I have a "charging system" on my RV that I am reviewing and making
sure I understand. (I just asked last night a question regarding an
isolator that I saw in the circuit.)
The primary charging source is, I believe, a 'second' alternator,
ordered as an option on a 2001 Ford F-550. The charging wire, leading
back to the batteries, is connected to the battery (the second battery
too on the 7.3 Powerstroke diesel) closest to that second alternator.
Is it appropriate for the wire to be connected to that battery rather
than to the alternator itself? What sort of charging current might I
optimally expect when I'm driving along between campsites? How do I go
about determining the specs of the alternator? (The owner's manual
isn't helpful.)
Thank you |
Clarification of Question by
clayboyrick-ga
on
12 Feb 2005 20:40 PST
Hmm, help me out a bit on what needs clarification so I cover the bases.
My truck camper has what seems to be a standard setup...one 12V batt
that provides DC current for lights and so forth. There's not much
there so I had
an additional bank of four 6V batteries added. These batteries are
charged either externally by applying a charger or a lead that comes
from one of the batteries on the truck itself with an isolator in the
circuit.
I want to understand what's going on better and one of the first
questions I had was, "is my recharging system in place adequate?" So,
I'd like to be able to find out what sort of current comes out of the
alternator. Since I'm not clear on even the basics of how these things
are set up, I wondered if it was appropriate that the lead came off
the battery rather than, say, the alternator itself. I do have a
Generator Current indicator that could measure what's coming out of
the battery...haven't checked that yet but thought that surely there
are some specs or something on the alternators that Ford puts on.
Heh, heh, I'm perfectly willing to acknowledge that I may not even be
asking the right questions but I'm trying to get a grip on what is
probably a pretty simple thing, just outside the scope of my
education...at the moment.
Thanks for your attempt to help. The above make any more sense?
Regards
Rick Waldbart
|
Clarification of Question by
clayboyrick-ga
on
14 Feb 2005 05:28 PST
Hi,
Thanks for your help.
>Hi Rick, a bit clearer. It?s a 12 volt system so do I take it you have
(installed or intend to) the four 6 volt batteries in parallel series
combination to furnish 12 volts, or do you intend two separate
additional 12 volts.>
Yes. It is a 12 V system with one bank of a 12V batt, housed in the
truck camper, not linked directly to the other bank of 4 6V Trojan
105's. What I'd like is for this bank to be *able* to be linked to the
other bank while not being linked directly...as with a marine
"one/two/all" switch. These are relatively new and identical linked in
parallel series to 12 V. (Specific gravity testing suggests they are
'good') An issue is that all batteries are located on the passenger
side of the vehicle, the house in a manufactured box, the 6V bank in a
storage compartment of a utility flat bed holding the camper.
The additional, the 6V bank, now linked in parallel series to 12V, is
linked to the system by a small, 10 ga(?) wire that must go back
across the camper. I don't think it's very effective, and I think the
house charger is defective in some way.
> Even then, it is still to
be avoided if possible. So could you clarify this.>
OK, I'm hearing you. I wish I could get a final sort of answer to
this. I bought the 6V per advice of a battery shop. Ultimately, of
course, I can buy whatever. It may be the sort of issue to which there
is no industry wide agreement. I run into that in my own profession
too, so I understand.
>You actually have two the alternators installed, or you intend to?>
The truck is a 2001 F550 and had the two alternators factory
installed, the second as an option but I have't found any info on
them. I do understand from a Ford Diesel site that they are 110 amp
alternators.
>One
alternator will still charge batteries of any capacity but your
problem is that auxiliary items (fridge etc) will drain the battery
and could leave you with a flat battery. So you need isolators?>
Got one in place, a Cole-Hersee 48161 Schottky Battery Isolator.
>The
sketch I drew will not avoid draining of the main battery -- only
serving to avoid discharging the auxiliary batteries as in ambulances
(which was what I was thinking of). Your set-up would be :-
?-|>| ---- Main Battery
Alternator ---|
?-|>| ---- Auxiliary Battery
Those are diode symbols (sort of). So in you case, does that make it
clear where the wires have to be connected?>
No. It looks to me that the lead is connected directly to the
alternator but that may be 'convention'. My lead is connected to one
of my truck batteries and is separated from the 6V bank by the
isolator.
