- Hide quoted text — Show quoted text -

Neil Danylczuk (ndany…@health.gov.sk.ca) writes:
> cn…@FreeNet.Carleton.CA (Dent Harrison) wrote:

>>Vancouver being the banana belt of Canada (after Windsor) block heaters
>>are never required!  Battery blankets are an excellent investment and if
>>I had to choose one cold start assistance device, this would be it.  However,
>>the blankets are usually too strong for use at temperatures above -15degC
>>where you will get boil-off of the acid (as I found out the hard way one
>>winter of prolonged use.)  These blankets have no thermostatic control.
>>The ideal temperature of the battery should be 85degF.

> Thanks for your 999th informative post by the way.

> What is the scoop on batteries, with regard to temperatures?
> I remember seeing a graph at some point showing that batteries
> actually are better at cooler temperatures, although not too
> cold.

> Also, what about the old myth not to put a battery onto cold pavement?
> One winter I brought a battery inside the house and was told by
> various people:
> "Don’t bring it in!  It doesn’t need to be kept warm!"

> "I always bring my battery inside to warm it up!"

> "If you bring it in, make sure not to set it on the
> cellar floor!"

> "Batteries must always be kept on wooden blocks!"

> Any shreds of validity to these cautions?

> BTW, no one yelled at me: "Battery acid will eat your clothes!"
> I got some crusts from the battery on my shirt and naively
> assume water would take them off.  Instead it seemed to
> promote the corrosive action.

I don’t know what graph you were looking at, or for what kind of
battery, but for the SLI (Starting, Lighting, Ignition) lead acid
batteries used in cars, the lower the temperature, the worse the
performance all around.

The optimum temperature for lead acid batteries is around 85degF,
for reasons of compromise of discharge, gassing, etc.  This is be
target temperature you want to achieve when you are contemplating
maintaining battery temperature.

As the temperature drops, the ability of the battery to discharge,
and to accept a charge decreases.  The following table gives you
an idea of how fast the battery performance drops off:

     Temp      Capacity
     (degC)     (%)
     25        100
      0         85  
     -18        63  
     -30        45
(source:  Friedel, G., "Scania Battery Heater for Heavy Trucks"
SAE Technical Paper 890014, 1989)

As you can see, if you were to size the battery for a car operating
in Arizona assuming the temperature stayed above 20degC, you would
have to add another battery, or two to get that car to start up
here.  But if you take a car from up here in the winter, and wait
until the summer rolls around and we jump to +30degC, there is a
significant excess of starting power available.

There are two battery standards in the market place, depending on
where you are in the world.  The SAE standard basically rates
batteries on their ability to deliver a very high current at a
minimum voltage level.  The DIN standard concentrates on the
sustained discharge of the battery at lower current levels until
a minimum voltage level is reached.  They can be summarized
basically as "starting the car standard" or "leaving your lights
on standard" respectively.  The SAE standard states the Cold
Cranking Amps rating of the battery.  This means that the battery
is sized to deliver, for example, 650 CCA.  The performance is
referenced to -18degC (0degF).  With this battery in the car, at
-18degC, you will have no trouble starting the car (especially if
it is an si engine.)  But when the temperature drops to -30degC,
you have lost 30% of the rating of the battery!  All this has
assumed that the starting power of the engine remains constant with
temperature.  As everyone is aware, engine starting power increases
as temperature decreases.  

So you are faced with the situation:  As the temperature drops,
the starting system performance drops, while the engine is getting
harder and harder to start.  This is why it has always been
advantageous to use the thinnest oil available for the expected
outside temperature.  There is one other problem to compound the
situation.  In the cold weather, the ability of the battery to
accept a charge decreases.  Therefore, if you have a sustained cold
period below -25degC, each time you start the car, the battery is
significantly discharged.  It will not, however, accept a full
charge.  After a few days, early one morning you will be greeted
with a car that barely turns over and have to wait while the CAA
or AAA comes several days later (since everyone else is in the same
situation) to give you a boost.  In Ottawa, it is common in late
January or early February for us to have a week or more of early
morning temperatures consistently below -30degC.  You then hear on
the radio the waiting times for boosting from the towing companies
are two or three days.  And these are 99% gas cars, most using
block heaters.  Looking good eh?

To get around this, you can install a battery blanket and leave it
plugged in all night while the temperature outside drops below
-18degC.  In the morning you will have a warm battery with about
50% more capacity than normal (at that temp).  The car will start
and the battery will accept a full charge and be ready for the cold
start at the end of the day (which is never as arduous as in the
morning.)  

