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Discussion Starter #1
Hi all..

My 8th gen 1.8 civic doesnt get used that often and as its parked outside, i wondered if the new crop of solar chargers would be any good for keeping the battery voltage up? The cig lighters are dead with the key out but the AA do one that uses the OEDB connctor.

Im wondering if i could buy one of those or buy a cheaper charger and wire an OEDB plug myself? Does anyone know where i could buy an OEDB plug and what the pin assignments are?

Also are such chargers just a useless gimmick due to their low output or do they work?? thanks

AA Shop | Solar Panel Car & Caravan Battery Charger
 

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That would take you weeks to charge your battery from flat. Its rated at 2.4A, most 4hour chargers or starter packs are at least 60A rated... It'd be ok to trickle top up maybe, but I wouldn't hold any expectations towards it. Even if you lived in the sunniest place in the world. Id go for useless gimmick.

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That would take you weeks to charge your battery from flat. Its rated at 2.4A, most 4hour chargers or starter packs are at least 60A rated... It'd be ok to trickle top up maybe, but I wouldn't hold any expectations towards it. Even if you lived in the sunniest place in the world. Id go for useless gimmick.

Late to the show as usual!
That solar charger is rated for 2.4W, not 2.4A. It's also not designed to charge your battery from dead, just keep it topped up when your car sits.

Your car will draw around 30mA when off, so the charger needs to average this to keep it topped up.

Quick calculation shows you would need that charger to charge at its maximum rated output of 0.2A for around 3 hours and 36 minutes per day.

No idea how efficient that solar panel is, and I'm sure the included cable would see a bit of a voltage drop over the 2.8m length, however I do believe it would go some way to keeping the battery charged, at least enough to start the car after sitting for a while during the summer. Probably wouldn't do a whole lot in the winter.

You could also use the option connector for a connection to the battery, rather than the OBD II connector.

http://www.civinfo.com/forum/how/64072-how-use-tap-into-fuse-box-option-connector.html
 

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I just went by fuse rating, either way, just compounds my point. Its no replacement for an alternator or charge pack.

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i'm gonna say there a waste of time

a while ago i had a toyota granvia that wasn't charging properly the battery was good but the problem was the alternator not putting out enough current so i thought i would try a solar panel to try n keep the battery topped up
the solar panel i got was one was about 3 foot across by a foot or so wide i forget the exact spec but it was far better than the average dash mounted solar panels

on an average day it would produce a constant 300 - 500 miliamps the maximum stated output was 2 amps but unless you lived in the sahara desert it wasn't happening
the ambient current draw of the granvia was around 300 miliamps which wasn't a problem with a healthy battery and alternator but with a dodgy alternator it was a bit of an issue
the solar panel made no difference at all the parasitic drain was enough to cancel out the benefits of the solar panel

you'd have to invest in a pretty substantial panel to make enough difference to put some charge back into the battery
 

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Solar panel panoramic roofs for the win! Transparent pv panels are ridiculously expensive at the moment though...

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I just went by fuse rating, either way, just compounds my point. Its no replacement for an alternator or charge pack.

Late to the show as usual!
There is no fuse rating on that page.

Of course it is no replacement for an alternator or charge pack, and it never claims to be, nor does the OP seem to be looking for that.

i'm gonna say there a waste of time

a while ago i had a toyota granvia that wasn't charging properly the battery was good but the problem was the alternator not putting out enough current so i thought i would try a solar panel to try n keep the battery topped up
the solar panel i got was one was about 3 foot across by a foot or so wide i forget the exact spec but it was far better than the average dash mounted solar panels

on an average day it would produce a constant 300 - 500 miliamps the maximum stated output was 2 amps but unless you lived in the sahara desert it wasn't happening
the ambient current draw of the granvia was around 300 miliamps which wasn't a problem with a healthy battery and alternator but with a dodgy alternator it was a bit of an issue
the solar panel made no difference at all the parasitic drain was enough to cancel out the benefits of the solar panel

you'd have to invest in a pretty substantial panel to make enough difference to put some charge back into the battery
Interesting readings, that panel certainly seemed to perform poorly, however that drain is also quite large.

