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Watchpower, recorded data values question

berniej

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I've just installed a combined 3kW 24V solar controller/inverter that I bought from Amazon. It has an LCD config screen and RS232 data i/f.
Seems kind of generic. No software came with it despite reference to a CD so I went hunting and found Watchpower 1.14 (I'm quite new to this).

Installed and connected OK and yesterday I grabbed a day of data, exported to Excel and took a look.

My objective is to end up with an answer to 'so how much am I saving' by determining what % of the load is provided by solar/battery compared with how it would be if I were running straight from my 240V main. ( Feb in UK, the answer will likely be "not much" but hey-ho )

I haven't worked that bit out yet but was puzzzled by why the "PV input power" column is always zero when I would guess it should be the product of the V and A.
Also, the "Battery capacity" values don't look sensible, particularly when switching to line mode and increasing to 100% in a few minutes which can't be right.

Are these just bugs/features/limitations of Watchpower or have I missed something please?
Also, are there any other similar programs/apps that might be better? I'm currently using RS232 but have a RS232->WiFi adapter on order to hopefuly network-enable.

Many thanks for any thoughts.

Regards,
Bernie (UK)

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A few questions:

first, can you link to the Amazon listing for the inverter? There are only a handful of OEM manufacturers (Voltronic, SRNE, etc) which can often be identified from the specifications, with each such base model having its own quirks. Your reference to “Watchpower” didn’t click with me initially- that’s a Voltronic app.

Second- what battery chemistry are you using- lead, LFP, etc? And what are your inverter Output Priority, Charge Priority, and Battery Type settings?

Finally- your PV input voltage appears to be very close to your battery voltage— many MPPT chargers require 1V or more headroom to charge at all, and perform best at 2x battery voltage or higher. You may want to rearrange your panels into strings of at least 2.
 
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Many thanks for your reply,

Here's the link: https://www.amazon.co.uk/dp/B0B4JCB26D?psc=1&ref=ppx_yo2ov_dt_b_product_details

and below is a pic of the sticker on one of the panels (I currently have 6 in parallel, increasing to 10 shortly).

I'm using 2 x 12V lead-acid deep cycle 110AH leisure batteries connected in series (both new).
The unit offers priorities of UTL/SOL/SBU I've chosen SBU although I think SOL might also work OK - they seem very similar.
Battery types offered are AGM/FLD/User Defined, I've set to FLD.

Regards,
Bernie

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Thanks for the extra details! It appears your system has a max VOC of 80V and should accommodate 2 of your panels in series.
You might try connecting just one pair of panels in series and see if the charging behavior improves.
 
Thanks. I'm not really sure if this is a Voltronic unit as I came about the Watchpower prog via a search (no software supplied with unit), downloaded it and found it seemed to work! Not sure how to find out - or if it is crucial to understanding the settings and readings....

However, I also checked the PV input value with a meter across the PV source and it was indeed 24.0V. I then disconnected the line from PV to controller and it then measured 33.5V. So I guess that it is the controller that is holding this down to 24V and not a lack of potential from the panels?

It has also just occurred to me that I don't know if the 'PV input power' value is computed in Watchpower from V and A or read direct from the comms....

Are there any other monitoring progs that would work with the RS232 comms that I could try for comparison?

Thanks,
Bernie
 
It is. However with the many rebrands of Voltronic, there could be some protocol differences that need to match up to the software versions.
I have MPP version 24V. If you like ESP32 you could put these together for under $20 and get Wi-Fi into home assistant or mqtt wherever you need. I like to promote what they did at pipsolar because it helped me get those power production plotted to dashobards. https://github.com/syssi/esphome-pipsolar It takes the RS232 into a TTL converter into ESP32 flashed with esphome.
I use homeassistant to sum with integration the instantaneous reads, then that gives me total power of the day. Previous to HA, I used InfluxDB to log the reads and get it into time log db.

the Power PV input voltage is read from the solar in, but under load it will drop slightly as the MPPT is consuming it. Measures the same with multimeter. The Power for battery charge is battery volts x charging current out of the MPPT. All these values out of the inverter charger like power and power actually turn out to be unrelated to the PV input voltage. It's just there to let you see it has the voltage coming from your string.

I also have 6 panels of 230W like this, but I have two series strings of 3 panels, and then paralleled them. Though my VOC max is 140V.
 
After reading a few more threads and exchanging some ideas I decided to swap over to an MPPT unit. I rewired my 10 panels to 2 strings of 5 producing around 140V each open circuit. This seems to work pretty well even in the current, rather miserable weather here in UK.

However, the new unit woun't talk to my PC - neither Watchpower not MultiSIBcontrol. It does however work with a generic WiFi adapter that I bought on Amazon and the SmartESS app. The app is a bit simplistic but there's also a web page available (although not widely known it seems) at dessmonitor.com that provides a richer set of features including reports that can be exported as xlxs. Unfortunately it doesn't include line power.

It uses a 4-wire connection to a 9 pin D and seems to use RI (held high) Tx, Rx and Signal ground. That seems pretty standard so I'm guessing it's protocol differences that are preventing it working direct over RS232 rather than signal connections.

I'm hoping to get some info about the protocol from the manufacturer's tech support which might then allow me to build a better system.
 
Though I'm pretty sure you're using a Voltronic https://voltronicpower.com/en-US/Support/Software
Some manuals and protocol docs are there too. Did you change entire inverter/charger model of the unit with higher VOC on the strings? Whats the new one?

Watchpower is OEM MPPtracker. The newer models do not use QPRI and changed protocol to P### https://github.com/amishv/voltronic_ESP8266_MQTT causing lots of headaches. You have to make sure the software version matches.

On my Voltronic MPP branded, even though it has USB and Serial both there, if I plug one in, the other stops working until I turn the inverter off and back on again. I couldn't figure out why my esp32home software was saying NaN, but after taking my USB out and power switch, I was like oh, look at that!
 
Yes, I swapped it for this one: Y&H 2400W Solar Hybrid Inverter

Thanks for the protocol info - not sure what mine uses, I tried various commands through the debug nterface in SmartESS but could only get 'null' or an error response.
 
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