Solar Battery Top Up

[futureechos]

Noticed a couple of slow (low battery power) starts on the car when left for a couple of weeks. I do have a couple of things in the Cigarette lighter (MagSafe Phone Charger) which has an LED which is likely to drain a tiny amount over time..  to combat this I was wondering if a Small Solar charge would add a small amount of charge over time to counter a tiny drain.

 

I'd like to leave a panel on rear shelf and plug it into the cigarette socket by handbrake and kind of forget about it, perhaps unplug when starting engine.

 

I don't want to faff each time I get in the car so disconnecting from battery each time is not what I am after.

 

So any experience of these Solar chargers?  I don't want a mains trickle charge to be honest, I think it's excessive as I drive usually 2-3 times every week and only leave for 1-2 weeks every so often when it might need a tiny top up.

 

Spend approx £40?

 

Appreciate Sunlight and UK not a good combo in the winter.

 

Loads on amazon etc (random example):

https://www.amazon.co.uk/Sunway-Solar-Maintainer-Motorcycle-Snowmobile/dp/B06WP95W51/ref=sr_1_5?crid=1W4VE7WIARF8F&keywords=solar+battery+charger+12v+car+lighter&qid=1672765505&quartzVehicle=29-10519&replacementKeywords=solar+battery+12v+car+lighter&sprefix=solar+battery+charger+12v+car+lighter%2Caps%2C100&sr=8-5

 

 

[Julian987]

I have looked at these and then read stories of cars ending up in flames as a result. Considering you drive it frequently I don't understand why you are worried about battery drain. 

[futureechos]

10 hours ago, Julian987 said:

I have looked at these and then read stories of cars ending up in flames as a result. Considering you drive it frequently I don't understand why you are worried about battery drain. 

On occasion it goes for a couple of weeks without a start then struggles to turn over (but starts), but doesn't feel great. This goes away as soon as I've driven for 20 mins.

 

I'm sure its the additional draw from the phone charger (and a bluetooth dongle) in the USB port is not helping.

I can't be arsed to keep unplugging and plugging in each time - the phone charger is from the passenger footwell port and all cabling nicely hidden but its a pain to get to from drivers side.

 

Hence doesn't need a mains charge just a bit of a top up for those times.

 

As lighter sockets are permanently live it seems like a reasonable solution?

[Julian987]

2 hours ago, futureechos said:

On occasion it goes for a couple of weeks without a start then struggles to turn over (but starts), but doesn't feel great. This goes away as soon as I've driven for 20 mins.

 

I'm sure its the additional draw from the phone charger (and a bluetooth dongle) in the USB port is not helping.

I can't be arsed to keep unplugging and plugging in each time - the phone charger is from the passenger footwell port and all cabling nicely hidden but its a pain to get to from drivers side.

 

Hence doesn't need a mains charge just a bit of a top up for those times.

 

As lighter sockets are permanently live it seems like a reasonable solution?

 

I think I would trust this above any cheap solar product

 

https://carbatterygeek.co.uk/ctek-cs-free-review/

 

https://www.ctek.com/uk/battery-chargers-12v-24v/cs-free

 

https://www.ctek.com/uk/battery-chargers-12v-24v/add-ons/usb-c-charge-cable-12v-plug

 

2mins in to this video...

 

 

[futureechos]

1 hour ago, Julian987 said:

 

I think I would trust this above any cheap solar product

 

https://carbatterygeek.co.uk/ctek-cs-free-review/

 

https://www.ctek.com/uk/battery-chargers-12v-24v/cs-free

 

https://www.ctek.com/uk/battery-chargers-12v-24v/add-ons/usb-c-charge-cable-12v-plug

 

2mins in to this video...

 

 

 

Actually that looks very cool - well built and thought out but £280 is OTT for my needs. .

 

 

[Ben]

On 03/01/2023 at 17:11, futureechos said:

Noticed a couple of slow (low battery power) starts on the car when left for a couple of weeks. I do have a couple of things in the Cigarette lighter (MagSafe Phone Charger) which has an LED which is likely to drain a tiny amount over time..  to combat this I was wondering if a Small Solar charge would add a small amount of charge over time to counter a tiny drain.

