DC/DC converter education . . where?

I'm boondocking for 3 days in the So Cal heat. I have a water supply 100' from me, I have 2 Honda 2ks running in parallel to run my air, plenty of gas, and the best part..my nearest neighbor is 500' away. Those generators will run all day if they have to.. but I've never run them at night.

Many people come on the board and ask about getting a gen to run the air, but, true the reality I always mention to them, I'm the only one here actually running my air.

Sorry to hear about your health issues. For the first few years, breathing So Cal air was not good for me (dust, sand) after breathing Seattle air for many decades.

2oldman wrote:
Gdetrailer...

Not EVERYONE keeps an inverter turned on 24/7 like YOU might..

No, they don't.

CONSERVATION is “key” to boondocking, it is far cheaper to CONSERVE energy when off the grid..

I don't conserve water either. I invest time and energy into getting more.

The more you waste means you have to have more battery and more battery means it takes longer to recharge, YOU must have more money to “burn” than me.

I do. Everyone has his or her level of comfort. When boondocking, I want to be as comfortable as I am on hookups. To me, it's not a test of endurance or how much money I can 'save'. I didn't invest thousands in solar, batteries and generators to see how little I could use them.

I don't BOTHER "boondocking", I do OVERNIGHT though.

I don't bother with "boondocking" because my "comfort" is far more important than trying to hyper mile my setup or go out of my way into the far backwoods. I pretty much have no choice but to book places with power..

Not because of my home fridge but because of my allergies and other health issues which pretty much requires the exclusive usage of airconditioning during the summer..

I can sometimes getaway with stopping overnight without A/C in the summer depending on how hot is was during the day.. Often I will just run the gen and A/C when I stop for a half hr which gets the inside temps down to a manageable 80 degrees..

For me sleeping with windows open will result in a trip to my doctors office and then to the pharmacy.. Done that a few times on several trips, don't like it..

It would cost me way too much to run a generator all night and all day just to keep my trailer at reasonable temps and humidity.. FAR, FAR cheaper to pay a little more for a campground WITH commercial power.

Gdetrailer...

Not EVERYONE keeps an inverter turned on 24/7 like YOU might..

No, they don't.

CONSERVATION is “key” to boondocking, it is far cheaper to CONSERVE energy when off the grid..

I don't conserve water either. I invest time and energy into getting more.

The more you waste means you have to have more battery and more battery means it takes longer to recharge, YOU must have more money to “burn” than me.

I do. Everyone has his or her level of comfort. When boondocking, I want to be as comfortable as I am on hookups. To me, it's not a test of endurance or how much money I can 'save'. I didn't invest thousands in solar, batteries and generators to see how little I could use them.

2oldman writes “When dry camping, my inverter is never off, so the 0.5a (in my case it's higher) is a 'sunk cost' to me. I turn off unneeded devices at night, but never the whole system. I have 640ah of batteries and 835w of solar. hondochica, while maybe not that endowed, sounds like he has plenty o' power too.

If you want or need to conserve, then yes, by all means turn your inverter off when you can. But on larger systems, where the inverter is never off, these "inefficiencies" are a very small part of the overall energy picture.

I don't know what hondochica's 'great' battery bank exactly is, but if it's large and easily rechared, he may too conclude it's not worth it. Is it wasteful? Yeah. Is it "incredibly wasteful"? No.”

Greenrvgreen writes “I agree with Oldman. While dc/ac/dc could cetainly acrue 30% loss, the amount of power lost is tiny. Much greater power draw would be a cheap "universal" charger that shorts out and fries your $2,000 laptop.

Power bricks are a major profit center for laptop mfrs, and they do all they can to ensure that aftermarket parts won't work right. The fact is that the OEM power brick is a consumable/sacrificial item that helps protect your expensive computer from power surges, spikes, MSW, zombies, etc."

While I certainly “agree” that “sometimes” it may not be worth it to eliminate as much loss as possible, I DO clearly understand the position of folks who DO want to eliminate unneeded conversion losses.

In the case of a cellphone charger, 5V at 2.4A is 12W, say the inverter has a .5A no load draw, that is 6W.

