Lost Bigtime Battery Studies

<snip>

A good reference for charging L-16 batteries is a Sandia National Labs report (year 2000) titled

“PV Hybrid Battery Tests on L-16 Batteries.”

Website: www.sandia.gov/pv.

.................................................. .................................................. .................................

That info above came from the Legendary Morningstar Corporation.

Page 51, 9.3 (L-16 Cells). TriStar Installation and Operation Manual.

How could a Government and Industry funded Study about 4 Brands of L-16 Batteries

just disappear off the face of the earth? One source saw it and says basically it was a landmark study.

Supposedly they talked about how to get twice as many Cycles (compared to average) among other things.


http://www.morningstarcorp.com/en/su...nual.04.EN.pdf

---

Batteries and PV Systems

By: Don Loweburg


http://www.advancedpowerproducts.com/batteriesandpv.php

http://homepower.com/view/?file=HP89_pg120_IPP

---

<Snip>

June 2007 Response to a Blog.

By: Bill Kaszeta

Photovoltaic Resources Int’l Tempe Arizona USA

Response:

These charge 12 Trojan L6 batteries via a Trace C40 charge controller. (Wired in a 24V configuration)

I assume you have L-16 batteries. You should be aware of the following. Sandia National Laboratories published the following interesting
document on charging a flooded lead-acid battery for use in PV systems. Author(s) Sandia National Laboratories, Albuquerque, NM Hund, Thomas D. Title Quarterly highlights of Sandia’s photovoltaics program : PV hybrid
battery tests on L-16 batteries. Volume 4, 2000. Report Number SAND2001-3521P
Classification Unclassified Unlimited Release Imprint October 2001. Description 8 p. Notes
<snip>

<snip> However when I try to link to the above electronic version, I find that a username and password are required even though the classification

is "Unclassified Unlimited Release".

Perhaps if enough people request the document they will make it available on-line. The printed report says that copies can be requested from

With difficulty (the front page is in red and has a red watermark) I have scanned the summary:

Summary While the L- 16 is a very good candidate for use in PV Systems, results of the PV Hybrid Test Procedure indicate several ways that
the L- 16′s performance can be enhanced. The first set of test results were obtained with 12 volt batteries (that is, two L16′s in series).
The puipose of this test procedure was to characterize charging profiles in a generic PY hybrid cycle. Results show that the L-1 6 battery can
quickly lose as much as 48% of its initial available capacity if the regulation voltage is too low, the time at regulation is too short, and the time
between the finish-charges is too long.

The data in this report suggest the following:

(1) L-16 regulation voltage in PV hybrids should be well above 2.40 vpc (14.40 volts) and may need
to be as high as 2.55 vpc or higher (15.3 volts for a 12 volt battery) depending on how the battery is charged.

(2) L-16 finish-charge time in PV hybrids should be at least 3 hours and may need to be longer depending on the time between finish-charges.

(3) The maximum interval between L-16 finish-charges should be about one week. (

4) Results vary significantly for different manufacturers.

The 12-volt testing was followed by 48-volt battery string tests that demonstrate how weak or low capacity cells will function within the
24-ce11 string. Further, results show the need for proper charge control and regular inspections.
This test identified a low capacity cell that was forced into reversal on discharge.
A cell in reversal wlll eventually be damaged and require replacement Additionally, the 48-volt battery string test provides information on
how specific gravity measurements, monoblock (a monoblock is the smallest packaged battery size – three cells or six volts in the case
of an L-16 battery) voltages, can he used to track battery health. Implementation of these procedures can help ensure that the L-16 will
achieve its maximum cycle-life and thus minimum life-cycle cost. ========== end of scan ==========

Anyone using L-16 batteries in PV or hybrid systems should read this report. Hopefully, it will be available on the web.

Other suggestions:

1. If you can, measure the short circuit current and open circuit voltage of each series string of 2 modules. Look for differences.

2. Look for loose connections in the junction boxes.

3. Has anything grown and shadowed the array? Even a small part of the modules?

Bill Kaszeta Photovoltaic Resources Int’l Tempe Arizona USA

---

As of 2011, ten to eleven years after the fact - these 4 references above were about the end of the line - on the Internet.

Concorde told me that they heard of the studies but who knows what happened to them.
They did some studies that had a similar outcome.

A few conversations with the brass at the Legendary ODYSSEY® Batteries Division of EnerSys Energy Products Inc.
and I heard a similar story but got a lot more details on THEIR latest AGM studies.
Naturally the numbers were a bit different but the principals for longer life cycles were very similar.

There were also other references to other 'Longer Life' Lead Acid Battery studies on the Internet.

This is the end of Part One. Next we will fast forward to this years developments.

Without information like this (and more) it would have been impossible to have formulated

'The Ni-Fe Theory of Battery-tivity' :-)


Bill Blake