Can I replace AC Inverter+DC Adapters with just DC Step Ups?

[minneapolismark]

I have a number of devices that are either powered or recharged using a DC adapter that plugs into 120V AC wall outlet, runs through a DC Adapter and into the device. Examples of the outputs from these DC Adapters are 15V DC (for a little battery powered guitar amp) and 19V DC (for recharging a battery operated vacuum). These DC Adapters appear as "wall worts" where the conversion box is bundled with the wall plug or a conversion box that has a cord leading to the wall outlet and another cord leading to the DC appliance. I have a 12V system at the cabin that is similar to an RV system. Can I purchase DC Step Up like a SMAKN DC/DC Converter and abandon the inverted AC system's DC Adapters? Do those DC Adapter that are used for battery charging include the charge controller inside the DC Adapter box?

[AzRoute66]

Technically there is nothing hard about stepping up (or down) the DC voltage for your device and it will work. First find the appropriately sized jack/adaptor with the right length wire, then make sure that it always get plugged into the correct supply with the correct over current protection.

The beauty of the wall warts is standardization, allowing you to plug your guitar into a wide variety of places without fuss or muss. Most people think the flexibility (and inherent safety) in this approach is worth the inefficiency of converting the power twice.

Something in the middle would be the 12 VDC cigarette style adaptor. If you can find them to supply the 15 and 19 V (whatever) you can at least stick to a standard 12 VDC socket, improve flexibility and safety, and not have to suffer the losses of power conversion twice.

I skipped over your final question because I am not sure I understand it. 'Charge controller' is a very specific term in this field.

[bcroe]

Certainly DC-DC is the way to go; lots of small inexpensive equipment out there. If your cabin gets
to be rather heavily loaded, you might consider going to 24V, with the correct DC-DC conversion
device (switching converter) added to each load to supply the actual needed voltage.

Note, many (most?) DC-DC devices tend to generate radio interference, but this can be contained
with simple shielding and filtering. Bruce Roe

[AzRoute66]

Certainly DC-DC is the way to go; lots of small inexpensive equipment out there. [...]

Sure, start with a 12 VDC socket, wired with a fuse. Then a 12 V male adaptor wired to the input of the SMAKN 12-15V 5A converter ($25 on Amazon) with a fuse. Then from the output of the converter through an appropriate fuse to the correct device jack for the guitar would create a comprehensive 12VDC guitar wall wart. Then rinse and repeat for the 19V vacuum charger.

[minneapolismark]

Sure, start with a 12 VDC socket, wired with a fuse. Then a 12 V male adaptor wired to the input of the SMAKN 12-15V 5A converter ($25 on Amazon) with a fuse. Then from the output of the converter through an appropriate fuse to the correct device jack for the guitar would create a comprehensive 12VDC guitar wall wart. Then rinse and repeat for the 19V vacuum charger.

I've got the fuse to the battery bank covered. I would prefer hard-wiring the converter instead of using a plug. For the examples I used I could accept a single access point on the wall instead of a socket + plug. I assume you're calling for a fuse on the adapter wire to protect that reduced diameter adapter wire assuming those adapter wires are rated at lower amps.

Do the step up converters draw power even when there isn't a load on them? If you're not sure I could just meter the first one I buy.

Regarding the second question in my original post: I imagined that appliances with rechargeable batteries required a charge controller for the same purpose as those required on solar battery banks: to protect from over charging / limit the rate. But, maybe that isn't required on those types of batteries or maybe it is built into the internal electronics of the appliance instead of the DC adapter.

[AzRoute66]

I assume you're calling for a fuse on the adapter wire to protect that reduced diameter adapter wire assuming those adapter wires are rated at lower amps.

Correct.

Do the step up converters draw power even when there isn't a load on them? If you're not sure I could just meter the first one I buy.

Way back wall warts were very unpredictable. I remember them getting very warm even with no load, but today's market demands that they be more efficient, I would be very surprised if you could find a smallish voltage converter (wall wart or not) that draws more than a couple watts under no load. Regardless, you should assume that they would all be different and measure (or at least just feel them for heat).

Regarding the second question in my original post: I imagined that appliances with rechargeable batteries required a charge controller for the same purpose as those required on solar battery banks: to protect from over charging / limit the rate. But, maybe that isn't required on those types of batteries or maybe it is built into the internal electronics of the appliance instead of the DC adapter.

Generally, the controlling is limited by the nature of the battery - supply the correct voltage and the battery will stop drawing current as it gets full. As it stops drawing power, the source stops supplying it - sometimes just by holding the charge voltage and sometimes by changing the voltage to a 'float' level.

Hope that makes sense for you.

Can I inquire as to how you plan to implement the "single access point on the wall" if not by means of a standard 12 VDC cigarette charger socket/plug?

[bcroe]

Even a properly sized DC-DC converter will have some standby drain: fix that by placing it downstream
of your plug/off-on switch. Bruce Roe

[minneapolismark]

Can I inquire as to how you plan to implement the "single access point on the wall" if not by means of a standard 12 VDC cigarette charger socket/plug?

In-coming to the DC/DC Step Up converter comes from the fuse box and is hard wired. Out-going from the converter is spliced directly to the plug that goes into the appliance. Also include an off-on switch between the fuse box and converter. If it is a dedicated circuit from the fuse box, the fuse can be rated for lower diameter converter wires.

[Wy_White_Wolf]

Check to verify that the charge controller is in the component and not the wallwart adapter. As long as it's in the component then a DC-DC converter matched to the input voltage is no problem. But if the component has no internal charge controller the DC-DC converter could easily overcharge the battery.

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