That 6W no load draw does not “go away” when a 120V load is applied.. Nope, that 6W draw is ADDED as a LOSS..

In the case of a cellphone charger that becomes 18W of power (provided no other 120V “load” is attached)..

As a side note, do you not own a 12V to USB 5V charger so you can charge your cellphone while driving?

I DO, makes it simple to be able to plug a cellphone right into a cig/power port on my vehicle while driving.

Not EVERYONE keeps an inverter turned on 24/7 like YOU might..

In my case, I switched to a home fridge, even in my case, my inverter does NOT run 24/7..

No, instead I bought an inverter which can sense if there is a 120V load.. When no 120V load is present the inverter SHUTS DOWN the 120V output stage and goes to sleep.. The sleep mode uses MICRO AMPS instead of the 1A no load draw it would have if I didn’t use the load sense feature.

This SAVES me a considerable amount of battery capacity! About 16 Ahr PER DAY (fridge on 20 minutes and off 40 minutes per hr).. While YOU may scoff at that, to me that IS considerable when considering I have 105 Ahr (half or 50% of 210 Ahr) to work with. 16 Ahr is about 15% of my usable capacity that I AM “saving”.. That is at least 20%-25% LESS generator recharge time when you take into account inefficiencies in the recharge cycle.

This allows me to only need ONE PAIR of 6V GC batts and still use lights, water pump, TV, computer, furnace and STILL have enough leftover capacity to only require recharging ONCE every 24 hrs.. And having only ONE pair of GC batts I save costs in battery replacements AND how long a generator would need to be run to bring the battery back up to near full charge..

The more you waste means you have to have more battery and more battery means it takes longer to recharge, YOU must have more money to “burn” than me..

CONSERVATION is “key” to boondocking, it is far cheaper to CONSERVE energy when off the grid..

"Homemade" electricity whether it is a generator OR solar is extremely expensive when compared to commercial shore power.. I would be hard pressed to be able to "compete" price wise to commercial power.. My commercial power rate is $.07 per Kwhr.. Running a generator is easily $.70 per Kwhr not including maintenance/repair/replacement of a generator..

I have no solar either.. Considered it, but just don’t boondock enough to justify the costs at this time..

Greenrvgreen, as far as those “cheap” no name power supplies burning up PCs, that is baloney.

You DO realize the manufacturer of your PC DOES NOT “manufacture” the power supplies that they include with the laptops? Pretty fair chance the power supply that came with your laptop is no better and in some cases WORSE “quality” than the “aftermarket” versions..

I HAVE been building and repairing PCs for nearly 30 yrs, never heard of a aftermarket power supply burning up a system board.. In fact I typically REPLACE the OEM internal power supplies when possible with BETTER quality and higher wattage power supplies.. Makes for a much more stable longer lasting PC, in fact my PCs outlive the average user by a long ways. I STILL have a “P4” running XP and it gets used daily and is on about 6 hrs a day at home..

The OEMs tend to buy the CHEAPEST things they can get their hands on, it is not always the “best quality” to start with.

Gdetrailer wrote:
Make sense?

Clear as a Bell!! Thank you soooo much!!

Happy travels

Kelly

A reasonable education on DC/DC converters is a very thick book indeed. But I can give you a short form

There are two types.. (Or more) if you need say 5VDC off a 12 volt line the most common is what I'm going to call an automatic resistor, The real name is 3 terminal regulator.. What this is is basically a transistor and a zener diode, the diode sets the voltage and the transistor conducts only so long as the output voltage is lower than the zener's set point. Now the problem is this.
If you are darawing say 1 amp at 5 volts (5 watts) the Three Terminal Regulator is drawing 1 amp at 12 volts (12 watts) or more likely 13.6


The other type is a switching regbulator, this is an A/B type

If voltage reduction is used you "Chop" the DC into square, or more precisely retangle waves. The output of this goes to a capacitor. a voltage sensor varys the width of the retangle turning it on and off based on the voltage at the Capicator. Because power is ON only part of the time this is very efficient. If you have 5 watts out you likely have less than six in They work very well.

Finally we have voltage INCREASERS (yes I have one< Radio Shack and others sell them (I actually have two).

