12v Trickle Charging

[BigRedSwitch]

Wondering if one of these would help with the winter 12v Battery drain.  But I have a query: if I put one of these on the back parcel shelf, or use suckers to attach it to a rear quarter-light glass, would the tinted privacy glass make the charger ineffective?

Option 2 might be to mount an external, lockable socket on the wall outside the garage and use a flat cable to power my CTEK Battery charger which will live in the boot all winter..

Any thoughts gratefully appreciated.

[yossarian247]

I seem to recall that CTEK sell some quite long 12v extension leads for their chargers. Might be worth looking as that would allow you to leave the charger inside the garage and just feed the 12v lead out to the car?

I've heard mixed reviews on those solar chargers, with a few saying they generate so little current as to be a waste of time.

[mrpj]

1 hour ago, yossarian247 said:

I seem to recall that CTEK sell some quite long 12v extension leads for their chargers.

2.5 metre long for a CTEK extension (around £13). I'm sure, without checking, that they don't recommend any longer extension (e.g. join two together) because of a possible voltage drop in the cable.

[Gerg]

On 10/11/2020 at 11:06 PM, BigRedSwitch said:

would the tinted privacy glass make the charger ineffective?

For some strange reason I can't see the link to the item that you are referring to in your posting.  But, guessing it is a solar charger, then I think this is fairly inevitable that the output would be reduced.  If you could drag the solar charger to the dashboard, then the charger output might be more reasonable.  In theory, the charger could be connected to the OBD2 diagnostic socket (which is near the bonnet release lever and is always 'live') as an entry point to the car's wiring, but this isn't what it was designed for, and just one or two people (a Mercedes owner was one of them) have reported damage to that OBD2/CANbus circuitry inside the car.

I don't quite understand why this is, given the tiny power output of a small solar panel, but I think some (most? all?) models of these devices have an unregulated output (for cheapness) which must only be relevant in glorius sunshine, but still.... 

The alternative would be to run a cable directly to the Battery (simple, but clumsy), or install an 'always live' connection for you to plug in to into the fuse box - probably the one behind the glove box (simple if you've done this before, otherwise not).

As a 'left field' suggestion, the connection to your drivers seat lumbar adjustment (if fitted) is permanently live, I think.  For convenience, someone could splice into that connection to fit an attachment point to connect your solar charger, that way avoiding going near the major wiring routes.  So good for someone not quite so confident about getting 'stuck in' to a hybrid car's dash wiring.....perhaps.

On 10/11/2020 at 11:06 PM, BigRedSwitch said:

Option 2 might be to mount an external, lockable socket on the wall outside the garage and use a flat cable to power my CTEK battery charger which will live in the boot all winter..

The only problem I can see with this would simply be that the mains lead to the charger might slightly damage the rubber boot seal, especially given for how long the cable will be sat in one place.  But it might not damage it at all!  You'll only know after you've tried it.

That you've mentioned a lockable mains socket, suggests that your garage and the area next to it is not especially private and secure, which, if so, must be taken into account on any suggestions?

[BigRedSwitch]

Gerg, in my "first" option I was indeed referring to a solar Battery charger connected directly to the Battery via an intelligent controller to prevent reverse flow and to avoid over-charging the Battery.

In the second option I would use a flat cable to minimise damage to the boot seal.  

My thinking with the external socket was a) that it would be fed from a socket inside the garage which is on a circuit I can turn on/off from the mains supply box in my house, and (b) that I wouldn't have to open the garage to disconnect the battery charger - this way I would just dump the charger power lead into the boot, lock the socket and away I go.  If I use the fly leads that CTEK provided I can leave the charger connected to the battery.

But why oh why couldn't Toyota foresee this problem?  Why no indicator on the dash to show low power in the 12v battery?  And what's the logic in having an electrically operated boot lid?  Yes, I know you can crawl into the boot and use the manual override if you're of lesser years and size but how much easier a cable operated latch would have been. But then you wouldn't have remotely operated boot lids - does the Corolla have one, I wonder?

[Gerg]

Yes, I can sympathize with your points.

The CTEK charger sounds the most straightforward route.

You might just need to make up a reminder to put on the dash - to stop you driving off with it still plugged in!

If you were still considering the solar charger, then getting its output to your car's wiring is much simplified with a piggyback plug-in fuse holder like this, which has the added benefit that it is quickly removable, That way any soldering or joining of wires can be done away from the car;

https://www.amazon.co.uk/Circuit-Line-Profile-Blade-Holder/dp/B01DRYDL2O/ref=pd_sbs_263_6/259-2421322-0088563?_encoding=UTF8&pd_rd_i=B01DRYDL2O&pd_rd_r=a14b3e7e-9702-40c0-b2fc-2a9767305c95&pd_rd_w=3sTSQ&pd_rd_wg=d0uZs&pf_rd_p=b9bf232d-9a8a-4c7d-aa9d-641c0995d3a2&pf_rd_r=2WE9X79V9JXAH13XHQP8&psc=1&refRID=2WE9X79V9JXAH13XHQP8

Also, the price of budget Chinese multimeters, means that leaving one in the car, or even wiring it in to your solar charging circuit for voltage and current measuring, becomes viable.  But I imagine you are looking for maximum simplicity - you just want to have the car available to drive, not for this to become a new hobby...

