Terrible Tom <silvereightynine@aol.com> wrote:
> David Gersic wrote:
>> On Sunday 21 September 2008 01:03 pm, SilverEightynine@aol.com wrote:
>>
>>>Perhaps - but if I isolate them, I'm back at the same problem... then I
>>>have two 136A systems, instead of one 272A system.
>>
>>
>> What do you need a 272A system for, though? No one thing you mentioned is
>> drawing anywhere near 200+A by itself.
>>
> Winches - under load can draw over 400 amps, depending on model and the
> load being moved. Jon has 3 qty, 1000 CA rated batteries in his Ram
> with his 12000 LB warn unit.
That might be the easiest route to take in this case also... I
guess it depends exactly what your use will be. You mentioned the
lights, and the plow and winch. Of course, the plow and winch won't
be going at the same time, so those ratings aren't really cumulative,
but you still want enough capacity for one or the other. I'm thinking
that the plow has the biggest potential for running down the system.
Although the current draw on a winch is large, it just gets used long
enough to get you out of a jam. A plow is another story since it gets
cycled a lot.
I'm guessing you're probably going to want to do a dual or triple
type battery setup in any case. Even with two alternators, you're
going to be relying on the batteries to make up the difference, since
even two alternators are probably not going to be able to keep up with
the full current draw.
Here is what I'm thinking... A dual battery setup (where your
second battery might be 2 batteries in parallel, like in my Ram) with
accessories such as your lights running off the main truck battery and
your winch & plow on the secondary battery. With a battery isolator,
both batteries can be charged by one alternator. As long as your
second battery is pretty beefy, it should be able to handle the high
current without getting discharged (and even if it can't, at least it
doesn't affect your main battery). Whether this will work or not will
depend on the capacity of your secondary battery and exactly what sort
of use you will be giving it. If you are going to be plowing in a
commercial capacity, going from dawn to dusk then it might get drawn
down too much; only you will be able to answer that question based on
your intended use.
However, even if that setup does prove to be inadequate, you can
always do the dual alternator idea at any point in the future, you
haven't really spent much money on this setup that you wouldn't be
spending anyway. Also, another option related to this is if you did
the above setup and discovered that you were plowing so much that the
secondary battery was proving inadequate, it would be pretty easy and
relatively inexpensive to simply add more batteries in parallel to
increase the capacity of the secondary battery, perhaps by building
some sort of mount at the front of the bed. This would be something
that you could stick in the bed just during wintertime; you would
need to run the cable back to the bed to tie into your secondary
battery, and the size of the "booster" battery bank in the bed can be
as large as you like, though it only needs to be as large as necessary
to get you through a day of plowing. When you park the truck at home,
you could plug in a battery charger so that they are always at 100%
when you come out the next day.
Even with all of the above said though, I'm thinking you *should*
be OK even with just a second, single battery and a ~140amp
alternator. That's all the 3/4 and 1 ton Dodges come with, and many
of those are used for commercial duty. Larger gauge wire from the
alternator and a second/better ground to the frame might be all that
is required.
That would be my approach anyway - getting the largest alternator
which will work, ensure adequate gauge wire is used for charging, add
a second battery w/isolator. It may be that is all you need. But, if
all that is up to snuff and you still need more capacity, you're not
really out any money since you would have done the above anyway, and
you can proceed from there as far as whether you want to go with
another alternator, more batteries, etc...
What I'm thinking is that trying to get an alternator (or
alternators) with the full current rating of your max draw is probably
way overkill and therefore more money spent than necessary to meet
your needs. Allow the batteries to take the hit and use the
alternator + time to top them off. The trick is to match the above
with your actual current use.
> I've been looking at the possibility of using a 24V winch... setting up
> two batteries in series wouldnt be hard - but it would require a 24 volt
> alternator. More money... heh... but the amp draw of a 24 volt winch
> is half what a 12 volt uses.
I'm not 100% sure on this, so don't go wiring anything just on my
say-so :-) but my gut tells me it would probably be possible to hook
two 12v batteries up in series (Battery A + to Battery B -) such that
you get 24v by hooking your winch to Battery A - and Battery B +, but
charge them individually with your 12v alternator(s). I guess it
would depend on how fancy you wanted to get with the electrics as far
as if you wanted this to be completely automated or not. I have a
feeling the cost/complexity of a fully automated system would probably
not be worthwhile, but consider that when you want to winch, you've
got to get out of the truck, hook up the remote, run out the cable,
etc. Its not really an operation where you just stay in the truck,
there are some other things to be done, so it might not be a big deal
to add one more step... What about two batteries which are separated
and normally charged as two individual 12v batteries, but by flipping
a switch, they are now one 24v battery; flipping the switch is just
one more step you need to do when winching. (To get away with just
using one switch, it would probably need to be at least a triple pole
switch.)
I dunno of that helps or just confuses things more, but there you
are. :-)
--
-Jon-
.- Jon Steiger -- jon@dakota-truck.net or jon@jonsteiger.com -.
| '96 Kolb Firefly, '96 Suzuki Intruder, Miscellaneous Mopars |
`-------------------------------- http://www.jonsteiger.com --'
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