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hydrotruth avatar image

MPPT 100/50 with Permanent Magnet Generator as input.

Greetings everyone, I am new to forum and would like to say hello.

I have a question regarding input on the MPPT 100/50.

Is it possible to use the DC output of a permanent magnet generator 60v-72v with maximum 70 amps to the input of 1 or 2 paralleled mppt 100/50 charge controllers?



Hydro and Wind Power
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2 Answers
swede avatar image
swede answered ·

Hi!

I think it will work good - at least with one MPPT - however only a fraction of available power will be used.

I was thinking about if load sharing will be a problem between two MPPT.

If I get it right your power is about 72 V * 70 A = 5040 W

What is your battery voltage? If your battery voltage is for example 12 V. The current to the battery can be 5040 W / 12 V = 420 A

So If you have two MPPT 100/50 you will be able to use 100 A of the total 420 A.

What is generating power to the DC generator? I was thing if there can be load sharing stability issues if the available power goes under 100 A?

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Hello Swede

Thank you for your answer.

I have never worked with mppts in the past.

I was under the impression that you are limited by the output of the mppt charger, regardless of input.

So if you had 5000w input, will the mppt attempt to output that amount of power even if its limited to lets say, the 2 x mppt 100/50 = 100amps ?

The DC generator, if connected directly to battery bank, will deliver the amount of power the batteries can absorb at the level of SoC. If they can only accept 40amps lets say, it will only deliver that amount. It wont attemp to force more into the batteries. If the SoC was very low, it will be forced to deliver the max amount it can handle and be limited to the 5000w.

In regards to a 12v system. "So If you have two MPPT 100/50 you will be able to use 100 A of the total 420 A" , if you are limited by the output of the mppt, I can live with that.

So load sharing is an issue when using the same spec mppts in parallel?

JohnC avatar image
JohnC answered ·

Hi Hydro. Another issue you may want to consider is that your 100/50 is rated for 60A on it's input. That's for solar short circuit conditions, I think largely a safety issue if an internal fault ever occurred within the mppt. Perhaps a graceful failure, rather than setting the place alight or blowing itself off the wall. Can't remember the explanation well enough to repeat it..

Maybe ask yourself how many A your generator might deliver if the mppt faulted within?

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Hello JohnC.

Thank you for your explaination.

In case of a short on the pma terminals, I guess as I have never tried it, worst case is the rectifier block would blow or the engine would stall.