Solar lights
 

SWMBO want a string of solar lights in the garden. I have noticed some have
ena,elled copper wire rather than the more usual plastic covered wire. Any
thoughts?

Solar lights
 

In article ,
JohnP wrote:
SWMBO want a string of solar lights in the garden. I have noticed some
have ena,elled copper wire rather than the more usual plastic covered
wire. Any thoughts?

I've had enamelled wire lights up at Christmas. The wire hides quite well
in tree branches. It all depemds on what you want.

--
from KT24 in Surrey, England
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle

Solar lights
 

JohnP used his keyboard to write :
SWMBO want a string of solar lights in the garden.

Don't expect them to operate for long, after dark in the summer and
probably not at all in a UK winter.

Solar lights
 

On Friday, February 19, 2021 at 10:02:58 AM UTC, undefined wrote:
JohnP used his keyboard to write :
SWMBO want a string of solar lights in the garden.
Don't expect them to operate for long, after dark in the summer and
probably not at all in a UK winter.


I.M.E you'd be lucky to get 12 months out of them

Solar lights
 

"fred" wrote in message
...
On Friday, February 19, 2021 at 10:02:58 AM UTC, undefined wrote:
JohnP used his keyboard to write :
SWMBO want a string of solar lights in the garden.
Don't expect them to operate for long, after dark in the summer and
probably not at all in a UK winter.

I'm surprised at how small the capacity of the rechargeable batteries that
are used in most solar lights. Part of the reason that they don't last very
long even in summer is that a lot of solar power goes to waste because the
batteries cannot accept any more charge.

Having said that, our lights do last a lot less time in winter, so the
amount of daylight is also an issue. I'd have thought that modern solar
cells would be able to produce usable power even on an overcast winter's
day.

Solar lights
 

On 19/02/2021 11:12, NY wrote:

I'm surprised at how small the capacity of the rechargeable batteries
that are used in most solar lights. Part of the reason that they don't
last very long even in summer is that a lot of solar power goes to waste
because the batteries cannot accept any more charge.


Overcharging can damage the cells.

--
Adrian C

Solar lights
 

NY wrote:
I'm surprised at how small the capacity of the rechargeable batteries that
are used in most solar lights. Part of the reason that they don't last very
long even in summer is that a lot of solar power goes to waste because the
batteries cannot accept any more charge.

Solar lights require a long cycle life (one charge/discharge cycle a day).
They're also repeatedly cooked and frozen. This is about the worst
situation a battery can be in. It is better to put in a lower capacity cell
that's more robustly constructed than a cell with maximum capacity that's
rarely going to be used, but is less able to withstand the harsh
environment. Carthorse v thoroughbred.

Having said that, our lights do last a lot less time in winter, so the
amount of daylight is also an issue. I'd have thought that modern solar
cells would be able to produce usable power even on an overcast winter's
day.

The cells probably work less well in the cold.

Theo

Solar lights
 

On 20/02/2021 14:28, Theo wrote:
NY wrote:
I'm surprised at how small the capacity of the rechargeable batteries that
are used in most solar lights. Part of the reason that they don't last very
long even in summer is that a lot of solar power goes to waste because the
batteries cannot accept any more charge.

Solar lights require a long cycle life (one charge/discharge cycle a day).
They're also repeatedly cooked and frozen. This is about the worst
situation a battery can be in. It is better to put in a lower capacity cell
that's more robustly constructed than a cell with maximum capacity that's
rarely going to be used, but is less able to withstand the harsh
environment. Carthorse v thoroughbred.

That may be true for some battery chemistries but not most. For example,
lead acid last longer if they don't undergo a deep discharge.

Solar lights will typically flatten its battery during the winter. I
would suggest the choice of battery chemistry is critical.

Having said that, our lights do last a lot less time in winter, so the
amount of daylight is also an issue. I'd have thought that modern solar
cells would be able to produce usable power even on an overcast winter's
day.

The cells probably work less well in the cold.

I would have thought the opposite, diodes have a sharper IV curve at
lower temperatures and reverse current leakage would also be lower.

Solar lights
 

On 18/02/2021 21:27, JohnP wrote:
SWMBO want a string of solar lights in the garden. I have noticed some have
ena,elled copper wire rather than the more usual plastic covered wire. Any
thoughts?


Should deter slugs :-)

Solar lights
 

Fredxx wrote:
On 20/02/2021 14:28, Theo wrote:
That may be true for some battery chemistries but not most. For example,
lead acid last longer if they don't undergo a deep discharge.

Solar lights will typically flatten its battery during the winter. I
would suggest the choice of battery chemistry is critical.

When people say 'solar lights' they usually mean the plastic sticks with a
small solar panel and a few NiMH cells. I've not seen those use lead acid.

Having said that, our lights do last a lot less time in winter, so the
amount of daylight is also an issue. I'd have thought that modern solar
cells would be able to produce usable power even on an overcast winter's
day.

The cells probably work less well in the cold.

I would have thought the opposite, diodes have a sharper IV curve at
lower temperatures and reverse current leakage would also be lower.

I meant the battery cells. The panel itself is happy in the cold (ask every
satellite).

Theo

Solar lights
 

On 19/02/2021 11:12, NY wrote:
"fred" wrote in message
...
On Friday, February 19, 2021 at 10:02:58 AM UTC, undefined wrote:
JohnP used his keyboard to write :
SWMBO want a string of solar lights in the garden.
Don't expect them to operate for long, after dark in the summer and
probably not at all in a UK winter.

I'm surprised at how small the capacity of the rechargeable batteries
that are used in most solar lights. Part of the reason that they don't
last very long even in summer is that a lot of solar power goes to waste
because the batteries cannot accept any more charge.

They don't do too badly in the summer, but they are designed for a much
lower latitude than the UK and come on in our twilight and have pretty
much given up by midnight when it is properly dark.

Having said that, our lights do last a lot less time in winter, so the
amount of daylight is also an issue. I'd have thought that modern solar
cells would be able to produce usable power even on an overcast winter's
day.

You would be disappointed then. The solar cells on them are typically
the cheapest polycrystalline going and can on a good sunny day manage
about 30mA at 3v output. Total charge is likely to be at most 3Ah/day in
mid summer continuous sunshine and next to nothing in mid winter.

It is an order of magnitude (or two) lower power under cloud. The
combination of cold, damp and being flat for the four winter months
destroys batteries even in professional roadside kit supposedly designed
for the duty.

The radar activated "Please go round the dangerous bend" signs here are
invariably dead in the water on cold frosty winters mornings...

--
Regards,
Martin Brown

Solar lights
 

I would really like some that had a timer - I could turn them off when no
longer appreciated to save flattening the battery every night.

Solar lights
 

JohnP wrote in
:



I would really like some that had a timer - I could turn them off when
no longer appreciated to save flattening the battery every night.


You'll need to roll your own then, decent panel (choose your angle), charge
controller (includes timer), SLA battery, low voltage cabling, marine box.
I've recently put in some non-solar using cheap GU10 spike lights but with
low voltage GU10 lamps instead of mains, very effective but the cabling is
an obvious overhead.