Unless someone has actually purchased this exact solar panel and measured the output I think it unfair to generalise. It even manages to get a 4.4/5 star rating on Amazon from 95 reviews.
AA Car Essentials Solar-Powered Car Battery Charger: Amazon.co.uk: Car & [email protected]@[email protected]@http://ecx.images-amazon.com/images/I/[email protected]@[email protected]@31UVwN5aa8L

Given the stated ratings, the panel should in theory be able to maintain a good charge level for a reasonable number of days on top of what the battery would normally last.

Without real data it would be impossible to say how many. And of course, the battery also naturally loses charge over time which I did not take into account with the basic calculations that I did.

There is also the question of what the needs are, for example if you expected this charger to keep the battery topped up after leaving the car for 6 months I would guess that is not likely. However if you only need the car to start after say 2 weeks instead of 1, that is more likely.

But again, without any real figures it is impossible to say whether it will work in this case or not. Even the position the car is parked in will play a huge factor in how much sun the panel gets, as well as what angle the panel is at etc.
 

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Discussion Starter #8 (Edited)
I appreciate the points made re current output of such devices but i do not think that is the main point of the solar panel. I think the main point is that it holds the battery above the 12v point thus preventing sulphation of the plates which apparently can occur when a battery isnt subject to frequent runs/ charging thus allowing the voltage to drop slightly and promoting such chemical changes.

Lead–acid battery - Wikipedia, the free encyclopedia
 

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I appreciate the points made re current output of such devices but i do not think that is the main point of the solar panel. I think the main point is that it holds the battery above the 12v point thus preventing sulphation of the plates which apparently can occur when a battery isnt subject to frequent runs/ charging thus allowing the voltage to drop slightly and promoting such chemical changes.

Lead–acid battery - Wikipedia, the free encyclopedia
But if the current output of the solar panel is not high enough then the battery voltage will drop below 12v, so the current output is actually very important.
 

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the one i bought was this one

Solar Powered 12V 15W Battery Charger | Maplin

although the reviews are favourable my experience with it connected to a vehicle with a 300ma parasitic draw in everyday use was it didn't make a lot of difference

if i connected the panel to a car battery on it's own not connected to anything else it would keep the battery charged ( a battery in the caravan )
the reality is although it's rated at 15 watts that's at it's best, in the typical cloudy days we get up here in lancashire you'd be lucky to see 500ma
on a good day you might see more but we don't get many of them and the time cars refuse to start is usually winter when the weather is at it's worst
it;s a bit of a catch 22 good weather and the car starts easily , bad weather when the panel is needed it isn't very efficient
 

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Sounds like a waste of money to me.

If you connect it to either the cigarette lighter or the OBD port, then these are only connected to the battery when the ignition is on. It'd need to be connected to a permanent 'live' somehow.
 

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the one i bought was this one

Solar Powered 12V 15W Battery Charger | Maplin

although the reviews are favourable my experience with it connected to a vehicle with a 300ma parasitic draw in everyday use was it didn't make a lot of difference

if i connected the panel to a car battery on it's own not connected to anything else it would keep the battery charged ( a battery in the caravan )
the reality is although it's rated at 15 watts that's at it's best, in the typical cloudy days we get up here in lancashire you'd be lucky to see 500ma
on a good day you might see more but we don't get many of them and the time cars refuse to start is usually winter when the weather is at it's worst
it;s a bit of a catch 22 good weather and the car starts easily , bad weather when the panel is needed it isn't very efficient
That's not a bad output though, and considering the drain on the Civic is 10x less than the drain you were trying to compensate for, I think it would actually work fine in this case.

The AA one could well be a more efficient panel, and get much closer to the 200mA output, even on a cloudy day.
 

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That's not a bad output though, and considering the drain on the Civic is 10x less than the drain you were trying to compensate for, I think it would actually work fine in this case.

