Re: [RE-wrenches] Xantrex C-40 Drifting

[Steve Higgins]

That's a pretty good size battery bank compared to the charge coming in, 
normally you only see this with very small battery banks.

A battery when under charge is going thru a chemical reaction, this reaction 
doesn't immediately stop when you remove the charge, if you have a strong 
source on a small battery bank. The chemical reaction can keep going on for 
several minutes after the charge has been removed.  The battery isn't charging 
it's self the chemical reaction is just still continuing.

To test this, you can put a small DC load (couple of 12volt light bulbs in 
series) across the battery, when you shut off the controller, turn on the dc 
load for a second or two and see where the voltage is...

Compare it to cooking a roast... when you pull it out of the oven, it's still 
cooking for about 30-45 minutes past the time you remove it out of the oven.

Some controller manufactures will actually back feed the panels for a short 
period of time to regulate, and prevent the overvoltage.

On flooded batteries this isn't much of a problem, but VRLA's if the time is 
excessive it can be an issue in the long term for the batteries.

Just a note... those full rivers can accept a bit more voltage than a standard 
AGM...

http://www.fullriverbattery.com/product/batteries/DC400-6



From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf 
Of Drake
Sent: Monday, May 18, 2015 4:58 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Xantrex C-40 Drifting

Hi Steve,

The battery bank consists of four, 415 AH in a Full River AGM deep cycle 
batteries wired  in a 24 volt series.

That is a new concept to me. Does the battery bank charge itself through its 
own chemical reaction? Would there be any issues with gassing in the VRLA 
batteries? Would you recommend doing anything about this situation, like change 
charge controllers?

Thanks,

Drake

Drake Chamberlin
Athens Electric LLC
OH License 44810
CO License 3773
NABCEP Certified Solar PV
740-448-7328
http://athens-electric.com/


At 07:10 PM 5/18/2015, you wrote:

Content-Language: en-US
Content-Type: multipart/related;
 
boundary="_004_414D424906AE60489EF1829E1EFA55712C9C56F2sbcexchsbcdomai_";
 type="multipart/alternative"

Hey Drake,

How large is the battery bank?

I've seen this before on VRLA's with a couple of companies controllers. Usually 
this will happen with small battery banks.

Best way to explain it is when the battery bank is charging and you remove the 
charge, the battery is a chemical reaction... it's still charging for a short 
period of time even though you have removed the source.




Steve Higgins
Technical Services Manager
P: +1.902.597.4020
M: +1.206.790.5840
F: +1.902.597.8447
Surrette Battery Company
Exclusive manufacturer of
[[]]

From: RE-wrenches [ mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf 
Of Drake
Sent: Friday, May 15, 2015 7:10 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Xantrex C-40 Drifting

I was thinking of a Blue Sky or a Morning Star replacement.

The Full River AGM L-16 batteries recommend a 29.4 absorption, very high for a 
maintenance free battery. I've triple checked this one.

At 09:30 AM 5/15/2015, you wrote:

HI Drake,

Iv'e never seen this happen. Â
But have you considered a small morningstar or similar?

A question, you list 29.4v, that seems high?

jay



On Thu, May 14, 2015 at 5:12 PM, Drake < 
drake.chamber...@redwoodalliance.org>
 wrote:
I have a Xantrex C-40 that won't keep its settings. It is important that it 
does because it is for a maintainer array (80 W) on an AGM battery bank, on an 
AC coupled backup system. Not only could high voltage damage the batteries, but 
when the voltage goes over 30 Volts, the AUX relay opens and the grid tie 
inverter is isolated from the grid.
After numerous sessions of reprogramming, Xantrex tech support sent me a new 
unit. The problem persisted as before. A new temperature sensor helped, but the 
settings still drift. It seems that rebooting the charge controller helps for a 
day or so, but then it drifts again.
The potentiometer settings are way below the calculated setting for 29.4 V, but 
it still peaks in the high 30s. I check the temperature compensated voltages on 
the Outback Mate, and the temp compensated voltage runs high.
In a related side issue, the AUX relay of the FX inverters is not based on 
temperature compensated voltage, which makes setting AC coupling charge set 
points more problematic.
Has anyone experienced a C-40 CC that drifts in its settings. What would be a 
good (inexpensive) charge controller to accurately control 80 W of PV?
Thanks,
Drake



--
Jay Peltz
Peltz Power
jay.pe...@gmail.com
___
List sponsored by Redwood Alliance

List Address: 
RE-wrenches@lists.re-wrenches.org

Change listserver email address & se

[RE-wrenches] Fw: Xantrex C-40 Drifting

[Jarmo . Venalainen]

Hi:

I didn't know that there were systems out there where a PWM charge 
controller such as the C-40 was producing an unhealthy, high battery 
voltage.  Since there are, I may have a possible explanation.

