Question for electrophiles...

[Sturm]

I ran across an older forum post (yes...Tesla) where the writer claimed to have installed a 2nd 12V battery (utilizing a product from West Mountain Radio called a "rig runner") in his frunk...that was able to get the 2nd battery to pony with the 1st to recharge from the main battery charge. They were then able to utilize the 2nd 12v to run excess...while keeping the primary 12v charged for "non-optional" use. Here's the thread:

https://teslamotorsclub.com/tmc/thr...cond-12-volt-battery-to-their-vehicle.234731/

I'd really like to (eventually) install a real cd/am/fm with good "wired" speakers (gah...i'm old...i can do bluetooth but do I want to?)...but? I don't think it's even close to smart to do that with just the 12V that needs to start/run things. I would really love to pop one of my stack of collected CD's in to my future Slate and feel the burn. ;-)

Do any of you that have electronic or car-wiring experience have a thought on this? Is it feasible...is it a pipe-dream? Does the set-up that the Tesla driver found sound like it would work? Will it even be possible to wire something like this up?

Thanks y'all!

 

[ClayJar]

Way back when I was taking 11,333-mile road trips in my Tiburon, I rigged an auxiliary battery to run things (car camping) when the car was off. The way I did it was pretty straightforward.

I had it pigtailed off a 15A fuse, with a chunky 1-ohm power resistor (20W rated) in line with the battery so the maximum current it could possibly transfer would be around 10A (under 15A for a dead short after the resistor). Usually, the voltage difference would be much less, so the current and dissipated power in the resistor would be much, much less.

I had a simple switch to disconnect the auxiliary battery, but it would be easy enough to also pigtail a circuit that's on/off with the vehicle and use that to actuate a relay to automatically isolate the auxiliary battery when the vehicle is off.

It wouldn't be an appropriate setup for, say, running a big sound system continuously, but for having a nice deep-cycle auxiliary battery for running laptops, phone chargers, lights, small inverters, etc, it worked just fine, and it wasn't much more than a couple bucks of materials from Radio Shack and some wire.

(The resistor also meant that the auxiliary battery wouldn't try to start my car and blow it's tapped-off fuse if the main battery was impaired. If I needed it to jump my own car, I'd just use cables. These days I carry a lithium-ion jump pack in my car for jump starting people's cars.)

I imagine the professional-style implementations might be kinda the same concept but done more thoroughly -- e.g. electronically remove the resistance when the batteries are in balance for efficiency and the most available power on the aux circuit, disconnect automatically when the vehicle is off, etc.

 

[Sturm]

Thanks for the good feedback. It's good to see what does and does not work. I will do more research in to resistors. I like the idea of being able to "disconnect"...will also do some studying on the "pigtailing".

I can build a barn. I can build a cabinet. I have shy 'ed away from understanding electronics. I might be getting old...but I can still learn. ;-)

Thanks again...good info.

Anyone else (I know from other threads that some of you want to do the same...rig a real CD (maybe AM/FM) with good speakers...and not rely on BT?

 

[ClayJar]

I am certainly not recommending this particular Vevor item, but just to show an example of pigtails/piggyback taps:

https://www.vevor.com/wiring-harnes...-ato-atc-atm-blade-fuse-holder-p_010691510150

 

[Trace26]

I ran across an older forum post (yes...Tesla) where the writer claimed to have installed a 2nd 12V battery (utilizing a product from West Mountain Radio called a "rig runner") in his frunk...that was able to get the 2nd battery to pony with the 1st to recharge from the main battery charge. They were then able to utilize the 2nd 12v to run excess...while keeping the primary 12v charged for "non-optional" use. Here's the thread:

https://teslamotorsclub.com/tmc/thr...cond-12-volt-battery-to-their-vehicle.234731/

I'd really like to (eventually) install a real cd/am/fm with good "wired" speakers (gah...i'm old...i can do bluetooth but do I want to?)...but? I don't think it's even close to smart to do that with just the 12V that needs to start/run things. I would really love to pop one of my stack of collected CD's in to my future Slate and feel the burn. ;-)

Do any of you that have electronic or car-wiring experience have a thought on this? Is it feasible...is it a pipe-dream? Does the set-up that the Tesla driver found sound like it would work? Will it even be possible to wire something like this up?

Thanks y'all!