> So it?s not really a case
of where the wire comes off because the alternator goes directly to
the isolator first.>
I've got the alternator, located in the engine compartment, and a
truck battery located in the engine compartment, passenger side. My
lead is connected to that battery then runs aft 12 ft or so to the
storage compartment of the flat bed on the passenger side, is
connected to the isolator there and then to the bank of 6V Trojans.
That's all good looking heavy gauge wire...then the smaller wire runs
back across the truck to the 7 pin connector plug. Ugh.
> Make sure of course that things which require
constant supply (such as coded radios) are connected to the battery,
not the alternator. Most likely it?s set up that way anyway. If you
search the Cole Hersee site there is a lot of info on isolators and
other stuff. Here it is again :-
http://www.colehersee.com/catalog_top/index.htm>
>But do you actually want to link the systems? If you have two
alternators you could run the auxiliary battery(ies) off the second
alternator with only a common ground and no isolator.>
I now understand that the alternators are linked 110's and the second
comes online when needed. There is only the one lead to that system,
the charging lead that comes back to the 'added and isolated' 6V
system.
<You should be able to find alternator specs from the truck specks (on
the web) or manufacturer of the alternator. Failing that though you
really need a Hall effect current meter -- any decent garage will have
one.>
OK can you give me a pointer on where to look? I can't get close
enough to the part to tell anything about it.
I do have a current meter and it registered about 15 amps coming off
of it yesterday and the same getting back to the 6V bank, but I don't
understand if that's OK, good, or poor.
Thanks for your help, don't mean to abuse you with all the info.
Regards, Rick
|
Clarification of Question by
clayboyrick-ga
on
15 Feb 2005 15:33 PST
guzzi,
>Hi RicK. Wish you could run up my driveway and we could sort this out
dead quick. Recently sorted out a VW camper system with a similar
function ?ZIG? box. Got to laugh on this one -- the auxiliary battery
was under the passenger seat and when it was pushed back (for
presumably the first time ever) it shorted the battery to chassis.
Armageddon. Major rewire job!>
Yikes! Some goofy stuff happens, I'm sure.
>Anyway, one at a time. As you seem to be aware, batteries in parallel
is not recommended because the voltages vary slightly and tend to
discharge into each other. I have seen it, straight from the factory
(extra power reserve reqd for tail-lift) but not nice. However,
checking the pH regularly, you can get away with it.>
I see pH here and understand the term but haven't heard of measuring
that at all. You mean specific gravity? I've also just decided to get
the local RV place LazyDays to install an inverter/charger, so I may
just switch out the 6V's then. Got no problem with that if it'll
improve things.
>If you are measuring the current, you?d need to put on lots of load to
see how much *can* come out of the alternator -- main beams, window
demisters etc. If you are measuring with an in-line meter (rather than
a current clamp) make sure the alternator output is never left open
circuit with the engine running. Some can go over-voltage and blow up.>
I understand. All I did was take the meter I have, a Hoyt model 663
Generator Current Indicator, and lay it on the one lead from the truck
battery going back to the auxiliary bank. I measured it at the battery
and then 10-12 feet back as it entered the storage compartment...about
the same 15 or so amps. That was a couple of days after I'd charged
that bank, engine idling. I'm sure that current varies with rpm and
charge of the bank, but it's a place to start. (Part of what you're
saying regarding leaving the alternator output open while the engine
is running is over my head. This meter just lays up against the lead
to measure the current and I've not come close to the alternator.)
>So do I take it that the alternator outputs are directly linked at the
moment? If so, was that done in the factory mod? Need this info first
before we can go further.>
The alternators are as is from the factory. I was just relaying some
info I'd gotten from the Ford Superduty 7.3 site. I understand that
they are linked but don't know anything more to say about it. The only
thing going on that is a modification with my little system is the one
lead from the battery going aft to the bank.