 

I'd like to leave a panel on rear shelf and plug it into the cigarette socket by handbrake and kind of forget about it, perhaps unplug when starting engine.

 

I don't want to faff each time I get in the car so disconnecting from battery each time is not what I am after.

 

So any experience of these Solar chargers?  I don't want a mains trickle charge to be honest, I think it's excessive as I drive usually 2-3 times every week and only leave for 1-2 weeks every so often when it might need a tiny top up.

 

Spend approx £40?

 

Appreciate Sunlight and UK not a good combo in the winter.

 

Loads on amazon etc (random example):

https://www.amazon.co.uk/Sunway-Solar-Maintainer-Motorcycle-Snowmobile/dp/B06WP95W51/ref=sr_1_5?crid=1W4VE7WIARF8F&keywords=solar+battery+charger+12v+car+lighter&qid=1672765505&quartzVehicle=29-10519&replacementKeywords=solar+battery+12v+car+lighter&sprefix=solar+battery+charger+12v+car+lighter%2Caps%2C100&sr=8-5

 

 

 

I was / am in the same situation and for the past few years have been using one of these :

 

AA 5060114614185 Solar-Powered Car Battery Charger, Black https://amzn.eu/d/adc7EIM

 

I plug it in to the obd2 socket when I know the car won't be driven for an extended period of time and it's been perfect in keeping the battery topped up.  I leave the panel on the back shelf and always unplug before starting the car. It probably helps that the car is parked in a south facing direction! 

 

Have to say that these won't ever produce enough charge to save a battery on its last legs but may help to prevent it.   I've not had a flat battery in the time I've used it. 

 

 

 

 

[futureechos]

On 06/01/2023 at 11:15, Ben said:

 

I was / am in the same situation and for the past few years have been using one of these :

 

AA 5060114614185 Solar-Powered Car Battery Charger, Black https://amzn.eu/d/adc7EIM

 

I plug it in to the obd2 socket when I know the car won't be driven for an extended period of time and it's been perfect in keeping the battery topped up.  I leave the panel on the back shelf and always unplug before starting the car. It probably helps that the car is parked in a south facing direction! 

 

Have to say that these won't ever produce enough charge to save a battery on its last legs but may help to prevent it.   I've not had a flat battery in the time I've used it. 

 

 

 

 

 

Thanks v much.. is the cable long enough to reach, presuming OBD2 port is drivers side under dash?

 

If they have a diode to prevent charge coming back into the solar panel then in theory shouldn't need to unplug when starting? I guess i manual says to unplug then that's the way to go.

 

Edit: in the item listing it says:

"Please note: the charger can only be used while the vehicle is parked and off."

Fair enough.

 

Edited January 7, 2023 by futureechos

[Ben]

14 minutes ago, futureechos said:

 

Thanks v much.. is the cable long enough to reach, presuming OBD2 port is drivers side under dash?

 

If they have a diode to prevent charge coming back into the solar panel then in theory shouldn't need to unplug when starting? I guess i manual says to unplug then that's the way to go.

 

Edit: in the item listing it says:

"Please note: the charger can only be used while the vehicle is parked and off."

Fair enough.

 

 

Yes the cable is more than long enough to reach from front to back. 

I have on a couple of occasions forgotten to unplug it before start up, but it doesn't  seem to have done any harm. But yes as a general rule I'd disconnect (and remember to remove it from the back panel as otherwise it slides off at speed at the first corner!) 

[Ben]

Just now, Ben said:

 

Yes the cable is more than long enough to reach from front to back. 

I have on a couple of occasions forgotten to unplug it before start up, but it doesn't  seem to have done any harm. But yes as a general rule I'd disconnect (and remember to remove it from the back panel as otherwise it slides off at speed at the first corner!) 

 

And the OBD2 port is actually on the passenger side, under the dash below the glove box 

[iSPY]

I've been using one for 2 years now as I don't have a garage or driveway. I was in the situation that due to heart bypass I couldn't drive for a few months and concerned about battery state. I purchased an Optimate 40W panel that comes with a controller that monitors the battery state 24/7 to prevent over charge or discharge at night, it plugs into the 12v socket in the passenger footwell. The panel is about 18" x 15" and just sits on the engine cover.

