LEAD ACID TUBULAR SOLAR BATTERY SHELL LIFE

[amarjithtk]

I was planning to buy a solar battery for my 100 watt dc only solar system. I went to a nearby dealer. They offered me a Exide solar tubular 6LMS75L battery. When I checked the manufacturing date, I saw that it was manufactured about 11 months ago. I am unaware of any potential problems that could arise due to purchase of a lead acid battery that is about an year old. So please help me understand the problems with buying that battery. Will the capacity of battery reduced from 75ah to a lower value because of keeping it in the shelves for a long period of time ? . Any other implications due to non usage of that battery kept in the shelf for about an year ?

Q) what is the terminal voltage of a new solatubular 6lms75l battery that I should check to verify the quality ?

 

[sunshine_eggo]

Lead-acid batteries eat themselves at lower states of charge. It starts at about 80% SoC and gets worse as you go down.

https://docs.exideindustries.com/pdf/industrial-export-batteries/products/ceil-solar-brochure.pdf

Flooded but claim low self-discharge rate: "Low rate of self discharge"

Typical flooded lose about 30%/30 days. Charging is typically recommended every 2-4 weeks or less.
Typical AGM lose about 3%/30 days. Charging is typically recommended once every 3 months.

This battery does not provide a recommendation. It might be beneficial to contact Exide and see if they have a recommendation.

For claims of "low rate of self discharge," I would expect about 5-10%/month on flooded tubular. At 10%/month, it's likely to be at 30-40% SoC.

A nearby dealer should know that batteries should be charged periodically to maintain performance. They are likely old stock they have been sitting on for a long time and are itching to get rid of them.

I would not accept any that were less than 6.2V, and I would check the specific gravity of all cells and confirm that they are within .03 of each other.