Updating your Alternator - CHAT & longish

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I now risk the wrath of those that know a lot better than me when it
comes to running spotlamps etc. on vehicles. But I have put extra
lamps on plant and equipment and as long as they were used with the
engine running the standard alternator coped with - it seemed - just
about anything.
But when it comes to running auxiliaries then you don't always have
the engine running and you need reserve power. And of course the
route to travel is via an extra battery/s. Some of the best systems I
have seen on a TLC have been on the 75 troopies used as de-mining
team ambulances where they have a lot of technical gear as well as
huge Warn winches. The systems used for these extras are a whole new
world from the usual auto system.
For over 25 years I have owned boats where the electrical circuit is
a critical part of the internal systems. Countless times I have heard
people complain that they need a higher power alternator, yet what
they need is to apply thought on what they want to get out of it and
how they will use it, and re-think their whole system.
In my boat I have 15 cabin lamps (fluorescent - some with 3 X 8w
tubes, tungsten and halogen), 1 halogen spotlamp and a combination
navigation light, two water pumps for domestic supply and shower pump
out, and a full size Lec domestic fridge with a 12v Bosch compressor
motor. Plus a 700w quasi sinewave inverter to run the TV, video,
radio and pc when cruising. All I need is 2 hours 15 minutes running
each day to be completely self-contained with power for another day
or so, yet that is with all systems working and no power saving
regimes - and I have a 55w alternator to power it all. This runs on a
slow revving dagga dagga dagga type of engine which at most when
cruising reaches 1000rpm.
I have two battery circuits, one 95ah starter battery, and 3 X 120ah
batteries in parallel to power the domestic system, all kept charged
by that one small alternator.
The key to getting the most out of your alternator is to make sure it
is getting the right message from the system to ensure it puts out
the power, and then give it a chance to achieve its potential output.
There is the rub, automotive systems nearly always have a machine
sensed system which closes the alternator's output down as soon as
the voltage at the alternator rises to about 14.4v. In most cases
that voltage is the 'surface' voltage of that sent back to the
regulator from the battery plates. Unfortunately the voltage is not
'soaked' through those plates to full charge.
So by all means fit an auxiliary battery, but make sure its a deep
cycle or at least a 'leisure' type. This will cope with constant
power draw for prolonged periods, they do not have a high cranking
capacity as do starter batteries. My 3 domestic batteries are of the
deep cycle type. But fitting an extra battery with a split charge
relay is not the end of the answer to the problem.
Next, make sure the alternator runs at near maximum speed as much as
possible. My little alternator runs at a ratio of about 6 to 1 to the
crank pulley. I had a mate make me a super small alternator drive
pulley as its a Magneti Marelli alternator and they are a bit
rare/obsolete. But smaller pulleys are available off the shelf from
auto electricians for the more common makes of alternator. Just
remember that you may need shorter drive belts - and fit a matched
pair (maybe an 8 digit manufacturing batch number stamped on the
outside surface, that should be the same on each) .
Finally, change the sensing of the system by buying a split charge
relay or diode splitter, and an alternator controller. I see - I
think - Roman suggested viewing the Adverc webpage. Its a good make
of controller but somewhat over the top, even for a boat, as they are
made more for emergency vehicles and are very technical. So look for
something a little more simple, and some overland equipment
preparation companies have alternatives, though a bit expensive.
The output of the alternator goes to the splitter and one of its
output leads goes straight to the starter via an ammeter, and
voltmeter if you want. That circuit will look after itself just as
the alternator manufacturer intended in a normal vehicle system.
The other output from the splitter takes a route described by the
controller manufacturer, which can vary but is usually quite
straightforward, it is the signal sent to the output of the
alternator that is the important part of the circuit. To achieve this
there are usually another 4 wires coming from the controller that
have to be connected to their instructions.
I have had a high tech 'Kestrel' made by Acorn engineering in Denton
Manchester (cost today about 130 quid), its efficient and can be
adjusted manually so you can tweak the volts up to 15 before it cuts
out. When fitting it you have to solder a wire to one of the
alternator brushes to connect to the controller. The final adjustment
of its output is related to the maximum output of the alternator in
relation to the battery capacity of the system in total. This in
order not to overheat the alternator or boil the batteries unncessarily.
I have now gone digital with a controller made by Sterling Power
Products of Worcester, again costing 130 quid. This is as good as the
Kestrel but more so. It has a facility to set it to the type of
battery cell it is controlling - though they recommend ordinary wet
acid cell types if possible - hence power output. It self senses the
a.h. capacity of the batteries it has to charge. It also has a
battery temperature sensor that you put directly onto a terminal of
the battery bank you are sensing and controlling. It also has a 4
stage charging cycle which builds-up its output. It also has
safeguards for over voltage etc. etc. But there are no user friendly
adjustments. Again, a cable has to be soldered onto one of the
alternator brushes.
When fitted-up correctly it all looks after itself, but it is
advisable to check battery acid level regularly. When I start the
engine, yes, the alternator whistles, and if the belt is not tight
enough it can slip. But an old cambelt tensioner rigged to tension
the belt and give more 'wrap' to the alternator pulley solves that
possibility. (I am not in a position to put twin pulleys or a polyvee
pulley on the crankshaft unfortunately). The combined reading from
the ammeters gets up to about 48 amps, but not very often. The engine
start circuit soon charges and the usual 10 amps on that circuit soon
drop to just on the plus side of the dial. The alternator whistle
will die away in proportion to the gaining charge. But I usually
cannot hear it after 10 minutes. The controller also has a self
regulating 'float' facility to meet any load applied when the engine
is running but after the battery systems have charged.
All this gear is out there, but you don't solve the problem by
putting on a higher rated alternator, or even adding another battery
to your truck, its a lot more complicated than that but simple to
apply - if that's not a contradiction.
The instructions for the Sterling controller are a scream to read.
One day when Julian and I arranged to meet I showed him the crazy -
but entertaining - instructions. Maybe he will let me write out a few
quotes from them one day.
I think I have written enough, but just wanted to provoke some thought.
Cheers
Jon
Grand Union Canal
'92 HZJ80 ex UN surplus from Bosnia
 
