do not work well. They tripped out all of the time when under load so they now carry wireless tools and just power the chargers off the inverter.


                • #9
                  Sounds like you have it figuired out as to what you want out of it and for what purpose. Could you not get away with a smaller unit say a 1500watt (should be fine for a 7 1/4 saw) Anyhow you only need to run 1 run of that cable to the back and use a small length for negative frombattery to a good bare metal spot on the frame then at the back use the another small piece of that 2 guage from bare metal on frame to inverter. your 30ft roll might just do it. SNO


                  • #10
                    From my understanding the things underneath the center console should be the amp (directly under the storage container) and the subwoofer (forward of the cup holders). This was changed in 2003 from a rear subwoofer (in the driver rear cargo area) to its current position.
                    Having a look; I dont see much usable room.... here are some pictures i snapped.
                    there is a molex cable running through the pictures, I planned on running 120v to the center console, so the cable is already in place (i had to do some work with the dash off, so it was the right time to do it.)
                    Heres a top down image
                    Click image for larger version

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                    Gives you an idea of what im looking at. The wires in the center there could be re-routed without too much work, but that little area is about 4x4x10? not much room for an inverter

                    Back of the console
                    Click image for larger version

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                    the metal bracket that is shown supports the center storage area, underneath the bracket is the amp for the bose system.

                    Front of console area
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                    I think this is the subwoofer. That black "pipe" to the top left of the image is the blower for the feet warmer. I apologize for the picture on this one, not much room for the camera.

                    Length picture
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                    This convenient little channel runs down the length of the center console. Not much room to put larger things, but a great way to route wires.

                    Int he first picture there is the black plastic molding (the one with the hole & chalk writing on it). After poking around I have no clue what is in there. It seems to be part of the larger frame of the center console so im iffy about chopping it up without an idea of what is underneath there. Guess you could say I'm just not as courageous as others around here.


                    • #11
                      Also, what are some preferred brands for inverters? When I was picking them up for the acura I was in a hurry, so I swung by home depot and picked up a 750w black & decker for cheap.
                      Then realized that I couldnt run 750w so I ended up returning it and buying the cheaper black & decker for 300w.
                      I imagine there are some higher quality brands around.


                      • #12
                        Sorry - just back from a gig. Some Hollywood band called Evil Beaver. (Yeah - some band! I saw them last week at another gig. Very impressed. Not everyone's cup of coffee being merely a drummer and a bassist/singer.)

                        Re inverters (and amps etc), a rough rule (or ROT = Rule Of Thumb) is to divide their output (Watts) to get input DC Amps. Hence a 2,000W inverter (or amp) will take up to or about 200A at typical 12V vehicle voltages under FULL load. That's more than most highbeams and may be of a similar Amperage to starter motors.
                        But that's at FULL output. (And it's RMS aka average output - peak Watts is irrelevant!)
                        And if you only run a 50W or 90W PC then it's only 5A - 9A instead of 200A... PLUS the inverter overhead ie standby current which these days is usually small - maybe a few Amps.

                        FYI - My first inverters were 150W etc for the odd 240VAC chargers I had. And of course the all important coffee grinder.
                        Though those 150W inverters have now been replaced by 600W inverters, my current consumption is the same because the loads have not increased. In fact the load is probably less since the newer 600W inverters have a lower standby (aka idling) current as well as better efficiency. (The latter despite inverters typically being most efficient at say 70-89% of full load, but since overall efficiency of the newer is better, a 10-20% loading of the 600W inverter is less than or similar to the 40-80% loading of the 150W inverter.)

                        I think you understand re heat and lifecycle/lifetime. If NOT running, the temp essentially does not matter. (Provided its "storage" temp specs are not exceeded. But whilst a device may only be rated to 85C for OPERATION, it may have a storage temp up to 110C etc.)

                        And essentially a device has a certain temperature rise during operation (at a specific load). Put that in an engine bay which is say 50C hotter than the cabin, then add 50C to its cabin operating temperature - hence a 32x shorter lifespan in simple theory based on half the life per 10C increase. (It will actually be cooler due to increase infrared heat losses, but hey, this is supposed to be a KIS else worst-case deign.)
                        But if a component exceeds its max operating temperature, then it's instant death. Many components have an 85C rating thou some have 105C etc (eg, some capacitors).
                        And engine bay temps vary greatly. Since most thermostats are rated at 85C, that means a coolant exit temp of at least 85C. If 85C, the air temp of air coming thru the radiator will be a MAX of 85C, but it might only be 60C etc depending on air speed. But then there might be cooler air from under the engine, but maybe (or probably) not in the upper engine bay where <whatever> is mounted. And then there's the MUCH hotter air coming from the hotter (than 85C) exhaust and splugs and maybe head. But if the sides of the engine bay are cooler due to wheel-well cooling and front venting... [Tho radiator cooled vehicles are usually designed to pull air thru the radiator - hence no other venting, and hence radiator shrouds etc. (Hence why removing shrouds or having bonnets partly open may result in engine overheating.)]

                        Geez I can go/ramble on. And on...!
                        In short, avoid the engine bay. Tho as SNO suggested, an enclosure - which is ALSO vented from outside - WITHOUT letting in water or dust & contaminants... (And IMO filters have their own hazards, but I'll skip that ramble!)

