Buck-Boost Flashing LED lights; no power
USMC_Mustang
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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!
Comments
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
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.
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?
-BillYou're as confused as I am, and I appreciate your patience. Testing again just now reveals
- 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!
Thanks!
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!
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
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!
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.