Battery Maintenance

[BillyBear]

As we plan our next trip into Spain for a couple of months I am wondering how to keep the batteries charged on our cars. Mains electricity is not feasible so am thinking of individual solar chargers attached inside the windscreen. I am particularly intrigued by the idea of charging through the obd2 socket and wondering if anyone has done this.

 

[Taran_Las]

I left my car for 7 weeks. It unlocked then started on the first turn. I did charge it up prior to leaving it.

 

[HKF]

I had a Corsa once that I left under a car port for 4 months over the winter. It opened and started up first time! I loved that runaround and was sad when I sold it.

 

[Sleeveless]

I left my car for 7 weeks. It unlocked then started on the first turn. I did charge it up prior to leaving it.

The manufacturer I once worked for, stipulated charging the batteries at least every 6 weeks for cars in storage, so you weren't too wide of the mark . I do the same as you and charge fully prior to leaving them.

 

[Landy Andy]

All depends on what type/age of car it is. On something basic like my Landy I can leave that for months, as it doesn’t have loads of tech draining its massive battery. But a modern tech car, has loads of stuff draining what is often a small battery.

If you have a tow bar then you can often back charge through that.

^{_{Subscribers  do not see these advertisements}}

 

[autorouter]

As we plan our next trip into Spain for a couple of months I am wondering how to keep the batteries charged on our cars. Mains electricity is not feasible so am thinking of individual solar chargers attached inside the windscreen. I am particularly intrigued by the idea of charging through the obd2 socket and wondering if anyone has done this.

Those small solar panels are quite good for this. I found that even a small 2.5W panel will keep a starter battery topped up in a car with low parasitic drain in reasonable sunlight. I would go for a 5W or 10W if I had to set up a similar thing now. I've not tried going through the OBD port, but it's a good option I think. The cigarette-lighter socket on my car is live when the ignition is switched off, so I use that (with a mains trickle charger) but most sockets turn off with the ignition, so the OBD port is a good way in.

 

[Sleeveless]

As we plan our next trip into Spain for a couple of months I am wondering how to keep the batteries charged on our cars. Mains electricity is not feasible so am thinking of individual solar chargers attached inside the windscreen. I am particularly intrigued by the idea of charging through the obd2 socket and wondering if anyone has done this.

To charge the vehicle battery from the OBD2, you need to connect to pins 4 (chassis ground) and 16 (Battery permanent live). This info only relates to the vehicle side of the connecter. There are plenty of OBD connectors on ebay etc , make sure that a fuse is present connecting to pin 16 though, and the circuit is only suitable for trickle charging.

 

[Richard n Ann]

Think I'm just going to disconnect my cars battery and the other car will be in the garage so I'll fit an SAE socket for the optimate.

The problem I've found with the small solar panels is that the 5w one I bought was taking the battery up over 15v on consecutive sunny days (I've got a Bluetooth logger on it) But if you fit a small regulator it uses more power than the panel makes on cloudy days.

So maybe a 40w panel with regulator? I'm just going disconnect the negative terminal.

 

[MichaelT]

Think I'm just going to disconnect my cars battery and the other car will be in the garage so I'll fit an SAE socket for the optimate.

The problem I've found with the small solar panels is that the 5w one I bought was taking the battery up over 15v on consecutive sunny days (I've got a Bluetooth logger on it) But if you fit a small regulator it uses more power than the panel makes on cloudy days.

So maybe a 40w panel with regulator? I'm just going disconnect the negative terminal.

Careful as lot of stuff needs power on modern cars and make sure you have radio code. Why not just connect a battery charger to them, it will keep it nicely topped up.

We've been away 10 weeks and never bothered with the car, always started 1st time on return.

 

[Landy Andy]

Most modern stuff doesn’t have radio codes anymore, the days of people stealing head units has passed and most are integrated into the dash.

^{_{Subscribers  do not see these advertisements}}

 

[RobertJary]

When we leave our car at Alicante airport, last time was for 5 months, I disconnect the battery. Reconnected when we returned and the car started like I'd left it a day earlier.

 

[Carpmart]

When we leave our car at Alicante airport, last time was for 5 months, I disconnect the battery. Reconnected when we returned and the car started like I'd left it a day earlier.

Nice warm climate helps…

 

[jockaneezer]

I ordered something from eBay and was sent one of those mini solar panels with suckers to go on your windscreen by mistake. They told me to keep it and sent me my proper order, so I thought I'd try it on the two batteries I have paralleled up for my Chinese diesel heater I have fitted in my garage. Like Richard n Ann said, you can get some really high voltages from them. Mine's on a South facing window and runs through about 8m of old twin speaker cable to reach the batteries and still can hit 16 volts even though I thought it would suffer from serious voltage drop given the size and length of wire I used ?
Not sure how many amps were actually reaching the batteries though, but I wouldn't be keen fitting an unregulated one of these to a modern car ?

 

[Ingwe]

I bought a little 10w panel that was intended to sit on the dashboard of my Audi A4. On the second morning, was visited by my local crime prevention police officer who said it was a bad idea to do this. Thieves would see the device and think it was something like a tablet or other desirable gizmo.
So took her advice. In the end, when away for anything over three weeks, I used to disconnect the battery.
No longer have the car.

 

[BillyBear]

Thanks for your replies everybody. Plenty for me to mull over there.

^{_{Subscribers  do not see these advertisements}}

 

[berni109]

Take the battery out and charge - leave on bench.
On return charge then put back in car.

 

[G-RMPS]

My BMW 520 started after 3 months away. I think the battery is original, so 12 years old.