Apollo T80 MPPT settings Help

serge74serge74 Registered Users Posts: 7
I was wondering since I have been reading through this forum, I have noticed that there isn’t enough discussion on the Apollo T80 MPPT charge controller.

If there was anyone that could help me with the MPPT controller settings. The PV system consist of the following
(4) 64w Solarex M64 panel 17.5 Vpp, 3.66 Ipp, 21.3 Voc
(4) 48W Siemens M48 panels 17.5 Vpp, Ipp???
(1) Apollo T80 MPPT solar charge controller
(1) 1800w 12v Xantrex Prosine true sinewave inverter (hard connection)
(8) 6v Energizer GC2 220Ah configured in a 12V parallel/series

There are two parts to my question
Part 1: Should I reconfigure my PV array voltage from 12v to 24v to maximize controller efficiency. Note the are currently installed using 12v configuration with proper gauge wire to account for voltage drop.

Part 2: Since I recently purchased and installed the Apollo T80 MPPT controller I am a little confused as to which setting in the MPPT setting menu to use for maximum efficiency. Considering that I live in Orlando Florida we do get a fair share of sunlight 80 plus degree weather. Should I set the “scan and seek” setting to every hour or should I extend that to a longer duration?

For the people who interested in reading the Apollo Solar T80 user manual follow this link and look at page 24.


Any help would gladly be appreciated.


  • WindsunWindsun Solar Expert Posts: 1,164 ✭✭
    Re: Apollo T80 MPPT settings Help

    With almost any MPPT controller the panels should be 2x roughly (or more, up to a point) your battery voltage for the best efficiency.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Apollo T80 MPPT settings Help

    elaborating further with what windsun said for going more than 2x may not be advantageous as the controller efficiency will decline even though you may have an offsetting gain by lowered voltage drop percentages. those circumstances may vary a bit and i'll go out on a limb and say that 1.5x would be better yet if it's applicable, which for your circumstance it is not an option unless you had series the pvs for 36v and used an output of 24v for batteries and loads making the 1.5x ratio. you have differing pvs so i wouldn't do such a thing even if you had the inverters and such for 24v battery operations.
    i do agree go ahead with the 24v series/parallel pv arrangements, but i am not familiar with the apollo to know those controller settings very well. i would assume it to be a similar sample as an mx60 would take, but i don't have one of those either. i am not sure how often the mx60 would scan, but more often than you presently have it at i would think as clouds could roll in or the general intensity would change just by the time going by, caused by an angle change from the sun. hopefully somebody else could more precisely say what to put it at.
  • loreleclorelec Solar Expert Posts: 200 ✭✭
    Re: Apollo T80 MPPT settings Help


    I have no direct experience with the T80, but can offer the following guidelines:

    1) I would wire the array for 24 volts. Most controllers like the T80 will exhibit a small drop in efficiency (something like 1-2%) with that setup, but this will amount to less than 10W in your case. There are two major benefits of wiring this way: A)the power loss in your wiring will drop by a factor of four, and B) you will always be able to track your array's maximum power point (the MPP of a 12v array will be near or below your battery's voltage once the array warms up, and so the controller would be unable to track it).

    2) I would use "P&O" instead of "Scan and Hold" for your MPPT. P&O will cause a full sweep of the array (from your battery voltage up to the Voc of the array) at your set interval (the factory default of one hour is probably fine), and will also run a more frequent "perturb and observe" algorithm that does the actual real-time tracking of the MPP. Scan and hold sweeps the array at the set interval, and then fixes the array at this voltage until the next sweep. Bottom line: P&O will respond to changes in the MPP much faster than S&H.

  • serge74serge74 Registered Users Posts: 7
    Re: Apollo T80 MPPT settings Help

    Man you guys have been great in responding and I do appreciate the followups. Thanks lorelec, niel, windsun for the insight. One last question, I am looking at buying (2) Evergreen ES-A-Series 195 Watt B Module from Sun Electronics to further add to my solar bug addiction. Does anyone have any negative feelings towards Sun Electronics. I just want to make sure that when I drop $1,162.00 that I won't be buying from a dud.

    Thanks again
  • halfcrazyhalfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Apollo T80 MPPT settings Help

    a lot of people including Solar Guppy have used and liked sun electric. they have some good deals thats for shure.
  • serge74serge74 Registered Users Posts: 7
    Re: Apollo T80 MPPT settings Help

    About a week ago I ended up ordering (2) Sun 205W panels from Sun Electronics. I must say that I received both panels the next day but it probably has alot to due with the fact that we are about 230 miles between each other. Nevertheless I am very pleased with the Sun 205 performance.
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