The C-series and other PWM type charge controllers operate by PWM whereby 
they very very quickly connect/disconnect the solar module to the battery 
bank.  The amount of time which the module is connected to the array is 
the PWM on-period.  These controllers do not have the ability to "smooth 
out" the output voltage.  All they can do is apply the full module voltage 
OR not apply any module voltage to the battery.  Here are some graphs that 
show this,

 

It 's supposed to work out when the battery absorbs, smooths out and 
averages the output voltage pulses coming out of the PWM controller.

Except, I'm hearing that, that is not necessarily true.  It sounds like on 
some systems the batteries will not average voltage very well over time 
and indeed experience increasing and undesirably high terminal voltages 
over time.

If this is the mechanism, I think one way alleviate or perhaps even 
eliminate the rising voltage problem is by matching the module Voc voltage 
to the desired battery float voltage.  For example, if a 28 VDC float 
voltage was desired, then the solar module Voc should be chosen as 
something slightly above 28 VDC.

i.e. I think the trick is to match the module Voc voltage to the desired 
battery float voltage.  Perhaps a 32 Voc module for a 28 VDC float 
voltage. 

I'm not sure what the right number is, but if I'm correct about this 
mechanism, then a 50 Voc module on a 12 VDC battery, should the kind of 
system which experiences this overcharging/over voltage problem.

You guys have seen many systems.  Maybe you can comment on whether the 
systems which have had this trouble are also ones where the module Voc is 
much higher than the desired battery float voltage.  Perhaps the "trouble 
systems" also tend to have a specific battery chemistry or even particular 
battery type.

JARMO



_
 


Jarmo Venalainen  |   Schneider Electric   |  Xantrex Brand  |   CANADA  | 
  Sales Application Engineer 
Phone: +604-422-2528  |   Tech Support: 800-670-0707  |   Mobile: 
+604-505-0291 
Email: jarmo.venalai...@schneider-electric.com  |   Site: www.Xantrex.com 
|   Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 








*** Please consider the environment before printing this e-mail

- Forwarded by Jarmo Venalainen/Canada/Schneider on 05/18/2015 07:02 
PM -

From:
Drake 
To:
jarmo.venalai...@schneider-electric.com, 
Date:
05/18/2015 03:35 PM
Subject:
Re: Fw: [RE-wrenches] Xantrex C-40 Drifting



Hi JARMO,

The battery bank consists of four, 415 AH in a Full River AGM deep cycle 
batteries wired  in a 24 volt series. The  80 W array is strictly  a 
maintainer  to keep the batteries charged when  the  AC  coupled  system 
is detached from the direct grid tie inverters. The only constant loads on 
the system are about 3 W of power that keeps the metering awake. The 
batteries are low self discharge. 

Thanks,

Drake


At 07:47 PM 5/14/2015, you wrote:
Hi: 

80W is a really small PV source, so I'm wondering how it can raise the 
battery voltage so much. 

What size is the battery? 

JARMO
_
 


Jarmo Venalainen  |  Schneider Electric   |  Xantrex Brand  |   CANADA  |  
Sales Application Engineer 
Phone: +604-422-2528  |   Tech Support: 800-670-0707  |   Mobile: 
+604-505-0291 
Email: jarmo.venalai...@schneider-electric.com  |   Site: www.Xantrex.com  
 |   Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 
  


*** Please consider the environment before printing this e-mail

- Forwarded by Jarmo Venalainen/Canada/Schneider on 05/14/2015 04:45 
PM - 
From: Drake  
To: re-wrenches@lists.re-wrenches.org, 
Date: 05/14/2015 04:30 PM 
Subject: [RE-wrenches] Xantrex C-40 Drifting 
Sent by: "RE-wrenches"  




I have a Xantrex C-40 that won't keep its settings. It is important that 
it does because it is for a maintainer array (80 W) on an AGM battery 
bank, on an AC coupled backup system. Not only could high voltage damage 
the batteries, but when the voltage goes over 30 Volts, the AUX relay 
opens and the grid tie inverter is isolated from the grid.

After numerous sessions of reprogramming, Xantrex tech support sent me a 
new unit. The problem persisted as before. A new temperature sensor 
helped, but the settings still drift. It seems that rebooting the charge 
controller helps for a day or so, but then it drifts again.

