BEST WAY TO KEEP A CAR BATTERY CHARGED UP?

TUVOK

With this extremely cold weather and it's effect on car batteries, I was wondering which is the best way to keep the battery charged up?
I can give the car a slow charge via a battery charger for 4 hours minimum  a day or could take the car for a 20 mile run twice a week.
I don't use the car every day, some times 2 to 3 days just sat outside in the cold.

rollingmoon

I only use my motorbike 6 months of the year, when it's not in use I have an Optimate battery optimiser that keeps the battery topped up as required. They use little electricity; certainly less than replacing batteries on a regular basis. You can get similar devices for cars - my friend has a motorhome, and he keeps its starter and leisure batteries topped up and in good condition in the same way.

Mildly_Miffed

If you're using it every few days, it'll almost certainly be fine - unless the battery's already knackered, or you're only using the car to go half a mile with lights and wipers on.

fred990

I use solar (non) 'chargers' on the van and car that don't get used much plus one on the mini digger (which sits for weeks at a time before finding a project/hobby to do in the garden!).

They keep the voltage above 12.4v which is the main thing. 

Beats the mains power charger route...ymmv

sevenhills

A small solar panel that plugs into the cigarette lighter socket?

I have issues with my car not starting. I tested the battery at the beginning of the week, it was 12.1v, then 11.9v, then yesterday it was 11.8v

It did start, so I kept it running until I got home. Still not a long run, but hoping it's ok. I will take the negative lead off the battery and charge it for a few hours, if required.

fred990

sevenhills said:

A small solar panel that plugs into the cigarette lighter socket?

I have issues with my car not starting. I tested the battery at the beginning of the week, it was 12.1v, then 11.9v, then yesterday it was 11.8v

It did start, so I kept it running until I got home. Still not a long run, but hoping it's ok. I will take the negative lead off the battery and charge it for a few hours, if required.

12.4v is the minimum for a pb battery at rest otherwise it will sulphate. 

Sounds like yours is shot...a ctek charger might recover it.

Mildly_Miffed

Solar's utterly pointless at this time of year.

Even if it wasn't on the dashboard, inside the car and behind glass specifically designed to reduce the effect of the sun passing through.

Ectophile

If you have to ask how to keep your battery charged, then you need a new battery.  A car should start with no problems if it's been left unused for a week, or even two.  So long as it gets a decent drive when it is used.

OK, that answer is rather simplistic - other problems could include a faulty alternator, or something that's draining the battery even with the ignition off.  But you'd still be better off fixing the actual problem, rather than messing about with car chargers.

Bigwheels1111

I purchased a battery tester a few years ago as was worried mine was on its way out.
Used it today to check mine.
As I only drive once or twice a week & my car is 7 years old.
Tests battery and alternator.
Basic ones are £18 on eBay.
Nice to have in the boot.
Plus you don’t have to rely on Halfords, Kwikfit etc to tell the truth.

sevenhills

Bigwheels1111 said:

I purchased a battery tester a few years ago as was worried mine was on its way out.
Used it today to check mine.
As I only drive once or twice a week & my car is 7 years old.
Tests battery and alternator.
Basic ones are £18 on eBay.
Nice to have in the boot.
Plus you don’t have to rely on Halfords, Kwikfit etc to tell the truth.

You can buy battery testers on eBay for £5, they appear to do as much as the more expensive testers.

https://www.ebay.co.uk/itm/314950469179?_trkparms=amclksrc=ITM&aid=1110006&algo=HOMESPLICE.SIM&ao=1&asc=20201210111314&meid=cf0cbec8d6f648d3a00fd433efd180bf&pid=101195&rk=3&rkt=12&sd=305076359117&itm=314950469179&pmt=1&noa=0&pg=4429486&algv=SimplAMLv11WebTrimmedV3MskuWithLambda85KnnRecallV1V2V4ItemNrtInQueryAndCassiniVisualRankerAndBertRecallWithVMEV3CPCAuto&brand=Unbranded&_trksid=p4429486.c101195.m1851&amdata=cksum:314950469179cf0cbec8d6f648d3a00fd433efd180bf|enc:AQAIAAABYObhgc4Nk8%2BdtAwOww4FKLaj%2FQ5qqgDlQCuqZA43WcPFUWDERCUugbbOk7XQv0JXlBfqCg2xKF3WcPghxGMFw2oSlXvfExEaMYr7I7LmrHcP6czY1wIMt0ORyKiCWt95xldincyyBx3g%2BNDW%2B%2FhWUgTaBhK6xAm%2BJIbCOMehu%2BdwEnCV8inBbzpNeNbFEKyg9F%2BL8BTtlOq88cNK%2BDDRLK5IjZopI%2BwHc3lGr47pLBT5DXypY1ra0mS2M7Ph6GzCyyE72iTD2yU2x9fivOeELUiOt1LkjdXlPE3dCCpkjjYM3dQWznDHxlHZr5TD16Annnzx76wFXkCEErFCQHU27m2jEjWK2XeGevIidE6Yd5BnCsJkunJXltPMFtr17IEdZr9phaevMIfxGd0C4MONnELvP1I6yEC9%2B0YfiMBB0x8vbmBy29SXa6%2F7UZZ%2FLMeVyeoVwwzRycrYwsYEjjBTkKY%3D|ampid:PL_CLK|clp:4429486

Veteransaver

A multimeter is cheap too, and has other uses.
Topping it up overnight once a week isn't a bad idea in this weather if you are doing mostly short journeys, but as long as battery isn't on its way out anyway it shouldn't be necessary
The most important thing is not to let the voltage ever drop below about 12.3V for any length of time as that shortens its life due to sulfation. In this cold weather it is more likely to drop low so topping up once a week certainly won't do any harm and you may get an extra year or so out of it.