Yes, and I do wish I could just pull up in the driveway. I've got lots
to learn and am willing to read extensively but nothing beats
practical experience and I appreciate it. I don't really mind having
the work done and paying for it but with the kind of travel I do, I'm
often out away from everything and don't necessarily know enough to
keep myself out of a bind. Heh, heh, as an example, I think I shorted
out a Trojan battery and looked on the internet to see the closest
dealer and I was about 2500 miles north of the closest outfit...in
Seattle. Need to understand more on my own.
Rick
|
Clarification of Question by
clayboyrick-ga
on
16 Feb 2005 08:25 PST
Hey,
>Your current meter sounds like just the business. Great. What I meant
about the open-....<big snip>...though probably top out at a few thousand
rpm.>
<So you think the alternators are indeed just wired in parallel. I do
wonder exactly how this has been arranged to work properly but that?s
not a concern for you. However, you should be able to physically see a
heavy duty wire connected from the output of one to the output of the
other -- and thence to the battery of course.>
I can check, do the best I can to see a link.
<Right.....
There is one in-built power source (the twinned alternators).>
...and, one 'house' charge that I believe doesn't function. It is
connected directly, through 'house' wiring to the one 12V 'house
battery'...and not to the larger auxiliary bank.
>The alternator (combined) is connected directly to the vehicle battery.>
Yes
<Have 12 volt vehicle battery.>
Yes, referred to as the 'house' 12V.
>Have auxiliary 12 volt (combination) auxiliary battery.>
Yes.
>Requirement is to charge both batteries from the alternator.>
Yes...and, eventually, with new inverter charger to be able to charge
both batteries from that 'house' charger.
>Requirement is that draining the auxiliary battery will >not drain the
vehicle battery.
Yes.
>Requirement is that draining the vehicle battery will not drain the
auxiliary battery.>
Yes
>Twin 250 amp rectifier isolator available.>
This another way of seeing the Cole-Hershee Isolator?
>Have external charger for auxiliary battery.>
Yes
>External charger not required to charge vehicle battery.>
Right...hopefully.
>Auxiliary loads consist of........? Specify.>
Ah, good, thanks for asking. Relatively minimal: DC reading
lights..can check draw .5 to 1 amp, circulation fans occasionally,
water pump occasional, refrigerator seems to need a minimal draw for
function. We're not talking 'operational' draws.
When I did the power needs assesment analysis for my sailboat I came
up with <25 amps/day. As a sailor I could be pretty frugal. With the
camper is a 'guess of double or triple that a reasonably functional
amount to deal with?
I'd love to be able, and have been, to go about 5 days without
worry...which is about the time water runs out and wasted tanks fill.
>Is that all correct?
Yes, with clarification.
> At present, with the isolator connected between
the alternator (or vehicle battery) and the auxiliary battery,
draining the auxiliary battery will also drain the vehicle battery.
It will? Here may be a major issue. I thought that the Cole Hershee
isolator was there to prevent that very thing!
> So
at present there is a spare terminal on the isolator?
Yes. One of the three terminals, the middle, holds the
"alternator/power in" to the bank (through the isolator, of course).
The other terminal holds the "alternator power out" (of the terminal
into the battery bank.)
One terminal is available...and, I was thinking to lead that to the
'house' battery for alternator charging.
Can't wait to see how *this* works out!
Rick
|
Clarification of Question by
clayboyrick-ga
on
17 Feb 2005 17:01 PST
Hi,
Heh, heh, you're right! It's a truck camper on a 4WD Ford F550 with a
10' custom flatbed.
>Vehicle = house. LOL. This thing is *big*.>>
>My slight concern with the double alternators is that there may be
some fancy way in which they are electrically connected in parallel.
If you can find a direct link I would be much happier. To check that
both alternator outputs go directly to the ?house? (vehicle) battery,
connect a headlight 12 volt bulb between chassis and the output of the
first alternator -- then do the same with the second alternator.
