Forum Discussion

gat75's avatar
gat75
Explorer
Nov 11, 2017

Lights dimming and brightening in 5V

My 2010 Blue Ridge has an issue with the 12V lights. While sitting inside RV, lights will suddenly get a lot brighter.

Dimming of the lights is more subtil, seems the dimming of the light is very gradual.

Due to hurricane Harvey, we have been living in this RV full time for the last couple of months. Previously, the trailer was parked at the lake, with intermittent use.

DW & I cannot recall this being a long term issue. We bought this trailer new.

I had installed a new Progressive Industries converter & a new interstate battery a couple of years ago.

I am beginning to be concerned that we may have a short somewhere.

Thanks in advance for you help!
  • stickdog's avatar
    stickdog
    Explorer
    Nov 11, 2017
    We had that symptom when our converter was going out. Not enough umph to charge the batteries and keep all the other 12v running.
  • time2roll's avatar
    time2roll
    Nomad
    Nov 11, 2017
    Check the 12v system voltage with a meter. 13.6 volts?

    Check the battery for excessive gassing and heat. Also check the water level.

    Then disconnect the battery as the PD converter should run the RV just fine with no battery. What is the voltage now in the fuse panel?
  • gat75's avatar
    gat75
    Explorer
    Nov 11, 2017
    time2roll wrote:
    Check the 12v system voltage with a meter. 13.6 volts?

    Check the battery for excessive gassing and heat. Also check the water level.

    Then disconnect the battery as the PD converter should run the RV just fine with no battery. What is the voltage now in the fuse panel?


    Thanks for the tips, I plan to troubleshoot it tomorrow morning.
  • newman_fulltime's avatar
    newman_fulltime
    Explorer II
    Nov 11, 2017
    take the battery out of the loop with your disconnect if it staightens up its the batt if it keeps doing it you have a bad converter or wrong one.
  • ScottG's avatar
    ScottG
    Nomad
    Nov 11, 2017
    Removing the battery should cause it to stay in one mode. So that's a good test. If it's rhythmically going from bright to dim it's probably the converter.
    It may also be that your PI is just going into another charge or desulfate mode. You should monitor the voltage to see what's it's doing. If it's switching between 14.4, 13.6 and 13.2V's, it's doing its job. When the converter drops the voltage to the next stage, the battery voltage itself slowly drops and so do the lights.
    It also goes into the desulfate stage something like every 20 hours and acts kinda strange.
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Nov 11, 2017
    ScottG wrote:
    You should monitor the voltage to see what's it's doing. If it's switching between 14.4, 13.6 and 13.2V's, it's doing its job.


    This is most likely the cause.

    Changing out the bulbs to LED probably would make it less noticeable......and less frequent.

    Probably nothing to actually worry about but it could be a sign that your batteries are getting weak or a connection needs tightening.

    I have found those little plug-in battery voltage monitors to be an invaluable tool.
  • gat75's avatar
    gat75
    Explorer
    Nov 11, 2017
    Well, had time today to begin troubleshooting. With battery disconnected, I had exactly 13.6V coming out of the Progressive Dynamic converter, (per my fluke tester).

    My interstate battery tested at 13.4V

    Guess I must have a short somewhere...
  • Edd505's avatar
    Edd505
    Explorer
    Nov 12, 2017
    How old are the batteries? If they are several years old take them in and get them load tested, it could be a bad cell.
  • Sam_Spade's avatar
    Sam_Spade
    Explorer
    Nov 12, 2017
    gat75 wrote:

    Guess I must have a short somewhere...


    I think that is a BAD guess.
    Those readings seem perfectly normal to me.

    You need to leave the meter connected.....so you can see what the voltage is doing when you notice the lights change.

    IF....the converter output is changing from say 13.2 to 14.5, like maybe it should do under some normal circumstances, you should notice that in the brightness of the lights.

    IF.....the battery voltage goes below 13.2, THEN you likely have a problem that needs to be investigated.
  • bartlettj's avatar
    bartlettj
    Explorer
    Nov 14, 2017
    I would check all of your battery cables/connectors for tightness between the panel and the battery (including grounds). I suspect a crummy connection, not a short. This would allow enough current through to charge the battery (you are connected all the time, so there's not a lot of current flowing normally), but not enough to support a load without dropping the voltage a bunch. Monitor the voltage at the battery terminals AND at the converter while the dimming and brightening is happening, I bet there's a difference.

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