If it's of any use, the following link is to the cheapest multimeter I can find, not a tool to 'proudly own', but does the job.  This one comes without its 9 volt battery for £2.40, postage from China included.  I inherited a near-identical one which originally came from Maplin - it works!  I think they sold there for £5, but that was about 12 years ago.

https://www.aliexpress.com/item/4001309978210.html?spm=a2g0o.cart.0.0.2e8b3c00ZNxXVD&mp=1

But, you'll need a slender No.0 size crosshead/philips screwdriver to get the back off and fit the Battery, though.

I can't remember if you said you owned a voltmeter in your previous posts, but yours will almost certainly be able to measure the tiny current that a car solar panel might produce.  I just have a miniature solar panel in a self-powered garden light to experiment with.  I'll dig it out (!), and have a play with it to see what readings I get.  It's only about 3 sq. in. and charges a 1.5 volt Battery I think, but still...!

 

 

 

[mrpj]

https://www.amazon.co.uk/AA-Essentials-AA1432-Battery-Charger/dp/B084M5ZL5L/ref=sr_1_5?crid=2VXX61U77K8TY&dchild=1&keywords=aa+solar+car+battery+charger&qid=1602669275&quartzVehicle=29-405&replacementKeywords=aa+solar+car+battery&sprefix=aa+solar%2Caps%2C164&sr=8-5

Not cheap at £36 but has the facility to charge through the OBD socket. Place on dash and no need to trail wires to the Battery through door seals etc..

I do know someone who has one and it does work effectively in daylight.

 

[BigRedSwitch]

Thanks for the links Gerg but I'm not going to modify the car's wiring because that would invalidate my extended warranty.  Electrical solutions that don't "modify" the existing wiring are another matter though. Since I turned off "smart entry" thanks to the information you provided me some time ago the situation is much improved so perhaps I don't have a problem on the same scale as before but then again, the Battery is getting older...

 

[Gerg]

Just out of interest, I put the small solar cell mentioned above ("miniature solar panel in a self-powered garden light") and connected it to a single small LED as a load, and also to a digital meter.

When put inside the back of the car, near to, and facing the rear passenger window, the solar cell was driving 1.42mA (milliamps) with the window down, and just 0.01mA with the (Excel trim, quite heavily tinted) window up.  The sun and cloud situation had not changed between these two readings which were taken within a couple of seconds of each other, which was the time it took to operate the window.  The solar cell had been placed on the back of the front seat, facing the rear glass, near to the front headrest

Five minutes later, repeating this, but with the solar cell facing the front passenger window this time (lightly tinted window, barely noticeable), was 0.54mA with the window down, and 0.18mA with the window up.  I suspect the cloud cover had changed from the first pair of readings, but wasn't aware of it at the time. 

I didn't expect a very lightly tinted window to make such a difference to the solar cell's output.

 

[BigRedSwitch]

Gerg, your findings confirm my suspicion; thankyou for taking the time to run your test.

[Gerg]

Hi Ian,

No problem. 

We have plenty of cars here, four of them slowly discharging their 12 volt batteries through lack of miles covered - in the middle of a pandemic it's good to know what will work and what won't.

[unclepoo]

I`ve fitted a solar panel to the rear shelf of my daughters yaris as it`s not driven too often. I`d tried the smaller panel that you`ve suggested. But I would strongly recommend a panel of 20w. anything less wont do the job. This is behind standard glass, no tint. So you may need to look at bigger wattage panels if you have tinted glass.

[BigRedSwitch]

More than 20W?  I reckon that takes solar chargers out of the equation.  I'm going to connect up my Battery charger once a week and hope that will suffice, or perhaps I'll start the car and leave it alone for an hour or so to let it "auto-charge".  It's on a private drive so I won't be breaking the law, the car will be secured with a StopLock Pro, and I'll check it every 10 minutes or so.

I wouldn't buy another Toyota hybrid unless it has a solution to this issue.

[unclepoo]

The 20w panel is about half the size of the rear parcel shelf. I drove the yaris today, it had not been driven for about 4 weeks. The Battery spun the engine over really well.

[BigRedSwitch]

Ok Stuart, but from what you suggest and with Gerg's testing, with my tinted glass I will need much more than 20W and it would have to be equpped with a voltage controller. Remember too, that the Auris hybrid engine is 1.8L and the Yaris is what, 1.5L?

Where did you source your 20W solar charger?

 

[Bob110023]

I keep a Halford Advanced Lithium jump starter under the front drivers seat. This will self charge through a USB connection every six months and is very small. It also has a led torch. Never had to use it yet but it's there if I need it.

[BigRedSwitch]

Like you, I keep an Artek (?) jump starter in my glove box just in case the Battery fails away from home.  I haven't had to use it yet but as winter approaches...

[unclepoo]

I`ve not used a controller with the solar panel, fused and a built in diode on the solar panel. With such a small panel, the car Battery simply absorbs any tiny peaks in output.

The yaris Battery is 45ah from memory.