How best to wire in 12VDC accessories, Like Ham Radio.

Aces-Truck

Well-known member
First Name
Kevin
Joined
Apr 25, 2020
Threads
7
Messages
113
Reaction score
162
Location
Seattle, WA
Vehicles
2007 Prius
Occupation
Mechanical Engineer
Country flag
I've started thinking about the 48V voltage system. I intend to run a 50W mobile Ham Radio in my CT. So now I have some head scratching as to how to do it. For those not familiar with Ham Radio, there are several Radio "Bands" that we use. The long distance guys do HF bands (High Frequency). All the electrical Hash that any EV puts out, will likely make that type of use "iffy" at best. But I would mainly be doing UHF/VHF bands. These can often handle the hash. But the issue for me will be all the radios out there are 12VDC. I see they make Buck Converters that can convert 48VDC to 12VDC. And they are quite cheap. I've seen models that can handle 10A at 12V on the output (120Watts) for $20. But how likely are we to be able to just tap into the 48V wiring? This is something Winches would have to deal with as well.

The other way to do this is to use the USB-C ports inside the cab. I'm surprised they are only 60W. But most Mobile radios are 50Watt. I wonder if we'll be able to find USB-C to 12VDC adapters?
Sponsored

 

Variable556

Well-known member
Joined
Sep 21, 2020
Threads
1
Messages
70
Reaction score
104
Location
West Virginia
Vehicles
Explorer, Escape
Country flag
I think your solution is simply to plug a converter into the 120 outlet in the center console
That would be what I’d lean towards trying first. With the way components talk to each other and/or may be monitored in canbus, I’d be afraid to tap into anything that wasn’t specifically provided for tapping. It might seem to work at first, then introduce gremlins down the road.😅
 

fhteagle

Well-known member
Joined
Sep 28, 2022
Threads
5
Messages
291
Reaction score
652
Location
Telluride, CO
Vehicles
2013 Volt, CT Res x2
Country flag
The other way to do this is to use the USB-C ports inside the cab.
There's such a thing as USB-C "decoy" converters that will take a PD source and spit out a predefined voltage like 9V, 12V, 15V, etc. Not sure the amperage ratings, ripple stability, etc. But I've seen various ones on Temu and AliExpress. Linus Tech Tips did a whole video about replacing DC in barrel jacks with those.
 


ÆCIII

Well-known member
Joined
Apr 27, 2020
Threads
10
Messages
1,062
Reaction score
2,497
Location
USA
Vehicles
Model 3
Country flag
The web site says that 120 VAC is also available inside the cab. So you may find it easiest to use a 12VDC power adapter off of those, or even use gear that operates at 120 VAC if the wattage is not too much:

Tesla Cybertruck How best to wire in 12VDC accessories, Like Ham Radio. 1701632275523


- ÆCIII
 

Jager

Active member
First Name
Jeff
Joined
May 25, 2020
Threads
2
Messages
41
Reaction score
161
Location
Virginia
Vehicles
2022 Model 3 LR AWD, Several Motorcycles
Country flag
...
The long distance guys do HF bands (High Frequency). All the electrical Hash that any EV puts out, will likely make that type of use "iffy" at best.
Well, if the CT ends up putting out "all the electrical hash that any EV puts out" it's going to affect your 2m rig, too. Not just HF.

The good news is that that old chestnut about EV's being electrically noisy is certainly not true across the board. I can't speak to other vehicles, but my 2022 Model 3 LR AWD is very clean from an RFI perspective. I run a 50-watt VHF/UHF radio in it without any problems.

I expect the CT to be every bit as clean.

As for how to power any 12v devices, a 120v inverter would work.
 

Zelectric

Member
First Name
T
Joined
Jan 26, 2022
Threads
1
Messages
16
Reaction score
20
Location
LNK
Vehicles
2015 Tesla MS P90D 2021 Tesla M3 LR
Country flag
48v to 12v convertors are common for forklifts and golfs carts as well.
 

scottf200

Well-known member
Joined
Jul 31, 2021
Threads
39
Messages
1,549
Reaction score
2,487
Location
Chicagoland
Vehicles
Tesla Model X
Country flag

Timelord

Active member
Joined
Apr 18, 2023
Threads
2
Messages
41
Reaction score
75
Location
North America
Vehicles
Subaru Ascent
Country flag
A winch will absolutely have to be 48v natively.
I think your solution is simply to plug a converter into the 120 outlet in the center console
Winch option exists, which means the power to draw from is there. 48v to 13.8v or 12v are readily available with 2kw or more capacity. A couple of 12v car audio system capacitors could even help shore up reliability and lessen stress on the converter. Native 48v winch would be 'ideal', but the massive selection and availability of 12v winches along with bonus 12v power makes it a very easy sell to go that way as well.

The poor man's option is a cheap low powered battery charger and dedicated 12v battery in the frunk with the winch. That would certainly work, but the other children would rightfully laugh at you, Ralph. 😅
 


Tiberius

Well-known member
Joined
Sep 2, 2023
Threads
0
Messages
190
Reaction score
400
Location
Texas
Vehicles
Model 3
Occupation
Chief cook and bottlewasher
Country flag
Lots of USB C to 12v adapters out there
 

agordon117

Well-known member
Joined
Jan 11, 2024
Threads
4
Messages
971
Reaction score
1,629
Location
Ohio
Vehicles
cybertruck foundation awd
Country flag
A winch will absolutely have to be 48v natively.
I think your solution is simply to plug a converter into the 120 outlet in the center console
Just found this thread, you cannot run a winch on the tiny 48v battery in the cybertruck. It won't support the load.
 

