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Elliot avatar image
Elliot asked

100-20 controller only shows voltage

Help setting up a 100-20 controller, wiring is correct, no blown fuses, it only shows voltage, under output, (state is on and current is 0 despite running an inverter).

Battery only shows voltage with current 0 and state is off.

Under solar, volts/current is both 0 with panels connected?

Under solar, minimal sun.. 10 volts coming in - (should be detected)

Under Battery - just volts despite load from inverter,

Under Load - Zero

My connections on the Victron 100-20 MPPT Controller are as follows:

Battery is connected with heavy wire to the Lithium 100/ah battery with a on/off relay so it doesn't drain the battery when not in use,

PV is connected to the panel,

Under Load on the controller - its left unconnected,

I was told to leave this alone.. is this correct?

in there a video for US versions that show how to set this up?

I was able to set up my battery correctly for lithium..

This is for my "Solar Generator Project" which uses a 100/ah lithium battery, 1200 watt inverter,

Smartsolar charger controller w/bluetooth 100-20, and then finally all that is set and programmed.

I would setup my Victron MPPT Control (Remote for Victron Blue Solar - Solar Charge Controllers)

MPPT Controllers
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wkirby avatar image wkirby ♦♦ commented ·

So to understand correctly:
Under "Solar", when sun is shining, there is Voltage and Current?
Under "Battery" there is Voltage, but no Current?
Under "Load Output" there is current or not?

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5 Answers
JohnC avatar image
JohnC answered ·

Hi Elliot. "10 volts coming in" isn't what you want to see. If the mppt is seeing that, then it won't work at all. Why is it seeing that? will be the issue.

Pull the wires PV + & - from the mppt and test with a multimeter. For V and *especially* polarity. You wouldn't be the first to get that a-about. Come back..

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wkirby avatar image
wkirby answered ·

Hi Elliot. Thank you for the additional information.
I just want to add, the MPPT will not be able to register any current that the inverter is taking from the battery.
The only way that an MPPT can register a load is via the LOAD output. However, you were correctly advised not to connect your 1200W inverter here. The LOAD output really designed for lighter loads like lamps.

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Elliot avatar image
Elliot answered ·

ok, question #2, I also have a Victron MPPT Control (Remote for Victron Blue Solar - Solar Charge Controllers) that I want to now connect. My goal with this unit is: 1) Read Battery voltage, 2) current being used by the inverter 3) Battery life remaining. 4) Read this info without turning on my 100-20 (when using an inverter at night and don't want to draw extra amps with the smartsolar controller being used) with that being said, I have a couple questions on how to use this in conjunction with my 100-20.

1) The Victron MPPT Control (Remote for Victron Blue Solar - Solar Charge Controllers) has a direct battery power connection - do I use this?

2) Has a communication cable to plug directly into the controller (which also powers it)

Now, if I want to use this independent of the controller, should I also use the direct battery connection supplied? This would mean two sources of power, one from the controller and one from the battery?

3) is this the right type of battery monitor to read volts, current being used, life remaining on the battery?

4) if this is the right monitor, how do I program this and use it correctly? Any videos would help greatly in setting this up on IMac/ipad/Iphone - I looked up setup on youtube but most of those videos were for either older unit or for European versions which had slightly differs software..


My main picture is a DIY solar generator using a 100ah lithium battery, Victron 100-20 controller, Victron MPPT control and a 1200 watt inverter. I have this setup so the 100-20 is on a separate switch so it doesn't use electricity when not being used like at night.



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boekel avatar image boekel ♦ commented ·

Please read the manuals first, most if not all your questions find answers there.

you'll need a battery monitor to accurately know state of charge. (BMV700)

Also you don't state what kind of lithium battery you use (Li-ion or LiFePO4) and what voltage / what setup.

if you use a Li-ion battery than you can use a cheap solution: use one of the many cheap battery SOC meters that work on voltage, or just make a table that converts voltage to SOC.

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Elliot avatar image
Elliot answered ·

For a battery I bought a Renogy Lithium-Iron Phosphate 12 volt 100AH, I'm starting to understand this a bit, so the Victron 100-20 MPPT Controller does not monitor the battery as far as what volts in/out and remaining, to that I added a Victron MPPT Control (Remote for Victron Blue Solar - Solar Charge Controllers) - Can I use this as a "Battery Monitor" if I add a battery temp sensor and a Victron shunt? The problem is that I already bought this instead of the BMV700 like you mentioned..

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boekel avatar image boekel ♦ commented ·

Have you read the manual of the MPPT?

here's the link to your battery:
https://www.renogy.com/renogy-lithium-iron-phosphate-battery-12-volt-100ah/
it has a low voltage disconnect inside so that will safe it fromdeep discharge.

btw I wouldn't use a relay between battery and MPPT, the relay draws power by itself.

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wkirby avatar image wkirby ♦♦ commented ·

Hi Elliot

It is not possible to connect a shunt to the MPPT Control. Despite their similar looks, the BMV and MPPT Control do really different things.
To monitor energy in and out of the battery you really need a battery monitor such as the BMV.
Correctly wired, the BMV will display SOC based on energy going in and out. It cannot differentiate the source of energy (eg MPPT or Alternator), nor can it tell where it went (eg Inverter or DC lamps). It can tell you instantaneous Volts, + or - Amps, + or - Power etc.

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Elliot avatar image
Elliot answered ·

Thanks for the info, Quick question 1) , what is the most efficient way to power on/off the mppt? I know the relay uses some current but it was recommended not to directly connect the power inverter to the lithium battery, so I use a 200amp relay to handle the current and just connected the mppt on the same relay since it was already installed which leaves me to Question 2) on the 100-20 ppt, what gauge wire should I use going from the mppt to the battery? and what type of switch should I use since the Victron is rated for 20 amps of charge.. a simple toddle 20 amp switch?

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