INEXPENSIVE WORK AROUND using a AC/DC FRIDGE

[themexicandoctor]

I haven't had all my questions answered yet however, for the needs of some* Users, this might be a fantastically inexpensive workaround using a household style, AC/DC Small Fridge.

Its an answer that no-one has presented before.

*you need to have Shorepower each night

*not all of my questions have been answered yet

*many of the Giants amongst us might have better questions

*not for everyone

Here it is from
jorgesweb@yahoo.com

Join Date: Jul 2019

Location: California

*Fridge 97 Roadtrek 190

I ordered the rm2310 also from Camping World website, the "new" refrigerator looked like it was in car wreck the outside had like bondo fillings. I also had the problem with fitting the back of it with the circuit board placement it would hit the propane gas fitting, anyway the thing did not cool at all and I returned it.
I ended buying a regular small fridge at target for $100 it works pretty good, I hook it up to power at night to freeze a freeze bag I put in the freezer and stays pretty cool during the day without power.

[mkguitar]

using my 3 way, we rotate the blue "freezer paks" from freezer ( frozen) to fridge section while driving on DC when it's hot


overnight on shore power or LP the freezer will freeze them well solid ( and cool the fridge section)

I think a few others do similar

mike

[themexicandoctor]

Yes, excellent Mate.

I cannot remember if you have Solar & what type of a Battery Bank do you have without scrolling through all your posts even thulogh you have given me excellent advice in the past as to electrical issues.

My question points to how much work does a battery have to do when driving & charging what we know are power hungry units on DC?

Are these traditional Lead Acid units or AGMs?

Does it cause them to heat up.

Does using them as such reducr their life or merely exercise them?

[mkguitar]

It's a 2006 PW Lexor, with an Interstate group 27 deep cycle marine battery from costco. No solar

while driving the alternator does all the work, the 275w heater coil draws just under 20A at 14 volts

the fridge is only solely on DC while driving- even midday stops I switch to LP to build cold

camping: shore power when we have it, LP when we don't
mike

[themexicandoctor]

Thank you Mike!

Are you satisfied with that batteries performance?

How often do you replace that battery & manufacturer & model is it?

I ask because it will help others.

[mkguitar]

6 years old, Interstate group 27 deep cycle marine battery from costco.


as above, when driving the DC for the fridge power comes from the alternator.


this is a stock system similar to what yours would have been before the improvements



our DC loads on the battery are quite low by design


no invertors- the tv is DC native, the lamps are all converted to LED ( 1/10th the power draw of an incandescent) the only items non dc native are the ac and microwave - neither of which we use.


the genny is still in place and working- never used it camping- but it's there if needed and part of the plan to power our home fridge in event of power failure

I exercised it yesterday, using it to power my hedge trimmer and leaf blower


I have a briefcase size solar cell which produces a max 1A at 14 VDC, we use that boondocking to top off battery - the fridge fans and control panel draw about 1 amp

mike

[themexicandoctor]

Another Class B Master amongst us.

Take a photo of that battery, its a small miracle.

I have a large 43 inch Samsung Smart TV in my rig which I only use to watch rugby, rugby league & judo - is there a way to convert this or remove a transformer so it can run native.

Yes I know its a big TV but if you cannot be there in person, this is better.

[mkguitar]

some of the samsungs run native 14 VDC and are sold with an external ac/dc transformer for home use



my 22" samsung in the van is one. by wiring direct into the DC power, the transformer is no longer needed. the tv has a coax connection


mike

[themexicandoctor]

Thank you, I now need to find a TV Guru to take the next steps.

In Santa Barbara parked outside Campo Vans, maybe they will know what I need to do next - I rarely if ever watch TV but when I do, not having a transformer should improve efficiency, correct?

[mkguitar]

using "native DC" is the most efficient use of your power



each 'conversion' from AC to DC current involves waste as the power goes through a diode bridge rectifier to lop the top and bottom off the sine wave to result in DC.


each inversion from DC to AC involves consumption of power to generate an AC sine wave



each step up or step down in voltage through a transformer also causes waste


waste is usually lost as heat, or bled to ground



the fewer steps in a system the more efficient use of power


and finally, Too much AC/DC causes hearing loss


mike

[rvsprinterguy]

Originally Posted by mkguitar

Too much AC/DC causes hearing loss

Plus, some extra text to allow this reaction to post.