Argodiode Battery Isolators | Victron Energy https://share.google/EBSIkaiqOSQSBhhJR

 

[FlyHappy]

I ran across an older forum post (yes...Tesla) where the writer claimed to have installed a 2nd 12V battery (utilizing a product from West Mountain Radio called a "rig runner") in his frunk...that was able to get the 2nd battery to pony with the 1st to recharge from the main battery charge. They were then able to utilize the 2nd 12v to run excess...while keeping the primary 12v charged for "non-optional" use. Here's the thread:

https://teslamotorsclub.com/tmc/thr...cond-12-volt-battery-to-their-vehicle.234731/

I'd really like to (eventually) install a real cd/am/fm with good "wired" speakers (gah...i'm old...i can do bluetooth but do I want to?)...but? I don't think it's even close to smart to do that with just the 12V that needs to start/run things. I would really love to pop one of my stack of collected CD's in to my future Slate and feel the burn. ;-)

Do any of you that have electronic or car-wiring experience have a thought on this? Is it feasible...is it a pipe-dream? Does the set-up that the Tesla driver found sound like it would work? Will it even be possible to wire something like this up?

Thanks y'all!

so, I'm a little con-fuzzled as to why you feel you need additional 12v power to run a traditional car stereo. I assume you are not talking some elaborate multi-amp/subwoofer thing, right?
the Tesla person you cite is starting with an 800w system (they call it "mild") but plan to grow it from there.

a regular old in-dash combo radio/amp/even cd player driving 2 to 4 speakers isn't any special electric load, nothing approaching 800w. The Slate can handle the electrical needs just fine.

Now, the physical installation, placement, antennae are different issues....

 

[KevinRS]

so, I'm a little con-fuzzled as to why you feel you need additional 12v power to run a traditional car stereo. I assume you are not talking some elaborate multi-amp/subwoofer thing, right?
the Tesla person you cite is starting with an 800w system (they call it "mild") but plan to grow it from there.

a regular old in-dash combo radio/amp/even cd player driving 2 to 4 speakers isn't any special electric load, nothing approaching 800w. The Slate can handle the electrical needs just fine.

Now, the physical installation, placement, antennae are different issues....

The issue is we don't really know what the capacity of the 12v battery in the Slate will be. It could be quite small, especially with the statement from Slate about no always on 12 power available at the dash. I don't think you need anything like a car battery or anything, but something supplemental that can run whatever audio and other accessories you put in for a while without any impact on the existing system makes sense. Probably too early until we know some more about what it does have though.

 

[r6tn]

The RigRunner is just a power distribution block with fuses. Wire it to the battery then wire multiple things into it for power. I have one I've used one for years.

 

[Sturm]

so, I'm a little con-fuzzled as to why you feel you need additional 12v power to run a traditional car stereo. I assume you are not talking some elaborate multi-amp/subwoofer thing, right?
the Tesla person you cite is starting with an 800w system (they call it "mild") but plan to grow it from there.

a regular old in-dash combo radio/amp/even cd player driving 2 to 4 speakers isn't any special electric load, nothing approaching 800w. The Slate can handle the electrical needs just fine.

Now, the physical installation, placement, antennae are different issues....

I appreciate your cofuzzlement of my confuzzlement.

No, I don't want a crazy pumpin-pimpin, high-watt system. I just think I'd like my (entertainment/audio) to be a bit more old-skool and not so much be tied to the Bluetooth of my fone (which I'd like to keep to communication, information & navigation).

Thus? I'm interested in a single-din cd/am/fm with wired speakers. This looks to be feasible but, will pull extra power from the 12v...which normaĺy powers all of the extras. You might be right. Maybe what I'd like to add wouldn't stress the system enough to need the boost & backup of a 2nd 12v.

I recognize electricity as being one of my many weak points.

Here's what I'm asking 1) whether it's really possible to go old-skool and wire something like such up...i know from other Slate-threads here that there are other people that would love to wire in a Din&speakers; 2) if a 2nd 12v auxiliary battery is needed or useful and; 3) if it makes sense...what will be the best path forward.

Thanks for the input!

 

[Sturm]

The issue is we don't really know what the capacity of the 12v battery in the Slate will be. It could be quite small, especially with the statement from Slate about no always on 12 power available at the dash. I don't think you need anything like a car battery or anything, but something supplemental that can run whatever audio and other accessories you put in for a while without any impact on the existing system makes sense. Probably too early until we know some more about what it does have though.

