Can i use a car battery?

Krakkkers

Getting a new car battery tomorrow as current one is getting a bit tired, is there any practical use i can put the old one to?
Thinking charge it on solar and then ??????????

greyteam1959

Not suitable for solar charging I don't think.
If it's a bit tired them it's probably useless for anything.
Take it to your local scrap dealers & cash it in.
Might get £5-6 for it 

retiringtoosoon

I’d hope an aging Tesla car battery would be worth more than £5!

vacheron

As above, your local scrap dealer will take it. 
Last time I checked the going rate was about 45p per KG.

cm4ever

Krakkkers said:

Getting a new car battery tomorrow as current one is getting a bit tired, is there any practical use i can put the old one to?
Thinking charge it on solar and then ??????????

..... that all depends on your background and interests - using a smaller 20/30W solar panel and a cheap PWM charge controller, you could build yourself a garden lights power source for example.

It's not going to run your house, but could run some 12v LED shed lights etc... many ideas really 

Scot_39

Personally - I'd say it wasn't worth the effort - financially - or longevity wise - but if interested in tinkering with electronics - an interesting little project none the less perhaps.

And remember if do take it on as a project - car batteries are only nominally 12V - for charging voltage (14V+ in many cars) - and fully charged - after settling out - so called resting voltage (12.6V+ a traditonal measure of healthy).

iirc 12V is sub 50% full charge

And they fail pretty quickly if spend a lot of time on low charge (not unheard of for owners only doing very low mileages can kill a battery in a year or two)

Qyburn

A retired car battery can work perfectly well in some cases, depending on what was wrong with it. Typically car batteries get replaced either because their cold star ability is deteriorating or because they don't hold enough charge for a cold start if the car's left for a period. 

Around six years ago we replaced the battery because it was getting alarmingly sluggish at cold starting. Since then the old battery has been in service as backup for the electric fence energiser. Normally kept on float charge, but allowing the energiser to run for well over two days if the power's off.

victor2

I use an old car battery that will no longer turn a starter motor to power LED lights and a 12V fan in my granchildren's outdoor playhouse. A 20W solar panel and charge controller keep it topped up. It was a project that I spent quite some time on. I disconnect the battery over winter when it isn't required as the first one died in the winter. Fortunately a friend runs a car workshop and can give me "dead" batteries FOC in exchange for a totally dead one, which goes for scrap. 

Gerry1

Together with a small inverter it might be useful for keeping a boiler controller working during rota power cuts if we have a cold, cloudy and windless winter.

Probably enough power left over for a few LED bulbs as well.  Why stay shivering in the dark?