Date: Mon, 21 Jul 2003 22:02:20 -0400
Reply-To: Dennis Haynes <dhaynes@OPTONLINE.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject: Re: Vanagon alternator too weak for Optimas.
In-Reply-To: <5.2.0.9.2.20030721192615.0a222fa0@pop.rcn.com>
Content-Type: text/plain; charset=us-ascii
Derek,
These kits do work on our alternators. I believe we have the 28 mm slip
rings, (Half Hiemers!). One must be careful about raising the voltage as
extended operation will overcharge most batteries. Dedicated battery
chargers compensate for temperature and other variables to determine
proper charging current. The ultimate charging scenario is to charge a
battery without any load. A proper charge for both flooded batteries and
the Absorbed Glass Matt (AGM) like the optima is to replace 107% of the
amp/hours consumed. Any charging system using a fixed voltage is not
smart enough to do this.
A healthy, charged battery will produce 2.1 volts/cell at room temp.
Flooded cell batteries should get charged @ 2.3 volts/cell for float
charging. This is why the Bosch regulators are set at 13.8. Higher
voltages are favorable for quick charging and are useful on occasion to
"Equalize" a battery. Equalizing is a process where the battery is
charged for an extended period so that weaker cells will be charged to a
higher state so that they will all have equal capacity. Intelligent
industrial battery chargers are matched to the battery being charged and
they are set to particular current curves, not voltage.
Flooded batteries, particularly the non maintenance free types are
tolerant to over charge conditions. The AGM batteries are not. The only
way to properly charge them is to use intelligent chargers that can
sense load and set the charge current based on time, temp., and state of
charge. There are actually intelligent voltage regulators for marine
alternators that perform these functions but they are expensive. Most
charge these batteries with a dedicated charger connected to shore power
or a 110V generator.
We use mostly flooded type batteries on our material handling equipment
at work. Within the last 3 years we have started using AGM for some
applications. I find them to be failure prone which is evidence by short
warranty periods, ( we have $3,000 batteries), and cell replacement is a
common practice.
What am I trying to say? Using the alternator to charge these things is
a compromise in itself. Unless you really need a sealed battery, I think
they are a waste of money for the capacity actually delivered. The
compactness is nice but what can they really that can not be done with a
Champion for $40. If you can afford the room, go for two 6V group 4 golf
cart batteries in series. ~220 amp hours and I've seen them as law as
$70 at sears. The good stuff, Trojan will cost ~$110. I am now on my 4th
season with those in the motor home. They do require regular additions
of water but they can still run the big furnace for a weekend.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf
Of Derek Drew
Sent: Monday, July 21, 2003 7:28 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Vanagon alternator too weak for Optimas.
Has anyone actually confirmed that the link below leads to kits that can
be installed in our vehicles?
These kits seem like a great way to be able to temporarily push a lot of
juice into the batteries in order to get them charged up fast and then
let the voltage come down after that.
At 04:20 PM 7/21/2003 -0500, you wrote:
Or you could do the Volvo fix
http://www.linkline.com/personal/dbarton/AdjustableVoltage.html
Mike
At 01:21 PM 7/21/2003 -0700, Steve Delanty wrote:
At 12:42 PM 7/21/2003, you wrote:
i read in the archives that Optima does NOT recommend
anything less than a 15 volt alternator output, if
this is true, then we are all undercharging our
optimas becouse the vanagon's Alt charges around
13-14V.
[snip]
The stock Bosch alternator is actually a pretty good piece.
It's decently made and has good current capacity.
The problem is that the crummy little internal regulator
is lazy and tends towards low voltage. Also it measures
the voltage *at the alternator* instead of at the battery
so when the electrical load is high, the voltage drop
across the charging wire (from alternator to battery)
causes the battery to see very low charging voltage
particularly under high electrical loads.
A reasonably simple (and cheap!) cure is to remove the
stock internal regulator, and replace it with a nice Ford
style external regulator. This works VERY well on the
Bosch alternator. You need to cut a couple leads on
the back side of the internal Bosch regulator and solder
1 wire on that will go out to the external (Ford) regulator.
Also, while you are at it, run a small wire from the regulators
"voltage sense" terminal up to the battery, so the regulator
measures the charging voltage AT THE BATTERY and
compensates for the voltage drop across the charging wire
and keeps the battery charge voltage much more constant
regardless of electrical load.
I did these things to the alternator that was in my vanagon
and loved it.
I don't have the URL's for the sites I found it at, but the
external regulator conversion seems popular with the Volvo
crowd. Type -Bosch Ford alternator- into a search engine and
you should find several websites with instructions on doing
the regulator swap.
It's pretty easy and works GREAT!
Steve
EJ22 -> '86 Westy "Escape Pod"
_______________________________________________
Derek Drew
CEO & Co-Founder
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