"Belief" needs to be supported by data. Believing they were installed correctly doesn't cut it.
thanks for your curt (pun intended) reply. Belief was based upon the fact that our smaller capacity setup was working just fine but agree that belief doesn't cut it. Contractor is a large operator and from what I garnered from others is competent but now I am wondering
0.2V could be chalked up to instrument error/calibration. 1.5V is outrageous. It indicates a SERIOUS issue and needs to be resolved.
I just checked the voltage at the batteries (with 2 separate multimeters) and at the high end of the charging range (29ish amps) there is a 1.0v differential (battery lower). This has to affect the charging but that is probably moot
- Are the chargers configured to hit 15.0V during charge? I have seen them go that high but not something sustainable
- Have you witnessed the batteries hit 15.0V during charge?
- Have you confirmed that all connections between the charge controller and battery are tight and secure?
- What is the gauge of wire between the charge controller and the battery?don't know but it was upgraded in anticipation of this new battery bank
I apologize. I just now saw your maximum solar charge current is 40A. This is inadequate. If your "solar contractor" agreed to install these batteries without indicating you needed to significantly upgrade your PV,
they are incompetent, and you need to take control of this situation, or you will never fix it.
not to defend the contractor too much but he did bring two more PV panels (100ish watts each) when we started noticing low voltages. Contractor was contacted today and he is coming by Monday. So my plan is to acquire more panels AND a bigger controller? Before I read your reply I was going to have him take two of the batteries at a time to his shop/home and charge them with his 110 and his 90 amp charger with the thought that our usage is so small that we would be able to sustain it with our minimal charging capabilities once we got "full" charge but now????
From:
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You need to read the entire document I linked and follow it.
I did pull this up and read it but understanding has been a cumulative process with outside input helping.
You need to triple the size of your array to meet the 10-20% requirement. You will need to upgrade/add charge controllers to handle this.
The current (sic) charger is only rated to 40 amps-Xantrex C40- so we will be needing to upgrade this again-this was an upgrade last season (march 2020) from the original 20 yr old inverter/charger. This should have been a recommendation by your "solar contractor" before they sold you the batteries. You will damage these batteries and shorten their life if you don't.
Here's how a proper charge should go:
Apply 89A of current to battery until 15.0V is achieved.
Hold 15.0V by decreasing current until current drops to 17.8A
At that point, the battery is fully charged.
If you are charging at less than 89A, and/or if you are charging at lower than 15.0V, and/or you are not holding 15.0V until your current drops below 17.8A, your batteries are undercharged and will never reach SG of 1.260-1.280. You should never equalize a battery that is not already at full charge according to the above criteria. How is one manipulating those 2 parameters (current and amperage in the charging-via the pot settings in the controller?) Thanks again for your time.
Again, please read that manual. You need to adopt best practices described therein to ensure you get the most out of your investment.