Buck-Boost Flashing LED lights; no power

USMC_Mustang
USMC_Mustang Registered Users Posts: 12 ✭✭
in Caravan, Recreational Vehicle, and Marine Power Systems #1
I recently installed a Victron 50A Buck-Boost DC-DC converter in my MB Sprinter RV to charge LiFePO4 batteries from the alternator. I *believe* I did the installation properly, but am not getting more than 1 volt and zero amps from the alternator feed. The LED displays show blinking blue for input (from starter battery alternator feed) and sporadic flashing green for output (to battery being charged). The Victron manual provides no indication of what's wrong and I haven't been able to figure it out. Any advice would be greatly appreciated!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #2
    Welcome to the forum USMC,

    This is the manual?

    https://www.victronenergy.com/upload/documents/Manual-Buck-Boost-DC-DC-converter-EN-NL-FR-DE-SE-RU.pdf

    And you used to software to program the converter?

    Your are just using the vibration detect (motor running) and the minimum vehicle battery voltage to start the charging?

    Do you have a good ground connection between the vehicle motor/chassis to the converter and to the house battery? Connecting to vehicle chassis (metal) is not always a good connection. For solar power, running a separate DC cable between battery negative bus, to your loads/charger and to the DC converter's ground connection and, to either the alternator case/motor ground or where the motor to chassis ground bonding is made (vehicle motors are generally mounted on rubber mounts, and they need a good quality connection from motor ground to chassis ground).

    Where are you measuring the "1 volt"? I would suggest that all voltage measurements be made with your voltmeter black lead on the ground stud of the DC converter (12.0 volts, 14.4 volts, etc.). 

    How are you measuring the current (you have an current meter in-line? Using a DC Current Clamp DMM?). How do you know the current meter is working? (sorry for the basic questions, but want to make sure our bases are covered)

    And regarding the input LEDs:
    • The IN LED has the following functions:
    • Green: The converter is switched on (by the engine running detection, or by applying a voltage on pin 1).
    • Yellow:The input voltage is lower than the set threshold to allow the converter to switch on.
    • Red: The internal temperature is higher than the set safety threshold. The converter is switched on
    • Blue: Short light pulses = the engine running detection is active, the converter turns on after a delay. Flashes slowly = the converter is switched off and blocked for switching on due to A too low input voltage.
    A little more information on how the input LEDs are behaving?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #3
    Thanks, Bill. New updates to my situation. 
    Yes, that's the manual I'm using. Yes, that's the setup (auto detect running engine).  Using a high-grade multimeter with current meter in-line and a DC current clamp, I apply the positive lead to the buck-boost input terminal and the negative lead to the BMV-712 shunt and now measure 26v at the buck-boost. Yes, 26v; which is beyond bizarre because at the other end of that cable, where it connects to the starter batter/alternator, it measures 13v. I cannot understand how one end of a cable measures 13v and the other end (connected to the buck-boost) measures 26v.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #4
    I am not sure I quite understand your 13/26 volt wiring comment...

    On the DC converter, from Input to ground you should measure ~13-14 volts when the motor is running. And on the output to ground you should measure ~24-29 volts when the converter is charging... The batteries set the bus voltage (more or less). And the converter moves current (power) from the 12 volt vehicle battery to the 24 volt house battery.

    Now, the above is assuming you have a 24 volt Li Ion battery... If you have a 12 volt Li Ion house battery, that is another issue.

    You will have a voltage drop from the converter to the house battery---And it can be a lot if the cables are long and too small of diameter (AWG) and you have lots of current.

