Reply To: additives or gadgets to fix or renew batteries

[Anonymous]

You can try it but I wouldn’t get my hopes up. Before spending the money I would suggest you spend an evening reading all the information found on the Trojan web site. http://www.trojanbattery.com  this is a great place to learn about batteries. You can also call the Trojan tech support people and they will answer any question you have about batteries. 800-423-6569 ext. 3045

What I believe you will discover is that the batteries you currently use are not really deep cycle batteries, but rather a cross between an auto battery and a true deep cycle battery. An auto battery has more plates than a deep cycle battery but they are thinner. This allows the battery to produce very high current output to drive starter motors but for a short time. Deep cycle batteries have fewer plates, but they are thicker. This means they can’t produce as high of a current output but can do it for extended periods of time. The marine batteries are a cross between the two. They have more plates than a true deep cycle battery and they are thicker but not as thick as a true deep cycle. They are used to start a boats engine so they need to have a high current output, but also are used to power the boat when the engine is off so they need to have longevity. As a result they will last far longer than an auto battery but due to the thinner plates will degrade much faster than a true deep cycle. For off-grid use here is a good rule of thumb, if the battery talks about CCA (Cold Cranking Amps) it’s not for you. That tells you that the battery is designed to start an engine so it’s main design isn’t longevity. A true deep cycle battery will give you it’s Ah (Amp Hour) rating two different ways. 5 hour rate and 20 hour rate. A battery produces it’s current by a chemical process and is determined by the speed of the process. For example, my Trojan T-105-RE’s have a 170Ah rating at 5 hours, and a 225Ah rating at 20 hours. They top out at the 100 hour rate at 250Ah. That means if I draw the batteries down completely in 5 hours I will get 170A x 6v = 1020 watts, but if I discharge it for 100 hours to draw it down to nothing I will get 250A x 6v = 1500 watts.

Since my batteries are 6v, but my panels (and the rest of the system) are 24v, I string 4 batteries in series to make a 24v string. I do that to two sets of batteries (8 total batteries) and connect the two strings in parallel to get one battery bank totaling 24v @ 500Ah (at the 100 hour rate). By doing this I seldom draw the batteries down below 20% DOD (Depth of Discharge) that way the plates endure very little degradation from the acid. I estimate my batteries should last in the ten year range.

The biggest factor in a batteries life (assuming proper maintenance) is DOD. The deeper you draw the batteries down the more the acid eats the lead plates. So in the end more batteries in your system save you money in the long run as you do them less harm from lower discharge rates. And the true deep cycle batteries are a must for total solar users like us.

Anyway, I’m rambling again. But do yourself a favor and read what the Trojan site has to offer (and it’s a lot) then talk to their tech support folks before spending any money on something that I doubt will help.

Zathris….