I have a 2014 Octavia MK3 diesel vRS. Since the lockdown the car has moved once in the last 5 weeks, and that was a less than 1 mile trip to drop it off for an MOT three weeks ago, and in all likelihood it will won't move for at least a month.  

 

The car is on it's original battery and I'm wondering if there's anything I can do prevent it running flat (or even dying) over the next few weeks. I do have a battery charger designed for lead acid batteries, but I don't know if that will work with the car's AGM battery, and because I only have on-street parking I don't have mains power at the car to run a charger, so I'd probably have to remove the battery from the car.   

 

So, best to leave it alone and deal the situation when I need to use the car again, or remove the battery (and work out how to lock the car) and charge it indoors, assuming my old charger works with an AGM battery? Or are those solar top up chargers worth buying given my lack of power at the car?

Top up solar will be useful as long as the battery hasn’t already got too low.

 

As for the charger, depends on what type it is (voltage outputs etc) as to if it is any good.

I think the battery level may have dropped too low. Using a multimeter across the battery terminals this morning i was getting 12.1V.

 

I did buy a "SARONIC 18V 12V 18W Solar Battery Maintaner for Automobile" from Amazon for £34 (I know that's half the price of a decent smart charger, but I don't have mains power by the car). I've set it this afternoon, and with clear skies and 20°C it appears to outputting about half an amp which I think is good enough to trickle/top-up charge a good battery.
I'm not well versed with how car charging system work, but I'm assuming the almost 12.5V I'm seeing at the moment is down to voltage the panel is putting out, so I'll check against once the sun has gone in.

 

Annoyingly, where the car is parked it's in the shade until about 3pm (never noticed until today), so I may see if it starts over the weekend and if it does, then take it a couple of mile down a fast road, and park it in the sun when I get back.   

0.5Amp for 2 hours a day probably isn’t that useful, but better than nothing. If you can get it into the sun for closer to  5 hours a day, that’s probably more than enough to at least stop the battery dying.
 

in theory that charger can put out 1.5Amp, so maybe play with angles to get it closer to 1 if you can’t move the car?

Edited 23 April, 20206 yr by cheezemonkhai

On 18/04/2020 at 17:39, GoodDoc said:

and that was a less than 1 mile trip to drop it off for an MOT three weeks ago

 

Did they do the MOT? It's not well advertised but all MOT's have been increased 6 months automatically but it doesn't trigger until a week before due. Mine is due early May.

 

https://www.gov.uk/guidance/coronavirus-covid-19-mots-for-cars-vans-and-motorcycles-due-from-30-march-2020

Edited 24 April, 20206 yr by Dave77

2 hours ago, Dave77 said:

 

Did they do the MOT? It's not well advertised but all MOT's have been increased 6 months automatically but it doesn't trigger until a week before due. Mine is due early May.

 

https://www.gov.uk/guidance/coronavirus-covid-19-mots-for-cars-vans-and-motorcycles-due-from-30-march-2020

They did.

I'd already made the decision to switch to 100% home working in early March, but by late March it was clear that the lockdown was going to get more significant and I was concerned that if garages were shut I'd have a car that wasn't road legal as the MOT expired on the 22nd of April, so I booked it in for an MOT on the 30th of March.

 

 This was all before the government announced that MOTs would be extended 6 months, and while the 6 month extension was announced before my MOT appointment I dropped the car off anyway.

 

15 hours ago, cheezemonkhai said:

0.5Amp for 2 hours a day probably isn’t that useful, but better than nothing. If you can get it into the sun for closer to  5 hours a day, that’s probably more than enough to at least stop the battery dying.
 

in theory that charger can put out 1.5Amp, so maybe play with angles to get it closer to 1 if you can’t move the car?

 

If I put the panel on the outside of the windscreen I get 0.9 amp, when placed inside the screen I get 0.5 amp, and the same 0.5 amp through the side windows (with door open to catch the sun). I'm assuming there's a protective layer in all the windows that's affecting the panel's ability to generate current. Looking at the specs of the panel I think 0.9 amp is pretty close to it's maximum.

 

The car hasn't moved at all since the 30th of March, and that was just around the corner to MOT testing centre and back, so it's done maybe 2 miles since the 9th of March. I'll try and start it tomorrow, and if it does, I'll take it for a spin down the dual carriageway and back.

17v is a bit concerning...

17V is an open circuit voltage similar to what I can measure from my old school battery chargers if not connected across a battery, it will stabilise at 13.3v max.

33 minutes ago, cheezemonkhai said:

17v is a bit concerning...

 

It actually puts out 19 V, but as J.R. points out below, that's with it not connected to anything (other than the multimeter), it drops once connected to the car.

It lists 21 as open circuit, but if you’re saying it drops on load then all good.

 

TBH it inside the car at least gives the car an amp a day of power. At the very least it’ll slow the drain and if you can get more hours it’ll probably keep it right.

I've noticed that my battery had dropped to 50% on the MaxiDot display when I last checked.

 

Normally this overs around 70% on mine which has the Start Stop. It's not an AGM battery but an EFB. 

 

The car started ok and after a bit of a run this returned to 70% the next day.

 

I do have a charger but not had to use it yet.  I've noticed my charger pulses up to 20V so if I do need to charge up the battery I will have to disconnect the terminals in case that voltage is too high for the electrical system.

Mine was a very good value SUAOKI Car Battery Charger:

 

https://www.amazon.co.uk/gp/product/B07793CK5K/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

 

 

Edited 25 April, 20206 yr by Plantman

My main commuter is doing double the mileage it usually does so no worries about the battery.

 

Our Octavia and Citigo are both parked up but fortunately they are on the drive and near power points so they are both connected to CTEK chargers. Just fit and forget.

 

https://www.amazon.co.uk/CTEK-MXS-5-0-Reconditions-Motorcycle/dp/B005O8YG44/ref=sr_1_1?dchild=1&keywords=ctek&qid=1587900375&sr=8-1&th=1

 

 

Well... that was an anti-climax. Car started first time, not even a hint it might struggle. Less than mile from the house the stop/start kicked in so the car must have been happy with the battery voltage.

 

So 5 weeks without moving (and three weeks of not moving prior to that short trip), some probably poor attempts at trickle charging, and it started fine. I have no idea how much of a difference the solar panel made, the car got maybe 12 hours at 0.5 amp, and 3 hours at 0.9 amp, and I definitely some low voltages  (down to 12.1 one morning) , but my gut feeling is that the battery was probably in better shape than I gave it credit for.

 

Took it for a 30 mile round trip to drop some tools off to a friend (doorstop drop and dash), and apart from a low tyre pressure warning (it had a new tyre during the MOT, so the TPMS may have been confused) the car behaved itself.

Not sure what to do with the solar panel now, they recommend not leaving it plugged in to avoid 'reversing charging' so I don't want to leave it plugged in for several days on a row, I may try to research solar charge controllers to see if the panel can used in a safer/better manner, but for the moment I'll just aim to take the car for a decent spin every two weeks.