You?ll need to wire up a bulb to do this of course. If both positions
give full brightness than they are indeed directly coupled. Hopefully
you can get access to the output terminals but you only need to hold
the bulb wire on the terminal by hand. See what you can find out
anyway.>
I'll check as soon as I can, probably need to give you a break anyway.
It's dark now by the time I got home and will be for the next several
days probably, winter here with short days though I'm in Florida so
it's not bad at all. Another idea might be to tell me the specific way
to ask the question, I'm on good terms with my diesel shop and they
know these trucks well.
Heh, heh, when I look under that hood with the old flashlight (torch?)
I can't tell an alternator terminal from a popsicle! A root canal is
muuuuuch more my speed!
>The in-built charger (possibly dead) connects from the outside world
to facilitate charging of the vehicle battery. Intended for plugging
into a mains outlet in camp-sites. Yes? >
Exactly.
>The way in which I think your
isolator is connected, it would also charge the auxiliary battery to
almost the same voltage.>
Yes, technically true the way I see it, but the wiring run is long
with small gauge.
>?Twin 250 amp rectifier isolator?. Yes, that?s a description of the
function. I got the 250 amp from the website but it doesn?t make clear
if it is 250 amps total or two times 125. I suspect the later. You
could send them an mail and ask. A rectifier (in case you don?t know)
only conducts electricity in one direction. Think of it like a water
valve which can only pass water in one direction. Nothing is for free
though and they do ?waste? a bit of voltage but Schottky rectifiers
waste less -- in your case less than a volt at full power. That?s why
it is a big lump of aluminium because they will get quite hot in use.
They are pretty reliable but almost always fail short circuit so even
if they died you?d still get full charging, just that the batteries
wouldn?t be isolated from each other. Often, manual switches are used
for isolation (very big and chunky) but people invariably forget to
switch them over. Slightly more reliable though -- if only the
operator were :-)>
Thanks for the explanation. I needed it.
>It?s wise of course to have isolated supplies for all the obvious
reasons but you might have been OK with only the single 110 amp
alternator. Nevertheless, the second one does give you more peace of
mind because you might be in a situation where you actually need more
oomph. Twin batteries gives peace of mind because if you accidentally
discharge the vehicle battery you could rig up the other battery.>
Hmm, the potentially dead charger is not isolated in any way from the
auxiliary bank, it may be as a factory setup isolated from the one 12V
house battery.
Also, technically, there's two batteries up front, that large 7.3 L
Powerstroke diesel, then the two banks behind (one 12V and the 4 6V),
and I never thought of using the house banks for engine start in case
needed. Good idea. Could get some cables made up.
>You are correct in how you think the vehicle battery should be wired
into the third isolator terminal. That would then give you both way
isolation.>
Hmm, I may not have explained well because the way I see it the
isolation wouldn't be *both* ways but rather the same way to two
banks....ie the charging lead would be isolated from both banks...the
vehicle battery isolated from each of the house banks. That the same
idea as what you put forth?
> At present, the alternator (dual) is connected to the
centre terminal *and* the vehicle battery.>
Yes, but it goes alternator(s)all factory...vehicle battery....(center
pole) isolator...(right pole) isolator...4 6V bank. Permitting, I
think, charging current from vehicle battery to house bank with no
draining current...uh, oh, maybe I see potential for trouble.
How does that rectifier really work? I *think* it means that if the
house battery bank is cooked it won't drain the vehicle battery but
does allow the charging current, and I'm not sure that makes complete
sense . But, does it work in such a way that if one, auxiliary bank
*or* truck engine, is cooked, it won't drain the other?
....and, recently, I just had an 'event' where both truck batteries
were dead as can be, no explanation. Conclusion was, first, that the
batteries were just bad, big trucks hard on them but I didn't buy it.
Of course, I bought new batteries but the new ones were dead in a
couple of weeks. Off to a new chassis electircal place, replaced the
BCM (maybe PCM)....I'm still picking up the pieces of that event
getting auxiliary tanks rehooked up.
