Carl Gibbs wrote:


I wanted to measure the drain on the battery today, but I've just
discovered my mulitmeter is with the SD1, but I guess it'd be a few
hundred milliamps, so I reckon a 15W panel should be enough to
counteract this. Any thoughts? Sound logic or would I just be wasting
my money?

Has enyone else had experience of using these as trickle chargers?

trouble is that the rated output is almost always for full solar
constant; i.e. facing the sun at the equator. If you incline it away
from normal, live somewhere of significant latitude (and thus have a
thicker layer of atmosphere), with notable humidity (and hence
scattering of sunlight) and most significantly cloud cover, then the
real output will be anything from maybe 20% (if you are lucky) to well
under 1% of the rated output.

Putting it behind glass (e.g. inside the car) also removes the UV, which
is a good thing from a skin health point of view, but is also the region
of the spectrum containing the high energy photons from which a god
fraction of the energy you net comes from.

Furthermore, as Steve F mentioned, the silicon panel itself, in the
absence of light, will actually drain the battery slightly (the better
ones have the diodes to prevent this); if the weather is against you,
then it is quite definitely possible for the nighttime drain to exceed
the daytime charge, and leave you worse of than you are without it!

If I were you, I'd fit a battery isolator switch somewhere inconspicuous.

"Albert T Cone" wrote in message
...
Carl Gibbs wrote:


I wanted to measure the drain on the battery today, but I've just
discovered my mulitmeter is with the SD1, but I guess it'd be a few
hundred milliamps, so I reckon a 15W panel should be enough to counteract
this. Any thoughts? Sound logic or would I just be wasting my money?

Has enyone else had experience of using these as trickle chargers?

trouble is that the rated output is almost always for full solar constant;
i.e. facing the sun at the equator. If you incline it away from normal,
live somewhere of significant latitude (and thus have a thicker layer of
atmosphere), with notable humidity (and hence scattering of sunlight) and
most significantly cloud cover, then the real output will be anything from
maybe 20% (if you are lucky) to well under 1% of the rated output.

Putting it behind glass (e.g. inside the car) also removes the UV, which
is a good thing from a skin health point of view, but is also the region
of the spectrum containing the high energy photons from which a god
fraction of the energy you net comes from.

It'd be mounted outside so no problem there

Furthermore, as Steve F mentioned, the silicon panel itself, in the
absence of light, will actually drain the battery slightly (the better
ones have the diodes to prevent this); if the weather is against you, then
it is quite definitely possible for the nighttime drain to exceed the
daytime charge, and leave you worse of than you are without it!

If I were you, I'd fit a battery isolator switch somewhere inconspicuous.

Entrance to the car is via electronic solenoid though. Plus I wouldn't be
able to switch the alarm on which means invalidated insurance.

I need to think about this a bit more I think. And check what the actual
current drain is.

Carl Gibbs wrote:

"Albert T Cone" wrote in message
...
Putting it behind glass (e.g. inside the car) also removes the UV,
which is a good thing from a skin health point of view, but is also
the region of the spectrum containing the high energy photons from
which a god fraction of the energy you net comes from.

It'd be mounted outside so no problem there
Fair enough, but then you have to worry about the thing being properly
weather-sealed. Also (and this probably isn't really a concern for you)
you get UV-degradation of the silicon in the panel, giving a gradual
degradation of performance over several years; this is one of the main
reasons that photelectric cells basically never pay for themselves.

Furthermore, as Steve F mentioned, the silicon panel itself, in the
absence of light, will actually drain the battery slightly (the better
ones have the diodes to prevent this); if the weather is against you,
then it is quite definitely possible for the nighttime drain to exceed
the daytime charge, and leave you worse of than you are without it!

If I were you, I'd fit a battery isolator switch somewhere inconspicuous.

Entrance to the car is via electronic solenoid though. Plus I wouldn't
be able to switch the alarm on which means invalidated insurance.
Ah, forgot about the funky door button thing. How do you get in with a
flattery? An external 12V jack? You could always fit a builders van
style hasp and padlock to the door...

I need to think about this a bit more I think. And check what the
actual current drain is.
Aye, good plan. I might also look at getting a deep cycle battery,
possibly someting like the optima things that Burgerman used to flog.
It'll still discharge, of course, but it won't lose capacity as quickly
as a result, and the v.low internal resistance means that it'll still
start the car even when damn near empty. I don't think they're cheap, mind.

"Albert T Cone" wrote in message
...
Carl Gibbs wrote:

"Albert T Cone" wrote in message
...
Putting it behind glass (e.g. inside the car) also removes the UV, which
is a good thing from a skin health point of view, but is also the region
of the spectrum containing the high energy photons from which a god
fraction of the energy you net comes from.

It'd be mounted outside so no problem there
Fair enough, but then you have to worry about the thing being properly
weather-sealed. Also (and this probably isn't really a concern for you)
you get UV-degradation of the silicon in the panel, giving a gradual
degradation of performance over several years; this is one of the main
reasons that photelectric cells basically never pay for themselves.

Furthermore, as Steve F mentioned, the silicon panel itself, in the
absence of light, will actually drain the battery slightly (the better
ones have the diodes to prevent this); if the weather is against you,
then it is quite definitely possible for the nighttime drain to exceed
the daytime charge, and leave you worse of than you are without it!

If I were you, I'd fit a battery isolator switch somewhere
inconspicuous.