Woodrick

Well-known member
First Name
Ed
Joined
Dec 30, 2023
Threads
3
Messages
2,345
Reaction score
2,891
Location
Gainesville Ga
Vehicles
Model 3, Model Y, SOON to be Cybertruck
Occupation
Consultant
Country flag
Just found this thread, you cannot run a winch on the tiny 48v battery in the cybertruck. It won't support the load.
While not necessarily disagreeing with you, remember to look at wattage and not amperage. 48V @ 3A is equal to 12V @12A.
And the bigger question is not necessarily the battery size, but how much will the HV battery to 48V battery supply.

And the biggest question is where can you get to the 48V connections and what is Tesla going to do to them. Are they one when you want them to be? Do they turn off automatically?

Tesla tends to monitor everything and will kick off loads that it doesn't like.

But in response to the OP, NEMA 14-50 in the back, full legal limit amp!
 

agordon117

Well-known member
Joined
Jan 11, 2024
Threads
4
Messages
971
Reaction score
1,629
Location
Ohio
Vehicles
cybertruck foundation awd
Country flag
While not necessarily disagreeing with you, remember to look at wattage and not amperage. 48V @ 3A is equal to 12V @12A.
And the bigger question is not necessarily the battery size, but how much will the HV battery to 48V battery supply.

And the biggest question is where can you get to the 48V connections and what is Tesla going to do to them. Are they one when you want them to be? Do they turn off automatically?

Tesla tends to monitor everything and will kick off loads that it doesn't like.

But in response to the OP, NEMA 14-50 in the back, full legal limit amp!
I know how electricity works. A winch for my jeep, with a 10,000 lb limit (cybertruck may need a beefier winch), can draw 465A. While the high voltage pack can certainly provide enough power, the 48v battery, likely cannot. No matter how you assume the conversion, you're still asking for ~115A from 48V, if you have something that converts (or a 48v native winch) with 100% efficiency in the conversion.

While I'm not an insider, and I don't know exactly how everything is wired up in cybertruck, I do think it's unlikely the 48v supply is capable of feeding that much power. We're talking about 5.5kW here. So likely something would have to hook up to the 240v plug in the bed. Even a jumpstart only needs to be 100A at 12v. So even if it's designed to be able to jump an ICE vehicle, that doesn't mean it can handle a winch.

I've actually been thinking about this topic quite a lot. I have a compressor in my jeep as well that I like a lot, it runs 12v. Don't have a way to run it in cybertruck. So the answer likely will be the one that tesla is selling (since there aren't many super tiny 120v options), but they haven't posted any specs of that compressor yet. So it's hard to know how it will compare.
 

Woodrick

Well-known member
First Name
Ed
Joined
Dec 30, 2023
Threads
3
Messages
2,345
Reaction score
2,891
Location
Gainesville Ga
Vehicles
Model 3, Model Y, SOON to be Cybertruck
Occupation
Consultant
Country flag
I know how electricity works. A winch for my jeep, with a 10,000 lb limit (cybertruck may need a beefier winch), can draw 465A. While the high voltage pack can certainly provide enough power, the 48v battery, likely cannot. No matter how you assume the conversion, you're still asking for ~115A from 48V, if you have something that converts (or a 48v native winch) with 100% efficiency in the conversion.

While I'm not an insider, and I don't know exactly how everything is wired up in cybertruck, I do think it's unlikely the 48v supply is capable of feeding that much power. We're talking about 5.5kW here. So likely something would have to hook up to the 240v plug in the bed. Even a jumpstart only needs to be 100A at 12v. So even if it's designed to be able to jump an ICE vehicle, that doesn't mean it can handle a winch.

I've actually been thinking about this topic quite a lot. I have a compressor in my jeep as well that I like a lot, it runs 12v. Don't have a way to run it in cybertruck. So the answer likely will be the one that tesla is selling (since there aren't many super tiny 120v options), but they haven't posted any specs of that compressor yet. So it's hard to know how it will compare.
Let's step through the questions.

The existing 48V connections are limited to 400w (I finally saw the spec). That's 30+A @12V, so while it's not bad, it isn't 465A.

A 5kW 12V AC inverter is pretty big and expensive. The most cost-effective solution may be to have one (or two or 3) lead acid batteries in the truck to have the CCA to run the winch. You can keep them on a trickle charge but need to be really careful about venting them. Aside from the flammability of the gases of the gasses coming out, the corrosive nature over time can be ugly. And these probably need to be classic car batteries, not SLA or others, to be able to get the CCA needed.

There are USB air compressors now and that's what you want to look at. USB-C can put out a fair amount of power. That's what the Cybertruck's charger is expected to be. And of course 120V is available. Just carry a little 3gal compressor and tank with you, so much faster!

For the serious off-roader, I think that I can easily see a vault in the back bed, maybe custom to fit around the spare, to carry things like the batteries and the winch.

Isn't that part of the fun? Making a vehicle your own? There are a number of third-party manufacturers that would probably love to get some ideas of products to make.
Sponsored

 
 




Top