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What/Where Is The Power Supply For The 12 Volt Battery?

Discussion in 'Prius v Accessories and Modifications' started by FlyboyTR, Jun 24, 2024 at 12:23 PM.

  1. FlyboyTR

    FlyboyTR Member

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    In the past I have used an inverter wired directly to the 12 volt battery. That has worked well for years. However, I am wanting to install a different inverter but want to install it in the engine compartment.

    So, where does the 12 volt power originate from that feeds the battery? Is this main 12 volt cable attached to the hybrid inverter? I know that on the bottom, back right hand side of the inverter (as viewed from the front) there is a single wire output lug...is that the main feed that goes to the 12 volt battery? If so...that would be convenient.

    Any insight would be appreciated! Thanks.

    Travis
     
    #1 FlyboyTR, Jun 24, 2024 at 12:23 PM
  2. ChapmanF

    ChapmanF Senior Member

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    Yes, that's the DC/DC converter output. However, the 125 amp fuse link protecting it is inside the underhood fuse box.

    A good place to make a tap for your inverter is along the 12-volt frame wire—the one running from the fat white connector in the fuse box back to the 12-volt battery + clamp. Your tap is then protected by fuse links on both sides, the 125-amp one in the fuse box between it and the converter, and the 140-amp one in the + battery clamp between it and the battery.

    Naturally, the wiring you add still needs its own fuse, unless both it and your chosen inverter can safely withstand the maximum fault current the 140-amp link could allow.

    When mounting the inverter aft, it is easy to add a ring terminal where the frame wire bolts to the 140-amp fuse link. i haven't personally done a project where the inverter was added in the engine compartment, but the same principle would apply.

    I lean toward seeing the back of the car as a less-hostile environment for the inverter than under the hood.
     
    #2 ChapmanF, Jun 24, 2024 at 12:42 PM
    Last edited: Jun 24, 2024 at 12:48 PM
  3. FlyboyTR

    FlyboyTR Member

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    ChapmanF,

    Thanks for the prompt reply and detailed info. I will take a look at the cabling you mentioned. Connecting after the fuse would always be a better option. I will give this some additional thought as installing the new inverter back in the rear, would be easier. :)

    For a number of years I have ran a large inverter under the hood of my Ram truck (Cummins diesel). We had to replace all the cheap capacitors and a few other components on the board. After that, it held up fine for 6 years. I primarily used it to operate a 110vac air compressor. So having the inverter close to the battery source (two batteries on the Cummins), reduced the line loss with having a long run to get the inverter inside the truck.

    Great to hear from you. Your info I always appreciated! Thanks again!

    Travis

     
    #3 FlyboyTR, Jun 24, 2024 at 12:51 PM
  4. ChapmanF

    ChapmanF Senior Member

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    If that'll be the primary use, a direct-wired 12-volt compressor might be another option with a simpler energy-conversion path. Alongside an inverter, if 120 VAC is still wanted for other stuff.

    [​IMG]
     
    #4 ChapmanF, Jun 24, 2024 at 1:10 PM
  5. FlyboyTR

    FlyboyTR Member

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    Three
    Good idea...but wouldn't work for our needs. We do a lot of off-road stuff...so we are frequently airing down and up large tires as well as close friends tires. The air compressor in the truck runs at 15 amps and provides 12.5 cubic feet of air per minute. The inverter in the truck is 6K watts so it can easily handle the starting load of the compressor.

    With the prius, we pull a micro-camper and the inverter in the prius basically provides current to the little camper to run inside/outside lights and our heated mattress pad. OH...and the heated doggie pad on the floor. Works good when we're cool/cold weather camping on the cheap. Otherwise...the Ram is pulling our fifth wheel for when we're doing normal people camping! LOL

    All things said...I believe it will be easier to just connect the new inverter back to the battery (as it was previously). We'll see!

    Thanks again!

    Travis
     
    #5 FlyboyTR, Jun 24, 2024 at 1:44 PM
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