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samuil avatar image
samuil asked

How long would it take my 20W solar panel to recharge my 12V 9Ah Lifepo4 battery?

Hello,

I would like to know if my Victron 20W solar panel be suitable to power my Invicta Lithium 12V 9Ah Lifepo4 Battery.

Victron solar panel specifications:

solar-panel-specification.png

Lifepo4 battery specifications:battery-specifications.png


Power manager (MPPT):

I would also like to interface the solar panel and battery using my Victron SmartSolar MPPT 75/10 solar charge controller.


The reason why I ask is to get an understanding of:

1. Compatibility between all three components, &

2. An approximate or average on long would it take to charge up the battery, if the battery was in a depleted state (at a cut off voltage of say 10.5v).


Your help would be much appreciated. Thank you.

Lithium Batteryvictron productsSolar Panel
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1 Answer
kevgermany avatar image
kevgermany answered ·

It will work.

These figures very approximate.

Charge time is dependant on how full the battery is and how much light there is.

Let's assume battery is at 20% depth of charge. So 1.8Ah remaining. Thus needs 7.2Ah of charge.

Panel will allow the mppt to output 20/14A =1.4A

So with full sun and a battery as low as you should take it, time to charge is 7.2/1.4=5.2h.



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samuil avatar image samuil commented ·
Thank you very much Kev!
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samuil avatar image samuil commented ·

Hi @kevgermany


I have one more question for you (hoping you know the answer, otherwise I can of course start a new thread.

In the Victron app for the MPPT it has the following options in the two screenshots below.

Question 1: Should I be changing max charge current to 9A to suit the battery?

Question 2: How do I adjust the low voltage disconnect and re-connect? If possible.

Question 3: What are your thoughts on temperature compensation? From my understanding the battery has a in-built BMS, should I let that control these variables or should I enable it in the Victron app?

222f8f42-449c-4562-b609-8e2cdecda473.jpg

894084ba-46cf-43e3-a18a-2380fca994cd.jpg


Thanks again for your help!

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