I didn't suspect that something might have happened with the
rectifier. Frankly, I run CB's, laptops, GPS, portable telephones and
so forth from the cab and I thoought there might have been a parasitic
drain from one of these devices. All that is an unknow at the moment.
> The auxiliary being
connected to one of the outside terminals.>
Yes...right side.
> So what happens in that
case is that current can flow from the alternator / vehicle battery to
the auxiliary battery, but cannot flow from the auxiliary battery to
the vehicle battery.>
OK, but could a dead auxilliary battery drain vehicle batteries?
> Therefore, you need to disconnect the cable which
connects the vehicle battery to the alternator,>
Wait! That's all factory...
> then connect a cable
between the vehicle battery and the spare terminal on the isolator.>
There is a cable between vehicle battery and the center pole now...but
not the spare pole. That would mean *two* cables from the vehicle
battery to the isolator, one to the center pole and the other to the
left spare pole.
>That means that all charging power, for both batteries, passes through
the isolator.>
Two cables from the camper banks back to the isolator, yes, but not
two from the vehicle battery....right?
> Each battery then has it?s own rectifier (valve) so the
power can flow from the alternator (centre) connection to the
batteries, but cannot flow from one battery to the other because one
of the rectifiers would block the flow. Does that make sense?
Yes. And, that's what I was thinking to do. The only mod required is
to cable from the other, left pole of the isolator, to the other house
bank of one 12V.
I've not done that yet but am planning it.
>There may be slight issues with other things connected directly onto
the alternators (rather than the battery) but if you check the
terminals I suspect there will only be the big beefy cable which goes
to the vehicle battery. Slightly unclear here -- does the connection
to the isolator come off the vehicle battery or the alternator at the
moment? >
My lead comes directly off the battery only...there's only factory
wiring whatever it is between the alternators and the alternators and
the battery(ies)
>If it comes off the battery, modification is easy (if
physically close) because all you?d need to do is swap the two cables
over.>
Ok,now, I'm not following this, perhaps it doesn't apply with the
clarification of the setup as I've just done. No swapping of cables.
Right?
> The isolator has to be in quite close proximity because you
don?t want a long length of heavy duty cable wandering all over the
place, soaking up power. Anything else which is at present connected
to the vehicle battery must be left in place. Doing a drawing might
make all this a bit clearer.>
The isolator is actually a good distance away from the engine
compartment...maybe 12 ft or so. It has the one cable from the one
engine battery.
>As for the external (inbuilt) charger, if you want it to charge both
batteries, connect it to the isolator terminal which goes to the
alternator. >
Ah. Any difficulty arise when the truck engine is idling, therefore
charging, and I am still hooked up to power, inbuilt chager working,
both through the isolator, two currentis incoming?
>If you want to only charge one of the batteries, you could
connect it either to the battery or its associated isolator terminal.>
This part making sense.
>Probably doesn?t need to be very heavy duty cable unless it?s a really
powerful charger.>
OK, there's 10 guage in there now. This is good info since I didn't
think much of the small wire. But, it's a big bank, mind you, 4 6V
Trojan 105's, maybe later, 4 12 V's unknown capacity.
>Since (suspect) the isolator is 125 amps per leg, it would be
theoretically possible to zap it if when the engine was running you
put on a humungous load. Not likely though and they are able to
withstand a brief overload.>
Load, you mean by that, what? I'm not a big inverter needy guy. If I
plan the microwave, rare, I'll start the gen. No intention of having
this setup do anything but low load, reading lights, fans, water pump,
gen set ingnition, over several days.
>We getting there?>
Yes. I think I'm a good deal more clear about this. I do have the
above questions about what the rectifier can do...maybe then I can
work backwards and make better guesses about what took place...and be
able to discuss it more intelligently with the tech who does the
install of the charger/power management system.
> I can attempt to draw a picture if it?s still a bit
fuzzy. Such a big a bunch of water between you and here. You ever
thought of an Atlantic crossing? Such interesting people one meets on
GA :-))
You in England?
