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I am picking up a TGB 11 later this month (so excited!). I don't plan to do anything huge to it for now (waiting on budget to grow a bit) but probably the first project I will tackle will be a 12V system so I can run a GMRS radio, headunit, and backup camera. What is the suggested way to get a 12v circuit running on the truck? I am considering a "converter/regulator" (not sure if that is the right term). I'm presuming these systems mean that I can share the ground but then utilize the positive 12v off the unit to power my electronics? I'll also want a 12v battery to smooth out the power I'm presuming and provide power while the truck is off (I intend to have the 12v circuit manually switched with a dash switch or keyed off ignition via relay). Love to hear what you all have done and or recommend.

Thanks!
-Phil

If you plan on adding a 12V battery then what you want is a 24V to 12V battery charger.
Given an electronics load, e.g. a GMRS radio etc. I'd recommend a LiFePO4 battery NOT
AGM or "wet" cell. The Lithium Iron chemistry has a higher output voltage over lead acid,
and tends to stay flat under discharge, they can take 1,000 of re-charges even after deep
discharge. They won't catch fire either -- nice feature They are EXPENSIVE, but
they will outlive any lead acid AGM effectively costing less over time. Several suppliers out
there, I've used a 60Ahr Bioenno for my 712, as well as one in the house for HAM gear.
Link below for a 40Ahr as you cab see they are way smaller and lite -- no lead !
https://www.bioennopower.com/collection ... blf-1240as

You have to make sure the charger you pick for your truck can be set to charge Lithium
batteries -- different voltage and charging profile than Lead acid. If you were planning
to also toss Solar panels on the roof I'd suggest a REDARC multi-source charger. I have
these in my trucks with panels and LiFePo4 batteries.

https://www.amazon.com/gp/product/B077J ... UTF8&psc=1

There are obviously other ways to get 12V in the truck, but the above has been my approach.

This is similar to my approach, and for all the same reasons. A "12V" lithium from the same mfg as rmel listed, and I used a solar charge controller to do the downconversion from ship's 24V. Using a separate battery like this ensures when you run your 12V accessories that you don't discharge the 24V battery needed to restart the engine. Also, it allows you to have minimal electrical noise for optimal radio performance.

Pay attention to the parasitic load from your charge controller (or simple downconverter) on the 12V system if your truck is like most and spends extended periods of time idle.

As to backup cameras, I'm running a Garmin setup and it's 24V compatible.

Thanks! This all sounds great. Any issue having the connection between the 24v to 12v charger run on a 24v relay that is only active when ignition power is on?

AppleTech wrote: ↑Wed Feb 10, 2021 1:42 pm Thanks! This all sounds great. Any issue having the connection between the 24v to 12v charger run on a 24v relay that is only active when ignition power is on?

if what you're suggesting is a disconnect relay between the 24->12V charger and the 12V battery so when ship's power is off there's no connection out of the charger to drain down that 12V battery, then yes, this is a great idea. That addresses the concern of leakage current from the 12V battery backwards into the charger.

Yes that's exactly what I'm thinking. In this setup that we're discussing, are the grounds shared or does the 12v need to have home run grounds to the devices?

-Phil

I don't know the grounding scheme on the TGB, but on my Pinz my ground gets shared joined at the roof-center antenna connection, and I send home runs back to the battery from the radio.

Couldn't you just change the the alternator to a 12v one....or make a braket and ad one. I believe my brother in law who had a c303 that original came from a Swedisch telephone company had a 12 v system....that's why it was easy to put the cylinderhead/ feulinjection on it.
He also had the original mech winch

This is the one :

Unfortunately switching from 24 to 12v requires rewiring the truck and replacing every electrical item. The C303 civilian versions came with 12v wiring and relays.

AppleTech,
As you noted, doing a 24vdc to 12vdc can be a major undertaking trying to source 12volt C303 parts.

Another option is to run a separate small 12vdc generator/alternator off of one of the two V belts. Obviously. one belt will have to be longer than the other and a mounting bracket will have to be fabricated.

Best wishes in your 12vdc sourcing.

Jim Molloy

Jim Molloy wrote: ↑Thu Feb 11, 2021 12:18 pm AppleTech,
As you noted, doing a 24vdc to 12vdc can be a major undertaking trying to source 12volt C303 parts.

Another option is to run a separate small 12vdc generator/alternator off of one of the two V belts. Obviously. one belt will have to be longer than the other and a mounting bracket will have to be fabricated.

Best wishes in your 12vdc sourcing.

Jim Molloy

Thanks Jim! That was another thought too. I do eventually want to add AC so I'm considering the engine bay free space as well as the load on the engine. I'll probably try to aim for 24v accessories as that is the simplest solution.

Trust me when I say this is all you need. https://www.google.com/search?q=bussman ... xqyFhc3ZtM

I have tried everything and these are amazing and stupid simple. You will have a 24V system with a 100amp 12V system on top. You will likely want to upgrade your alternator at some point as well because the stock one is a bit weak.

The fore mentioned setup does not require a special battery, solar panels or any other type of user manipulation. You can use a smaller 24/12V buck converter for a memory circuit if you wish.

dokatd wrote: ↑Mon Feb 15, 2021 12:09 pm Trust me when I say this is all you need. https://www.google.com/search?q=bussman ... xqyFhc3ZtM

I have tried everything and these are amazing and stupid simple. You will have a 24V system with a 100amp 12V system on top. You will likely want to upgrade your alternator at some point as well because the stock one is a bit weak.

The fore mentioned setup does not require a special battery, solar panels or any other type of user manipulation. You can use a smaller 24/12V buck converter for a memory circuit if you wish.

That's a neat setup. Does it get powered by relay connection so it doesn't drain the batteries while the truck is off? What 24v alternator upgrade options are available for the B30A? The only immediate concern I would have is that the 24v system might be "noisy" for radio equipment? Maybe the separate battery setup gets you cleaner power?

This Eaton unit is an Equalizer, it maintains equal charge
in both batteries while the bottom battery is used for 12V
loads -- shunting charge from the top battery to the bottom.
The 12V output should be pretty clean. The disadvantage
of this system is the risk of discharging your 24V while your
running 12V equipment with the engine off.