Stereo receiver to avoid voltage drop

[clikrf8]

I know someone out there has a solution to this issue. We often camp off grid, that is, solely using 140 watts solar and 2 AGM batteries (Deka) rather than 30 amp shore power. We have a factory installed Magnadyne Linear Series RV5055 AM/FM stereo Multi-media Receiver. We will turn it on after we set up for the night and after a few hours or less it will shut itself off or intermittently come back to life then cut out again. I called the toll free number and actually got a real live person who confirmed what we thought: voltage drop. Fully charged, we are at 14 (volts or amps, I am a right-braainer so techy stuff makes my head spin). We rarely go below 12.5. The guy at Magdadyne said that it should be powered into the 11s. But, he also said that even though our controller or whatever gives the readouts, is actually in the 11s due to something which I didn't understand.

I have been looking online for answers and don't really understand what is being said. Can someone here provide a clearer picture of what is happening and how to remedy it?

Should we get THIS ?

I am looking at marine systems also because of our PNW weather (dampness) and we would like NOAA weather channel (used it all the time when fishing SE Alaska in the 70s). I found this on THIS or a similar one with less wattage?

Our equipment that draws power:
Hallmark Power roof lift system (a motor like MRIs use )- just takes a minute or two to raise and lower
NovaKool Compressor fridge (4+ Cubic feet)
all LED interior lights
Atwood 17,000 watt heater
Fantastic fan

Power equipment:
140 watts solar
Blue Sky Solar Boost 2000E charge controller
ProWAtt SW SW Sine Wave Inverter
2 DEKA 12 volt batteries.

Any help out there? Should we work with what we have or get another model that draws less power? We like our music and don't crank it up.

Thank-you and Happy Thanksgiving!!!!

[pianotuna]

Hi,

Compressor fridges do use less power than an absorption fridge when running on 120 volts AC power.

A modern absorption fridge running on propane requires up to 1.5 amps when the gas valve is open. Duty cycle is about 2:3, so they use about one amp per hour, or 24 amp-hours in a day. Converting that to watts makes the number about 288 watt-hours per day.

The nova cool draws 4.4 amps @ 12 volts. I do not know the duty cycle, but it will certainly be less than the absorption fridge. It might well use fewer watts than an absorption fridge running on propane.

[pianotuna]

Hi,

Measure the voltage at the connection to the stereo. Then measure the voltage at the battery. Now turn the fridge ON and do the same.

I suspect who ever installed the stereo used tiny wire with a long wire run causing lots of voltage drop. The real solution is to rewire with much thicker wire.

Adding a boost unit such as the one KD4UPL suggested would also work.

[pauldub]

There's no way that a compressor fridge will use less power than a fridge running on propane. On the ferry, you just shut it off the propane for the time that you're on the ferry and don't open the fridge door. The ferry trip time isn't an obstacle unless you're taking the ferry to Alaska. I've turned mine off on the trip to Vancouver Island and that's probably the longest ferry trip around here. Turning up the temp on your fridge probably won't make a noticeable difference in your 12V power consumption. I really think a propane fridge would solve all of your power problems, at least until your furnace uses up all the propane. I guess I don't understand the concern about running a propane fridge on back roads. I suppose if you had a 3-way fridge you could run it on 12V while underway without having a propane concern or a power consumption concern.

[clikrf8]

We were told by many people that a compressor fridge is better if you rely on solar as it uses less power. Also, as we travel on back roads we don't like to use propane even less. Plus, on ferries, your propane tank must be OFF. Some ferry rides are hours. We did have a 3 way fridge in our Four Wheel camper and it really used the power. Thus, the switch to a compressor fridge. Thanks for all your help. I guess either a lower wattage radio or the MFJ voltage booster or pile on more blankets or get a warmer sleeping bag to cut down heater use. And, turn down fridge (no ice cream). Happy Thanksgiving!!!

[pauldub]

Either the furnace or fridge or both are causing a voltage drop that's more than the radio can stand. Not sure why you don't have a propane fridge, they use an insignificant amount of fuel. You need more battery or more charging capacity or both unless you want to run a genny. The MFJ voltage booster previously mentioned would work but it's not fixing your root problem. A different radio might work down to a lower voltage; however, that sort of tricks you into discharging the batteries more than you should.

[MNtundraRet]

Your batteries are 12.7 volts when fully charged. Anything else is just surface charge and worth a minute or two in time.

