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Seeking Help: Issues with Solar Charging and AC Converter in Our Van Setup

Hey Victron community,


We’re experiencing some issues with our solar setup in our van and would greatly appreciate any insights. Our system includes a Victron MPPT-100-50 solar charge controller and a Victron LYNX distributor 1000 DC, all integrated together. Additionally, we have a Renogy 2000W Pure Sine Wave Inverter Charger.


For the first two months, everything worked perfectly. Recently, however, our system has started acting up. The solar charging is behaving oddly. Instead of keeping the batteries topped up, it’s going into absorption and float modes when the battery is only at 60-70%, despite being in perfect sunlight. This issue seemed to start after the batteries reached 100% charge several times, which caused the Renogy inverter charger to emit a continuous beeping noise until we shut off the solar panels. We’re concerned that this might have caused some damage to our system.


Now, whenever we plug in a device with slightly higher wattage, the AC converter throws an error code 04 (low voltage) and starts beeping continuously. It won’t stop until we turn everything off and reset it, which takes a minute.


While we suspect the Renogy inverter charger might be part of the problem, we’re looking for advice primarily on how the Victron components might be interacting and if there’s something we’re missing in our setup.


Has anyone experienced similar issues or have any suggestions on what might be going wrong and how to fix it? If there’s any more information I can provide that might help us figure this out, please let me know.


Thanks in advance for any help!

MPPT Controllersbattery chargingSolar Panellynx distributor
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2 Answers
delf67 avatar image
delf67 answered ·

Some more detail about your system.... What panels? What batteries? Where are you getting the battery SOC from? And maybe a screenshot of your MPPT settings.

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juicyfig avatar image juicyfig commented ·

We have 2 Renogy 200w panels and 4 Renogy 100w panels. Our batteries are 400ah of Litime LiFePo4 batteries (2 batteries, 200ah each). We have a Renogy battery monitor that we've been getting the SOC from. It has seemed accurate and without issue until recently. I've attached a photo of my MPPT settings. I've also include the expert settings which we keep toggled off, but I'm not certain whether they still affect the operation.img-3134.pngimg-3135.png

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delf67 avatar image
delf67 answered ·

There are several things here. Firstly I believe that the "smart lithium" preset is specifically for Victron smart lithium batteries so you should probably enable expert mode and put in the settings recommended by LiTime (probably not very different, but from a quick search it looks like absorption voltage could be a little higher).

I take it you have checked all connections and fuses across the whole system? The Renogy reporting low voltage is suspicious. Even if the batteries aren't fully charged they should still deliver enough current to supply high power items without the voltage dipping too low (unless the cables are too thin).

When the Renogy was alarming at 100%, what was the battery voltage then? The BMS should prevent the batteries from being overcharged, so that again is a bit confusing.

Are the battery monitor and inverter configured with the correct settings for your batteries?

Also, you have 2000W of panels but your MPPT is limiting that to 568W (40A x 14.2V). If you have 2 batteries in parallel that is only 20A into each battery .

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juicyfig avatar image juicyfig commented ·

We've checked all fuses. Everything looks fine.

We didn't actually check the voltage as it was alarming, but that would be good to know. The battery monitor was configured and has seemed accurate for 3 months now. Inverter is configured for lithium batteries.

On the panels - I typed wrong earlier and edited it. We have 800w of panels. 2 x 200w, and 4 x 100w. On a sunny day, the Victron app will tell me we're pulling 700w or more.

Currently, the solar controller is in float mode, and our battery monitor is telling us we're only at 58% charged. I'm wondering if the battery monitor is somehow wildly wrong all of the sudden. But that still doesn't solve the issue with the inverter sounding an alarm and shutting down.

Doing my best to understand these systems and problem solve. Everything worked without issue up until the past few days, with no real event to pinpoint when this started.

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daan-de-willigen avatar image daan-de-willigen juicyfig commented ·

Does the battery monitor also show voltage? What voltage does it show at said percentages?

This battery discharge curve is from the LiTime manual. See if it matches what the monitor says.

img-20240711-214640.jpg

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juicyfig avatar image juicyfig daan-de-willigen commented ·

Battery monitor says we're seeing 13.1v, at 58% charge. Victron app says we're pulling 13.5v, currently in Float. We've been in the sun for days, and we're in Float, so I'm wondering if we're actually near 100% and the SOC % is somehow incorrect.

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daan-de-willigen avatar image daan-de-willigen juicyfig commented ·

The mppt measures 13,5v and indeed goes into float.

A way to rule out the battery monitor or its shunt, is to measure the battery poles with nothing else attached, directly with a multimeter.

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juicyfig avatar image juicyfig daan-de-willigen commented ·
and in theory, if there's no issue with the monitor, the battery poles should show the same voltage as the multimeter?
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daan-de-willigen avatar image daan-de-willigen juicyfig commented ·

Yes, the multimeter should approximately show the same voltage as the battery monitor. In the specsheet of the monitor it might specify the margin of error, but i do not know the monitor model.

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