The potentiometer settings are way below the calculated setting for 29.4 
V, but it still peaks in the high 30s. I check the temperature compensated 
voltages on the Outback Mate, and the temp compensated voltage runs high. 

In a related side issue, the AUX relay of the FX inverters is not based on 
temper

Re: [RE-wrenches] Fw: Xantrex C-40 Drifting

[Ray Walters]

Hi Jarmo;

Early solar systems actually tried to use the principle of matching 
array Vmpp to battery voltage  in lieu of charge controllers.  The 
biggest issue is that when it is is hot the module voltage can drop 
below the battery voltage needed, and when its cold the voltage will 
still be too high.   Batteries were either over charged or never reached 
full charge depending on the conditions.
I've used the C40 successfully for decades, so I'm wondering if the 
circuitry changed recently, or if different tolerance components were 
substituted that may be causing the drift?


Thanks,

R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760

On 5/19/2015 10:31 AM, jarmo.venalai...@schneider-electric.com wrote:

Hi:

I didn't know that there were systems out there where a PWM charge 
controller such as the C-40 was producing an unhealthy, high battery 
voltage.  Since there are, I may have a possible explanation.


The C-series and other PWM type charge controllers operate by PWM 
whereby they very very quickly connect/disconnect the solar module to 
the battery bank.  The amount of time which the module is connected to 
the array is the PWM on-period.  These controllers do not have the 
ability to "smooth out" the output voltage.  All they can do is apply 
the full module voltage OR not a


___
List sponsored by Redwood Alliance

List Address: RE-wrenches@lists.re-wrenches.org

Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org

List-Archive: 
http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html

List rules & etiquette:
www.re-wrenches.org/etiquette.htm

Check out or update participant bios:
www.members.re-wrenches.org

Re: [RE-wrenches] Fw: Xantrex C-40 Drifting

[Jarmo . Venalainen]

Hi:

We haven't changed anything the in C40.  The essence of my idea was that 
perhaps the "trouble" systems are the ones which have much higher module 
Voc versus battery Vfloat.

JARMO
_
 


Jarmo Venalainen  |   Schneider Electric   |  Xantrex Brand  |   CANADA  | 
  Sales Application Engineer 
Phone: +604-422-2528  |   Tech Support: 800-670-0707  |   Mobile: 
+604-505-0291 
Email: jarmo.venalai...@schneider-electric.com  |   Site: www.Xantrex.com 
|   Address: 3700 Gilmore Way, Burnaby, BC V5G4M1 








*** Please consider the environment before printing this e-mail




From:
Ray Walters 
To:
RE-wrenches , 
Date:
05/19/2015 11:00 AM
Subject:
Re: [RE-wrenches] Fw:  Xantrex C-40 Drifting
Sent by:
"RE-wrenches" 



Hi Jarmo;

Early solar systems actually tried to use the principle of matching array 
Vmpp to battery voltage  in lieu of charge controllers.  The biggest issue 
is that when it is is hot the module voltage can drop below the battery 
voltage needed, and when its cold the voltage will still be too high.   
Batteries were either over charged or never reached full charge depending 
on the conditions.
I've used the C40 successfully for decades, so I'm wondering if the 
circuitry changed recently, or if different tolerance components were 
substituted that may be causing the drift?

Thanks,
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer, 
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 5/19/2015 10:31 AM, jarmo.venalai...@schneider-electric.com wrote:
Hi: 

I didn't know that there were systems out there where a PWM charge 
controller such as the C-40 was producing an unhealthy, high battery 
voltage.  Since there are, I may have a possible explanation. 

The C-series and other PWM type charge controllers operate by PWM whereby 
they very very quickly connect/disconnect the solar module to the battery 
bank.  The amount of time which the module is connected to the array is 
the PWM on-period.  These controllers do not have the ability to "smooth 
out" the output voltage.  All they can do is apply the full module voltage 
OR not a


__
This email has been scanned by the Symantec Email Security.cloud service.
__
___
List sponsored by Redwood Alliance

List Address: RE-wrenches@lists.re-wrenches.org

Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org

List-Archive: 
http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html


List rules & etiquette:
www.re-wrenches.org/etiquette.htm

Check out or update participant bios:
www.members.re-wrenches.org



___
List sponsored by Redwood Alliance

List Address: RE-wrenches@lists.re-wrenches.org

Change listserver email address & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org

List-Archive: 
http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html

List rules & etiquette:
www.re-wrenches.org/etiquette.htm

Check out or update participant bios:
www.members.re-wrenches.org