Solar, charging, noise, RV's and more. Sort of a Ham radio thread.

Discussion in 'On the Road' started by KL2WX, Jul 12, 2021.

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  1. KL2WX

    KL2WX Premium Subscriber QRZ Page

    I'll try not to ramble...

    My camper converter creates a ton of RFI, so I'm researching replacing it. I just ordered a Progressive Dynamics PD9260CV Inteli-Power 9200 Series Converter/Charger with Charge Wizard - 60 Amp and I will plug it in and test the RFI before I install it.

    Separate issue I have is the charging and battery system in the new RV. The battery never seems to fully charge, the single 100w solar panel doesn't seem adequate and the single battery isn't cutting it, so I purchased 2 Duracell group 31 AGM batteries to install. I didn't want to install the new batteries until I got the new converter installed as I didn't want to keep them in a constant state of under charged and ruin them.

    Another separate observation from ham radio portable operations. I have a go box that I built with a 20aH LiFePo4 battery and PowerWerx power supply. I installed a WMR EpicPWRGate and recently got a 200w portable solar panel to supplement the go box. the PWRGate has a solar input and manages the charging from the panel and power supply.

    Similar to the go box, I also operate portable with just a radio and battery. I recently found and ordered a BuddiPole PowerMini so that I could add a portable solar panel to my portable operations as I've burned through my 16aH battery a couple of days running 100w.

    Back to the RV. The converter only connects to AC and the battery. The solar charge controller only connects to the panel and the battery. According to the documentation, both the converter and the solar charge controller rely on battery voltage to determine the charge cycle and rate. There seems to be no connection between the solar charge controller and the converter. How is this even supposed to work. I haven't done testing yet, but as best as I can tell the converter sees the ~14v that the solar charge controller is putting out and never goes into full charge mode. Then at night when the panel isn't producing voltage anymore and I've shut down the genny for the day the voltage drops straight to the low 12's and by morning I'm in the low 11's.

    How is it that there's no power gate, smart controller or intelligent box deciding when to charge the battery with the converter or panel and paying attention to the state of the battery in these RV systems? In the RV world you see tons of problems with batteries only lasting a year or even less. My supposition is that the charging systems are poorly designed and the batteries are poorly managed, yet it seems most or all RV's are designed this way.

    If anyone is aware of a solution, please point me in the right direction before I go and come up with something on my own.

  2. K0VWA

    K0VWA Ham Member QRZ Page

    Congrats on the new RV! I'm not an expert but the trailer hasn't caught on fire yet so I'll give this a stab.

    How many RV batteries do you have? What type are they and what is their capacity? If they've been in the low 11 volts range they may already be compromised.

    I have two 6 volt AGM batteries (Vmaxxtanks is the brand). Each has a capacity of 225 Ah. The stock converter that came with the trailer killed those batteries in a few years by over charging them. I replaced the converter with one that can handle flooded, AGM, lithium, etc. So far so good. I don't often operate radio while connected to shore power but don't hear any RFI from the converter when I do. My setup is just like yours - it's only connected to AC, batteries and the internal trailer wiring bits. The converter I bought sets the float voltage at 13.3(ish) and charge at 13.8 for AGM batteries.

    I added a solar charge controller (Renogy 20amp) - in parallel with the trailer converter. The charge controller is connected to the batteries and four 100W solar panels wired in parallel. I can use the regular trailer 12V system and also have the switchable output from the charge controller that we use to charge devices and run a 600W sine-wave AC inverter in case we need to run something small on AC. The solar controller shows how much voltage and current comes from the panels as well how much is pulled from the switchable circuit - but doesn't show how much we use from the regular 12VDC trailer circuits since that all runs over the stock wiring. I can kind of get an idea of how much total power we use based on how much the solar controller pulls from the panels.

    Our panels are not mounted on the trailer - meaning I can unplug them if needed. I bring that up because I've never connected shore power while using the solar panels - it's one or the other for me. You might want to have some type of disconnect switch if your panel is permanently mounted and you can't turn off the solar controller.

    Lastly - I'm not sure what your RV current draw is but a single 100W panel probably isn't going to maintain your batteries. We can get by with 200 watts in summer when it's sunny and we're not using the heater but any other time, the 400 watts is really welcome. Consider investing in one of those cheap ammeter shunts from the Middle Kingdom. Great way to know exactly what your power plant is producing.

    We typically see a lowest voltage of 12.5V right before the sun comes up when it's cold out and the heater is on. If the heater stays off a bit the voltage will slowly creep back up to 12.6 or 12.7. By the time it's light enough to drive without headlights, the thing is charging. It'll even charge on a snowy overcast day. Did some winter camping in April when it got down to 11°F and the solar worked like a champ. Bathroom froze and I had to put handwarmers on the batteries but it was a great trip.

    As to RV quality - you're correct. They're some of the most cheaply built things I've ever seen. I won't name names but I used to work for a major appliance manufacturer. We got a contract to supply a radio/CD player type device to a really big RV manufacturer. We sourced that contract from customer returns. We would plug it in, turn it on. If it worked and was cosmeticially perfect, we'd ship it out.

    The only time I get RFI from the solar is if I have the coax crossing or next to the wires from solar panel to controller.

    Good luck!
  3. KL2WX

    KL2WX Premium Subscriber QRZ Page

    I currently just have the flooded NAPA RV battery that came with the trailer. I have 2 new Duracell AGM's waiting to go in until I can figure out how to charge and maintain them correctly. I have the new converter on the way. I think I will need to add at least 1 more 100w panel at a minimum.