                        How would I design it? Let's assume a rear mount for all the reasons above.
                        A 22' run - lets make that 10m (33').
                        Assume my (ideal) design limit of 0.5V max drop.
                        And let's go the full 2kW for now.
                        Hence 200A at 0.5V (max drop). V=IR hence R=V/I = 0.5/200A = 2.5 mR (milli-Ohms) for 10m (=0.25mR/m) = 250mR = 0.25R per 1km.
                        From powerstream's 'merkan Wire Gauge Table, 00G is 0.255512 R/km.
                        Damn - too big (a cable) for my usual design approach.

                        Ok, defeated for now...
                        Let's assume 2G and be more accurate.
                        2G = 0.1563 R per 1000 feet or mR per foot. (Dear Lord, forgive me for using Imperial! But hey Man Esq, let's face it - it makes sense in this case! PS - IMHO of course!)
                        Hence 22 x 0.1563 = 3.4386 = 3.5mR.
                        200A a 3.5mR = 700mV = ~0.7V for that 22' run at full 2kW output.
                        Ok, not too bad...
                        Let's assume a total 1V drop at full load taking into account a fuse & various connection losses BUT assuming a negligible GND resistance - ie, a short run of 2G or better (2 x 2G?) to body/chassis which gives a near zero resistance to battery -ve.

                        Many inverters cut out at 10.5V (usually to protect the battery, but can also be to protect the inverter), hence with 2G, full 2kW output should be achievable with a battery terminal voltage of 11.5V and higher.

                        I'll leave it there because the next step needs definition - eg, what is your battery terminal voltage @ 200A - and that depends if the alternator is charging (and what it outputs at the relevant RPM) or not.
                        But assuming it's the only load with engine off and the battery is fully charged (say 12.7V internal voltage), that means a batter internal resistance of less than [12.7-11.5V = 1.2V/200A = ] 6mR which essentially means an AGM battery - and that's only for start up. How long it lasts depends on batter capacity. (Tho AGMs are usually ~12.8V internal voltage, but that's only minutes difference.)

                        Ooops - I was going to leave it yet I started the next step's confustigation.
                        Last edited by OldSpark; 04-11-2014, 11:39 AM. Reason: Evil Beaver ate too many letters & words!


                        • #13
                          Wow, that is a lot of useful information.
                          Funnily enough, I'm in school as a mechanical engineer and the imperial unit drives me insane as well. Unfortunately, it's hard to reset the hands on portion of the brain to metric when everything is written in imperial. I'm not averse to using 00 gauge wire if that's what needs to be done. I was just hoping for an easier solution. Alas it is better to run 00 and run it once than run too small a wire and spend the remaining time kicking myself for being cheap.


                          • #14
                            Whether it needs depends on many factors.
                            I've given an example for a 200A load with a max drop of 0.5V - ie, max 2.5mΩ total - and assumed it's all cable - ie 33' of cable. But even that is too thin if you're running solely off a fully charged AGM battery with ~6mΩ internal resistance. And since your cranking battery is probably a flooded type and hence probably over twice that internal resistance (eg, ~14mΩ), it still won't work.
                            Remember - when cranking, a battery's terminal voltage might drop to 10.0V or lower but an inverter at that voltage would simply turn off.

                            However, if the alternator is charging and outputs say 250A at idle or 2,000 RPM hence maybe a 400A alternator etc...

                            Or if you only have a 500W load instead of 2kW...

                            And there is a point where the battery becomes the issue - ie, drawing 200A for a minute may severely effect battery life - as well as leaving you stranded somewhere. So hence dual batteries which ~halve the internal battery resistance, or maybe 2 separate AGM batteries in parallel each with similar capacity to your wet-cell cranker which would have 1/4 the internal resistance of the cranker.
                            And since the extra battery(s) might be in the rear & hence a shorter run to the alternator... However if the inverter is to run for a long period whilst the alternator is charging, then there is no saving in cable sizing. In fact the cable needs to be larger if battery recharge currents are involved.

                            But that's typical Engineering. There is no single design nor solution - it depends on what is desired and what is used etc.
                            The first step however is to decide what load you are designing for - ie, how many Watts? (Then how long for, with or without the alternator, etc.)

                            If you have the 2G already, I'd do a temp install or mock-up and test that.
                            Last edited by OldSpark; 04-11-2014, 01:43 PM.


                            • #15
                              Standard use for the inverter will be for xbox & TV, etc for road trips. Small battery chargers (18v), the laptop, when working on stuff. Small mini fridge for camping trips (not even sure about the mini fridge).
                              Larger more non-standard use will be... plugging in blender when at the beach, powering a small pump to clean out the little horse trough, running small air compressor when the tractor tire pops off in the field.

                              Currently my plan is as follows...

                              AGM battery installed in the secondary battery position in the truck (There already a mounting place for that). Isolator to prevent the truck from being drained.
                              2 Gauge wire running from the battery to the isolator to the alternator (most likely excessive, but I have the cable so why buy anything smaller, right?)
                              000 gauge wire running from the battery to the back of the vehicle for the inverter. I will also line off the 12v for a set of lights off the back. They are smaller lights (3") and only use 55w so it really shouldn't be an issue, but I upgraded the wire size for that reason.

                              Ideally I should never need to pull all 2000w from the inverter for more than a few minutes and I most definitely wouldn't do it with the truck off. In the event the truck does die (as is my luck) the starting battery is isolated anyway. I would worry about the inverter damaging the battery, but seeing as most do an auto kill at 10.5v (i remember mine doing that) im not too worried.

                              Whatcha think?