The AA one could well be a more efficient panel, and get much closer to the 200mA output, even on a cloudy day.
by the looks of the spec on the AA solar panel it's rated at optimal working current of 130 to 200ma at 12.7 volts ( taken from AA's web site )
a car battery needs a minimum of 13.2 volts charge rate ( 2.2 volt cells X 6 ) any less and the battery wouldn't be kept at it's optimum
the size of the panel doesn't really inspire me with confidence either it also looks like it's exactly the same kind of panel as the one i bought but a lot smaller

i'm not trying to give a science lesson but my experience of solar panels not just the one i have mentioned here is you need to spend a bit to get something that will do the job they claim to do
the size of the AA panel i would be very surprised if it was up to the job you've got to remember car batteries are charged with amps of current not a couple of hundred milliamps
at best i think it would stop any parasitic drain below 100ma but as far as charging is concerned it would take days

But....

i have been wrong before
 

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by the looks of the spec on the AA solar panel it's rated at optimal working current of 130 to 200ma at 12.7 volts ( taken from AA's web site )
a car battery needs a minimum of 13.2 volts charge rate ( 2.2 volt cells X 6 ) any less and the battery wouldn't be kept at it's optimum
the size of the panel doesn't really inspire me with confidence either it also looks like it's exactly the same kind of panel as the one i bought but a lot smaller

i'm not trying to give a science lesson but my experience of solar panels not just the one i have mentioned here is you need to spend a bit to get something that will do the job they claim to do
the size of the AA panel i would be very surprised if it was up to the job you've got to remember car batteries are charged with amps of current not a couple of hundred milliamps
at best i think it would stop any parasitic drain below 100ma but as far as charging is concerned it would take days

But....

i have been wrong before
No I totally agree, the voltage does not inspire confidence, however it should be high enough to fulfil its purpose. I suspect if it did not work at all then the reviews would be a lot different.

Solar panels vary widely in their efficiency. You'd like to think that given the smaller size, and relatively high cost of the AA one that it should be reasonably good quality and efficiency.

With regards to the charging, the point seems to be getting missed again. No one is claiming these will charge your battery from low or dead. The sole purpose, and the purpose the OP seems to want it for, is to simply counteract the 30mA draw (and natural discharge) of the battery whilst the car is sat for a while not being used.
 

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No I totally agree, the voltage does not inspire confidence, however it should be high enough to fulfil its purpose. I suspect if it did not work at all then the reviews would be a lot different.

Solar panels vary widely in their efficiency. You'd like to think that given the smaller size, and relatively high cost of the AA one that it should be reasonably good quality and efficiency.

With regards to the charging, the point seems to be getting missed again. No one is claiming these will charge your battery from low or dead. The sole purpose, and the purpose the OP seems to want it for, is to simply counteract the 30mA draw (and natural discharge) of the battery whilst the car is sat for a while not being used.
i think the only way to find out is for the OP to buy one and tell us if it's up to the task :)
for what he wants it for it'l probably do
 

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Hi All;,

I have had a solar charger for the MX5 that sits in the garage over winter. It's very similar to the AA one linked and of a similar size and it does help but it's certainly not a replacement for a decent mains charger. I bought it as the Mazda has a particularly small AGM battery that can only be trickle charged and, once left unused for more than three of four weeks, was going flat through parasitic immobiliser drain such that the car wouldn't start.

Since having the solar charger this has been less of an issue. I have the short connector permanently wired to the battery terminals (battery in the boot) and the solar panel hung at the west facing garage window so that when I get my bags etc. out I can plug it straight in. The voltage the charger produces is high from memory at about 21v (tested it with a multimeter) but it needs to be to push charge into the battery. The current flow is very low though (again tested with a multimeter) due to resistance and the relatively small voltage difference but it appears to cover the parasitic drain sufficiently to extend the life of the unused battery though a few months over the winter. There is still some drain but it is a much better situation as I don't need to get the charger out every time I want to use the car (bearing in mind an AGM battery has to be trickle charged over a number of days and die if they go flat or are incorrectly charged this can be a pain!).

I'm hoping it will be better still in our new house as the garage window, whilst still west facing is more open and less shadowed than in the old house.
 
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