    Some questions:
    • What is van battery voltage when engine off? What van battery voltage when engine is running? (Input to Gnd terminals)
    • What is the house battery voltage? What house battery voltage when engine is running? (output to Gnd terminals)
    • How long and what AWG from alternator to DC converter input?
    • How long and what AWG from DC converter output to house battery?
    • What is the connection from DC converter Gnd terminal to engine battery/chassis ground?
    • Do you have a heavy cable (AWG?) from house battery to DC converter ground?
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #5
    Bil:
    You're as confused as I am, and I appreciate your patience. Testing again just now reveals
    - At alternator/starter battery 14V
    - At the other end (converter input), zero volts.
    - At the converter output to ground 13.9v (12v pack)

    Answering your questions:
    - Input to ground battery voltage when on OR off 14v
    - 1/0 AWG from alternator to converter for an 18' run
    - 4/0 AWG from converter to house battery
    - Ground connection is chassis, which tests properly/adequately when wired to the batteries
    - AWG from house battery to converter ground is 1/0, about a 4' run

    Much appreciated!
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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #6
    Issue resolved! It was a bad ground, something wise experts tried to tell me, but this gnarly old Gyrene wouldn't listen. Thanks for your patience and assistance!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #7
    Glad to hear you got it fixed.... Grounds are frequently a problem in power systems.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #8
    Continuing/new issues:

    USMC_Mustang Registered Users, Users Awaiting Email Confirmation Posts: 5 ✭
    I previously received excellent support troubleshooting a Victron Buck-Boost 50A DC/DC charger for a 12v LFP battery bank. Now that I have it all set up, the converter OUT LED never comes on. The IN LED is green, indicating everything is good on the input side. But the OUT LED winks out after the initial flashing during the startup interval. I don't see any troubleshooting material to explain this condition and would be grateful for forum input.
    Thanks!

    USMC, what is the voltage on the terminals--Specifically on the output terminals (ground, +) with your meter?

    Do you have some sort of battery cutoff between the House battery and the Converter's output?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #9
    Bill:
    Voltage on input terminal is 14.14. Voltage on output terminal is 14.24. The converter output LED flashes red prior to engine start and power on, but stops flashing completely (turns blank) once the input LED turns green.
    I do have a Blue Sea ACR between the starter and AGM house battery under the hood. I'm trying to use the Buck-Boost to charge an additional LFP bank mid-ships.
    Thanks!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    edited December 2020 #10
    Is the ACR on or off--I worry that if the ACR is on (connected), you have the classic problem of the DC converter using the vehicle battery to charge the house battery to charge the vehicle battery...

    What about the other LEDs? Is the Purple on/flashing?

    What is the voltage between ground connection and actual vehicle ground (should be near zero volts).

    There are a lot of settings with the configuration software. Have you gone through them to make sure they are close/match the manual's base configuration? Have you tried resetting the software/unit to default and starting over with configuration?

    I see there are programmable delays too... That could cause confusion if your expectations of a few seconds to change state vs a possible 15-60+ second program delay.

    14.24 volts is about charged (depending on the settings of the converter)... You have programmed the Lithium battery settings into the converter?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #11
    Bill:
    Your last points are the most challenging. As far as I can determine, there are no "lithium battery settings" to program into the converter. In fact, the absence of clear programming instructions for TSCONFIG is a large shortfall of Victron's implementation of this converter. There may be a lot of settings with the configuration software, but none that are recommended for any specific use or provide a "base configuration." If you have data that provides this information, it would be a huge help.

    I have taken the program delay into account. With the engine off, the converter sits with the IN LED blinking yellow and the OUT LED blinking red. At engine start and upon converter startup (after the program delay), the IN turns green and the OUT goes blank. There is never any purple LED.

    The OUT voltage is 14.24 at the converter, but at the battery the voltage is 13.8 (float).

    You may be on to something about the ACR, although there is no indication of whether it is on or off and I'm not quite following the logic.

    Many thanks!
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #12
    I am guessing/assuming the screen shot in the manual would be a starting point for configuring the unit (there is a reset to default that might be worth trying to get things to something less confused--I think you have to do a "SAVE" to actually transfer from the computer and write to the converter.