>I shall of course look in tomorrow -- our flaky electricity excepted.)
Regards
Rick
|
Clarification of Question by
clayboyrick-ga
on
18 Feb 2005 03:21 PST
Hi,
Off early and return after the weekend probably, may come in briefly.
>Hi Rick. Yes you were late tonight, I too. So I?ll do a bit of
digesting before I respond in full to root canal work on your RV. Not
England (heaven forbid) -- Scotland. Some day I?ll experience your
Everglades.>
Oh, yes, now you're talking! I've just broken off a 30 year almost
unbroken string of week to month long visits by kayak and a couple of
shoal draft sail boats.
>Mmmm, don?t really know the best way to frame questions to your
friendly truck shop. Perhaps just what you are at the moment --
getting to grips with the fundamentals. It may be that you decide to
get them to do all the mods but it?ll help to know the whats and whys.>
Yes. I meant, though, something like, do you know how the two
alternators are typically wired up at the factory?
>The alternator terminal(s) should be easy to find, if you can find the
alternators (guess you?ll know that they are driven by a belt). Big
terminal, heavy cable, same one (colour and gauge) as ends up at the
battery.>
I found them but couldn't determine too much with the flashlight.
>The long run, thin wire from the external charger is no problem
because the charge current would only be a few amps. Shouldn?t be too
thin though.>
It's 10 ga now.
>I never thought of using the house banks for engine start in
>case needed. Good idea. Could get some cables made up
You mean ?auxiliary? rather than ?house?? The ?house? being the
"vehicle" one which cranks the engine.
Ohhh, I've been misleading you! I've been using "house" almost
interchangeably with "auxiliary". My meaning may have been
inconsistent but my intent was to convey that by "house" I meant
"camper"...which has two banks...the first the original single 12V
original camper factory equipment...and the second, what I've been
calling the 'auxiliary' the 4 6V. At times, 'house' might have, in
certain contexts been the original battery or both banks.
"Vehicle" or "truck" or "in the truck engine compartment" refers to
the two starting batteries of the truck engine.
>Sorry it?s getting very late (early) but I?ll continue tomorrow if you
can bear with me. Ta>
No problem at all. Our discussion has evolved into a electrical education for me!
Regards
Rick
|
Clarification of Question by
clayboyrick-ga
on
19 Feb 2005 04:04 PST
Good Morning, Andy,
>OK if you catch up when you can -- not experienced sailor myself but a
fair bit of work on the North Sea, West Coast (Scotland) and the
Baltic. Couldn?t live far from the sea though. In the blood.>
Ah, but our West Coast of Florida...a whole different deal...sun,
sand, protected areas to tuck into at night.
<There has been some slight inconsistency in the terms. I thought we
had standardised but seems not, so.....?>
Ah, no, I see that I haven't been clear. The whole machine is a truck
camper that consists of a large Ford pickup truck with a large truck
camper sitting on top of a custom flatbed with storage boxes. With
conventional email I could send you pics.
>1) There are two batteries in the whole machine, of which :->
There are two batteries in the forward engine compartment of the
truck. Large diesel truck, and these are located under the hood of the
truck.
>2) One, big single 12 volt one for cranking the engine and headlights
etc. This we call ?vehicle?.>
Two large single 12V batteries for engine, headlights ect.
>3) One 12 volt battery bank consisting of four 6 volt units connected
in series / parallel. This we call ?auxiliary?.
Two banks associated with camper, one a single 12V factory installed
small compartment on the camper referred to as house. Another
auxiliary (to house)bank 4 6V.
>Are these statements correct?>
My additions are.
>I trawled for several hours tonight on the subject of twin alternators
and the most interesting site I found was this :->
Thank you.
http://www.adverc.co.uk/technical/technical-twin.asp
>...and there?s actually a circuit diagram (if you delve) of a dual
rectifier isolator installed.>
I'll go check asap, on the run for the weekend at the moment, using
above camper to go to a workshop.
z.So it would seem the outputs *are* connected in parallel, but there is
?communication? between the alternators. I shan?t bore you with the
details of why this is required, or why I anticipated something of
this nature. Still I would be happier to have daylight :-)
confirmation from you.z>
Will try to determine.