Or, you can do what you said and bring the battery inside each
evening.  This is the best solution for several reasons.  When you
bring it inside, you will warm the battery close to 25degC.  You
also have the option of charging the battery while it is inside and
at the optimum temperature.  When you cart it outside the next
morning and install it, you have a battery that has more than twice
the capacity of the cold battery would have.  In effect, you are
getting a boost with a plus:  After you start the car, the battery
will accept a charge very easily and be ready for the evening
start.  

Repeating this procedure every night will preserve the life of the
battery and guarantee that you never get stranded.  Doing this at
least once a week in the winter will also significantly help
matters.  I did this for two winters when the temperature dropped
below -20degC and had no trouble starting our stone-cold diesels.
The lowest temperature I did this was -37degC and the engine
started with only one activation of the glow plugs and 15 seconds
of cranking (I use my watch to time these things out of habit.)
The car was not plugged in and was outside in the forest of
Gatineau Park where I live.  It did have 0W30 in the oil pan to
ensure good lubrication, and was using normal No. 1 diesel fuel.

As for setting it on the floor, I prefer setting it on an
overturned milk crate to allow air to circulate fully around the
battery to warm it up as fast as possible.  If you spill acid on
concrete, it can harm the concrete, which is why it is preferable
to place it on wood.  If you get battery acid on your clothes, you
can use baking soda to neutralize the acid.  Or you can dunk them
completely in water, but you have to act fast.  

Batteries should be kept clean and dry.  There should be no
corrosion anywhere on the posts or terminals.  As always, respect
the power of the battery and use all safety precautions when
handling and charging.

I hope this sheds a little light on the situation.

Cheers,

–
Dent Harrison, P.Eng.
Chelsea, Quebec, Canada
cn…@freenet.carleton.ca

: Neil Danylczuk (ndany…@health.gov.sk.ca) writes:
: > cn…@FreeNet.Carleton.CA (Dent Harrison) wrote:
: >
: >>Vancouver being the banana belt of Canada (after Windsor) block heaters
: >>are never required!  Battery blankets are an excellent investment and if
: >>I had to choose one cold start assistance device, this would be it.  However,
: >>the blankets are usually too strong for use at temperatures above -15degC
: >>where you will get boil-off of the acid (as I found out the hard way one
: >>winter of prolonged use.)  These blankets have no thermostatic control.
: >>The ideal temperature of the battery should be 85degF.
: >
: > Thanks for your 999th informative post by the way.
: >
: > What is the scoop on batteries, with regard to temperatures?
: > I remember seeing a graph at some point showing that batteries
: > actually are better at cooler temperatures, although not too
: > cold.
: >
: >
: > Also, what about the old myth not to put a battery onto cold pavement?
: > One winter I brought a battery inside the house and was told by
: > various people:
: > "Don’t bring it in!  It doesn’t need to be kept warm!"
: >
: > "I always bring my battery inside to warm it up!"
: >
: > "If you bring it in, make sure not to set it on the
: > cellar floor!"
: >
: > "Batteries must always be kept on wooden blocks!"
: >
: > Any shreds of validity to these cautions?
: >
: > BTW, no one yelled at me: "Battery acid will eat your clothes!"
: > I got some crusts from the battery on my shirt and naively
: > assume water would take them off.  Instead it seemed to
: > promote the corrosive action.
: >
: >
: >

: I don’t know what graph you were looking at, or for what kind of
: battery, but for the SLI (Starting, Lighting, Ignition) lead acid
: batteries used in cars, the lower the temperature, the worse the
: performance all around.

: The optimum temperature for lead acid batteries is around 85degF,
: for reasons of compromise of discharge, gassing, etc.  This is be
: target temperature you want to achieve when you are contemplating
: maintaining battery temperature.

: As the temperature drops, the ability of the battery to discharge,
: and to accept a charge decreases.  The following table gives you
: an idea of how fast the battery performance drops off:

:      Temp      Capacity
:      (degC)     (%)
:      25        100
:       0         85  
:      -18        63  
:      -30        45
: (source:  Friedel, G., "Scania Battery Heater for Heavy Trucks"
: SAE Technical Paper 890014, 1989)

: As you can see, if you were to size the battery for a car operating
: in Arizona assuming the temperature stayed above 20degC, you would
: have to add another battery, or two to get that car to start up
: here.  But if you take a car from up here in the winter, and wait
: until the summer rolls around and we jump to +30degC, there is a
: significant excess of starting power available.