Another 4-6 months and things should be a bit more clear on so many questions...thanks for the grounding. I'm trying to keep myself from diving into the rabbit-holz but, it's hard.

 

[FlyHappy]

I appreciate your cofuzzlement of my confuzzlement.

No, I don't want a crazy pumpin-pimpin, high-watt system. I just think I'd like my (entertainment/audio) to be a bit more old-skool and not so much be tied to the Bluetooth of my fone (which I'd like to keep to communication, information & navigation).

Thus? I'm interested in a single-din cd/am/fm with wired speakers. This looks to be feasible but, will pull extra power from the 12v...which normaĺy powers all of the extras. You might be right. Maybe what I'd like to add wouldn't stress the system enough to need the boost & backup of a 2nd 12v.

I recognize electricity as being one of my many weak points.

Here's what I'm asking 1) whether it's really possible to go old-skool and wire something like such up...i know from other Slate-threads here that there are other people that would love to wire in a Din&speakers; 2) if a 2nd 12v auxiliary battery is needed or useful and; 3) if it makes sense...what will be the best path forward.

Thanks for the input!

I'm one those "other people". I fully intend, if possible, to install a "traditional" FM stereo.
Power is the least of my concerns. The Slate isn't any less of a normal car, in this respect. Just like every other car, it will have an "accessory" position, it will have ability to keep headlights on, and operate interior items, even when the errrrr... "engine is off"

 

[Johnologue]

Most problems I've had with my car, personally, have come from the cheap, tiny OEM 12V battery.

The issue is we don't really know what the capacity of the 12v battery in the Slate will be. It could be quite small, especially with the statement from Slate about no always on 12 power available at the dash.

I've definitely said this before, but I would be disappointed to find Slate using a cheap/small 12v battery; it seems like a spot where the money counts and can prevent a lot of problems.

...I wrote a lot here, but I actually did realize that I know less about the 12V systems on electric cars...looking it up, they can be jumpstarted (but cannot jumpstart other cars).

So, carrying around a portable jumpstarter battery might be worth considering, for both your vehicle and in case you need to help someone else.

But, rather than having a two-battery system for accessory drain, you might get the results you want by just having a larger battery (or Slate's 12V battery/charging being adequate to begin with) and a jumpstarter for emergencies.

 

[Tom Sawyer]

I just think I'd like my (entertainment/audio) to be a bit more old-skool

I'm trying to keep myself from diving into the rabbit-holz but, it's hard.

If it's 'old school' you want, a regular power source should do fine without the complication of adding an extra battery. Slate has not yet released details on their power supply for radios - but with a little patience I'm sure they will provide that info in time.

 

[Kopsis]

In a normal EV, just like a normal ICE, power is normally drawn from the 12V battery only when the primary power system is "off". Once the HV system is active, there's a HV-12V converter that fills the same role as an alternator to provide operating power to the 12V systems (and re-charges the 12V battery). You would only need an auxiliary power system if you were going to have loads with a continuous draw that exceeds the capacity of the HV-12V converter (not yet documented).

Slate's hesitance to prove an "always on" 12V source is likely not related to system capacity. The low amperage demand on the 12V (no cold engine to start) means EVs often use a relatively small 12V lead acid battery. If they allow parasitic loads to drain that battery when the vehicle is off, then they may need to implement a battery tending feature where the HV is periodically activated to top off the 12V charge. And, with uncommanded activation of the HV, then they need to add visible indicators so service people don't hit the disconnect with the system active. Kia EVs do all that and it took them years to get the bugs worked out of the system. It stands to reason that this kind of snowballing complexity is something Slate would like to just completely avoid.

 

[Hootowls]

There are radios designed to not have a constant 12 volt. See my post from April.

Search for Car Radios with:
1. Car Radio with Non-volatile memory
2. Zero Memory Draw
3. Preserved Settings when powered off

For some reason, marine, RV, and heavy-duty radios often have this feature. Crutchfield does not list this in their features. The Sony DSX-M80 is an example, though the price is too high for me. Some of the $100-$150 Pioneer and Jensen's seem to have it (Maybe??). A person on Reddit said his preserved his stations, audio settings, and bluetooth, but not the clock. These radios are available if you look. Let me know what you find.
HootOwls 🦉