Piss poor Trace SW preformance in "sell" mode. [RE-wrenches]

Jeffrey Wolfe, Global Resources global at sover.net
Wed Oct 18 13:48:53 EDT 2000 

The idea of setting the float voltage lower does not really work on 
reducing the charge needed for the batteries. You still have charger 
inefficiency, and the lowered voltage is really just like lowering the rim 
on the water bucket. Still have to keep dribbling water in to make up for 
evaporation, the height of the rim doesn't matter (much).

Also, if you are not running an MPPT unit, then lowering the float voltage 
will also lower the pv operating voltage, which lowers the power input.

I do not believe we're really going to get anywhere by just tweaking 
settings. If we could, one of us would have thought of it already! Also, 
any installation we use with a standard SW is for backup power, meaning 
there are always loads connected to the inverter for power. A solution that 
shuts off AC to the inverter is not a solution. The Trace ST series does 
that just fine (I believe).

I think we need the external controller that does what Trace should do, 
namely:

1.  When the sun's shining, connect the inverter in a traditional sell 
mode.
2.  When the sun's not shining, turn the inverter based charger off. This 
could be done by a relay powered off the PV. No PV, relay opens.
3.  Have an overide available to allow grid charging either manually, or if 
the battery voltage drops below a preset value.

In my mind, the key is not to get the inverter off (we have search mode for 
that), it's to get the CHARGER off.

What do you think?

Jeff

Jeffery D. Wolfe, P.E.
Global Resource Options, LLP
A Woman-Owned Vermont Limited Liability Partnership
4 Kibling Hill Road
P.O. Box 51
Strafford, VT 05072
802/765-4632
802/765-9983 (Fax)
global at sover.net
www.globalresourceoptions.com


----------
From: 	Doug McCorkle[SMTP:dmccorkl at sover.net]
Reply To: 	RE-wrenches at topica.com
Sent: 	Wednesday, October 18, 2000 7:25 AM
To: 	RE-wrenches at topica.com
Subject: 	RE: Piss poor Trace SW preformance in "sell" mode. [RE-wrenches]

Hello Kurt et al,

I think I can answer part of your question.  I found that it goes right 
into
a bulk charge cycle when set into Sell mode, but I'm not sure if it's any
time AC1 is (re)connected.  I know it's a pain, but you can also change the
time and voltage settings for the charges (I set mine for a 10 minute bulk
to 26.4V and floating at 25.6V while I was playing with getting it set up),
so that a lower battery voltage wouldn't set off a charge cycle.  Of 
course,
then you would have to reset the values to do a full bulk charge.  Also a
pain in that all settings reset to default when the DC supply is
disconnected.

On a related note, do you really need to keep the batteries floating at
26.4V all the time (in Sell mode), or is a lower voltage adequate to keep
them fully charged?  (although it didn't seem to make a very big difference
in the power required to float them)

Thanks to all for the great information

Doug McCorkle

-----Original Message-----
From: Kurt Nelson, SunWise [mailto:sunwise at win.bright.net]
Sent: Tuesday, October 17, 2000 9:42 PM
To: RE-wrenches at topica.com
Subject: Re: Piss poor Trace SW preformance in "sell" mode.
[RE-wrenches]

Greetings Carl,

You are on the right track here, as the Trace drops into inverter mode
when AC1 is disconnected.  It would be my understanding that in order to
maintain high efficiency though, the inverter can't be reconnected to
the utility until after battery voltage comes up above the bulk voltage
setting (solar), or the inverter will go into a charge cycle.  My
thinking may be wrong here but I think the inverter will initialize a
bulk/absorption/and then float charge cycle every time power is "lost"
to AC1 and the unit transfers over to just being an inverter.  By
waiting to reconnect to the grid until voltage is above bulk setting, no
additional energy should come from the utility to bring this about.  I
think this is the logic behind using a voltage controlled "AUX" relay to
pull in that contactor the next day.

Another question I still have is will the inverter do a low battery
transfer (LBX) type thing and utilize the grid to charge the battery if
the battery voltage goes too low while the inverter is in the inverter
mode (disconnected from the grid).   While in LBX, the inverter would go
to AC1 for juice.  In sell mode, (and switched over to inverter from
loss of AC1) would we utilize AC2 input with utility also available
there?

Kurt Nelson

> - - - - - - -
> To send a message:
>  RE-wrenches at topica.com
>
> The archive of previous messages:
>  http://www.topica.com/lists/RE-wrenches/
>
> To unsubscribe send a message to:
>  RE-wrenches-unsubscribe at topica.com
>
> To check out the other RE-Wrench participants:
>  www.mrsharkey.com/wrenches/index.html
>
> Hosted by Home Power magazine:
>  www.homepower.com
>
> For info contact list moderator by email:
>  michael.welch at homepower.com
> ___________________________________________________________
> T O P I C A  The Email You Want. http://www.topica.com/t/16
> Newsletters, Tips and Discussions on Your Favorite Topics

- - - - - - -
To send a message:
 RE-wrenches at topica.com

The archive of previous messages:
 http://www.topica.com/lists/RE-wrenches/

To unsubscribe send a message to:
 RE-wrenches-unsubscribe at topica.com

To check out the other RE-Wrench participants:
 www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine:
 www.homepower.com

For info contact list moderator by email:
 michael.welch at homepower.com
___________________________________________________________
T O P I C A  The Email You Want. http://www.topica.com/t/16
Newsletters, Tips and Discussions on Your Favorite Topics

- - - - - - -
To send a message:
 RE-wrenches at topica.com

The archive of previous messages:
 http://www.topica.com/lists/RE-wrenches/

To unsubscribe send a message to:
 RE-wrenches-unsubscribe at topica.com

To check out the other RE-Wrench participants:
 www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine:
 www.homepower.com

For info contact list moderator by email:
 michael.welch at homepower.com

___________________________________________________________
T O P I C A  The Email You Want. http://www.topica.com/t/16
Newsletters, Tips and Discussions on Your Favorite Topics

- - - - - - -
To send a message:
 RE-wrenches at topica.com

The archive of previous messages: 
 http://www.topica.com/lists/RE-wrenches/

To unsubscribe send a message to: 
 RE-wrenches-unsubscribe at topica.com

To check out the other RE-Wrench participants:
 www.mrsharkey.com/wrenches/index.html

Hosted by Home Power magazine: 
 www.homepower.com

For info contact list moderator by email:
 michael.welch at homepower.com

___________________________________________________________
T O P I C A  The Email You Want. http://www.topica.com/t/16
Newsletters, Tips and Discussions on Your Favorite Topics

More information about the RE-Wrenches mailing list