question

greekgeek avatar image
greekgeek asked

solar charger not charging?

My solar charge controller shows zero charging input some cloudy days. Has enyone experienced something similar? is it normal? i have attached two solar charger in my battery each of them providing power from a different string; i have also connected a smart battery sensor that provides data to the chargers. am i doing something wrong here? thanks for your input, cheers

smart solar charging behaviour
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klim8skeptic avatar image klim8skeptic ♦ commented ·
Perhaps you could share your mppt's history with us?
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greekgeek avatar image greekgeek klim8skeptic ♦ commented ·
u r right, i will do that asap
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greekgeek avatar image greekgeek klim8skeptic ♦ commented ·

as you can see, 4 days ago the load output from string 1 (2s2p) is zero while the output from string 2 (1 240w/24v panel) is 50 wh. This was a cloudy day with minimal electricity usage from the system, just a couple of lightbulbs. Both solar controllers are set at the same configuration (battery=>victron 2=>deep discharge).

screenshot-2021-12-04-09-17-37-223-comvictronenerg.jpg

the same thing happened a few days ago

screenshot-2021-12-04-11-42-45-441-comvictronenerg.jpg

screenshot-2021-12-04-11-43-03-764-comvictronenerg.jpg

the first controller is on float mode while the second is still in absorption. Any input is much appreciated, cheers.

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4 Answers
klim8skeptic avatar image
klim8skeptic answered ·
3 comments
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greekgeek avatar image greekgeek commented ·
so you mean to make a network between the two chargers without connecting them to the battery sense?the article provides very few details, cheers
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klim8skeptic avatar image klim8skeptic ♦ greekgeek commented ·
From what I have read, 2 mppt's will communicate and go into master/slave config.

Plz confirm.

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greekgeek avatar image greekgeek klim8skeptic ♦ commented ·
first of all thank you for your patience and expertise, i set up the controllers in the manner that you suggested yesterday, i ll check the readings tonight so that a full 24hr has passed. I hope that it will solve the problem.

in my previous setup i set up a network between the smart bat sense and the two controllers. I thought that this is the optimal setup so that both controllers receive data from the sensor. anyway i will let you know.cheers

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kevgermany avatar image
kevgermany answered ·

Might be worth checking the settings on your controllers as well.

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greekgeek avatar image
greekgeek answered ·

this is getting weird

screenshot-2021-12-07-19-42-19-724-comvictronenerg.jpg

screenshot-2021-12-08-18-50-44-055-comvictronenerg.jpg

the first controller reports a max battery voltage at 14.35v while the second one at 14.45v (i cannot be certain about the min bat reading )

both controllers are set in a network working in tandem



screenshot-2021-12-08-18-50-59-934-comvictronenerg.jpg


each controller has also the same settings

set-1.jpg

set-2.jpg

any input is wellcome.


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greekgeek avatar image greekgeek commented ·
i would like to add that the two strings are loacted side by side. Is there a possibility that the voltage differences are attributed to the sun going down on the panels (and similarly going up in the morning)?
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klim8skeptic avatar image klim8skeptic ♦ greekgeek commented ·

I would like to see the amount of time each controller has spent in bulk/ and absorb. Just to see if the controllers have switched state at about the same time.

You could use your Smart Battery Sense to the network for better voltage and temp compensation.

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greekgeek avatar image greekgeek klim8skeptic ♦ commented ·

so i added the smart sense to the network

screenshot-2021-12-10-18-28-42-404-comvictronenerg.jpg


and after a cloudy/rainy day i checked the readings last night


screenshot-2021-12-10-18-27-53-863-comvictronenerg.jpg


screenshot-2021-12-10-18-28-17-971-comvictronenerg.jpg

the first controller is attached to a 2s2p string producing 100w @ 24v and the second one a single 230ish w @ 24v. The first controller is hit from sunrays first in morning, while the second one gets maybe half an hour of sunshine more, in the afternoon (they are side by side facing south).

What is meant by master/slave configuration? is it that the master (probably the first one that comes alive?) does the heavy work and the slave contributes when needed?

the readings recorded yesterday were due to minimal voltage produced because of the cloudy weather? what is the worst thing that can happen to the battery? I mean what if one controller is in absorption mode and the other in bulk?the extra voltage will eventually bring both in the same level sooner or later. Right?

i am really confused and also disapointed from the fact that i cannot talk to a qualified Victron person/installer (not salesman) in Greece although their products are sold here.

any help is much appreciated, cheers

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kevgermany avatar image
kevgermany answered ·

Could be a poor battery connection causing resistance and a voltage drop.

The switch from absorption to float is based on time elapsed. Not sure if this can be different on the two controllers. If it is, it shouldn't be

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