Date:         Mon, 15 Mar 2004 20:06:40 -0600
Reply-To:     Jim Felder <felder@KNOLOGY.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Jim Felder <felder@KNOLOGY.NET>
Subject:      Second battery, the story on relays.
In-Reply-To:  <DNEFLHPPMKKCMAEKKDCCCENHCOAA.jhecht@alum.mit.edu>
Content-Type: text/plain; charset=US-ASCII; format=flowed

I just installed a hella relay on sunday after fretting over which
route to take for months.

A relay works like a switch with an electromagnet in it. When current
is applied to the electromagnet, it closes a switch. When no current is
applied, the switch opens.

The switching that the hella relay does is to join or separate the two
circuits, cranking battery circuit and auxiliary battery circuit.

When the two circuits are jointed, the alternator charges both
batteries. When they are separated by the switch, they are independent
of each other.

The clever trick with the hella is that you use the wire that makes the
alternator idiot light come on to power the electromagnet I was talking
about. So, when the idiot light comes on--which is only when the
alternator is charging--the two circuits are joined and both batteries
get charged. When there's no current from the idiot light circuit--like
when the engine is not running--the two circuits are separate.
Therefore, one battery can totally discharge running auxiliary stuff
(or cranking the engine) and not affect the other battery.

The hella relay also has a fuse built into it, which is cool.

The blue wire out of the alternator (seen again under the drivers seat)
is used as the trigger circuit in this setup.

With a relay, there's almost no overhead compared to a diode. It
doesn't compromise the marginal vanagon charging system further than it
already is.

I will send you a sketch of the wiring diagram if you need it.

I take no credit for any of the above, the good people on this list and
the diesel list provided all the information. I'm just encapsulating it
for your convenience.

FYI, I went to a battery store and bought a deep cycle that I thought
would fit, but it wouldn't. So I went to autozone and saw the price on
the Optima yellow top and left the store. I came home and installed a
lawn and garden battery (brand new) and today I turned on all the
interior lights and two small 12v fans to test its longevity.It turned
out to be a test for brevity.  I did this at 2:00, at 7:30 the battery
level indicator was showing the red LED. That's just not long enough,
especially when you consider the drain that the sink pump, computer and
other gadgets would add.

So I guess I'll skulk back down to autozone for the optima unless
anyone has any leads on other batteries that would fit the space in a
diesel westy in front of the right rear tail light. Plenty of footprint
is available, just not as much height as the usual deep cycle battery
requires.

Jim


On Mar 15, 2004, at 12:08 PM, Joy Hecht wrote:

