smartsolar 100/50 parallel

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tothepoint asked Dec 9, '22

smartsolar 100/50 parallel

Question.

I now got 780w Solar on a 100/50 smart charger. This is connected to a 12v 600A lifepo4 battery.

As I spend winter time in Spain I want to upgrade the solar panels to shingled hyundai 415w each 3x.

That's to much for the 100/50 to handle so adding a second 100/50 could do the trick.

Is it possible to run parallel 2x smartsolar 100/50 and feed them with for example 1000w combined? Maybe networked over VE ?

Got this investment of the 100/50 and buying 100A controller could be the solution if I find a sponsor.

Greeting and tnx for any advice

JP

MPPT SmartSolar

2 |3000

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daver-1 answered · Dec 09, 2022 at 07:57 PM

is your question "can i run two mppt's in parallel on the battery side", then please you do a little research i think you can easily find your answer.

by example:

if you do a search query in this community with the following terms

"multiple mppt" you could have found this
"multiple smartsolar" you could have found this

is your question "can i also run two MPPT's in parallel on the solar side" then the answer is no.

MPPT stands for maximum power point tracking. As far as i know the Victron MPPT's can not sync on the same string. For this reason both mppt's would begin fighting for the control of the maximum power point. Another reason is that if one MPPT fails and shuts down, you are pushing the maximum amps through the remaining charge controller which could cause failure in the other MPPT. If you have 2 MPPT's it is advised to run a independent PV strings per charge controller.

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tothepoint commented · Dec 10, 2022 at 04:00 PM

2 mppt solar side. Did a search and I only found battery side q&a. That clarifies that it not possible. I thought maybe true the VE-direct connection but alas. Anyway going to set 2 seperate strings up with second 100/50. Tnx for the explanations why solar side parallel doesn't work.

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Answer 1 · 2022-12-09T20:17:37Z

djsmiley answered · Dec 09, 2022 at 08:17 PM

You might consider a 100/30.

Run 2 panels in series on the existing 100/50 and the 3rd panel on a 100/30.

No need to get a second 100/50

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daver-1 commented · Dec 09, 2022 at 08:56 PM

Can i correct you on this?

You should put two panels parallel on the 100/50 and one panel on the 100/30. Proper design of the installation is a must. so please use victron's MPPT calculator for that.

combining a 100/50 and a 100/30 is a good solution unless a 4th solar panel is wanted.

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kevgermany ♦♦ daver-1 commented · Dec 10, 2022 at 05:00 AM

It might help if you explained the reason for the parallel connection of the panels.

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tothepoint kevgermany ♦♦ commented · Dec 10, 2022 at 03:45 PM

415+415w and a % of about 92 makes approx 764,6w now with various panels 780w it makes 720w full sun. Seen 53 53A. Got 4 panels full solar cells and 2 half cut. Half cut is way more efficient then full cells with clouds. Hyundai shingled is more efficient when clouds and has a higher % rate. 21-22. Thus with the config now it max out. The panels now are +- 22v the Hyundai 46v. That bit more makes me scared that it would be to much. Or I can opt for 395w Hyundai shingled. I just weighing options.

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daver-1 tothepoint commented · Dec 10, 2022 at 11:16 PM

Please read this, it will explain your questions about the design of your system.

I will try to explain why you should put the solar panels in parallel, just hope it's not to technical:

The spec's of your pv panels are tested in Standard Test Conditions. These are measured under the following lab conditions: 1,000 Watts per square meter solar irradiance, 25 degrees C cell temperature, air mass equal to 1.5, and ASTM G173-03 standard spectrum

When a system is designed you should take into account the coldest expected temperature. The colder it is, the higher the open circuit voltage on a PV array will be. (you want to know why please google it) The Victron MPPT's are not protected for over voltage, the 100/50 will allow a maximum voltage of 100V.

when we calculate with a minimum temperature of by example -10°C we get the following:

(STC temp – lowest temp) x temp coefficient % VOC x VOC + VOC = VMax

(+25°C - (-10°C)) x 0.27%VOC x 46.7 + 46.7 = VMax

35x0.0027x46.7+46.7= 51.11V

So if you put 2 PV panels in series you get a combined voltage of 102.23V and that's to much for the MPPT100/xx

What i read is that you are worried about exceeding the 50A output rating. This isn't a problem, as if they do so it will just clip to 50A as long as the solar array is (over)sized to max 130%. You should know that an oversizing of 130% results generally in less than 1% annual energy loss). when combining the two panels the Victron MPPT calculator calculates an oversizing of 119%. so using two 415w panels in parallel should be fine.

If you click on the calculations button of the mppt you would like to use you will see the Max current and Max Voltage numbers i was speaking about.

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tothepoint daver-1 commented · Dec 10, 2022 at 03:53 PM

Indeed, then there be spare space ( Watts ). Alas the roof of the Van will be full with 3 panels. But when one fails then I got enough on the good one. Tnx for the intell

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tothepoint commented · Dec 10, 2022 at 03:49 PM

Came across my grey mass between the ears to put 2 panels on one 100/50. Maybe I get the 395 ones. To much to consider. Tnx for thinking with me.

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kevgermany ♦♦ tothepoint commented · Dec 12, 2022 at 04:14 AM

The panels are fine. It's the wiring. Parallel will be good.

Most of the day panels output less than their rated output because the sun is lower in the sky.

Normal to put more panels on so you still get good output in winter when sun low. The Victron calculator will often recommend an MPPT below max panel output for this reason.

You should also do the MPPT output current calcs at charging voltage, not nominal voltage of 12V.

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