: There are two battery standards in the market place, depending on
: where you are in the world.  The SAE standard basically rates
: batteries on their ability to deliver a very high current at a
: minimum voltage level.  The DIN standard concentrates on the
: sustained discharge of the battery at lower current levels until
: a minimum voltage level is reached.  They can be summarized
: basically as "starting the car standard" or "leaving your lights
: on standard" respectively.  The SAE standard states the Cold
: Cranking Amps rating of the battery.  This means that the battery
: is sized to deliver, for example, 650 CCA.  The performance is
: referenced to -18degC (0degF).  With this battery in the car, at
: -18degC, you will have no trouble starting the car (especially if
: it is an si engine.)  But when the temperature drops to -30degC,
: you have lost 30% of the rating of the battery!  All this has
: assumed that the starting power of the engine remains constant with
: temperature.  As everyone is aware, engine starting power increases
: as temperature decreases.  

: So you are faced with the situation:  As the temperature drops,
: the starting system performance drops, while the engine is getting
: harder and harder to start.  This is why it has always been
: advantageous to use the thinnest oil available for the expected
: outside temperature.  There is one other problem to compound the
: situation.  In the cold weather, the ability of the battery to
: accept a charge decreases.  Therefore, if you have a sustained cold
: period below -25degC, each time you start the car, the battery is
: significantly discharged.  It will not, however, accept a full
: charge.  After a few days, early one morning you will be greeted
: with a car that barely turns over and have to wait while the CAA
: or AAA comes several days later (since everyone else is in the same
: situation) to give you a boost.  In Ottawa, it is common in late
: January or early February for us to have a week or more of early
: morning temperatures consistently below -30degC.  You then hear on
: the radio the waiting times for boosting from the towing companies
: are two or three days.  And these are 99% gas cars, most using
: block heaters.  Looking good eh?

: To get around this, you can install a battery blanket and leave it
: plugged in all night while the temperature outside drops below
: -18degC.  In the morning you will have a warm battery with about
: 50% more capacity than normal (at that temp).  The car will start
: and the battery will accept a full charge and be ready for the cold
: start at the end of the day (which is never as arduous as in the
: morning.)  

: Or, you can do what you said and bring the battery inside each
: evening.  This is the best solution for several reasons.  When you
: bring it inside, you will warm the battery close to 25degC.  You
: also have the option of charging the battery while it is inside and
: at the optimum temperature.  When you cart it outside the next
: morning and install it, you have a battery that has more than twice
: the capacity of the cold battery would have.  In effect, you are
: getting a boost with a plus:  After you start the car, the battery
: will accept a charge very easily and be ready for the evening
: start.  

: Repeating this procedure every night will preserve the life of the
: battery and guarantee that you never get stranded.  Doing this at
: least once a week in the winter will also significantly help
: matters.  I did this for two winters when the temperature dropped
: below -20degC and had no trouble starting our stone-cold diesels.
: The lowest temperature I did this was -37degC and the engine
: started with only one activation of the glow plugs and 15 seconds
: of cranking (I use my watch to time these things out of habit.)
: The car was not plugged in and was outside in the forest of
: Gatineau Park where I live.  It did have 0W30 in the oil pan to
: ensure good lubrication, and was using normal No. 1 diesel fuel.

: As for setting it on the floor, I prefer setting it on an
: overturned milk crate to allow air to circulate fully around the
: battery to warm it up as fast as possible.  If you spill acid on
: concrete, it can harm the concrete, which is why it is preferable
: to place it on wood.  If you get battery acid on your clothes, you
: can use baking soda to neutralize the acid.  Or you can dunk them
: completely in water, but you have to act fast.  

: Batteries should be kept clean and dry.  There should be no
: corrosion anywhere on the posts or terminals.  As always, respect
: the power of the battery and use all safety precautions when
: handling and charging.

: I hope this sheds a little light on the situation.

: Cheers,

: —
: Dent Harrison, P.Eng.
: Chelsea, Quebec, Canada
: cn…@freenet.carleton.ca

: Excellent treatise on battery-temperature relationship Dent.
: Congratulations. Let the voice of experience tell you that placing
: batteries on concrete floors does indeed discharge them. I was merrily
: placing my excess stash of batteries on my basement’s concrete floor,
: smuggly content in the thought that I would have a supply of batteries at
: my service when I wanted, & lo, every time I wanted to use one, it was as
: dead as a door nail. I lost 5, yes 5 perfectly good batteries to that
: concrete floor before a little bird told me that I had better discontinue
: this practice. Then yrs. later I read a paragraph in an article that said
: that batteries discharge when placed on concrete floors. What a twit I
: was I said to myself, for having lost those perfectly good batteries. So
: don’t put your batteries on concrete.
: Ashoke Nijhowne. 5-time loser of batteries.

