[RE-wrenches] intermittent battery problem

Dave Palumbo dave at independentpowerllc.com
Sat Oct 22 08:26:34 PDT 2011


I have been following this topic over the past couple of weeks. What Dave
Katz said matches up with what I have seen over the years. Although it can
be difficult to diagnose battery issues from long distance there has been a
fair amount of information that points to sulfation. I think Mr. Katz is
right on the money. 

 

David Palumbo

Independent Power LLC 

462 Solar Way Drive

Hyde Park, VT 05655

www.independentpowerllc.com 

NABCEP Certified PV Installer

Vermont Solar Partner

23 Years Experience, (802) 888-7194 

 

 

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of David Katz
Sent: Saturday, October 22, 2011 11:01 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] intermittent battery problem

 

Ron,

I don't think it was the water.  It was probably the 10 hours they ran the
generator that brought them up a bit.  If the water is low, the electrolyte
is more concentrated and will make the s.g seem higher.  Adding water to the
proper level will make the reading more accurate.  

I still think they are pretty sulfated.  When they said they reached 29
volts in 5 minutes every morning with a charge of less than 30 amps (an
assumption, since they are running a 2500 watt generator), that sounds like
a battery with very little capacity.  The fact that they stayed at 25.7 all
day was probably because of the 800 watt PV array and light loads.  It would
be interesting to do a real equalization and a capacity test to see what is
left of the batteries.  

David

 

David Katz

CTO & Founder

AEE Solar Inc

P: 707 825-1200

F: 707 825-1202

dkatz at aeesolar.com

www.aeesolar.com

 

 

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Ron Young
Sent: Friday, October 21, 2011 11:39 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] intermittent battery problem

 

Hi Maverick & everyone,

 

I visited the site a couple of days ago and load tested the batteries,
checked individual voltages in the string of six Surrette 4KS25's (4.3v
each), checked all connections etc. The client told me that when they would
go to bed battery volts read 25.7. Through the night this would seem to stay
steady. About 4 a.m. as far as they could tell the voltage would drop to
about 24.5. This happened without a load present and with no charging
present (calm, no wind, no sun). They would start up the generator for five
minutes in the morning and see the voltage come up to just above 29v then
turn off the generator (a small Honda 2500) and the voltage would settly at
25.7 and remain there most of the day even when using their light loads,
some lights, phone system, laptop and the Sunfrost.

 

When checking the batteries I noticed they needed watering and mentioned
this to the customer. The electrolyte was just over the plastic screen above
the plates by about 1/4 inch. He said he had just watered them and always
kept them filled. I replied that they were low and when he looked he said
no, that's where I keep them! When I checked the specific gravity reading it
was very rich reading around 1.275 - 1.280. I topped them up properly to
about 1/4 inch below the bottom of the cell channel which took about 5 cups
per each battery. Of course as soon as I topped them up the s.g. dropped to
around 1.175. I told him to put the generator on for about ten hours and
call me in the morning. 

 

I heard from the client today and in the last two days the voltage has only
dropped from 25.6 to 25.4 overnight and s.g. reading is at 1.260 or better
so problem seems to be solved. 

 

So it appears the battery was under watered for several years. I'm still not
sure why this would result in a sudden voltage drop, especially in the
middle of the night with no loads present and no charging. Any additional
thoughts appreciated.

 

Best Regards,

Ron Young

earthRight Products - Solareagle.com

 

 

On 2011-10-21, at 5:18 AM, maverick at mavericksolar.com wrote:

 

Ron,

 

Just curious what the outcome was?

 

Thank you,

 

Maverick

 

 

Maverick Brown

BSEET, NABCEP Certified Solar PV Installer R

President & CEO

Maverick Solar Enterprises, Inc.

Office:     512-919-4493

Cell:        512-460-9825

 

Sent from my HondaJet!

 

 

On 2011-10-11, at 12:11 PM, Maverick Brown [Maverick Solar] wrote:

 

Ron,

 

Sounds like you might have a voltage drop in the system at point of
measurement. 

 

A large voltage drop can happen for a few valid reasons.

1. High current demand. > Trimetric or better yet PentaMetric can show this
demand.

2. Poor Cable connection. Visual / Thermal inspection or local Vdc
measurement along the cable chain.

3. Low to moderate current demand with low SOC. Check the MX60 Logging
function to see when the last day "Float" happened, i.e. how many minutes of
Float in the last 60 days, etc. If there are none or few, then you still
might be at a low SOC. (Trimetric or better yet PentaMetric can show the SOC
as well).

 

Of course, not sure what happened to the Sunfrost, but a DC Clamp meter,
might determine if it is normal now.

