[RE-wrenches] battery venting; Corrosion

[Larry Crutcher, Starlight Solar Power Systems]

Hello William,

My understanding is once the SO4 is fully absorbed, excess H and O are produced and could be vented if the pressure rises above 5psi. So, when saturation is complete, voltage should be reduced and no gassing would take place. For this reason, I always recommend using charge current as the method to transition to float with VRLA batteries. Of course, proper voltage and temperature compensation are vital.

I am not surprised that MK would say this. Their battery is manufactured by Deka. We just stopped selling ALL Deka AGM batteries because we are experiencing many failures after about 1-3 years of use. In almost all cases, the tops of the battery show evidence moisture because of excessive venting. The cases are also sucked in as a vacuum is created from the loss of electrolyte. My charging systems are all programmed to the letter of Deka's charge specifications. They will not warranty any.

We have been equalizing AGM batteries for many years. When done properly, .05C of constant current with unregulated voltage, adjusted for temperature and time limited, the results are good in most cases.

Larry Crutcher
Starlight Solar Power Systems



On Jan 6, 2012, at 11:16 AM, William Miller wrote:

Larry:

I always thought that any breach of a valve in a VRLA battery was a sign of a failure.   I recently spoke with a technician at MK Batteries and learned that venting and/or seepage is not uncommon and not a sign of failure.

I have also heard in the distant past and then read recently on a manufacturer's web site that VRLA batteries can and should be equalized.  The parameters are different from an FLA battery.

William Miller




At 09:12 AM 1/6/2012, Larry Crutcher, wrote:
> You beat me to that one, Kent. Also, if your VRLA battery is emitting any gas, you've got trouble.
> 
> Larry Crutcher
> Starlight Solar Power Systems

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