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Jon

| I now risk the wrath of those that know a lot better than me
| when it comes to running spotlamps etc. on vehicles. But I
| have put extra lamps on plant and equipment and as long as
| they were used with the engine running the standard
| alternator coped with - it seemed - just about anything.
Certainly no wrath, and an interesting write-up.
Many years ago in my old VW camper I added an auxiliary battery attached to the ordinary charging system via a split level charging relay. (For those wondering what that means, it is simply a relay plus fuse wired to turn on only when the alternator is delivering current. So with the engine off the auxiliary circuit is isolated from the normal electrical system.)
The only problem I had was the relay fuse (30A) blowing when the alternator (55A) was trying too hard after the battery (70AH) got very discharged, otherwise it worked fine and took away the "if I run the lights & fridge will I be able to start the engine?" worry completely. So if my experience is anything to go by lack of alternator capacity is not an issue.
I'd definitely echo your thoughts on using "leisure" (deep cycle) rather than "car" batteries for low to medium current auxiliaries. I use electric fencing for the horses, and typically leave the batteries out there for 2 months between charges, and as the fencer draws about 25mA average they get fairly run down.
I used to use cheaper "car" batteries, but they tended to die after about 18 months of this treatment. Now I use leisure ones and after 4 years they are still going strong, although the hygrometer shows that they are not in their first flush of youth any more! Certainly they handle the deep charge/discharge cycle much better, and seem to hold their charge for longer too.
I'd question whether the cost of sophisticated charging gear is worth it in a vehicle though. I bought 2x 110Amphour leisure batteries for the Pony Club (yes, horses again!) catering caravan earlier this year, and they cost =A348 each. I accept that more controlled charging, giving a higher peak voltage, will extend battery life but at that price is it worth the cost and hassle?
If all I wanted to do was to run a fridge, lights etc I think I'd just bolt the auxiliary battery into the existing charging system via a split level charging relay, and add a solar panel if I was going somewhere sunny. The KISS approach.
I wouldn't use one of these leisure batteries for high current things like starting or winching though, unless it was an emergency. But with that in mind I think I'd try to choose one with terminal posts that would allow me to swap it into the normal battery slot.
Christopher Bell
Devon, UK
1996 1HD-FT
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In response Chris wrote...
Many years ago in my old VW camper I added an auxiliary battery
attached to the ordinary charging system via a split level charging
relay. (For those wondering what that means, it is simply a relay
plus fuse wired to turn on only when the alternator is delivering
current. So with the engine off the auxiliary circuit is isolated
from the normal electrical system.)
The only problem I had was the relay fuse (30A) blowing when the alternator
(55A) was trying too hard after the battery (70AH) got very
discharged, otherwise it worked fine and took away the "if I run the
lights & fridge will I be able to start the engine?" worry
completely. So if my experience is anything to go by lack of
alternator capacity is not an issue.
SNIP
Thanks Chris, so your last line agrees with my little diatribe then
! Its not an alternator problem. And we all respect your
professional experience as a technician in the vehicle world.
As for blowing fuses on the relay, frankly I have never seen a fuse
on a split charge relay, or inserted one in a split charge circuit,
so its not a problem I have ever encountered. The commercial wiring
diagrams that are sold for DIY boat installations do not include
fuses in the charging circuit, and in fact on one occasion I put a
fuse in the supply to the control panel just as a safeguard for the
instruments etc. as that wasn't included either. Perhaps a fusible
link might be an idea as a fire prevention measure, though the engine
room of a boat and the electrical control panels are not as hot as
under the closed space of a TLC engine bay on a sunny afternoon, so
overheating cables are not usually a problem. By the way I use
12.6mmsq cables on the charging system.
As for the battery type, yes that is where people often fall down
with their installation as when they come to buy them, they find that
the deep cycle type are up to 3 times the price of a starter type.
No response from Julian though, who posed the question. By the way
Julian, after phoning me about snow chains, I hope you got some in
time for the recent blizzards in Gloucestershire?
Cheers
Jon
Grand Union Canal
'92 HZJ80 ex UN surplus from Bosnia
 
