regulated 12VDC circuits?

[avanti]

As far as I can tell, it is still standard practice to feed all 12VDC loads in a rig directly from the positive battery terminal, which means they are also directly connected to one or more chargers and quite possibly the chassis electrical system. This, of course, means that the voltage is typically no where near 12VDC and bounces all over the place, as well as being subject to various sources of electrical noise. This is certainly the way that my rig is set up.

This made perfect sense back when most rigs had a few incandescent light bulbs, a water pump, a furnace and a couple of cigarette-lighter outlets. However, I am currently using this method to drive a bunch of sensitive LEDs, some with electronic dimmers, a DC television and sound system, laptop chargers, electronic thermostats, an electrically-fussy Espar, several electronically-controlled fans, and who knows what else. So far I have gotten away with this, but I must say it makes me nervous. (And then there is the issue of lithium batteries tending to sit at significantly higher voltages).

Has anyone addressed this? Is it as simple as getting a hefty buck/boost converter such as this:
https://www.amazon.com/Stabilizer-Co...cs%2C88&sr=1-9

Is 30 amps the right size, or is it overkill? Smaller ones get a lot cheaper. They also vary widely in price, even with identical specs. Am I getting anything for the extra money besides "peace of mind"? Or would it be better to get a bunch of little $4 units an put one on each consumer?

Does anybody else worry about this? If so, have you done anything about it?

[Bud]

Originally Posted by avanti

As far as I can tell, it is still standard practice to feed all 12VDC loads in a rig directly from the positive battery terminal, which means they are also directly connected to one or more chargers and quite possibly the chassis electrical system. This, of course, means that the voltage is typically no where near 12VDC and bounces all over the place, as well as being subject to various sources of electrical noise. This is certainly the way that my rig is set up.

This made perfect sense back when most rigs had a few incandescent light bulbs, a water pump, a furnace and a couple of cigarette-lighter outlets. However, I am currently using this method to drive a bunch of sensitive LEDs, some with electronic dimmers, a DC television and sound system, laptop chargers, electronic thermostats, an electrically-fussy Espar, several electronically-controlled fans, and who knows what else. So far I have gotten away with this, but I must say it makes me nervous. (And then there is the issue of lithium batteries tending to sit at significantly higher voltages).

Has anyone addressed this? Is it as simple as getting a hefty buck/boost converter such as this:
https://www.amazon.com/Stabilizer-Co...cs%2C88&sr=1-9

Is 30 amps the right size, or is it overkill? Smaller ones get a lot cheaper. They also vary widely in price, even with identical specs. Am I getting anything for the extra money besides "peace of mind"? Or would it be better to get a bunch of little $4 units an put one on each consumer?

Does anybody else worry about this? If so, have you done anything about it?

Hold up avanti, what happened with the Transit? I do understand that the're in short supply.

[avanti]

Originally Posted by Bud

Hold up avanti, what happened with the Transit? I do understand that the're in short supply.

Did I say I was thinking of upgrading my Sprinter?

[GeorgeRa]

I considered using step down DC>DC converter for Maxxair which was prone to failure at voltages above 13.8V. The project ended on the to-do list never getting attention with other things passing towards the top of the list. https://www.fordtransitusaforum.com/...oo-high.69690/

I never had a failure which I could contribute directly to voltage being too high. Recent issue with fridge LED light bulb was due to failed 24V to 12V converter (Danfoss/Secop) resulting with 24V frying 12V bulb.

I have 100W 12VDC LG LED DMD projector which I could feed directly, but decided to use a 300W Morningstar high efficiency inverter, in practice my main inverter used for all other electronic gadgets like PC, battery chargers or tablets.

[booster]

You could probably just use a DC to DC charger also, as long as the voltage is settable, as they should clean it up well AFAIK. I think the problem with any stabilizing is the inefficiency you put into the system and increased battery use, which could be an issue for a lot of people. When I used a small stabilizer on a native 12v TV, it used the same power as running the TV on AC through a small inverter.



As I have mentioned elsewhere, we have gone to a small inverter an device factory AC chargers for the sensitive stuff. Still trying to decide what to do with Maxxfan, though. Can you block voltage above a fixed level with a Zener diode, or does it take some other stuff to go along with it?

[@Michael]

Could you isolate the sensitive components to a single circuit?