Entrance to the car is via electronic solenoid though. Plus I wouldn't
be able to switch the alarm on which means invalidated insurance.
Ah, forgot about the funky door button thing. How do you get in with a
flattery? An external 12V jack? You could always fit a builders van style
hasp and padlock to the door...

There is a way, but if I told you I'd then have to kill you

I need to think about this a bit more I think. And check what the actual
current drain is.
Aye, good plan. I might also look at getting a deep cycle battery,
possibly someting like the optima things that Burgerman used to flog.
It'll still discharge, of course, but it won't lose capacity as quickly as
a result, and the v.low internal resistance means that it'll still start
the car even when damn near empty. I don't think they're cheap, mind.

I will look into it. Thanks for the heads up!

In article , Albert T Cone
wrote:

Entrance to the car is via electronic solenoid though. Plus I
wouldn't be able to switch the alarm on which means invalidated
insurance.
Ah, forgot about the funky door button thing. How do you get in with a
flattery?

Is there room for a second battery somewhere you could have on an isolator?
I have also seen in the past batteries with a seperate section used when
the main part goes flat... no idea of name or make though.

HTH
Mitch

--
Terminal_Crazy

Mitch - 1995 Z28 LT1 M6
Lancashire England http://www.sand-hill.freeserve.co.uk/terminal_crazy/

"Albert T Cone" wrote in message
...
Carl Gibbs wrote:

"Albert T Cone" wrote in message
...
Putting it behind glass (e.g. inside the car) also removes the UV, which is
a good thing from a skin health point of view, but is also the region of
the spectrum containing the high energy photons from which a god fraction
of the energy you net comes from.

It'd be mounted outside so no problem there
Fair enough, but then you have to worry about the thing being properly
weather-sealed. Also (and this probably isn't really a concern for you) you
get UV-degradation of the silicon in the panel, giving a gradual degradation
of performance over several years; this is one of the main reasons that
photelectric cells basically never pay for themselves.

Furthermore, as Steve F mentioned, the silicon panel itself, in the absence
of light, will actually drain the battery slightly (the better ones have
the diodes to prevent this); if the weather is against you, then it is
quite definitely possible for the nighttime drain to exceed the daytime
charge, and leave you worse of than you are without it!

If I were you, I'd fit a battery isolator switch somewhere inconspicuous.

Entrance to the car is via electronic solenoid though. Plus I wouldn't be
able to switch the alarm on which means invalidated insurance.
Ah, forgot about the funky door button thing. How do you get in with a
flattery? An external 12V jack? You could always fit a builders van style
hasp and padlock to the door...

I need to think about this a bit more I think. And check what the actual
current drain is.
Aye, good plan. I might also look at getting a deep cycle battery, possibly
someting like the optima things that Burgerman used to flog. It'll still
discharge, of course, but it won't lose capacity as quickly as a result, and
the v.low internal resistance means that it'll still start the car even when
damn near empty. I don't think they're cheap, mind.

2 Odysseys will fit where a normal battery would go. Put in a 4x4 dual battery
isolator and you're golden. One is out of the circuit with the car off and is
only used for cranking.

Fraser

In article ,
Albert T Cone wrote:
I need to think about this a bit more I think. And check what the
actual current drain is.
Aye, good plan. I might also look at getting a deep cycle battery,
possibly someting like the optima things that Burgerman used to flog.

Please don't. They are over hyped and over priced. You can get a battery
with a longer warranty for a lot less money from Halfords. And no lead
acid of any type likes being run totally flat. Although some types can
cope slightly better than others.

--
*How do you tell when you run out of invisible ink? *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
Albert T Cone wrote:
I need to think about this a bit more I think. And check what the
actual current drain is.
Aye, good plan. I might also look at getting a deep cycle battery,
possibly someting like the optima things that Burgerman used to flog.

Please don't. They are over hyped and over priced. You can get a battery
with a longer warranty for a lot less money from Halfords. And no lead
acid of any type likes being run totally flat. Although some types can
cope slightly better than others.

Quite a lot better. I'm not at all sure that it's enough of a margin to
justify the cost, but if it happens a lot it might be worth it from a
ease-of-life standpoint.

"Albert T Cone" wrote in message
...
Dave Plowman (News) wrote:
In article ,
Albert T Cone wrote:
I need to think about this a bit more I think. And check what the
actual current drain is.
Aye, good plan. I might also look at getting a deep cycle battery,
possibly someting like the optima things that Burgerman used to flog.

Please don't. They are over hyped and over priced. You can get a battery
with a longer warranty for a lot less money from Halfords. And no lead
acid of any type likes being run totally flat. Although some types can
cope slightly better than others.

Quite a lot better. I'm not at all sure that it's enough of a margin to
justify the cost, but if it happens a lot it might be worth it from a
ease-of-life standpoint.

I'll look into it.

Car was dead again today, and that's after being hooked up to a proper
trickle charger (was supposedly fully charged Sunday evening). Took a
longer route to work (still only about 5 miles or so though) and this
afternoon it wouldn't start again. Reckon it might be new battery time
anyway.

Still can't find my multimater though grrrrr

In article , Carl Gibbs
wrote:
Took a longer route to work (still only about 5 miles or so though) and
this afternoon it wouldn't start again.

Get a clamp meter on the alternator. Mine would quite happily put out 20
to 50+ Amps with everything on but the load was virtually the same so sod
all was going into the battery.
Mitch

--
Terminal_Crazy

Mitch - 1995 Z28 LT1 M6
Lancashire England http://www.sand-hill.freeserve.co.uk/terminal_crazy/