Batteries

[a101960]

I have a Ford Focus 1.8 TDCI which has been a bad starter. It was fitted with a 60 AH battery and the motor always cranked relatively slowly. Most times it would eventually start after many attempts, but not always. Sometimes it would just not start, and inevitably the battery would go flat. The standing voltage measured 12.7v and the alternator is delivering 14.7v. I fitted a new starter motor and new  glow plugs which made no difference. Anyway I have now bought a new battery rated at 70 AH and it has transformed starting. Engine cranks much faster and it starts almost straight away even in cold temperatures. So, can anyone offer an opinion on the battery? Was the old battery US, or simply not man enough for the job? I know nothing about batteries and would be interested to hear from anyone that does. Seems to me that although the old battery seemed to check out OK it was probably on its way out.

[Swarfcut]

They don't last forever, and if it is a maintenance free type, could be the electrolyte is a bit low and could do with a top up. Some are very well sealed, others quite easy to open. Distilled water or melted frost from the fridge is good enough as a top up .
 Bear in mind the electricity comes from a chemical source, and chemical reactions are slower at lower temperatures, plus the cold thickens the oil, and like you they become a bit sluggish on a cold morning.

 I had to get a new battery a few weeks ago, running fine, next day dead, reading around 10 volts. Would not take a charge, so suspect failure/internal short of one cell. Got a good cheapie on eBay, so worth waiting a couple of days rather than a trip to Halfrauds. Got a bigger capacity battery than the O.E. penny pinching original for less money.

 A battery may show a good no load voltage, but this is no guarantee that it will supply a high starting current.

 I have  added an extra heavy duty earth lead directly to the engine block from the battery earth, the original braided types are exposed to corrosion etc and will not pass a high starting current. But check that earth lead and chassis connection anyway. It may have been a dirty battery connection and swapping batteries just gave a better contact.

Don't sling the old battery just yet, charge it from time to time, keep as a standby, and invest in a nice 12v LED shed light.

 At this time of the year you have the assurance that the truck will start, so whatever the cost, money wisely spent.

Swarfy.

[a101960]

Swarfcut thank you for your response. Seems from what you say that just because a battery appears to check out OK it does not mean that it is. Interestingly finding an up rated battery proved quite difficult. Eventually Ebay came up trumps. Halfords had nothing suitable, they had up rated batteries but none that would fit my battery tray.

[Greybeard]

When I was a motor mechanic I learned about poor battery connections. The symptoms are, the starter motor is sluggish. Customer uses his battery charger and succesfully charges battery. Car starts well for a few days but then the same symptoms occur. Many customers would just buy a new battery and have no trouble for a while.
The cause may be a 'dry joint' in the terminal clamp, particularly those tapered post jobbies. The high starting current passes through the poor connection but the much lower charging current does not. