Pieta

Gabriel sure if you can sort out the comms problem you would be able to reflash it yourself without getting it bricked by an "a"xpert! Always nice to learn by doing it yourself and there is really very good reading material on this forum to help. After all the prep work for the big rains you might still have some time to sort it before the warranty expire!

hi @ebrsa, you've got a point there! the warranty will expire next month and then i have to update again and schlepp to capetown and back twice and sit without solar for maybe two weeks... hmmm... its a no-brainer. i'll rather harvest some skywatts and do something productive in the meantime - like preparing for the big rain and cometh the hour flash with 73.00b from down under, voila, fixed

Noticed your comments after I had posted mine @Pieta and we are telling the same story. The update program will certainly not see the COM port if you entered the wrong one. Good luck @gabriel. I hope all works well.
 

@gabriel I just run the updater from a Windows 7 laptop as a user and all works well. This is the same problem I had last time. Go to Control Panel on the laptop and open Device Manager. Look under Ports and see which COM port the USB to Serial converter selected. Mine selected COM2 last time. Then set the update program accordingly and try again. There is always a nail biting wait from the time the update program detects the COM port before it starts to upload the new firmware so just be patient  for a minute or two. Make sure the firmware is 73.00b or you will have to upgrade again as I will have to do because only 73.00a was available when I updated about 3 weeks ago.

Hi Gabriel
Check in device manager if Communication Port is selected to Port 1?
 

Hi ,
First off all thanks for all the amazing topics that are available!  For a newbie like me on Solar this certainly helps a lot!!!
Wonder if someone can help? It might have been discussed before but I could not find anything on the problem as set out below...
Have written a program in VB6 (Please don't laugh!!!) to interface with 2 x Axpert 5KVA Inverters but has found a problem as the PV input currents does not add up...When measuring current from the Solar panels to the inputs of the Axpert Inverters with an amp probe the current seems to be less than the current indicated as PV Input current on the Inverter display and different software available. The PV input voltages however are more or less the same when measured with a multi-meter.
If the Wattage of the Solar panels are calculated by multiplying PV Input currents measured with an amp probe and with the PV input voltage measured with a multi-meter then there seems to be an error. It seems that the PV Input Current shown on the inverter is actually not the PV Input current but the MPPT output current. We think that the PV input current readings that we get from the inverter display and when polling is measured only after the MPPT's has already made its conversion. That is why the PV input current that is displayed is higher as when measured with an amp probe on the Solar input side. All the information are not available when polling with QPGS and a ratio has to be used to get to the correct Solar PV input current. We think this can lead to incorrect Solar panel input wattage display. We have used the ratio of the Battery voltage divided by the PV Input voltage and then multiplied by the "PV Input current"  (MPPT current) as given when polling to give the real PV Input current. PV input volts x PV input current = MPPT output volts ( Same as battery voltage ) x MPPT output current (Battery and Load current when in inverting mode - This is similar to the ratio of transformer input to output voltages and currents) When we use this ratio the PV Input current before the MPPT's are more or less the same as when measured with the amp probe. There might be a slight difference due to losses.
Hope someone can maybe lead us in the right direction if we misunderstand the concept.
Kind regards
Pieta
 
 

Hi Daniel
We see it that when current flows in any circuit that has resistance then volt drop will be experienced over that resistor. (That is the reason why you can use a shunt resistor to determine current flow (V =  I.R)) If a shunt resistor is used to determine current flow in a DC circuit you keep the resistance of the Shunt as low as possible to have very low volt drop over the resistor when current is flowing through it. Usually in milliVolts output to keep the Wattage or heating component as low as possible. The wattage is determined by the Volt drop over the Shunt multiplied by the current flowing through it (P=V x I) The Volt drop over the resistor is directly proportional to the current that is flowing through it. (A 600 Amp 50 mV shunt will give out 25mv when 300 Amps flows through it)
The same thing will happen when batteries are charged in series. There will be volt drop over each cell/Battery. Volt drop over each cell or Battery is determined by the current flowing through the string in series and the resistance of each cell. If the resistance of the batteries are different then different volt drops over each of the cells/Batteries will be experienced. This out of step condition causes some of the cells/Batteries to overcharge and some to undercharge. Differences between cell/Battery voltages indicates this condition. Obviously all cells/Batteries will not have exactly the same resistances but it should be kept as near as possible to each other. This is where the use of battery balancers come in.  Overcharging will definitely cause overheating of these cells/Batteries with the higher resistances and voltages cells/Battery as the Wattage component (P=V x I) becomes more on these cells. Unfortunately if the cells/Batteries are kept in this state for too long damage might occur.