RCT Axpert Inverter never stops charging - fan constantly on

[morneode]

Hi all,

I have a RCT-AXVP1-1K-5K Inverter, a 12V unit with 2x batteries in parallel.  When the unit is not connected to the mains, it is quiet.  Once I connect it to a wall outlet, the fans ramps up, and the unit starts charging the battery. The problem is that the battery never stops charging. After a while, the batteries' Voltage, levels off at 13.5V, but the Inverter doesn't stop charging, and the fan keeps going.  I even changed my float Voltage setting to 13.5V, but this proved unsuccessful. 

Has anyone else experienced this issue?

[Richard Mackay]

How do you know if it doesn't stop charging?

[morneode]

Hi @Richard Mackay,

The display (see attachment below) shows the following:

- the battery bars stops filling, which shows that the battery is full, I suspect. But,

- the battery is still connected to the charging circuit.

If I disconnect the mains, the LCD shows that the battery is not connected to the charging circuit any more (the line goes away)

Edited October 16, 2020 by morneode

[Richard Mackay]

Have you got / can get a multimeter??

If so measure the current feeding into the battery and the voltage on the battery terminals..

[Coulomb]

On 2020/10/16 at 3:52 AM, morneode said:

After a while, the batteries' Voltage, levels off at 13.5V, but the Inverter doesn't stop charging, and the fan keeps going.

13.5 V is likely the float voltage. If setting 05 is FLd or AGM, it will use 13.5 V as the float voltage setting and ignore setting 27 (float voltage setting, for IF/WHEN using battery type USE).

It's normal to continue charging the battery at the float voltage. When float charging, the CHG LED will typically turn solid green (not flashing). This is considered "charging complete", even though it's still putting an amp or so into the battery to keep it at 13.5 V.

As for why the fan continues running, I have no idea. 12 V firmware is rather different to the 48 V firmwares that I'm more familiar with.

[Dean Lennox]

Same problem here. Wish there was a way to turn the fans off. Obviously a 12v firmware bug. 

[JamesF]

Not a bug, the 12, 24 and 48v units (pip, Axpert, Synapse) all do the same thing. 

If you are floating OR charging the batteries, PV or utility (Eskom) the fans will run at minimum 30% if CPU / Board temp is over 40deg C. If 30% fan speed can get the temp down under 30deg C, the fans will switch off.. (however, temp will probably get back to 40deg C within 20min anyway)

The only time the fans will not run is if you ONLY use PV input, and there is 0v from PV ie, night time, and your load is very low. (This is the same as not charging or floating - and in this state, you are using the batteries)

I have 12 months left of my warranty - in that time, I am going to attempt to write a patch for my firmware to change the upper limit of the fan control (40deg C to 60?) If anyone has experience with the .hex firmware, please let me know? (translations, debugs, ect)

After that 12 months, I am going to;

1. disconnect the fans and see how high the internal temp actually gets while floating the batteries.. Interesting to note, during float, only 1 fan is used.. So my thoughts are if just 1 fan can be disconnected (bridged with resistor to not get FAN lock errors).

2. Reverse the fans to check temp differences. 

3. Sell and upgrade to Victron.

[TomFer]

I have experienced the same phenomenon with inverter fans running non-stop and charging process never stopping. I have an MKS 3K 24V Plus with  2 x 100ah Royale DC31 batteries running without solar merely as utility backup.

The batteries as confirmed with supplier are flooded type.

On my display it keeps showing the last bar (in battery charge level) flashing and the charging never completes. Even after 10 hours +.

My bulk, float and abs voltage are set correctly on defaults yet the inverter takes the battery voltage up to 29.2 which exceeds all of these parameters, verified with a multimeter. 

My guess is that this has something to do with battery equalization seeing as the battery type 05 setting is on FLD.

I changed this to AGM and the inverter stopped continuously charging and blowing the fan.

Everything seems to be ok now but I don't know if this is ideal since one would think that flooded batteries should be charged on the FLD 05 setting not AGM. I don't know if battery equalization should really take this long and whether the voltage should go this high. And even if it does and after one cycle it will only do this again after 30 days as per setting 37, I am not willing to take the risk of a bug causing this frequently when I am not around. Frequently charging the batteries to 29.2V+ for prolonged periods makes me a bit nervous. So for now I am just leaving it on AGM battery type setting even if it is not ideal for long term health of flooded batteries.

Any comments are most welcome.

[Coulomb]

5 hours ago, TomFer said:

My guess is that this has something to do with battery equalization seeing as the battery type 05 setting is on FLD.

Is equalisation turned on? By default, setting 33 (Battery equalisation) has the value EDS (disabled). It needs to be EEN to enable equalisation at all.

I've never used equalisation, or 24 V models.