    Both my chargers "work", but I don't think the system works well as a whole. The main problem that I think I have is that the converter measures circuit voltage to determine what charge stage to be in and if the converter is seeing 14v on the circuit because the 100w panel is putting out 14v at 2A then the converter doesn't think it needs to do anything because the battery is "full" according to the circuit voltage, but the reality is the battery is dead or low.
  4. WB6TIX

    WB6TIX Ham Member QRZ Page

    If the battery is discharged, chances are the solar charging system won't be able to supply enough current to bring the battery voltage high enough to confuse the shore power converter/charger.

    As the battery charge increases and the battery voltage rises, then there will probably be a point where the two systems could confuse each other. But, I don't think this condition would last very long nor likely to cause a big problem....the battery voltage rises enough to make one system goes to trickle mode while the other continues on in full charge mode and this continues until the voltage rises enough for the 2nd system to switch modes as well.

    As for quality and build consistency, I have a truck camper and most of the stuff "isn't too bad", but...... :)
  5. AC0GV

    AC0GV Ham Member QRZ Page

    One comment on converter noise. Yours is not the only one in the campground. Others parked not so near by will also cause problems for you.
    I like to boondock with solar. BTW I use a 100 watt panel and normally have a full charge by mid-morning but carry a 2200 watt Honda for back up and air conditioning.
    AA5LS and N3AWS like this.
  6. KL2WX

    KL2WX Premium Subscriber QRZ Page

    I don't think that the converter has anyway to measure the battery voltage independently from the circuit voltage. That being the case when the solar panel is producing voltage to the circuit that is what the converter sees. I don't do campgrounds often mostly boondock. Noise testing as follows: Start generator, no noise. Plug in camper to generator. Noise. Unplug camper from generator. Noise goes away.
  7. KC4WEB

    KC4WEB XML Subscriber QRZ Page

    I'm personally not very knowledgeable on this topic. However, I think that Victron has products that manage joint solar/onboard converter configurations.

    They have a product training tour across the United States this summer and into the fall. If this is in your area you can probably get definitive answers to your questions.
  8. WB6TIX

    WB6TIX Ham Member QRZ Page

    I do believe the converter will see the circuit voltage. But, with the low current output of the solar charging, the circuit voltage will be whatever the battery's charge state "allows" because the battery will load down the solar charger output.

    This could be verified by letting the battery discharge to about 80%, then allow the solar charger to begin charging the battery while watching the circuit voltage. My *GUESS* is that it will rise slightly when the solar charging begins, but then continue to slowly rise as the battery becomes charged and then stop rising when the battery is fully charged. So, if the battery was at 12.2 volts, connecting the solar will bring the voltage up to 12.3 volts or so, and then over the next several hours, it will slowly rise up to the fully charged voltage of "13 something volts".

    More guessing...if you then also hook up the shore power and allow the converter to charge the battery, the voltage will rise a bit more and then continue to rise up to the full charge voltage. So, again if the voltage was 12.3 volts with the solar going, the circuit voltage would jump up to something like 12.4 or 12.5 volts and then (because of the higher charge current) "faster than solar alone" rise up to the fully charged voltage of "13 something" volts.

    If you can measure the charge current from each system, you should be able to tell if one system is causing the other system to shut off too early.

    As for the noise testing procedure you described, I think it's perfectly valid. I have done the same thing and get the same results.

    Tomorrow, if it's not "9 billion degrees", I'll measure the charge current from both systems on my camper. I'm in the Phoenix, AZ area, so the "9 billion degrees" isn't too much of an exaggeration. :)
  9. K6EEN

    K6EEN Ham Member QRZ Page

    Typically manufacturer cost considerations. If buying an owner a new battery under the warranty is cheaper than installing a "smart converter-charger", then the manufacturer will just buy new batteries for the few that file a claim under warranty, rather than install a smart charge controller in every vehicle.

    Many new RVs now come with a "Charge Wizard" type device in the power converter to prevent battery abuse. They were not common equipment until quite recently, though were available as an add-on module for many years.

    I'm not sure how solar figures into the mix these days. I don't think the basic "charge wizard" device has solar as input, it is just a standard smart charger to charge/monitor/float a 12 V battery from 110 V A/C shore power. Usually the solar manufacturers sell a charge controller you incorporate into your system with the panel. If solar is available (daytime, no clouds) as well as 110V A/C shore power, the controller should decide which one charges/floats the battery. In the absence of shore power, the decision is easy. When shore power is present, I'm not sure what the solar controller does.

    If the output of the 110V converter is hooked directly to the battery, as is the output of the solar charger, then the two chargers are going to battle one another. Probably need a "yet again smarter controller" that takes both the 110V converter output and the solar panel output as inputs, and produces a single managed charge current to the battery. Could be as simple as a relay box that switches the charge current to the 110V converter when it is present, shunting the solar. Then when 110V goes away, the relay switches to the solar and stays there.
    Last edited: Jul 14, 2021
    KL2WX and N0TZU like this.
  10. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    I have been RVing and Hamming for years
    The Facts: Solar, charging, and RV's = RFI noise,
    If you get yours fixed (not easy$$$) the RV next to you will have Bad RFI
    Too much junk coming out of China
    AA5LS and K6VOX like this.

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