Thanks for your 999th informative post by the way.

What is the scoop on batteries, with regard to temperatures?
I remember seeing a graph at some point showing that batteries
actually are better at cooler temperatures, although not too
cold.

Also, what about the old myth not to put a battery onto cold pavement?
One winter I brought a battery inside the house and was told by
various people:
"Don’t bring it in!  It doesn’t need to be kept warm!"

"I always bring my battery inside to warm it up!"

"If you bring it in, make sure not to set it on the
cellar floor!"

"Batteries must always be kept on wooden blocks!"

Any shreds of validity to these cautions?

BTW, no one yelled at me: "Battery acid will eat your clothes!"
I got some crusts from the battery on my shirt and naively
assume water would take them off.  Instead it seemed to
promote the corrosive action.

>>Has anyone installed a block heater in 1989 Jetta? How difficult is it?  The
>>Bentley manual doesn’t cover such a mundane procedure.

>   The other thing is that eventually the rubber seal for the block
> heater will disintergrate eventually (took about 3 years) and I had to
> repeat the procedure (drain, remove heater, find a right size seal,
> re-install, refill coolant, test for leaks, etc…).

As a long time diesel owner, and therefore someone who takes a special
interest in block heaters, I think I can offer some opinions.  We have never
had a block heater seal fail.  The heater on my car is original, and
after 262,000km and 6 years, it still goes strong.  We do experience
some failures of the heaters electrically, usually at the heater/cord
interface, but dialectric grease solved that problem several years ago
and has not been a problem since.  The replacement heaters available
from VW are the best and should only be used.

>   I would suggest instead an in-line coolant heater/pump. It goes on
> an upper coolant hose, should be much easier to install, and the
> benefit is that it circulates warm water most of the engine instead of
> just by convection and conduction with the block heater.

I would caution against this.  These heaters are typically 1500W and are
way to strong for these small engines.  The most heat you ever need is
a 400W block heater and 1-2hours and the engine will start reliably.  These
"circulation" heaters do not have any sort of pump, they actually boil the
coolant, and this bubble then travels up and new coolant falls into the
chamber and the process begins again (which is why they caution to place
the heater with one end up.)  The block heater boils the coolant locally
however, being a smaller element in a larger heatsink, the convection currents
set up mitigate the circumstances some what.  Neither heater though has
any thermostatic control.  The thing is on all the time.
        Coolant condition greatly influences the efficiency of the block
heater.  And the block heater will affect the condition of the coolant.
The localized, prolonged boiling affects the additives and results in a more
acidic coolant.  There are several SAE papers on the subject which are
very interesting.  That is why 400W is the standard size, and at the most
3 hours at -30degC are all that is required and that a 1500W in-line
heater is not recommended by the heater makers.  It is also a very
good reason to use only VW coolant and distilled water.

   With the in-line heater, if you don’t want the heater, just replace

> the hose. With the frost plug out, there’s no turing back. Either put
> in the block heater, or one a clamp-in replacement (never as good as
> the factory frost plug.

>   In Vancouver, it rarely gets very cold, so on the ’90 golf, I just
> use a battery blanket/warmer and a magnetic oil pan heater when I
> venture into cold climes.

Vancouver being the banana belt of Canada (after Windsor) block heaters
are never required!  Battery blankets are an excellent investment and if
I had to choose one cold start assistance device, this would be it.  However,
the blankets are usually too strong for use at temperatures above -15degC
where you will get boil-off of the acid (as I found out the hard way one
winter of prolonged use.)  These blankets have no thermostatic control.
The ideal temperature of the battery should be 85degF.
        Magnetic oil pan heaters should be used with care.  They are really
meant for large oil sumps with lots of heat capacity.  You can, if you leave
the heater on too long, burn the oil.  (And if there is fuel in the
oil, blow the oil pan right off the engine as happened to a mechanic I know!)
        It does raise one point.  None of the coolant heaters do anything
for the oil in the sump.  When you start the engine, the oil is still at
ambient temperature and therefore, the use of a block heater is no substitute
for proper oil viscosity (in my situation, 0W30).