I'd be concerned about the reliability of electronics sourced from random Amazon vendors, the line noise on less expensive electronics, and the parasitic power draw on a component like this.

FWIW - Victron makes 12/12 DC/DC converters for some reason - must be a demand?

[avanti]

Originally Posted by @Michael

Could you isolate the sensitive components to a single circuit?

I am starting to think that this may be the best approach--one or more "clean" circuits, each with its own small converter. I already make it a practice to have multiple, separately-switched circuits, controlled by a nice impressive-looking marine switch panel ("datacom","media", "inverter" and so on) . Makes it easy to manage parasitic loads. Easy enough to regulate a subset of them.

Using a marine DC-DC converter is a good idea. I wasn't particularly suggesting buying from Amazon. I must say, however, that over the years I have had better luck doing so than many people. A lot of that stuff comes off exactly the same line as name-brand products. You just have to avoid counterfeit components.

[hbn7hj]

I use a stabilizer that sets the voltage at 12.8 volts. It is only good for 10 amps so I won’t chase down the purchase info. The other suggestions are better.

The point is-yes, use a voltage stabilizer. I did it to boost the lead acid battery voltage but it also works for dropping the 13.3 volts of a lithium battery.

[roadbiker1]

I put in a "120Watt DC-DC Voltage Reducer Regulator Voltage converter regulator, input range DC 8-40V " from Amazon for $35, of unknown manufacture for the tv and radios, so far so good but it warned that the input DC negative could not be connected to the output's DC negative, so no common chassis ground. Took an isolation x - former to allow use of the built in TV antenna's coax feed. Be careful in there ;- )

[ikanode]

As I remember from the last time that I used a buck-boost converter:

There was a volt or two of voltage drop between the input and output. e.g., with 12 volts in, the maximum output was about 10 volts. It could step up or step down but not regulate. (Also, the output voltage may have fluctuated with the input voltage.)

My "take-away" is to get and read the specs for the device you're considering. Something sold as a Low-Voltage-Drop regulator may work better for your needs.

[W9TR]

Originally Posted by avanti

As far as I can tell, it is still standard practice to feed all 12VDC loads in a rig directly from the positive battery terminal, which means they are also directly connected to one or more chargers and quite possibly the chassis electrical system. This, of course, means that the voltage is typically no where near 12VDC and bounces all over the place, as well as being subject to various sources of electrical noise. This is certainly the way that my rig is set up.

This made perfect sense back when most rigs had a few incandescent light bulbs, a water pump, a furnace and a couple of cigarette-lighter outlets. However, I am currently using this method to drive a bunch of sensitive LEDs, some with electronic dimmers, a DC television and sound system, laptop chargers, electronic thermostats, an electrically-fussy Espar, several electronically-controlled fans, and who knows what else. So far I have gotten away with this, but I must say it makes me nervous. (And then there is the issue of lithium batteries tending to sit at significantly higher voltages).

Has anyone addressed this? Is it as simple as getting a hefty buck/boost converter such as this:
https://www.amazon.com/Stabilizer-Co...cs%2C88&sr=1-9

Is 30 amps the right size, or is it overkill? Smaller ones get a lot cheaper. They also vary widely in price, even with identical specs. Am I getting anything for the extra money besides "peace of mind"? Or would it be better to get a bunch of little $4 units an put one on each consumer?

Does anybody else worry about this? If so, have you done anything about it?

In my view this is a solution looking for a problem.

I don't worry about it because the battery itself is a pretty good voltage regulator/limiter.

I guess it depends on how well the other 12V stuff is designed. If it designed to automotive standards, it can handle 48V spikes and keep on trucking. If not, somethiing like this might save it. Or not.

I'm sure this device will work, but adding another component between your battery and coach electronics can only reduce reliability. The 2 star rating would give me pause as well.

[HarryN]

The way that I handle it is to build all power systems with either a 24 or 48 volt battery pack.

Try to run as much from the DC or 120 vac as possible.

For refrigerators and heaters, the biggest problem is too low of voltage, and using 24 volts solves most of this problem directly.

For the sensitive electronics in the temperature activated 12 volt fans, it pretty much requires regulated DC - DC converter no matter what battery voltage is used, so might as well gain the benefits of 24 volt or higher.

There are some commercial 24 and 48 volt fans on the market and I have toyed with the idea of gutting a max fan and replacing the parts with better components.

As far as the quality and reliability - I tested a number of them and a lot are junk.