Thread: Will your battery go flat if you don't start car for a few weeks?

Even with brand new batteries IF they don't get charged for long periods of time they will go flat eventually.
Either drive your disco more often and I don't mean just a 5 min run up and down the street as it takes more than that to fully charge the battery or put a trickle charger on it when you are not using it.

yeah, normal.
At the start(fresh/new) batteries seem to be invincible, but after some time they do that.
Same with brothers Td5(2 x Optimas). They appear to be in good condition, take charge, will hold for a couple of weeks after a charge.

Like Trout said, get a small cheap charger and keep it connected. I reckon do it with solar.

For the brothers, I'm looking to get a cheapo fold up (say 10w) solar blankety type thing to pop inside the windscreen(faces the sun for a short period), and connected to an always on plug of some description.
The 12v/cig lighter is not 'always on' so is not a good spot to plug these solar chargers into, unless you can re wire it to direct battery power instead.

For brothers Td5(sits in my backyard now), I've sequestered his solar panel(he uses for camping) and place it in various location in my yard to keep them batteries charged up.
Even just an hour a day charge(every day) will keep it topped up enough to give it a start up when you need it too weeks later.

Yes. How long it takes depends on the vehicle, the battery, the battery condition, and probably other factors.

All lead acid batteries self-discharge, but the rate is variable. However, don't expect a battery wirth nothing connected to still have something like the original charge after a month.

Most cars have something that draws power when parked, if only a clock - the newer the car the higher this drain is expected to be. Some of the drains include self-locking equipment, radio, body computer, burglar alarm.

Best answer is as suggested above - a small solar panel that you connect every time you park it at home. If no sunlight in the area, then a mains trickle charger is indicated.

I did this with my tractor that is used infrequently, not only is it now ready to go when needed, but batteries last far longer.

Yep, solar panel is the go. Keeps batteries healthy by charging during the day and resting at night.

I have a few vehicles. I fitted a Ctek charging connector to each incl the camper, with a built in LED indicator.

Now I just look out for the yellow or red flash visible without opening the bonnet or car, to tell me when to connect the Ctek charger.

The system is working so far. Winter seems to have an effect on batteries.

Originally Posted by AK83

For the brothers, I'm looking to get a cheapo fold up (say 10w) solar blankety type thing to pop inside the windscreen(faces the sun for a short period), and connected to an always on plug of some description.
The 12v/cig lighter is not 'always on' so is not a good spot to plug these solar chargers into, unless you can re wire it to direct battery power instead.

Ahh well this all makes sense then, I thought that would be the case. Took it for a decent drive yesterday which charged it up good and proper. I measured the batteries yesterday before jump starting it back up from the dead and the second battery was still on about 12.5v which seemed healthy enough (I guess the isolator works) but the cranking battery was on about 10.2v

Took a while with the jumper leads connected from the other car to bring that thing back from the dead haha but it's cranking like a champ again now it seems.

There is no sunlight where it's parked so maybe a trickle charger, or I'll just drive it each week, I'm not too crash hot on the idea of leaving a mains charger turned on always in the garage for safety reasons...

So with the cigarette lighter ports do you just plug in a solar charger to one of those and it feeds back into the battery that way??? I did not know this. I'm pretty sure the ciggy lighter in the dash is actually wired to be always on and that's probably connected to the cranking battery because it's the original one before a second battery would have been installed. If this is the case, I would just plug a solar kit straight into this and it would feed back into the battery and charge it up?

Hi folks and a single drive, once a week is just not going to fix the problems caused by infrequent use, especially at this time.

When any battery is not charged to its full capacity, at any time, it progressively looses capacity.

NOTE, I stated to its full CAPACITY.

All batteries ( including Lithium batteries ) require recharging times that are usually way longer than anybody drives for, and this results in a S-L-O-W but progressive lose of capacity and then when you carry out a charge cycle, be it by driving or with an external charge device, solar or battery charger, you will only succeed in charging the capacity that can still be charged.

A single long drive or one long charge cycle with a battery charger will reverse the capacity lose, but if you have lost say 50% of your batteries capacity, that one single long charge will be lucky to regain no more than about 5% of the lost capacity.

Some additional suggestions.

If you are going to use a cigarette power socket as the connection between the charging device and the battery, DO NOT use anything bigger than a 5 amp power source.

These sockets do not handle currents much above 5 amps, particularly for long periods, without the potential of them melting.

I my opinion, solar recharging and maintenance of batteries is by far the best method to use and Young Angus, you may be able to use a solar panel, if you can make up a LONG 12v extension lead and connect The solar panel to the battery that way.

Not sure of your situation so you may only be able to use a charger. Again, if so, use a small one and try controlling it with one of those cheap times from Bunnings. Set it to be on for say 4 hours and off for 20.

Originally Posted by drivesafe

Hi folks and a single drive, once a week is just not going to fix the problems caused by infrequent use, especially at this time.

When any battery is not charged to its full capacity, at any time, it progressively looses capacity.

NOTE, I stated to its full CAPACITY.

All batteries ( including Lithium batteries ) require recharging times that are usually way longer than anybody drives for, and this results in a S-L-O-W but progressive lose of capacity and then when you carry out a charge cycle, be it by driving or with an external charge device, solar or battery charger, you will only succeed in charging the capacity that can still be charged.

A single long drive or one long charge cycle with a battery charger will reverse the capacity lose, but if you have lost say 50% of your batteries capacity, that one single long charge will be lucky to regain no more than about 5% of the lost capacity.

Some additional suggestions.

If you are going to use a cigarette power socket as the connection between the charging device and the battery, DO NOT use anything bigger than a 5 amp power source.

These sockets do not handle currents much above 5 amps, particularly for long periods, without the potential of them melting.

I my opinion, solar recharging and maintenance of batteries is by far the best method to use and Young Angus, you may be able to use a solar panel, if you can make up a LONG 12v extension lead and connect The solar panel to the battery that way.

Not sure of your situation so you may only be able to use a charger. Again, if so, use a small one and try controlling it with one of those cheap times from Bunnings. Set it to be on for say 4 hours and off for 20.

Excellent thank you for that info, when I say a long drive yesterday I was out driving around on highways and such for a good hour straightI think.

I wonder how I test to see if I've lost capacity in my nice new'ish batteries? I want to keep them in as good condition as I possibly can so if a solar panel setup is the best idea maybe I can put on on the roof on the garage and run a cable down to the car where it gets parked. Should I hook this up to both cranking and accessory battery to keep them both healthy? Or will just keeping it hooked up to the crank battery with my (not older) red arc isolator do the job of keeping both charged?

I don't have to use the cigarette lighter port by the way, I was just interested that you could do that. If it's parked in the garage getting charged I'm happy to hook it up the best safest way possible.