 

good luck,

 

Maverick

 

 

  _____  

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Ron Young
Sent: Tuesday, October 11, 2011 2:00 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] intermittent battery problem

Wrenches, 

I received some additional info from the customer this morning. They have
asked me to hold off my visit until they get a few more clues but some of
what they are telling me doesn't necessarily jive with a sulphated battery.
Would appreciate comments - here's a quote from their email: 

 

Hi Ron 

Still having problems with system.  If the batteries are sulphated would the
system return to full charge when you remove the load???  Checked our
hydrometer against another and it is working fine. Batteries are all either
in the green or on the line between green and blue this morning.  Display
showed the batteries at 25.2 when we got up this morning. About 10:30 this
morning---I had just tested all batteries with the hydrometer---the readings
dropped to 23.8.  Retested batteries---they were in the green.   I turned
off all loads----the readings returned to 25.2.  I turned on the
Sunfrost---readings immediately dropped to 23.8.  I turned off the
Sunfrost--- readings returned to 25.2.  I turned on all lights in the house
and the readings remained at 25.2.  I turned the Sunfrost back on and the
readings again stayed at 25.2.  The one other thing that happened in the
meantime is that the sun came out and we started buying power from the solar
system---.1-.3kw.  This all seems to be part of a pattern where as soon as
we start buying power---whether from sun, wind or gen. the system returns to
normal---But we are still suspicious of the Sunfrost because of our problems
a few months back.  

 

Ron Young

earthRight Products - Solareagle.com <http://Solareagle.com/> 

Alternative Energy Solutions ~ Renewable Energy Products

 

On 2011-10-09, at 11:56 AM, Ron Young wrote:

 

As always, impressed and gratified by the number of thoughtful replies from
Wrenches, thank you again! It looks like a hefty EQ is in order. I've
successfully recovered badly sulphated batteries by putting them through
multiple charge/EQ/discharge cycles on more than occasion. Will check out
that Sunfrost as well. My mistake was believing that the hydrometer could
tell the truth, the whole truth and nothing but the truth but apparently it
takes an amp hour meter to keep it honest. 

 

Ron Young

earthRight Products - Solareagle.com <http://Solareagle.com/> 

Alternative Energy Solutions ~ Renewable Energy Products

 

On 2011-10-09, at 11:12 AM, Jonathan Hill wrote:

 

Ron- 

We've seen this issue before,and it is almost always due to badly sulfated
batteries. I'd try a LONG (8-12 hrs) EQ charge at 32 volts. We've done this
with Hawkers and fixed the problem. I believe the Surrettes could handle
this kind of charge, though you might contact Jamie Surrette.

 

Jonathan Hill, senior system design engineer

Sierra Solar Systems

563C Idaho Maryland Road

Grass Valley, CA 95945

Celebrating our 31st year in solar!

tech info and foreign orders:  (530) 273-6754 

order line: (888) ON-SOLAR (US only)   FAX:  (530) 273-1760

e-mail:  <mailto:solarjon at sierrasolar.com>

world wide web:  <http://www.sierrasolar.com <http://www.sierrasolar.com/> >

 <http://www.youtube.com/watch?v=WY-0UuabPEk> 
Check out our 2 minute video at: 
http://www.youtube.com/watch?v=WY-0UuabPEk 

Because of the high volume of e-mail to which I respond, please 

leave _all_ of the previous messages (unless it's unbearable) in

  your reply so I can better remember your original message.

 


<att6eade.png> 

 

On Oct 8, 2011, at 6:42 PM, Ron Young wrote:

 

Thanks Bob but he has a tubular type hydrometer, not the pointer type.
They're usually ok but I'll check it against mine when I go there which
looks like a certainty. 

 

They EQ the batteries on a regular basis as per my instructions (they say)
but will have to nail them down on that. The small 2500w generator worries
me but they have 800w solar and a Whisper 100. The wind blows a lot.
Inverter is a 3524 Outback.

 

Ron

 

On 2011-10-08, at 5:07 PM, bob ellison wrote:

 

I bet he has a cheap pointer type hydrometer, I have seen them be way off
from reality.

My guess is that the gravity is low the voltage changes quickly, specific
gravity changes slowly in a battery bank.

To fully charge a 24 volt bank you need to get it to 29 + volts and keep it
there for several hours, depending on the battery bank size.

Charging it to 25.4 is nothing in the long run.

Give them a LONG full charge, what are the inverters? Does it ever get an EQ
charge?

Bob Ellison

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Ron Young
Sent: Saturday, October 08, 2011 2:02 PM
To: RE-wrenches
Subject: [RE-wrenches] intermittent battery problem

Howdy Wrenches,

One of my customers that lives 3 hours out in the back country is having an
intermittent problem that I haven't encountered before. The batteries drop
rapidly in voltage but hydrometer readings are in the green. Turning off the
inverter and just using DC doesn't change anything. Meters on the Mate,
Outback MX and Whisper controller are all the same so it's not a metering
problem. On the way to bed the batteries were at 25.4, overnight with no
loads they dropped to 22.9 then a short 15 min. charge with a generator
brings the batteries back up and two hours later they are at 25.8. This
scenario has occurred several times and then doesn't appear for a day or
two.

It doesn't seem to be sulfation as the batteries are reading good on the
hydrometer every time. All cells check out. The inverter doesn't seem to be
the problem. They have a Sunfrost on a separate DC circuit. It sounds like
an intermittent circuit problem or electronics issue. Customer has checked
and tightened all the connections he can get at but hasn't been inside the
components. Would appreciate any suggestions or clues before I make the
trip.

Ron Young

earthRight Products - Solareagle.com <http://Solareagle.com/> 

Alternative Energy Solutions ~ Renewable Energy Products

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