Thanks everyone, this is all good info and what I was looking for...and what I was suspecting. It sounds like the DC-DC converter that is pulling from the HV battery to charge the 12v battery acts like an alternator in a typical car....meaning that when the car is parked the FEH radio will be powered by the 12v battery, when you turn the truck on, the contacts close and the hv battery charges the 12v battery through the converter...just like an alternator in a gas version. So if we hook a higher amperage device(s) to the 12v battery (like we do in afermarket car audio in "normal" cars) we will be able to power them with the car off....then when it's powered on the converter/hv battery will charge it again...and with the car ON even though we're physically hooked to the 12v battery, it's the hv battery/converter that is powering the high amp draw electronics, just using the 12v battery like a capacitor to help with surges as gpsman mentioned...
So the limiting factor is the size of the dc converter, if I pull more than that can put out the 12v battery will be dead quickly, no different than sizing to match alternator output in gas cars...which gpsman mentioned can put out over 100amps? Is that correct or is that figuring in a surge supplied from the 12v battery? Gotta admit that's more than I was picturing being available. As I said before, this will be a simple system compared to what I'm used to building for my clients, upgraded front speakers, probably a center channel (when the new DSP processor I'm waiting on shows up) and an upgraded sub, the sub amp will be the largest amp draw...other stuff like integrated bluetooth kit will be small amperage draws.
I'll keep you guys updated when I actually get my hybrid, I don't see to many people on here working on the audio portion so it might be a bit more than your used to seeing, but it will look fairly stock and sound amazing, I promising you that

But for now, did I get my non-technical layout of the electrical sytem worded correctly above?

 

Hey Slick,

I used to be in the stereo/audio business & we sold/installed competition mobile sound systems so I know what you're talking about.

I have a pretty good system in my 06 FEH although it is by no means competition grade (& I don't care). I have an Eclipse DVD/NAV/Bluetooth/BU camera etc HU hooked to a 4 channel 70x4 (at .05%) MTX AMP installed under the driver seat. I replaced all the factory speakers with Infinity components & installed Dynamat Extreme in all the doors, TG etc.

I added a self powered Kenwood sub/AMP with passive radiator under the passenger seat & I still use the factory SUB in the rear.

The FEH handles this easily for over 20,000 miles now.

Welcome to the site :-)

~John

 

Hey John. Yes I checked out your website, nice work. Your one of the few on here I've seen upgrading the audio portion, it's just habit for me, I can't leave anything alone and I love to build things way to much So in hooking up your amps, I assume you just used normal methods...i.e. back to the battery for + ? Any idea how many amps that dc-dc converter is rated at?
I'm figuring on a new sub (and amp) in a similar location to the factory and possibly an amp for the front upgraded speakers...or I may use a new dsp processor/factory integration unit that JBL has coming out that has power onboard already to power my main speakers to save some amperage, then I just need one amp for the sub....I don't want to loose to much space either...the whole reason I'm upsizing from my Focus is I need more room for my many rescued dogs, gotta keep the hatch free of obstacles for the four legged friends

 

I can't give an exact number because I've never maxed it out, but you can take at least 100 amps. I've taken 100 amps from the 14.4v system with engine off, key to run before. ( not using the 12v battery )

 

Great, thanks 100 amps is more than enough...out of curiousity where did you hook up, at the DC converter? Where is that located?

 

No.... I removed the 12v battery totally from the car after it was started, and then turned on all the headlamps, fog lamps, brake lamps, A/C fan, dome light, radio... everything, to see if the HV battery could power everything with a 12v battery dead ( or removed ), and it could.... for 24 minutes.... and all that adds up to 100 amps +/-.

 

I'm the same way (it drives my Wife nuts at times, but she's used to it by now). I remember well her reaction when I bought a brand new Harley for $17,000 & then she came home a week later & found me with the engine all apart for mods)

I hooked the AMPS back to the battery with a 4 gauge Street Wires kit with gold ends (probably overkill, but I had the kit just lying around unused so I decided to use it)

~John

 

The information gpsman1 has provided is correct, and applies in kind also to the Toyota hybrid systems. In my TCH, the 12-V battery has an internal temperature monitor, and the dc-to-dc converter control circuitry also monitors the battery's voltage, and I think current too, so as to ensure that it isn't overcharged, or charged/discharged at too high a rate. It's an AGM (Absorbent Glass Mat) type of battery, that can take repeated deep discharges, but this type must not be charged/discharged too rapidly.

Stan