>Some people seem to prefer totally isolated systems -- one alternator
per battery with no link between. That reduces one of the benefits
though, which is on tick-over with two in parallel you can still get a
good charge. They aren?t bad on tick-over, but in your situation you
might be grateful for the extra.
>External powering when the motor?s running will be safe. In the very
nature of the way the charger has to be designed.>
>12 feet for the isolator is a wee bit long. I was understanding that
you fitted this? Since to achieve all requirements, *all* charge
current has to pass through the isolator before being distributed to
the batteries so it should at least be short in length to the vehicle
battery.>
Yes, I understand this but the overall of the vehicle is 28 feet or
so. The run is shortest possible.
>Oh dear, half past three in the morning so I shall have to leave it
there for the mo. Just time for a glass of sloe gin.>
Oh, man, hit the sack!
I'm off to improve my right brain with an art course where the
'scenery' is always delightful!
R
|
Clarification of Question by
clayboyrick-ga
on
19 Feb 2005 20:22 PST
Hi Andy,
> Great sailing off Florida, apart from the occasional hurricane.>
Yes. Of course, I rarly sailed even close to hurricaine season. My
seanson was early December to end of Feb ...just too hot.
>I got an idea of what your vehicle looks like from the web. Seems
quite popular and would walk over a Humbie.>
Sure, and I've got plenty of pics and could get others. I'm handy with
the digital camera. Got to send me an email address and don't know if
that's kosher.
> Found this recall site
which might be worth checking out :-
http://www.car-recall-database.com/ford-f550-super-duty-recall-46670.htm>
Yes, will come back to it later, maybe get to it at coffee toorrow AM.
>So........
>Two large single 12V batteries for engine, headlights ect.
Correct.
>As far as I can establish on the web, these are connected in parallel
for 12 volts?>
It's definitely a 12V conventional auto system.
>Two banks associated with camper, one a single 12V factory
>installed small compartment on the camper referred to as house.
>Another auxiliary (to house)bank 4 6V.
>So that?s 3 battery units -- though actually 7 individuals in total.>
Correct.
>Terminology :-
The two under the hood for headlights, starter etc -- vehicle
The factory installed 12 volt in the camper -- house
The four 6 volt serial / parallel 12 volt -- auxiliary>
>Is this correct now?>
Completely.
>And you want to isolate which two batteries from each other??
Anything associated with the camper isolated from the vehicle batteries.
Right now only the auxilliary is linked to one of the vehicle
batteries with the isolator between. That lead, I refer to as a
'charging' lead, is connected up front in the vehicle engine
compartment to one vehicle battery which runs back 12 ft or so to
terminate at the center pole of the isolator. The right pole of the
isolator goes to a + terminal on one of the joined 6V's.
Ultimately, I want also, the other camper battery, the house, to be
charged from that same battery (from the alternators) and ultimately
connect a cable from that battery to the left pole of the isolator.
Also, ultimately, since I fear the connection of the auxiliary bank to
the house is so week...another long run, now across the camper
bed...that it is not very functional, I'd like to connect up those two
camper banks...the house and the auxiliary. These two banks are really
relatively close to each other but have not been connected prior to
this since I'd have to punch holes in my new camper. Now, less of a
concern.
I plan this as I discuss the installation of a new inverter/charger
and power monitoring system.
I began all of the questions so that I'd be a bit more heads up as I
enter the discussion phase.
...and, you're helping a good deal.
best regards
Rick
Oh the written word is so difficult isn?t it. Art speaks for itself.
But we?ll get there :-)
Best
Andy
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Clarification of Question by
clayboyrick-ga
on
21 Feb 2005 13:29 PST
Yikes! Great sites! Nothing like that whirlpoos on the gentle west
coast of Florida. I've seen some things, on a smaller scale of course,
paddling our Grand Canyon, similar. Also, witnessed an exciting tidal
bore on the bay, Turnagain Arm near Anchorage Alaska this past year.