> Thanks very much to everyone who provided all the details on our
> problems
> with the isolator.
>
> It looks like there are two reasonable choices open:
>
> -    Exchange the Sure Power isolator for a Sure Power separator and
> install
> that.  I don't know how much the separator costs - I assume it's in
> the same
> range as the isolator ($70).  It sounds from some of the emails like
> it may
> be easier to install, because we can do it between the two batteries
> and
> don't have to rewire to the alternator, but I'm not sure if I've got
> that
> right.
>
> -   Return the isolator (the RV place said if it's in good shape,
> which it
> should be, they'll give me most of my money back) and buy the Hella
> relay
> kit that Busdepot sells for $20.  Some people have sworn by the Hella
> kit,
> others have said the separator would be better.
>
> I'd appreciate anyone's knowledge of pros and cons of the two options,
> particularly regarding:
>
> -    ease of installation - what we have to be able to access to wire
> it,
> whether we can use the setup we already organized - Optima battery in
> its
> hole, separator or relay in the cabinet under the sink, wires running
> under
> the carpets from batteries to sink), and
>
> -    performance - does one setup or the other have significantly
> better
> power management characteristics or less waste or not recharge fully
> enough
> or other things?
>
> And another question - I now have some understanding of what a diode
> is, and
> therefore what an isolator does.  If anyone could explain to me - on
> about
> the level of a high school shop course - how relays and separators
> work, I'd
> appreciate it!
>
> Oh, and for all who said I need the Bentley - yes, yes, I'm ordering it
> today.
>
>
>
> Joy
>
>
>   -----Original Message-----
>   From: RAlanen@aol.com [mailto:RAlanen@aol.com]
>   Sent: Monday, March 15, 2004 7:42 AM
>   To: vanagon@gerry.vanagon.com
>   Cc: jhecht@alum.mit.edu
>   Subject: Re: problems installing second battery
>
>
>   In a message dated 15/03/2004 12:04:49 AM Eastern Standard Time,
> LISTSERV@GERRY.VANAGON.COM writes:
>     The full detail, along with a couple of pictures to explain, is on
> the
> web
>     here:  http://users.rcn.com/jhecht/batteries.  The basic situation
> is
> that I
>     bought an Optima yellow-top, and on the instructions of someone in
> an RV
>     shop we bought an isolator (the type with two diodes inside to
> direct
>     current) that is used by RV folks to connect their second battery.
> Steve
>     first wired the old battery to the isolator, and with just that
> connected
>     the van wouldn't start.  He checked it and played with it but
> couldn't
>     figure out why it wouldn't work.  It was dark out by then, so we
> couldn't
>     experiment further, but he also felt he needed more knowledge than
> we
> had.
>
>     If you think you might have any suggestions, please take a look at
> the
>     website, which includes the wiring chart we're following, photo of
> the
> old
>     battery explaining what we connected (bad quality, unfortunately,
> it was
>     dark when I took it), and a list of hypotheses as to what might be
> wrong.
>     And if you reply, PLEASE copy Steve on your email
>       I did not copy Steve as I don't find his email address in your
> message
>     (all those ormswyn
>     addresses - I don't know which he actually checks) so he'll be
> able to
> mull
>     over your thoughts.  He's not on the vanagon list.
>
>       Joy, I just went through this process on my Westy and helped out
> a few
> others with info.  See the archives for lots more details.  First
> thing I
> will say to you is to use the Sure Power model 1315 to bridge your two
> batteries.  Of all the methods I have personally tried this one is the
> most
> successful in all respects albeit more expensive but in the long run
> it is
> the best way period.  I am going to copy below a few messages I sent to
> others who involved in the same task as you and hopefully all this
> info gets
> into the archiove for future benift of all.  Good luck and hope to see
> you
> soon at Everybus.
>
>   Start of copied messages ............
>
>           <<<<<No, I did not miss you post.  I've been mulling over
> all the
> advice on this issue now for a few days and decided that the Sure-Power
> gadget was the right way to go.  Called up to the local RV place and
> they
> had two in stock at $124.  Went up and got one and spent most of Monday
> installing it.  I see a big difference in the voltage of the aux
> battery
> after shutting down the van after short runs now.  Battery is always
> up to
> above 13 volts at shut down.  I chose to use the aux battery start
> option so
> ran a #4 wire from the main battery to the aux battery under the van.
> Ran a
> # 14 wire up to the start switch for the start position trigger.  The
> two
> batteries need to have a large wire connecting them, this idea of a 14
> gauge
> wire to limit the dumping of the main battery into the aux battery at
> start
> up is not right.  It limits the charge to the aux battery on short
