Battery care in grid BU systems (was net metered system question) [RE-wrench

[Bill Brooks]

Allan (and other grid-connected wrenches),

A floated battery is a happy battery. The Trace SW does not have a very
exotic way of dealing with batteries in grid-connected systems, so I stand
by my earlier recommendation.

Keep the system in SELL mode, do not use the GRID USAGE TIMER, set the
system to a float voltage of between 53.6 and 54.2 Volts (48 volt nominal
system), and make sure you temperature compensate this setting (and any
secondary charge control settings). I would not advise telling the customer
to equalize the batteries. If the wrench wants to equalize them as part of a
maintenance program, have at it. The biggest issue is keeping water in the
battery. Hydrocaps are definitely advisable for the flooded grid-connected
systems since it is likely that they will not be frequently maintained.

This is very simple, but it works. I have over two years of operating
experience on my own house in this mode and it works just fine.

Bill.

> -----Original Message-----
> From: Allan Sindelar, Positive Energy, Inc.
> [mailto:allan at positivenergy.com]
> Sent: Friday, March 02, 2001 9:08 PM
> To: RE-wrenches at topica.com
> Subject: Battery care in grid BU systems (was net metered system
> question) [RE-wrenches]
>
>
> Bill (and my question is directed to all wrenches),
> OK, I appreciate where you're coming from, but it's not what I
> asked. I have
> several customers with Y2K systems (it's been over a year now), and more
> with backup systems; some interconnected, some just floating away. Most of
> them have 2V industrial cells, 1,000-1,600 ahr; a few have L16s.  What
> should I advise them?
> Allan @+E
>  P.S.-I think that this on topic, and many of us can benefit from this
> discussion. Anyone prefer I take this off this list?
> Allan
>
> > Great question--you are exactly right about our experience with off-grid
> > systems. You almost have to forget everything you ever learned about
> > off-grid batteries when considering an on-grid system. I am a firm
> believer
> > in Absorbed Glass Mat (AGM) batteries for on-grid systems for two major
> > reasons.>
> > 1. On-grid people will normally not mind their batteries (they
> don't check
> > the oil in their SUV so how are you going to expect them to maintain
> > batteries).
> > > 2. More importantly, Lead-Antimony (golf cart, L-16 type)
> batteries have
> a
> > high self discharge rate. This causes higher losses at float than AGM
> > (lead-calcium grids).
> > > To answer your question, wrenches should be using AGM
> batteries in float
> > application. These batteries should not be equalized and are designed to
> > stay in float all the time. This is another reason that it is not
> advisable
> > to use Bulk charging since it is possible to gas a VRLA at Bulk
> voltages.
> >
> > Bill.
> > > > -----Original Message-----
> Most of our battery care advice is for off-gridders, who cycle their cells
> routinely.  What is proper care
> for batteries that sit in float all the time on grid-backup systems? How
> often should they be equalized, if at all? And what is their life
> expectancy
> in relation to mfgr's rated cycle life, and also to their real-world
> expected life?
>
>
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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  -- Learn More. Surf Less. 
Newsletters, Tips and Discussions on Topics You Choose.
http://www.topica.com/partner/tag01