[RE-wrenches] Battery Experience

[John DeBoever]

Wrenches,

Forcing a lead acid battery to cycle for the fun of it reduces its cycle life.

In a nutshell, lead acid batteries have “five lives”, each varying depending their specific intrinsic technology attributes developed by the battery OEM:

o   Cycle life

o   Corrosion life

o   Stratification life

o   Shorting life

o   And… Temperature life

These lives are all inter-connected and temperature is the one that is the most influent to all of them. The interesting part is that all of these “5 lives” are 90% of the time exacerbated by the system sizing (cyclic/non-cyclic, loads, insollation, PV array, battery bank size, wiring and power conditioning losses, etc.), the install, the setting points commissioning, the maintenance, not to forget the load patterns (perceived vs. reality dynamics and growth of the load).  Cycling for cycling does not increase the battery life. Adequate cycling based on adequate full recharge keep the battery in good health.

John

John F. DeBoever
Global Technical & Projects Director – Renewable Energy
Trojan Battery Company

12380 Clark Street
Santa Fe Springs, CA 90670
Tel: +1-562-236-3000 Ext. 3139
Cell: +1-845-514-7600 – NY office time zone: USA EST (GMT-5)
Skype: john.f.deboever
Fax: +1-562-236-3239
jdeboever at trojanbattery.com<mailto:jdeboever at trojanbattery.com>
www.trojanbattery.com<http://www.trojanbattery.com/>


From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of larry at starlightsolar.com
Sent: Friday, July 13, 2012 12:18 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Battery Experience

Jason,

Forcing a lead acid battery to deeply discharge does not increase capacity or life of the battery. It only shortens battery life and may damage the battery. This is one of many battery myths.

Larry Crutcher
Starlight Solar Power Systems
-------- Original Message --------
Subject: Re: [RE-wrenches] Battery Experience
From: Jason Lerner <wapalco at rockisland.com<mailto:wapalco at rockisland.com>>
Date: Fri, July 13, 2012 7:28 am
To: RE-wrenches <re-wrenches at lists.re-wrenches.org<mailto:re-wrenches at lists.re-wrenches.org>>

Hello John,

This time of year I service off grid summer cabins where people come up once a year for a few weeks.  The batteries in these systems generally do not die from over cycling,  but from over/under watering,  acid stratification, corrosion,  and generally being ignored.  The more savvy customers I will recommend they turn off the PV's when they are there to get a deep discharge in.

Could you recommend any thing else they could do to lengthen their battery bank lifespan? These systems generally have a small PV charging capability,  and float charge 350 days a year. It seems ironic that these systems that really never get used,  and my battery bank at home that gets used (but not abused) and cycled daily, will last the same number of years.

Thanks very much,

Jason Lerner

Waldron Power and Light Co.


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