Thise work a lot like the switching supplies only they chop the signal into square waves, then feed a transformer, High frequency transformers are both small and efficient. Then its a standard power supply from there on.

I agree with Oldman. While dc/ac/dc could cetainly acrue 30% loss, the amount of power lost is tiny. Much greater power draw would be a cheap "universal" charger that shorts out and fries your $2,000 laptop.

Power bricks are a major profit center for laptop mfrs, and they do all they can to ensure that aftermarket parts won't work right. The fact is that the OEM power brick is a consumable/sacrificial item that helps protect your expensive computer from power surges, spikes, MSW, zombies, etc.

The best way to save power if you're trying to get by on solar is to shut things off whenever possible, as said. I'm aware of plenty of 12V substitues for common appliances, but AFAICT they're generally underpowered, as the wiring fat enough to handle the huge amps involved is too expensive.

Gdetrailer wrote:
Make sense?

Of course it makes sense, it's just that in many situations it's just not worth worrying about.

When dry camping, my inverter is never off, so the 0.5a (in my case it's higher) is a 'sunk cost' to me. I turn off unneeded devices at night, but never the whole system. I have 640ah of batteries and 835w of solar. hondochica, while maybe not that endowed, sounds like he has plenty o' power too.

If you want or need to conserve, then yes, by all means turn your inverter off when you can. But on larger systems, where the inverter is never off, these "inefficiencies" are a very small part of the overall energy picture.

I don't know what hondochica's 'great' battery bank exactly is, but if it's large and easily rechared, he may too conclude it's not worth it. Is it wasteful? Yeah. Is it "incredibly wasteful"? No.

2oldman wrote:

hondochica wrote:
.. converting dc to ac to dc is just incredibly wasteful - I've read upwards of a 40 percent loss of power.

That sounds like a lot, but typical chargers use so little power to begin with, it's peanuts. You may find it's more trouble than it's worth.

A great battery bank and solar shouldn't have any problem at all.

Granted "typical" chargers won't use a lot of battery capacity.. BUT using 120V chargers run from an inverter IS extremely wasteful by adding in uneeded voltage "conversions".

Each conversion ADDS a lot of "overhead" in wasted energy.

If one can REMOVE a "layer" of "conversion" then one will be able to maximize their battery capacity between charges.

Most devices like cellphones, tablets, BT devices charge from a 5V "supply".. Makes zero sense to run a inverter for several hrs which would waste several Ahr of battery capacity in the process.

For those devices you buy a simple and cheap 12V cig to 5V USB charger.. No need for 120V..

For laptops, a universal 12V to laptop charger will work perfectly fine.. Those devices use a switching power supply designed to take 12V to 18V, 19V, 20V, 21V for different Laptops..

So, to recap, instead of 12V >120V > laptop 18-21V you go 12V > Laptop 18V-21V and cut out .5Ahr or more of inverter overhead per hr of use..

and for Cellphones, tablets and BT devices you go from 12V > 120V > USB 5V to 12V > USB 5V..

Make sense?

hondochica wrote:
Great replies all!! Thanks . .

Yes, phone, bluetooth and tablet have USB ports - though it seems to take much longer.

As for DC laptop charger . . Huh!! I had looked for one a few months ago - for my older HP laptop and got 0 results!! And I tried every possible search I could think of . . hmmmm where was this hiding?? Thanks for the link! I had actually called HP and was told that they did not make a dc power cord for my laptop - although they made them for other models - typical!

Guess I just need another 12v usb device so I can charge 2 items at once (of the smaller stuff).

Appreciate your help. I don't know what a "buck" converter is . but will look for one on Amazon.

thanks

Kelly

You buy the items I showed you and you will not have a "need" for any "buck" converters.. The devices I linked DO the "work" for you without you needing to design and build your own power supplies.

As I mentioned, for the Cellphones, tablet devices you NEED to make sure the 12V cig charger IS rated at least 2.4A PER PORT.

Many cheaper ones will only have 1.1A or one 1.1A and one 2.4A ports, 1.1A amp USB ports will take forever to charge.

If you really dig around there are some USB chargers which have 3A or a bit more available those may be of interest to you to maximize the speed your devices recharge.