Date:         Mon, 9 May 2005 18:58:44 -0400
Reply-To:     Dennis Haynes <dhaynes@OPTONLINE.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject:      Re: [VWVANFULLTIMERS] more electricity questions
Comments: To: roadguy@roadhaus.com
In-Reply-To:  <000601c55498$1b112dc0$41a54e45@t41>
Content-type: text/plain; charset=us-ascii

http://www.trojanbattery.com/Tech-Support/BatteryMaintenance.aspx
http://www.Batteryuniversity.com/
http://www.quickcharge.com/Images/charge%20curves.pdf


Larry,
The three sites above both give a lot of information regarding the
charging of lead acid batteries. To charge deep cycle batteries, you
really need a 3 stage charger and to extend the batteries life, an
occasional 4th or equalizing stage.

The 3 stages are bulk, absorption, and finish. The occasional equalizing
charge is a maintenance step to break up sulfation and equalize
differences in the cells.

13.8 volt will get you through the bulk charge and given time, the
absorption stage. You really need to get to 14.5 volts to finish though.
During this stage, current has to be closely monitored as the battery
will start gassing. This has to be controlled, particularly with sealed
batteries such as the Optima. This can not be accomplished with
alternator based charging unless you are willing to spend some serious
money on smart regulation. A good 110v charger should be used to
occasionally get the battery up to capacity. It should be noted that
when a battery is fully charged, the top 10% will be lost in ~24 hours
after the charger is disconnected. This is why float charging is used in
standby applications. You can't simply set the output to 14.5 volts
since maintaining this voltage after the battery is charged will damage
it.

Another thing to consider is battery choice. The only advantage of a
sealed battery such as the Optima is the no leaking or maintenance. For
the size, it has a lower power density than flooded batteries and
regardless of claims by the manufacturers, the life expectancy is from
30 to 70%. I have many years of industrial experience to back this
claim. I deal with batteries from small UPS units up to 36 volt, 1250
amp hour jobs. Yes, 3,000 lb. batteries exist. And for marine or RV
batteries, Trojan is my choice.
I hope this info helps.

Dennis



-----Original Message-----
From: Larry Chase [mailto:roadguy@roadhaus.com]
Sent: Monday, May 09, 2005 9:08 AM
To: 'Dennis Haynes'
Subject: RE: [VWVANFULLTIMERS] more electricity questions

Dennis,

So at 12.3 - 12.4 I'm about 75-80% charged, maybe a tad more.

What would you do to improve the efficiency of the charge system.



Larry Chase
www.roadhaus.com
www.roadhaus.com/shops.html
www.roadhaus.com/music.html
www.roadhaus.com/recipes.html
www.roadhaus.com/store.html



-----Original Message-----
From: Dennis Haynes [mailto:dhaynes@optonline.net]
Sent: Thursday, May 05, 2005 5:13 PM
To: roadguy@roadhaus.com; VWVANFULLTIMERS@yahoogroups.com
Subject: RE: [VWVANFULLTIMERS] more electricity questions


These batteries fully charged will have an at rest voltage of 12.6 to
12.8.
and would probably deliver a lot more current before dropping off.


Dennis

-----Original Message-----
From: Larry Chase [mailto:roadguy@roadhaus.com]
Sent: Thursday, May 05, 2005 5:46 PM
To: VWVANFULLTIMERS@yahoogroups.com
Cc: dhaynes@optonline.net
Subject: RE: [VWVANFULLTIMERS] more electricity questions

Dennis,



I know what you state is true ... but I'm a confused by my "Actual
Results".
In theory I don't

think things should work as well as they actually do.



Set Up.



Two Optima Red tops at 50ah each = 100ah total



Each night I run these batteries down to 11.2 - 11.5 volts over a period
of
~4-5 hrs.



Each day I drive 40 minutes to and from work = 80 minutes total
drive/recharge time.



In principle, I don't think this is enough drive time to recharge these
batteries .. even to a

75-80% level. The batteries are recharged to 12.2 - 12.3 volts.



How is it possible that I can do this night and after night.





larry chase

roadhaus.com



On Thu May  5  6:13 , Dennis Haynes <dhaynes@optonline.net> sent:



Now, the next challenge is battery charging. The stock

>alternator system will really only return an average of 15 -20
amps/hour

>to the battery, and it will rarely get it over 80%. So figure that you

>will need to drive for 4 hours to put any reasonable amount of charge
on

>it.