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Hi Jon,
My original question was about drop in upgraded alternators and as far
as I can tell there are some available, if you look hard enough.
Eddie at Frogs Island had sourced some 120Amp alternators but needed to
make up a bracket for it to fit. He was wondering if there was a
market for making a few of the brackets, but I'm not sure if there is -
I'm gathering up the feedback to pass back to him.
No haven't got the snow chains yet, despite getting 5" of snow on
Monday night - all the chaos that was reported on the telly on
Monday/Tuesday was on the A417 500yrds from our house, very
entertaining watching people struggle because they didn't have a clue
how to drive in snow. Out local gamekeeper spent most the evening
towing people around and when interviewed commented on that fact.
My eldest daughters school was closed on Tuesday due to the snow and
yesterday morning I had to tow three cars up some hills on the way to
the school as well as spread grit over about 1/3rd mile of icy hill -
the council had kindly put the piles of grit there, but nobody had
bothered to spread it.
It was actually quite spookey going out first thing on Tuesday to see
so many cars just abandoned on the side of the road, there must have
been around 100 cars parked up on the side of a mile long stretch of
road.
The tank did well, although was sliding around a bit fully locked
towing on sheet ice up a steep hill. I had been toying around with
lowering the tyre pressures, but actually think having higher pressures
helped dig into the ice.
The only other time I skidded was putting the power down on a
corner/turning causing the back end to come out, but it is very easy to
control which is comforting to know, there is nothing worse than a
vehicle that snaps out of line.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
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Hi Jon,
My original question was about drop in upgraded alternators and as far
as I can tell there are some available, if you look hard enough.
Eddie at Frogs Island had sourced some 120Amp alternators but needed to
make up a bracket for it to fit. He was wondering if there was a
market for making a few of the brackets, but I'm not sure if there is -
I'm gathering up the feedback to pass back to him.
No haven't got the snow chains yet, despite getting 5" of snow on
Monday night - all the chaos that was reported on the telly on
Monday/Tuesday was on the A417 500yrds from our house, very
entertaining watching people struggle because they didn't have a clue
how to drive in snow. Out local gamekeeper spent most the evening
towing people around and when interviewed commented on that fact.
My eldest daughters school was closed on Tuesday due to the snow and
yesterday morning I had to tow three cars up some hills on the way to
the school as well as spread grit over about 1/3rd mile of icy hill -
the council had kindly put the piles of grit there, but nobody had
bothered to spread it.
It was actually quite spookey going out first thing on Tuesday to see
so many cars just abandoned on the side of the road, there must have
been around 100 cars parked up on the side of a mile long stretch of
road.
The tank did well, although was sliding around a bit fully locked
towing on sheet ice up a steep hill. I had been toying around with
lowering the tyre pressures, but actually think having higher pressures
helped dig into the ice.
The only other time I skidded was putting the power down on a
corner/turning causing the back end to come out, but it is very easy to
control which is comforting to know, there is nothing worse than a
vehicle that snaps out of line.
--
Regards,
Julian Voelcker
Mobile: 07971 540362
Cirencester, United Kingdom
1994 HDJ80, 2.5" OME Lift
 