    Generally, with wiring, if there is no current flow (no voltage drop, no V=I*R). With yours, measuring 14.24 at the converter and 13.8 volts at the battery bus would indicate either substantial current flow (you ave pretty heavy cables), or there is no/poor connection from converter's output. I.e., the converter is "holding" 14.24 volts on one end of the wire, and the battery is "holding" 13.8 volts on its terminals.

    The issue with ACR Relay--If on, you are connecting the vehicle battery to the house battery. And your converter is taking energy from the vehicle+house battery bus and feeding current from that bus back into the vehicle+house battery bus.

    The "right way" would be for ACR to be off/open, and the converter takes energy from the vehicle battery bus (and alternator) and feeds it to the house battery bus (no connection from house battery back to vehicle battery).

    Do you have a DC capable current clamp meter?

    https://www.amazon.com/gp/product/B019CY4FB4 (example of mid-price "nice" meter)
    https://www.amazon.com/gp/product/B00O1Q2HOQ (example of a low price "good enough" meter)

    Note there AC current clamp DMMs (digital multi-meters) and AC+DC current clamp DMMs.... AC only are perfectly good meters, but will not work for DC system current measurements.

    AC+DC current clamp DMMs are great for debugging and understanding your systems. DC mode, they also can tell you which "direction" the current is flowing (watch +/- sign)... Note the +/- direction is also dependent on which way you run the wire through the clamp--So you have to pay attention. I play with the vehicle battery to learn how to use the clamp meter/current direction. Clamp on battery cable (note if front or back of meter is "facing" battery), then turn on head lamps... You know the battery is discharging, so not current direction.

    Also, DC clamp meters need to be "zeroed" for accurate current measurements (and they drift over time).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #13
    Bill:
    Yes, I have a DMM with current clamp. I will do more testing with it to capture more metrics. And, yes, the cables are all very heavy duty.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #14
    Remember that current flows "down hill"... From high voltage to low voltage. If you do not see that happening, then there are issues (no/poor connections, not connected the way you think it is, etc.).

    If you do not see a voltage spread--Then there may be no current flowing or you have very heavy/short wiring with little resistance.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #15

    Friends:

    I continue to be frustrated by my Victron Buck-Boost 50a installation. Most recently I’ve removed the ACR altogether and connected the Buck-Boost to the same ground (negative) as the other batteries. When running, the Buck-Boost input (from the starter battery) is 14.1v and the output (to the LFP bank being charged) is 14.2v. That SEEMS to suggest everything is working properly, yet I cannot get any amps to flow. The voltage on the LFPs is 13.2 and they are NOT charging from the Buck-Boost. 


    Any idea what I’m (continuing to) doing wrong? Is there a way to simply test the Buck-Boost to verify that it’s not broken or malfunctioning?

    Many thanks,

    Steve
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,886 ✭✭✭✭✭✭
    #16
    You should be able to adjust the output! Have you tried that? I did not read previous posts but even with the engine off, you should be able to adjust the output voltage. Try this with another car battery in case the one you are using is bad.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #17
    Thanks, Dave. Yes, I tried several adjustments, but nothing seems to work. The Input terminal on the Buck-Boost displays a healthy green, but the Output post is blank (no color).
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    edited March 2021 #18
    Are you trading 13.2 volts right on the converters battery terminals?
    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #19
    Bill: I'm reading 13.2v on the LFP battery bank that is connected to the Buck-Boost.
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,886 ✭✭✭✭✭✭
    #20
    Sounds like the victron is not happy.  I would still try another battery on the output to make sure.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    edited March 2021 #21
    I am asking the voltage measured right on the Victron converter.
    Wondering if there is a broken connection or blown fuse from rv battery to Victron converter.
    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,886 ✭✭✭✭✭✭
    #22
    Yes ! You have to do what Bill is asking or the show is over. You seem to say you did check on the Victron terminals in other places in this thread but this needs an answer?
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

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  • USMC_Mustang
    USMC_Mustang Registered Users Posts: 12 ✭✭
    #23
    As others have previously suggested, the issue (again) is a grounding problem, now resolved. Thanks all!
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