12v power for starting problem

[Gregory OConnor]

2 amp draw could also be failing alt on the engine (check for heat
or disconnect to see if amp draw ends) there are also some
continious duty solenoids in the bus like winter/summer
selections). once you start a diesel with low charged batteries the
starter begins to fail and requires more and more juice to spinn a
start.
GregoryO'Connor
94ptRomolandCa

--- In WanderlodgeForum@yahoogroups.com, ebirder2000@... wrote:
>
> As I re-read my email I apologize for coming across as if you did
not
> understand battery circuits. I was only trying to lay a ground
work for our
> discussion.
>
> The "booster" switch (called the Aux Bat switch on my coach)
originally
> activated a solenoid that put the generator battery in parallel
with the coach
> batteries.
>
> The original configuration of my coach had the solenoid for
the "booster"
> behind the step. When the solenoid was closed the generator
battery was
> connected to the coach circuit at the bulkhead connecting point
on the inboard side
> of the frame under the drivers seat. This was a direct connection
to the
> starter. The generator battery current did not have to "go
through" the coach
> batteries or their connections.
>
> Your coach very possibly could be different as mine is now. Some
of the
> coaches were changed such that the auxiliary battery was no longer
available as a
> booster. The generator battery is isolated from the rest of the
coach and if
> the coach batteries are drained new 75 or 100 amp chargers
operated by the
> generator will recoup the coach batteries in short order.
>
> It still sounds as if there is a problem with the connection from
the three
> 12 volt batteries to the starter.
>
> Many of our coaches have been modified. Sometimes well
intentioned people
> put add on circuits in the coach that bypass the disconnect
switches. Case in
> point, the original refrigerators in older coaches did not
require a 12 volt
> circuit as they were manually operated. If the refrigerator in
the coach has
> been replaced it probably requires a 12 volts for the monitoring
circuit. This
> could be your 2 amp stray current. Other options are electric
clocks,
> thermometers, alarms, radios, cb's etc.
>
> Steve Anderson
> 79 FC 35
>
>
>
>
>
> In a message dated 4/9/2008 8:55:36 A.M. US Mountain Standard
Time,
> dhetzel@... writes:
>
>
>
>
> Steve,
>
> Yes, I'm aware of the different types of batteries (starting vs
deep cycle,
> etc) and
> know what I have now is not the original configuration.
>
> However, I have tested all combinations of any 1 or 2 or all 3 of
the
> starting batteries
> and no-go. Also, when I apply extra power with the booster, it's
being
> applied to the
> terminals of one of the batteries and still has to pass through
the existing
> cabling
> from the batteries to the engine/starter/from
>
> Yes, the 3208 is normally a very easy starter, and when the
problem occurs
> the
> batteries can't even turn it over once.. Also, even with the big
disconnect
> switch
> on the dash thrown to off, there is a small (2 amp or so)
discharge current
> from
> the batteries sometimes.
>
> Dorn Hetzel
> 77FC35
> Hogansville, GA
>
> On Wed, Apr 9, 2008 at 11:45 AM, <_ebirder2000@ebirder_
> (mailto:ebirder2000@...) > wrote:
>
>
>
>
>
> Dorn,
>
> Original configuration on most (almost all vintage FC's) was
four 6
> volt batteries in series-parallel configuration. That's
essentially two 12 volt
> batteries each made up of two 6 volt batteries. Your
configuration of three
> 12 volt batteries in parallel will certainly work but there are
several
> considerations you should be aware of. First, when combining
batteries whether in
> series or parallel, all of your batteries should be the same
voltage and
> amperage rating and age.
> Second, batteries that are made for starting engines are
generally rated
> in cold cranking amps the higher the cca's usually the more
capacity of the
> battery to deliver a high current to start the engine. The
batteries in older
> FC's are used for starting for sure, but, they are also used for
supplying
> the 12 volt electrical power to the coach for lighting etc.
Batteries that are
> used for supplying electrical power for house use are generally
rated in amp
> hours. A typical series pair of 6 volt batteries making 12 volts
is rated
> at around 220 amp hours. Therefore the original combination of
four
> series/parallel wired 6 volt batteries provided 440 amp hours for
house current. BTW
> there is a major difference in the construction of cranking
batteries and
> batteries that provide lower current over long periods.
> Since the 3208 engine is a relatively easy starter and therefore
does not
> under most conditions draw unusually high starting (cca) current
for long
> periods, the series parallel 6 volt battery combination although
not the greatest
> for starting is acceptable and works great for lighting and
general coach
> power.
> My recommendation to you is to change your battery set up to
four 6 volt
> batteries in series parallel. If that doesn't set well with you,
you should
> at the very least make sure that all of your 12 volt batteries
are the same
> age and size. Most likely the smaller 12 volt battery is dragging
down the
> performance of your newer larger 950 cca batteries.
> As always you should ensure that all battery connections are
clean and
> tight all the way to the starter and frame ground. Also ensure
that the
> starter ground strap (cable from starter to the frame) is clean
and tight. I found
> the ground strap on my coach originally ran over to the front
compartment
> sheet metal and was not tight. I had intermittent starting
problems so I changed
> to the strap running to a clean frame connection and had no more
problems.
>
> Steve Anderson
> 79 FC 35
> Poulsbo, Wa
>
>
>
>
>
>
> In a message dated 4/9/2008 7:43:12 A.M. US Mountain Standard
Time,
> _dhetzel@..._ (mailto:dhetzel@...) writes:
>
>
>
>
>
> I'm having an odd issue with my 77FC35.
>
> Alternator seems generally OK, 14-ish volts when engine running.
>
> Shore power DC supply seems maybe a little less ok but does seem
to run all
> the lights, etc.
>
> Can freshly charge main batteries which are three 12v batteries,
two 950
> cranking amps, one smaller, all parallel.
> (This doesn't look like the original config (was that four 6v
series
> parallel?) but it's how the bird came to me)
>
> On fresh charge to main batteries with external charger/booster
the engine
> will start fine,
> but after either driving around for a while or sitting for a
while on shore
> power, the mains seem unable to
> start the engine. I have put two brand new 950 cranking amp
batteries in
> within the last week, so I'm
> pretty sure it's not the batteries.
>
> If I connect the charger to the batteries, it says within a
minute that they
> are full, but the engine won't crank
> unless I use the booster, then it cranks fine.
>
> Any thoughts on what the issue might be and how to diagnose
further?
>
> Regards,
>
> Dorn Hetzel
> 77FC35
> Hogansville, GA
>
>
>
>
>
>
>
>
>
>
>
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