[futureechos]

I got one of these yesterday:  https://www.amazon.co.uk/dp/B07TY3HGF7?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

Decided on one with a controller too as going cheap probably not a great idea.

 

Will test a bit and feedback.

[zcacogp]

Frankly, I wouldn't bother. Those portable panels are very small (in the world of solar panels) and very low-grade cells. You wouldn't get much power out of one under ideal conditions. 

 

Then add in the fact that they are packaged with a layer of glass over the top of them, which will knock the output down by 30-40%. And then you put it inside the car, underneath another layer of glass, which will knock another 30-40% off the output (and probably nearer 40% because it's not perfectly clean). And then the panel will be shaded for a good portion of the day by the roof / trees / anything else nearby, which will reduce the output by another 50-80% for the period during which they are in shade. 

 

Then consider that the time of year which is hardest on the battery in the car is the winter time, when there is precious little sunlight around for most of the day. 

 

In short: they are a waste of time and money. Really, don't bother. 

 

(Yes, I do have quite a lot of experience of electrochemistry and commercial production of solar panels. The figures I'm quoting are on the conservative end of the scales. Apart from those for daylight in the middle of winter, which are obvious to anyone who looks out of the window.) 

[iSPY]

17 hours ago, zcacogp said:

Frankly, I wouldn't bother. Those portable panels are very small (in the world of solar panels) and very low-grade cells. You wouldn't get much power out of one under ideal conditions. 

 

Then add in the fact that they are packaged with a layer of glass over the top of them, which will knock the output down by 30-40%. And then you put it inside the car, underneath another layer of glass, which will knock another 30-40% off the output (and probably nearer 40% because it's not perfectly clean). And then the panel will be shaded for a good portion of the day by the roof / trees / anything else nearby, which will reduce the output by another 50-80% for the period during which they are in shade. 

 

Then consider that the time of year which is hardest on the battery in the car is the winter time, when there is precious little sunlight around for most of the day. 

 

In short: they are a waste of time and money. Really, don't bother. 

 

(Yes, I do have quite a lot of experience of electrochemistry and commercial production of solar panels. The figures I'm quoting are on the conservative end of the scales. Apart from those for daylight in the middle of winter, which are obvious to anyone who looks out of the window.) 

Funny how my 40w panel has been faultless then and kept my battery FULLY charged for nearly 3 years now, even during a period I couldn't drive for over 3 months. Mine is located on top off the engine cover and partly shaded by a large Oak tree !

Edited January 17, 2023 by iSPY
Spelling

[iSPY]

https://www.optimate.co.uk/products/optimate-solar-40w

[futureechos]

On 16/01/2023 at 17:08, zcacogp said:

Frankly, I wouldn't bother. Those portable panels are very small (in the world of solar panels) and very low-grade cells. You wouldn't get much power out of one under ideal conditions. 

 

Then add in the fact that they are packaged with a layer of glass over the top of them, which will knock the output down by 30-40%. And then you put it inside the car, underneath another layer of glass, which will knock another 30-40% off the output (and probably nearer 40% because it's not perfectly clean). And then the panel will be shaded for a good portion of the day by the roof / trees / anything else nearby, which will reduce the output by another 50-80% for the period during which they are in shade. 

 

Then consider that the time of year which is hardest on the battery in the car is the winter time, when there is precious little sunlight around for most of the day. 

 

In short: they are a waste of time and money. Really, don't bother. 

 

(Yes, I do have quite a lot of experience of electrochemistry and commercial production of solar panels. The figures I'm quoting are on the conservative end of the scales. Apart from those for daylight in the middle of winter, which are obvious to anyone who looks out of the window.) 

 

Getting 15.5 volts out of it in morning daylight conditions on the engine cover.

So early test and a car start test show it to be topping up, which I'd class as doing what I thought it would.

 

(Yes, I have a lot of experience with a volt meter in the amateur production of quick and not entirely empirical data. My figures are on the 'what I measured' scale, and where I live we also get daylight in the middle of the day, and sometimes a few hours either side of it. I've not looked out the windows but will have a look tonight to check light levels).