>Fraid the Gurgle honchos axe anything with an email address, but
anyway, at last we are progressing. What a pair of dummies eh :-)>
Wonder how (waldbart) the keep up with all the (duty.com) messages? Amazing!
(there's an at between).
>So at present, the ?house? battery is unconnected?>
Unconnected to the vehicle charging system...it is connected to the
house system electrical...and to that maybe dead house charger.
<As you may appreciate by our previous discussions of parallel
connecting batteries, the four (Trojans?) shouldn?t be directly
connected to the house battery because they are different types.>
Yes, and ultimately I believe I'll go back to 12V batteries. In the
meantime, what I'd like is a way for the house to draw on the
auxilliary bank in a better way than it does now...while perhaps not
"connected" directly to the house battery...sort of the way I had
boats rigged, a mechanical "ONE" "TWO" "All" sort of thing.
>When the engine is not running, with your present connection of the
auxiliary to the vehicle battery (via the isolator), vehicle loads
(headlights etc) won?t drain the auxiliary battery, but auxiliary
loads can drain the vehicle battery. This is of course undesirable.>
Umm, yes. I see...and, that, I belive is what has occurred.
>Connecting the house battery to the other isolator terminal will
isolate the house and the auxiliary from each other, but loads on
*either* can drain the vehicle battery (when engine is not running).
Gottcha now.
Got to run some beefy cable to the house and auxiliary if there is
likelihood of heavy load, or perhaps as a contingency. Don?t want it
to lose power in the cable (and / or overheat). *Must* incorporate a
suitable fuse at the vehicle end of the cable. Heavy gauge cable will
ensure that it is the fuse which blows and not the cable -- like the
camper I rewired!>
If, and I believe I do, by a heavy load, you mean an inadvertent one? A short?
Something unusual, like the seat in the VW....
>To solve the problem of draining the vehicle battery, I think the
easiest way is to incorporate a hand operated mechanical isolator
switch -- and just remember to switch it when you stop for the night.
These are readily available from camper van sources (and at least one
of the links I sent). Alternatively, a big power relay (specifically
for the job) might be available which is automatically activated off
the ignition switch. I can try to hunt one down if you would prefer
that option.>
I'd love to know about the options, the power relay activated off the
ignition, and a hand operated mechanical isolator, when discussion
begins with a tech on a new system.
>As for the external charger, it would be connected to the centre
terminal of the isolator (bearing in mind that between the isolator
and the vehicle battery I am envisioning a mechanical disconnecting
switch).>
Yes.
> If you wanted to charge the vehicle battery too, that hand
operated mechanical disconect would give you that option. However, if
you incorporate an automatic relay, you could direct the charge either
with a hand operated change-over switch or another isolator. The
charge wire would then go to the centre connection of the new
isolator, one leg would go to the centre connection of the original
isolator, and the other leg would go to the vehicle battery. The only
slight problem with this is that the lowest voltage battery would hog
the power, and the voltage is not an absolute indicator of charge
state -- different batteries are slightly different. We can explore
the options if all seems cogent so far.>
Yes. I believe I'm with you so far.
>So the angle I?m aiming for is the least amount of wire messing under
the hood. Is this good for you?
Oh, yes. Of course.
> Once you have settled on options I
should try to do you a picture.>
I've an appointment for tomorrow at the diesel mechanic's place to
rehook the wiring for an auxiliary fuel tank. I'll ask how the second
optional alternator functions with the original one. Also, will review
a bit of the possibilies on that dead battery event I had...where they
replaced the batteries only to have them be dead later.
*Now* I see that only parts of the issues were addressed, for the
camper system was left disconnected.
Rick Waldbart
My 'domain' is duty
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Clarification of Question by
clayboyrick-ga
on
25 Feb 2005 04:23 PST
Hi Andy,
I had to push my meet back with the diesel folks...too much at the office.
and, I'm supposed to be semi-retired!
Regards, Rick
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