The likely culprit causing the voltage to drop to low for the stereo is your compressor refrigerator. After a few hours your battery voltage has dropped enough to have the voltage under load needed to drop below current needed to run the stereo. The current needed to start the compressor causes a sharp drop in voltage from the batteries, causing stereo to cut out.
That's why RV's do not use compressor refrigerators. Fine for shore-power, but a game ender for camping on non-electric sites.

[RoyB]

My RULE NUMBER ONE is never do anything with my truck start battery. This is there to start my truck and get me home...

If your coach batteries are running down to low with your current battery drain then get more coach batteries and more AHs capacity...

I am running three standard issue GP24 Interstate deep cycle batteries in parallel giving me a total of 255AHs capacity. This works pretty good for me back off the power grid.

Roy Ken

[KD4UPL]

What you need is a device that hooks between your 12v supply and your stereo. It will take the input voltage, whatever that may be and step it up to 13.8 volts. Your stereo should be happy with that.
One product is made by MFJ, model MFJ-4416.
Another choice is N8XJK super booster available from TG Electronics.

[clikrf8]

Thanks for all the replies. We will try to limit the bass (hubby is the heavy hand on this one). He will check out the wiring; should it be shorter and thicker? Or thinner for less resistance? I don't remember much from college physics. We will nix running wires from truck batteries also. Batteries are just a little over a year old brand new when we bought camper in 10/2012. Maybe another radio with less wattage? As I said, I would like one that has NOAA weather band and is more protected from our damp weather like a marine grade radio. What receiver do you all have?

[LittleBill]

what kind of wiring is between the battery and the radio and how long?

radios don't do well with volatage drop, also if remove bass from the stereo it will do better as well, since it takes more power to push bass frequency's

[ewarnerusa]

I'm not sure how you would run things off the truck's batteries. I assume your refrigerator gets its power from the inverter. The inverter gets its power from the camper batteries, and if it is installed properly it will be hard wired directly to the batteries with very short fat wires.

If you mean removing the camper batteries and replacing them with the truck batteries, I suggest not bothering. It might make it appear to work normally at first since the truck batteries are probably fully charged at this point, but they are not deep cycle batteries and are not really meant for RV-style power consumption. Then you may end up running those batteries down and have no 12V batteries charged strong enough to get the truck started!

[ewarnerusa]

clikrf8 wrote:
Hubby suggests running it off the two truck batteries in our F250 Super Duty. Would this help?

We had a Four Wheel Camper with solar (70 watts plus 12 volt battery) with a 3 way and it gobbled up batteries (just 2, maybe 3 cubic foot) plus we used lots of propane. We opted for compressor fridge for less battery draw.

I guess we can turn down fridge (hubby had ice cream so we turned up the cold). We don't use a whole lot of lights but do use heater and its fan when it is when it is cold.

More solar? No room in battery compartment for another battery).

If the fridge is truly the source of the problem, then I don't think turning it down would make much difference other than going longer between compressor cycles. Once the compressor cycles on it will draw the same power and result in the same sized voltage drop that your stereo will object to.

More solar won't help either since the problem is happening at night. Although more solar would mean that your batteries would more likely be full before sundown, giving you a longer period of time before the stereo shutdowns.

Are the batteries very old? Are they still healthy? I'm not a battery guru, so I don't know much about how to trouble shoot that.

Your heater (propane furnace, I assume) will definitely cause a big voltage drop when the fan kicks on. Does a stereo shut down coincide with the blower fan turning on?

[clikrf8]

Hubby suggests running it off the two truck batteries in our F250 Super Duty. Would this help?

We had a Four Wheel Camper with solar (70 watts plus 12 volt battery) with a 3 way and it gobbled up batteries (just 2, maybe 3 cubic foot) plus we used lots of propane. We opted for compressor fridge for less battery draw.

I guess we can turn down fridge (hubby had ice cream so we turned up the cold). We don't use a whole lot of lights but do use heater and its fan when it is when it is cold.

More solar? No room in battery compartment for another battery).

[ewarnerusa]

I don't think the item in your first link would provide any benefit, it is for isolating a battery from a system. When you are running your 12V stuff off-grid, you need your batteries connected.
Since the stereo only begins to cut out after a couple hours, then this suggests that everything works normally when your batteries are full. Only after you have discharged them a ways do voltage drop issues occur.
I suspect that some of your other equipment is causing the voltage drop on the system, then your stereo cuts out when that happens. Probably your compressor on your fridge kicking on causing a voltage drop on the system, then your stereo picks that up and shuts down.

Try unplugging/shutting off the fridge next time you are getting intermittent operation from the stereo. See if that stops the stereo from shutting down again.