question

enevis85 avatar image
enevis85 asked

How many amp panel need to make to MPPT controller started charging battery?

Hi.

I'm wondering how many amp mppt controller need to received from panel to start charging battery?

As I noticed, most of times mppt need from panel need more then 2.2A to start charging.

As you see on screenshot below ones even 2.41A and 28 W to battery wasn't enough to start charging, (battery is on idle not charging).

Or i think wrong and this is normal?


screenshot-20230927-124834-chrome.jpg

MPPT Controllers
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3 Answers
Michelle Konzack avatar image
Michelle Konzack answered ·

It is not the Amperes but the Voltage.


The MPPT need a Voltage which is 5V higher thrn the Battery voltage.


Since you have a 12V system, i assume, that your panel is 18V. This minght give in the UK a serious problem


I suggest you to install a second Solarpanel of the exact same type in series to increase the Voltage or use a singel 32-38V module.

2 comments
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matthias-nagel avatar image matthias-nagel commented ·

The 5V offset is correct, but I am confused by the provided screenshot as well. According to the screenshot the MPPT delivers 37W at 2.41A and runs in bulk charging mode. The AC system is switched off. The battery is discharged with 28W at 2.1A. (I assume that positive numbers at the battery imply that the battery is discharged, not charged.) This means there is a total of 65W of power and 4.51A of current which "magically" leaks out of the system.

Does the screenshot fall short of showing DC loads?

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kevgermany avatar image kevgermany ♦♦ matthias-nagel commented ·
As I said, screenshot shows battery charging. If it was discharging there would be a negative value. Please don't confuse things with false assumptions.
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kevgermany avatar image
kevgermany answered ·

I'm in a similar situation with the same weather. But the screen shot does show the battery is charging, just not quickly. As said above, more panels needed for this weather. But in a month or two, there will be little or no solar.

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mjs500 avatar image
mjs500 answered ·

Your Victron mppt controller watch model 75/15 or 100/20 ? and is the panel on camper roof ? i.e. flat if so you may wont consider ground mounted panels so you can change panel angel in to sun all year round as an add on to your system you will need to add second solar control in parallel battery side as power point will be different add on panels

if your setup fix roof mount i.e. shed

ever way from your vrm mppt dater you need more PV volts as sun moves south in the sky day by day your solar power will get low

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