question

ball-kth avatar image
ball-kth asked

Max Charger Current for MPPT on Multiple Parallel Lead Acid Battery with Load

Hi,

I have the system of 1unit of MPPT 150/100 with 3 sets of Lead Acid Battery (150AH) in connected in parallel for 450AH to supply to the load, 8A-15A.

The battery specification mentions the maximum charging current at 30A.

So what "Max Charger Current" value shall be set?

a. Setting 90A as from 3 sets of batteries in parallel --> 3x30A = 90A

b. Setting 100A (Max) as from 3 sets of battery in parallel Plus load


If not as above, please help to advise.


MPPT SmartSolarcharge current limitcurrent limit
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Alexandra avatar image Alexandra ♦ commented ·
Do you have a GX?

Have you overpaneled the mppt?

How likely is it to stay pinned at 100A?

If not leave it at 100A, dont limit it.

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ball-kth avatar image ball-kth Alexandra ♦ commented ·

Thank you for your response.

Well, there is no GX. Also, the panel capacity is over-rated than MPPT.

For the setting at 100A, will it be harmful for the batteries in case of low load and the battery took the current over 30A/set?

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kevgermany avatar image kevgermany ♦♦ ball-kth commented ·
If you're overpannelled, there's a good chance of exceeding the max charge rate for long periods. Although short periods a little over 90A won't do damage, extended periods will. It would be a good idea to watch battery temps, overheating will have a big impact on service life.
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1 Answer
mvas avatar image
mvas answered ·

Do you have a shunt?

A shunt would measure the actual Charging amps vs MPPT amps output.

If the manufacture states ... 30 amps max charge rate, then follow their rule. Unless you know more about charging their batteries than than they do. Electrical Engineers always design within a safety margin, we do not take unnecessary risks.

Do you have a diagram of how those 3 batteries are connected in parallel? There is a correct way and many wrong ways.

Mfr and model # of battery or URL?

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