[RE-wrenches] Trojan L-16 charge settings

William Miller william at millersolar.com
Mon Jan 18 18:43:05 PST 2016


Colleagues:



I have an off-grid customer for whom I replaced a set of 8 Trojan L-16s as
well as upgrading her inverter and charge controller.  Right after the job,
we found several batteries with low specific gravity.  We spoke with the
local distributor and received two replacement batteries.



The system continues to perform poorly.  The customer EQs every 30 days to
60 plus volts for 3 hours.  They try to get a full bulk and absorption
charge in every day but this time of year may not. The specific gravity
readings continue to diverge and generally go lower.



We contacted the distributor who told us they have had problems with Trojan
batteries since the company was sold about two years ago.  We were told
they had a brand X battery that tested better than the Trojans.  We agreed
to try the Brand X but then were told that we had not charged the Trojans
adequately.  Below are the settings recommended directly by Trojan



These settings are significantly higher than any I have used before.  Also,
I don’t recall it being possible to set different bulk and absorption
voltages with any of the equipment I use.  I use Trace, Outback, Schneider
default settings of 57.6 bulk, 54.4 float and reprogram to 60.5 for
equalization.



I am curious about what charge settings you find successful for flooded
lead-acid batteries and what any of you might think about the recommended
settings as seen below. Do you feel it is practical to achieve these
settings in an off-grid scenario?  Would these high settings cause
excessive water consumption?



Thanks in advance.



William Miller



[image: Gradient Cap_mini]
Lic 773985
millersolar.com <http://www.millersolar.com/>
805-438-5600







I looked at the spreadsheet and the SG. readings across each battery are
uniform which tells be that it is highly unlikely that anything is wrong
with the batteries except for being under-charged. Take a look at our
User’s Guide on the Trojan website on page 19  ( Recommended Charge
Profile) or FLA batteries.

The Bulk stage should be @ 59.3V, Absorb @ 58.8V, Float @ 54V and
Equalization @ 64.8V. When the User notices drops in the SG such as in this
document, an EQ charge should be performed in order to get the batteries
back up to full charge (full charge SG being in the range of 1.270 to
1.280. When performing the EQ, the user should take SG reading for a
“pilot” battery every 30 minutes until the voltages reach that range.
Termination should happen when SG reaches full charge range or if battery
temperature reaches 112 degrees F, which-ever comes first. SG readings can
be taken during EQ, but you have to make sure that you bump the tiny gas
bubbles off the Hydrometer float to prevent erroneous readings.

Seeing the SG readings decreasing after each month is an indication that
maybe the Absorb Time needs to be increased, maybe from 3 hours up to 4 or
5 hours.
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