[themexicandoctor]

SSSHHHHHHHHHHHHHH!

I would hate for the Moderators to think you were giving medical advice, your wonderful post might get banned ...

😃

[booster]

We had a discussion or two a while ago on the native 12v vs 110v for accessory stuff, and it appears that the metric is changing a bit on it.


When we got a new different TV for the van, it was a 19v model as the 12v versions are getting very hard to find except in trucker versions which until recently weren't very good picture viewing angles. I had to get a 12v to 19v adapter for it. It also used the same power as the native 12v on with a stabilizer on it we had before. I then checked the power use using the factory 110v brick and it used less total power than the either the 12v version or the new 19v did on 12v. I then got a small, high efficiency and low parasitic, Samlex inverter for it and measured power again. Came out essentially the same as the previous 12v or new 19v with adapter did. Put it it in with the inverter so now we can also run any Blueray player also in 110v.


I repeated the exercise with a new 19v laptop we got that uses a lot of power if on a high video use job or game at 180 watts. Luckily, when charging it limits to 90 watts so a 100 watt charger also works OK. I used a 12v adapter charger on it and was not comfortable with the heat it generated. I then checked the power use at full charge rate and repeated that test with 110v factory brick and the small Samlex inverter. Power use was the same and the factory brick ran much cooler, so safer.


We used to be 100% 12v adapters, but are going to 110v/small inverter on all new stuff. I put a second Samlex in the van setup as a 110v charging station with multiplug outlet with USB connections. No more, somewhat scary random quality, 12v adapters once we work through the few we still have.



I think the 12v adapters are not very efficient, and some of them generate a lot of heat and/or interference so also not very efficient. The newer 110v stuff is energy saving designed in many cases so the bricks are quite efficient compared to the older models so when coupled with a modern high efficiency low parasitic inverter they can match the power use of the native adapters, but with higher quality and probably cleaner power to the accessory.


Hopefully, in the the future, we will see larger inverters that are super efficient and low parasitic like the smaller ones are now as then they could run the whole van without need of smaller ones for efficiency and a big one for high power when needed.

[rvsprinterguy]

Originally Posted by themexicandoctor

I have a large 43 inch Samsung Smart TV...

Yes I know its a big TV but if you cannot be there in person, this is better.

That is amazing!

[engnrsrule]

I recently upgraded my inverter. The original TrippLite produced modified sine wave AC which was not tolerated by my TV or DVD player. The new inverter supports the TV just fine. Interestingly the TV in my 2006 RT was upgraded by previous owner. I am thinking the original TV probably ran OK on modified sine. I have this upgrade detailed in a separate thread but will add that I retained the TrippLite and configured it to operate in Charge-Only mode. While I know there are probably better alternatives I have been satisfied with its charging performance.

I have observed that my 3-way Dometic fridge is a power hog on 12v. It totally killed my original 12V 90 AH coach battery and inspired me to upgrade to two 6V Golf Cart batteries for 235 AH. That has made a world of difference. As for the 3-way Dometic, I have the following protocol:

-Run on 110 VAC whenever on shore tie.

-Run on 12V whenever rolling. I leave it on 12V for short stops, like fueling or meals.

-Run on Propane whenever we are Boondocking. (I usually secure propane at the tank when rolling, as some of our regular routes have propane restrictions.)

[mkguitar]

Originally Posted by engnrsrule

As for the 3-way Dometic, I have the following protocol:

-Run on 110 VAC whenever on shore tie.
-Run on 12V whenever rolling. I leave it on 12V for short stops, like fueling or meals.
-Run on Propane whenever we are Boondocking. (I usually secure propane at the tank when rolling, as some of our regular routes have propane restrictions.)

yes.


BTW the correct DC current draw is 1.5 A for the 175W heater, 2.7A for the 325W ( if unsure which heater the dc resistance of the coil is 80Ω for the 175w, 44Ω for the 325W)


mike

[rvsprinterguy]

Originally Posted by booster

Put it it in with the inverter so now we can also run any Blueray player also in 110v...

We used to be 100% 12v adapters, but are going to 110v/small inverter on all new stuff.

I've also quit trying to buy 12-volt native appliances. I have a pure sine wave inverter installed near the entertainment devices and am happy to be able to shop for Blu-ray/DVD players and TVs based on feature set and price.