Microtek SMU 6024 is an excellent choice for converting your existing dual battery inverter into a solar inverter. The SMU stands for Solar management unit. That means this is a Solar Charge controller (PWM based).
6024 means that its a 60Amps charge controller for 24V solar panels (upto 1440W panels) and 24V inverter/battery.
It has a one year warranty, even though its MRP is 7499, you should be able to get it around 3000 to 3500 rupees.
It has protection against panel reverse and battery reverse (just in case if you are stupid enough to do such things – mind you some installers are pretty stupid and connect in worse ways than you could imagine).
We need to connect the DC output from the solar panels to the SMU, and the SMU output DC to the battery. Also the AC input will be given via the SMU to the inverter.
It will work in such a way that when there is power in the solar panels, it will charge the battery – and when the battery reaches enough full voltage (approx 29.5v), it will disconnect the power to the inverter. So the inverter will be running from the battery/solar.
When the battery voltage goes down upto 23V, the SMU will reconnect the mains supply to the inverter, while continuing to charge the battery on solar.
Photos of Microtek SMU 6024
This unit was installed and checked in a location in Kuriachira, Thrissur district, Kerala state, South India for a customer by Buff Power. The location was good for solar purposes because its a little high altitude with no trees or tall buildings nearby.
So the amount of light available here was excellent. The inverter already present with the customer was Microtek SEBZ 1500, so he was already familiar with the brand. Microtek provides very good after sales service and support compared to other brands.
Also Microtek solar panels and cables was used. Microtek 24V 320W panel – 4 nos were used bringing the tally to 1280Watts. I had insisted on using 4 panels since it should easily meet his current requirements and his future requirements in case if he wishes to upgrade the inverter up to 2500va.
Microtek 10 sq mm solar cable was used to connect the panels to the SMU. This thick cable was used to limit any loss in current.
So the culmination of all these means that we were able to get pretty good results. By around 7 – 8 am, the batteries are fully charged and the SMU will switch off the mains to inverter and it will run on solar for up to 5 – 6 pm.
Pros of Microtek SMU 6024
– Low cost
– Top after sales service
Cons of Microtek SMU 6024
Unless you use it with quality solar panels and proper wiring (like the one explained above) you are not going to get good results. While this is not a con, usually people blame the PWM based charge controller without seeing the cost versus output factor for small solar installations.
I am not sure that the connectors on back of the back of the SMU can handle the 60amps. The connector on the review unit burned (could be because of loose connection), but I changed it to a bigger one which can handle 60Amps.
Another issue that I noted is that in the evening, when the SMU switches back the inverter to mains supply, again the inverter takes a lot of time to charge the battery. This could be because the SMU changes the inverter back to mains only when battery voltage reaches 23.8V – which by my thinking is too low – again the SMU and inverter combined have to charge the batteries back to 28.8V. This is done mostly by inverter as the sunlight might be too low for the SMU to charge by this time in evening.
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