[RE-wrenches] Battery Charge Settings.

[Starlight Solar Power Systems]

I have long been a fan of aggressive charge voltages for flooded batteries in daily cyclical use. As Steve has emphasized, temp. comp. is imperative, especially using higher absorb voltage as over-voltage at high cell temperature rapidly reduces cycle life. 

It is my observation that most L16 size batteries don’t do well with lower absorb voltages and I have seen more Trojan L-16 failures than I care to. For L16’s, I recommend 2.5Vpc with extended absorb time until current drops to  0.5A/100AH C. 

Steve, I concur with your finding about higher voltages. Here’s something I have been doing with success: I have been testing CC/CV/CC charge regime, also called IUI. This provides what I call a mini EQ cycle prior to entering Float charge. Every day when the absorb timer terminates, I start the EQ cycle for about 30 minutes. This drives the voltage up to 2.65Vpc. The current is naturally limited by battery resistance since the battery is nearly full. The results have been impressive for battery life and capacity recovery. Here’s some examples...

1. A customer using this method with Lifeline AGM batteries is in the 10th year of use with only about 20% capacity degradation. 
2. Another customer that has 5 year old T-105 batteries began doing this about 6 months ago and has reported capacity being increased.
3. Another has Rolls 530’s (we did not sell or install) in a 12 volt system. After 2.5 years he came to us with the capacity problems. His chargers were set to 2.4Vpc and he had not performed any EQ cycles as mandated. We installed a charger capable of EQ voltages and began the daily EQ cycle and he too has reported capacity recovered.

I think it is worthwhile to consider higher charge voltage and/or trying the IUI charge method for anyone experiencing battery capacity loss. 

Larry Crutcher
Starlight Solar Power Systems




On Jan 19, 2016, at 9:01 AM, Steve Higgins <steve at surrette.com> wrote:

The testing that we have done with our batteries, is well over 90% completed has actually increased cycle life and performance even at the higher charging voltages… We are testing at 2.6vpc just for your information, these batteries have actually tested at over 110% capacity.  That being said this is also in a lab, where temps are controlled.. In a “real world” situation temperatures are a killer for any manufactures batteries, this is why all systems need a BTS installed.   It’s hard to believe how many don’t install them, nor do they install them  correctly…  As all of you know they should be on the side of the battery, below the level of the plates, this is normally about 1/3 to ½ way down the battery.   They should never be on the top.
 
 

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