How to tell if a car battery is fully charged

thescouselander

Wig wrote: »

An hydrometer is a good test, but a lot of batteries are sealed now. and those that aren't sealed the acid barely covers the plates so it's difficult to get your hydrom.. filled up.

I havent encountered a battery yet on any of my cars that couldn't be opened up. Even the so called maintenance free batteries can be got into. That's not to say their all like that but I've had no problems at least.

sassy_one

A good sign a car battery is full is if thr car starts on the turn of the key; try it

Other than that the car has it's own charming system and will charge the car while the engine is running; if the changing system has no faults and has a good battery.

johnnyroper

cyclonebri1 wrote: »

Tyres have minimum wear blocks, these run in the grooves and when you are running on these you are illegal.

not true when down to wear bars this is an indication tyre is getting low and should be replaced they indicate tyres have 2mm tread left so not illegal.

cyclonebri1

johnnyroper wrote: »

not true when down to wear bars this is an indication tyre is getting low and should be replaced they indicate tyres have 2mm tread left so not illegal.

Not according to my tyre guage, plus when they are at that level the block prevents clearing of water from the grooves as it becomes a dead stop.,

johnnyroper

cyclonebri1 wrote: »

Not according to my tyre guage, plus when they are at that level the block prevents clearing of water from the grooves as it becomes a dead stop.,

i never said they would clear water just that the wear bars are at 2mm.:)

personally would not go that low on my car 3mm is the min i go to.

cyclonebri1

johnnyroper wrote: »

i never said they would clear water just that the wear bars are at 2mm.:)

personally would not go that low on my car 3mm is the min i go to.

I never said you did say, I was just stating the fact, , so we agree.

I change my tyres when there is the slightest doubt for an mot, or rather when it would be an "advisory", at the wear blocks if that is reached in summer, and more recently at about 3 mm in winter considering the recent 2 years.;)

cyclonebri1

Getting back to the subject of battery health, my normal check, and this is because it gives a dam good idea if the problem lies with the battery, alternator or a drain, is to;

Check the battery voltage at the battery with the engine running. It shold be 12.5 to 13.5, pref 13.5V.

Less than that and suspect the alternator or battery

Leave it for 8 hrs or so and check the voltage again before starting, any significant drop and there is a problem with the battery or it's being drained.

Repeat the test but disconnect everything from the battery, if the battery voltage doesn't fall there is a drain somewhere.

If it does fall significantly it's the battery.

PS, make sure you have the radio code before you try this, ;)

babyshoes

It is a common misconception that the tread wear indicators are there to tell you when the tyre is at the legal minimum. They are not! Each country has a different legal minimum, and the tyre manufacturers will not change their manufacturing process for each country they sell to, so the tread wear indicators are set at a fairly common minimum level, which could vary from manufacturer to manufacturer. There is no legislation about how deep they should be. They are usually around 2mm high, but you can't rely on them to be exact, especially not on budget brands made in China or similar!

What they are intended for is to highlight uneven wear on the tread (even long before the tread is worn enough to consider replacement), which is a valuable diagnostic tool for someone trained to spot it. They coincidentally provide a handy clue as to the general depth of tread remaining on the tyre, but should not be relied on to show legality of the tyre.

To answer the original question - find the TWI as described above, and if it seems close to the surface, get it checked properly either with a simple tread depth guage or by a professional - the decision about what depth to change them at is your own, but I believe the police change theirs at 3mm...
If it is at the surface then your tyres may already be illegal, and are certainly not pumping water as well as they should, so I would suggest you get them changed ASAP.

Also get your tyres checked if the sidewalls look crackled or perished or if there is a cut or bulge. If there are any bald patches on the tyre, get them changed ASAP. If the tread seems to be wearing faster on one part of the tyre, also get it checked - there are a couple of problems that can be diagnosed this way - and getting them fixed early will save you money in the long run.