Oversizing Solar Panels

If you take a look at the specs of the EB3A it mentions that the solar panel(s) should have a VOC between 12 and 28 V and a max. current of 8.5A.

My question: could I use a larger panel with a higher current? As long as the VOC is within range? Shouldn’t the MPPT be able to just limit the current?

The two reasons I’m asking this are:
1.) I’m thinking about getting second hand panels. There it’s much harder to find the “perfect match”
2.) I rarely have perfect solar conditions. I want to have a reasonable output under those conditions. It’s okay to waste some potential when conditions are better.

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The short answer is yes, From what I have read as long as you do not go over the max input voltage you can over feed current and it will just be limited by the MPPT. Its fairly common to “over panel” a system because you rarely get the listed output from a solar panel. Now if you live somewhere where its almost always sunny like Nevada, Arizona, Florida, Etc. maybe you wouldn’t need to over panel aa much but if your in a less sunny area and you’re buying used panels you may want to consider doing just that.

I concur with @doecliff. The EB3A MPPT controller will not pull more amps than it supports, but it will break if you feed it too high a voltage. Generally you’ll want to find panels with an open circuit voltage as close to 25-26V so you can get the most watts when wiring it in parallel with a similar panel. 2 panels a lower Voc wired in parallel will max out the 8.5A current input and you won’t be able to get close to the 200W input limit. So if given the choice between multiple panels, chose the one with the higher open-circuit voltage but under 28V. For better efficiency, your panels’ Voc should be as close as possible.

Hi @tschaboo , welcome to BLUETTI community!
There is no problem with having more current/power as long as it is within the open circuit voltage range, just that the extra will be wasted.
Have fun and hope you enjoy using EB3A :blush:.

Many thanks to all three of you for your very helpful answers!

Hi, I had a similar question because I have two 18 volt 60 watt solar panels and I want to connect them in series to the EB3A, but I realized that would give me 36 volts, and that would exceed the 28V max on the Bluetti solar generator, so I plan to include a 36 volt step-down voltage & current reducer and place it in my solar wiring setup to prevent over voltage, and over current. I have never done this before and I am self-taught, so does anyone feel as though this would not work for some reason? I’m going to include a 12 amp resettable fuse breaker before the step down converter module because the module is rated for 20 amps and I don’t want to get anywhere near 20 amps. On the other side of the module of course the amps will be lower because I’m going to set the Max amperage probably to 5-6 A with the step-down converter.

I don’t think it is a good idea to use a voltage reducer inline. Solar panels are not ideal voltage sources, they have a non linear VI curve that voltage down regulars may not work well with.

Note that you never have to be concerned about over current, just over voltage. If the panel can supply 20A in full sun but the device can only accept 8, only 8 will flow. Just like how your wall socket can supply 15A at 120v but it won’t blow up your iPhone charger that takes just 0.01A

I was thinking the same thing Julietti-69. I’d like to run my two 100 watt solar panels in series and place a buck converter to step down the voltage from 43.2 to 28 if possible. Have you tried it yet? If so, what were the results? Thanks