> hauls.
> Granted if you drive for a few hours it will work but when using the
> van for
> short runs day in and day out day after day with no long runs you will
> eventually kill the aux battery if you have any load normally on it.
> Found
> a sopping wet floor under the carpet while trying to run that wire and
> then
> the throttle pedal link popped off and had to dive under to remove the
> plastic cover to reinstall, found the four screws rusted to the point
> they
> needed drilled out.  Ended up cleaning up that mess, dumping Krown oil
> all
> over the area and replacing the screws with nice big stainless ones.
> Still
> trying to get the floor matting and carpet dry and still use the van.
> PITA
> this winter weather.>>>>>>>
>
>       <<<<<<<I chose the 1315 because it has the aux battery start
> option.
> Just need to run a wire from the Sure Power to the ignition switch
> wire that
> activates the starter.  Big red and black wire coming from the ignition
> switch wiring connector if I remember correctly.  Better check Bentley
> or do
> a test with a probe.>>>>>>
>
>      <<<<<<David, I mounted the Sure Power unit on the floor of the aux
> battery box, as far to the RH side and in that small nook as possible.
>  This
> gives plenty of room for the Optima to fit.  I ran a number 4 gauge
> cable as
> recommend on the Sure Power install sheet from the main battery to the
> Sure
> Power under the van.  Out the bottom of the main battery box along
> side the
> main wire and through the same grommet and then drilled and new hole
> in the
> floor of the aux battery box floor and used an appropriate sized
> grommet.
> Use caulking to seal up the space between the wires and the grommets if
> there are any.  Used 4 gauge wire from the Sure Power to the aux
> battery and
> from the aux battery ground post to ground at the battery hold down
> bolt
> location.  I did install the start option so ran a 14 gauge wire up to
> the
> start switch as described in the instructions. Depending on what kind
> of
> terminals you use on the aux battery they and all the wires leading
> too them
> my come very close to the seat swivel plate when turning it round.
> Use a
> piece of heavy carborad as an interface to check.  If it is too close
> you
> can remove the lip of the swivil plate in the area where it is too
> close.  I
> did this and that solved the problem of turning the seat and having it
> short
> out on the battery positive post.>>>>>>>
>
>       <<<<<<The stock relay is not needed if you want to connect your
> fridge
> to the aux battery directly.  Just remove the relay.  The wires coming
> to
> the relay from the front of the van; 12v power from the main battery,
> large
> red wire, this wire should now be used to send power to the front of
> the van
> to power the cabin lights, radio and any other circuits you want to
> run from
> the aux battery,  You will need to trace this wire to its location on
> the
> back of the fuse relay block, disconnect it and then find the wires
> for the
> accessories you want to power by the aux battery then make a 10 or 15
> amp
> (depending on the circuits you choose) fused connection between them
> and the
> big red wire.  The other end of this wire at the aux battery box will
> now
> connect directly to the positive terminal of the aux battery.
>       The other two wire coming from the front to the relay are the
> control
> wires that should now be used to control the Sure Power unit.  I forget
> which colour does what but one becmes 12 v positive when the engine
> starts
> and the alternator light goes off.  This is the 12v wire needed to
> activate
> the Sure Power unit at the positive position.  The remaining third
> wire is a
> triggered ground from the front that should now be connected to the
> negative
> position on the Sure Power unit.
>       The two red wires coming from the small fuse block behind the
> drivers
> seat are the positive power wires for the fridge, sink water pump and
> control panel on the sink/stove cabinet front.  Both these wires
> should now
> be connected directly to your aux battery positive terminal if you want
> those function to operate off your aux battery.
>       Hope I've been helpful and not confused you too much.  Wiring is
> complex issue to describe and I hoe I've said it all right.  You may
> need to
> consult the Bentley workshop manual wiring diagram for your particular
> Vanagon to make sure you know which wires do what before you make some
> mistake and case damage.  I don't always remember and I ALWAYS go get
> my
> manual and look at the wiring diagram when doing these installs.
> Better
> safe than sorry !>>>>>>>>>
>
>
>
>   Cheers,
>
>   Frank Condelli
>   Almonte, Ontario, Canada
>   BusFusion a VW Camper camping event, Almonte, ON, June 10 ~ 13, 2004
>   '87 Westy & Lionel Trains
>   Member: Vanagon List, LiMBO, IWCCC & CCVWC
>   Vanagon/Vanagon Westfalia Service in the Ottawa Valley
>   STEBRO/Vanagon Stainless Steel Mufflers
>   Frank Condelli & Associates or http://frankcondelli.com
>