Battery dropping fast to 50v

OffGridInTheCity

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Southern Oregon
Can you please elaborate more on this point? I didn't get what do you mean by it.
Let's say a battery is sitting at 12.0v. If a charger set's itself to 12.0v, then no current will flow and the the battery cannot be charged 'higher' than 12.0v. To get current to flow, a charger has to raise the voltage higher at the battery.. say 12.5v... and then the current will flow into the 12.0v battery. Once the battery get's to 12.5v, then current will stop flowing and no further charge will happen.

In other words, a charge controller will show you a higher battery voltage while charging is going on. During bulk charge (CC portion of charging) it will be noticeable. If it's nearly full the current will taper off (CV portion of charging). At 100% full charge / float - the charge controller is barely doing any current at all which means the charge controller voltage = battery at rest voltage.
 

timselectric

If I can do it, you can do it.
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Maybe switch to user defined battery settings.
And change low cutoff to 48v.
 

ghostman

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Apr 13, 2022
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How are these wired? Are they wired in a balanced manner or ?? Any pics?
an electric technician took care of the wiring. I just called him, he said that they are wired as 2 banks of 6 batteries each with 2 batteries set as stand by in each bank (I'm not sure how this is possible), and the batteries are connected to an optimizer.
 

ghostman

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Maybe switch to user defined battery settings.
And change low cutoff to 48v.
Yes I believe this is the best approach, I will do it once I reach home. thanks for your help.
Now after 8 hours of battery mode, battery voltage is at 49v (load is stable at 800w), is this considered good so far?
 

timselectric

If I can do it, you can do it.
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Yes I believe this is the best approach, I will do it once I reach home. thanks for your help.
Now after 8 hours of battery mode, battery voltage is at 49v (load is stable at 800w), is this considered good so far?
Not bad
 

MisterSandals

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an electric technician took care of the wiring. I just called him, he said that they are wired as 2 banks of 6 batteries each with 2 batteries set as stand by in each bank (I'm not sure how this is possible), and the batteries are connected to an optimizer.
Now i am REALLY curious... would love to see a pic.
 

MisterSandals

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they are wired as 2 banks of 6 batteries each with 2 batteries set as stand by in each bank
from what I described, is this an efficient setup?
As described it sounds wrong to me. To get 48V from 12V batteries, 4 need to be in series. If you have 8 batteries, then the 2 sets of 4 in series are paralleled (preferably balanced with the wiring to/from the + of one bank and the - of the other bank).

Not sure how to do that with 6 batteries and have no idea what 2 as stand by could mean.

I'm still game for a pic or 2.
 

ghostman

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As described it sounds wrong to me. To get 48V from 12V batteries, 4 need to be in series. If you have 8 batteries, then the 2 sets of 4 in series are paralleled (preferably balanced with the wiring to/from the + of one bank and the - of the other bank).

Not sure how to do that with 6 batteries and have no idea what 2 as stand by could mean.

I'm still game for a pic or 2.
I will take some pics when I reach home
 

tarek

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May 2, 2022
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Beirut
It seems u r using C20 Tall Tubular Lead Acid battery.
You need to equalize them first, then set the bulk to at least 57.6 Volts and the float to 53.6 volts.
Apparently, the voltage drop you are experiencing is a result of not fully charged battery.
You need to consider also the charging current for the batteries.
 
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