Ford Focus - Car battery charging - mouton

Hello - any battery nerds out there? I have a CTEK charger for my 13yo focus (the battery has been replaced at some point), and have recently had to use the charger for the first time. I'm pretty busy working from home at the moment, so the car gets very few outings - maybe a 6-mile round trip to the shops once every week. This has resulted in one very dead battery, and I've had to jump-start it quite a few times in the last month.

This week I decided to crack out the maintenance charger... It seems to work really well. I plugged it in yesterday to charge the battery. All indicators were good. Then it started raining hard, so after only one hour and a half, I had to disconnect everything to prevent my extension leads from swimming down the pavement!

The car started perfectly after that, and I gave it a drive to the shops. But, when I plugged the charger in again when I got home, the indicators showed that the battery was fully-charged (permanent green light) and the bulk light was flashing red.

1. I don't understand how the battery can be full from utterly dead after just 1.5 hours charge and a very short drive. The manual says it's supposed to take at least 7 hours of charging.

2. CTEK's faq ( tell me that the indicator combination could mean there's an unexpected current drain. This might explain my dead battery, aside from my poor treatment of it... but I always leave the air vents off, car locked and radio unplugged when I close up. So where could the current be going, and can someone confirm that the flashy led combination I'm seeing is indicative of current drain?


Ford Focus - Car battery charging - bathtub tom

I'd suggest your battery's on its way out. 13 years for two batteries ain't bad, however.

I'm not familiar with CTEK chargers, so can't comment on the LED combination.

You'll need to take it to a garage or someone with the skills and equipment to check for current drain and the chances are they'll tell you a new battery's required.

Take it to a decent motor factors. My local one won't charge for testing a battery if it results in a sale.

Ford Focus - Car battery charging - mouton

I did have the batt checked this time last year, and they said it was fine. Suppose it's possible it could have sulphated in the interim though!

Ford Focus - Car battery charging - mouton

Actually, what am I talking about? I have a voltmeter. I can check if it's held its charge through the night.

Ford Focus - Car battery charging - Simon

If you have had to jump start it a few times recently then the battery has deep cycled a few times and will almost certainly be on its last legs.

These smart chargers are not foolproof so I would not pay too much attention to the flashing lights especially seeing as you haven't charged it and left it on - you used the car in the middle of this charging/recovery period.

Before looking for a drain I would do the most obvious thing - replace the battery for a new one!

Ford Focus - Car battery charging - Cyd

I'd say your battery has just about had it. Car batteries DO NOT LIKE repeated deep discharges - it knackers them.

If the battery is on it's last legs then the short period of charging could be giving out a false reading to the meter.

It's your mistreatment that's done it. I've had it happen to me a couple of times. I now keep my car with a conditioner connected.

Ford Focus - Car battery charging - Peter.N.

They will also still start the car with remarkably little capacity left, until you leave something switched on, then they die.

Ford Focus - Car battery charging - Cris_on_the_gas

All battery chargers whether they are Intelligent, conditioner or any other name the manufacturers give them work on the same principle. The voltage of the charger is higher than the voltage of the battery. Clever chargers sense this and alter the voltage accordingly. Back to Ohms law this regulates the current flowing into the battery to prevent excessive current buckling the plates in the cells.

I would get the battery in a fully charged state. ( don't take offence but you need to get out more, at least an hour or so or give the battery a good charge with the charger.

As you have a voltmeter, after the charge leave the car for at least an hour, then connect up the voltmeter. Try to start the car while observing the voltage of voltmeter. If it drops below 10V then you need a new battery. If it does not then you have a good battery but maybe you are not charging it enough. Remember if car has alarm then this will drain battery slowly if left for a few weeks.

Ford Focus - Car battery charging - mouton

Yes, I can now officially confirm that the battery is dead! It does hold just enough charge for 2 days, but nothing more than that... So yeah. I need to get out more and get a new battery :)


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