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Jon
| Thanks Chris, so your last line agrees with my little
| diatribe then ! Its not an alternator problem. And we all
| respect your professional experience as a technician in the
| vehicle world.
I b'aint no "professional auto technician"! Or maybe your tongue is in your cheek.
My degree is in Civil Engineering, my current job is writing engineering software used mainly for car crash and seismic analysis, and the engineering consultants for whom I work (Arup) mainly do structural work.
Any electrical knowledge is self-taught, and stems from the days when, aged 7, my Hornby trains broke and I discovered that it didn't require rocket-science to fix them. (Although in those days of Thunderbirds and Dan Dare I did want to be a rocket scientist...)
Sadly most of my day-to-day work is behind a bank of computer screens, programming mainly in C and Fortran, as the latter-day engineer is really an applied mathematician. I don't get enough exercise!
Reverting briefly to the topic in hand: I would always tend to put some sort of fuse in an auxiliary charging circuit, mainly due to many year's experience of Sod's Law, but also to place an upper limit on the alternator load. New fuse 10p, new alternator =A3150!
However this raises the issue of "how do you charge the auxiliary battery if it's near flat and the fuse keeps blowing?" I think the best solution would to wire something like an old headlight bulb in parallel with the fuse, as this would allow enough current though for the auxiliary battery to trickle charge to the point where you could safely re-insert the fuse. Also, by glowing faintly, it would indicate that the fuse had blown.
Purists might choose to substitute a 10 ohm, 20 watt wire wound resistor. Not-so-purists, or the desperate, might insert a piece of wire (or a kit-kat wrapper) in place of the fuse!
Christopher
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Chris,
The old bulb will work if you put it in series with the fuse,
take the bulb out when it starts to get dimmer. This is what I do when
I am cycling batteries.
Regards, Clive.
 
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Clive
| The old bulb will work if you put it in series with the
| fuse, take the bulb out when it starts to get dimmer. This is
| what I do when I am cycling batteries.
Agreed, but you really want something you don't have to think about
unless it goes wrong.
I suppose the best solution would be a timer which forced a trickle
charge through the bulb (or resistor) for the first ten minutes or so,
just to take the edge off the battery's hunger. This would also give
the alternator time to get the ordinary car batteries up to speed after
a start, so that it wouldn't be subjected to such heavy initial load.
And I think those with the 1HD-FT motor fitted with an air pre-heater
screen would definitely want to prevent any extra load until this has
cut out, as judging by my dash voltmeter it must draw a horrendous
current.
CB
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Chris wrote...
However this raises the issue of "how do you charge the auxiliary
battery if it's near flat and the fuse keeps blowing?" I think the
best solution would to wire something like an old headlight bulb in
parallel with the fuse, as this would allow enough current though for
the auxiliary battery to trickle charge to the point where you could
safely re-insert the fuse. Also, by glowing faintly, it would
indicate that the fuse had blown.
SNIP
Well the best answer I can give is to fit a professionally made
alternator controller and then it is not an issue. It will cut out
the charge from the alternator and flash about 6 warning lights at me
on the control panel if anything overloads. I have had the 320ah
domestic battery bank just about flat and the alternator controller
has managed to charge it up with my little 55 amp alternator quite adequately.
Again, sorry to veer towards the marine market, but unlike the MoT
which does not test the design of the vehicle, we are inspected every
4 years for our own safety certificate, which includes the charging
system and the safety of high current cables, to the point that they
are all secured at a maximum interval and battery terminal connectors
have to be of a certain type. So they pass a stringent test without a
requirement for a fuse in the main charge cables.
JULIAN - I can't find it now - just when I want it - but I have seen
an advert several times for a firm doing alternative alternators of
all frames and voltages based, as far as I can remember, in St Neots.
I would hope that a Google search might drag them up for you.
I trust that you will now go and buy those chains before you really need them !
Cheers
Jon
Grand Union Canal
'92 HZJ80 ex UN surplus from Bosnia
 
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