The ultimate engine heater for those with money to spend is the Webasto
Thermo-Top T or S.  These are fuel fired heaters which are mounted in the
engine compartment.  They draw fuel from the fuel tank, which powers a
small boiler.  The boiler and a 12V coolant circulation pump move the
coolant around and provide even heating.  You can even have it start up
the interior fan to defrost the windows and heat the interior.  They are
activated by an electronic timer and run for 1 hour (which is all you need
on a very very cold day.)  They are available from Webasto for about
Can$2,000 for diesel or gas cars.  They are standard equipment on the larger
cars from Benz, BMW.  They are an option from Land Rover.

–
Dent Harrison, P.Eng.
Chelsea, Quebec, Canada
cn…@freenet.carleton.ca

Save yourself the major pain in labour and pay up for an inline (hose)type
heater.  $60 vs $25, installation ease is worth the $35.  And the inline
heater is far superior, more warmth and proper circulation due to the
pump/valves in the inline.  Block heater warms the block, just barely after
2+hours, inline warms the whole system, in under an hour.  Tim

Hi,
  I’ve installed a block heater in an ’85 Golf (gas, automatic, 8v).
This was a block heater that I intsalled into one of the frost plugs
on the side of the engine block facing the fire wall.
  To answer your question about difficulty: it was not a pleasant job.
If I recall:
-drain coolant
-raise front of car on jack stands (not just a tire changing jack!!)
-knock out a frost plug (tight spaces, not much room)
-install heater with washer, tighten (but don’t overtighten)
-replace coolant
-fire up the engine and watch for leaks

If all goes well, a one hour job. The problem is getting a tool into
the tight area to dislodge a frost plug. I ended up using a 3 foot
long piece of pipe place against one side of the frost plug and using
a hammer on the other end. There may be a special tool for taking out
frost plugs. Tightening the bolt to lock the heater in place was a
pain in the tight work area.
  The other thing is that eventually the rubber seal for the block
heater will disintergrate eventually (took about 3 years) and I had to
repeat the procedure (drain, remove heater, find a right size seal,
re-install, refill coolant, test for leaks, etc…).
  I would suggest instead an in-line coolant heater/pump. It goes on
an upper coolant hose, should be much easier to install, and the
benefit is that it circulates warm water most of the engine instead of
just by convection and conduction with the block heater.
  With the in-line heater, if you don’t want the heater, just replace
the hose. With the frost plug out, there’s no turing back. Either put
in the block heater, or one a clamp-in replacement (never as good as
the factory frost plug.
   In Vancouver, it rarely gets very cold, so on the ’90 golf, I just
use a battery blanket/warmer and a magnetic oil pan heater when I
venture into cold climes.
  That’s my experience, hope that helps.

-Tony.

Burnaby, B.C. Canada     TonyW…@Mindlink.bc.ca

I put a block heater in my ’89 Jetta a few years ago and I would
recommend that unless $$$ is a real issue you might want to consider a
dealer for the install – not because it is complex, but because the
freezeout plug where the block heater goes is: 1) very hard to get at,
it’s best gotten from underneath with the car on a lift, although it’s
possible to get it by reaching in behind (just real hard to get any
leverage to pry it out – which brings me to point 2)  The freeze plug
can be _very_ tight – especially on an ’89 you where you might find
considerable corrosion which will make it difficult to remove.

One other suggestion is to get an Autobahn brand block heater from VW
– the Kat’s heater that I tried first just wasn’t right and it leaked,
but the Autobahn fit much better and has been in there since ’90.

As far as the proceedure:  Drain the radiator and save the antifreeze
if it’s less than a year old, then remove the plug that’s on the
passenger side (end) of the engine (closest to the timing belt) – I
usually try to knock a hole in them and pry them out with a
screwdriver, but it’s real hard to get in there to pry, etc – be
careful not to score the hole and if you do take some fine sandpaper
and touch it up or it will leak.  I can’t remember the direction for
the element, but all that should be on the directions in the box,
which will also tell you a tightening torque.  Run the wire so it
can’t get pinched, etc and refill with antifreeze and test  –  I’ve
always used VW antifreeze (non-phosate) but I’ve heard others argue
that it doesn’t matter.  

I hope this doesn’t discourage you from either installing or getting
one installed,  I’m a real proponent of block heaters, and most I’ve
put in have been easy – but this one was a real nightmare.  Of course
I waited until it was the middle of winter to do it and after trying
to work with no gloves and rolling around in the snow for hours any
thought of it being a "breeze" were gone    – Good luck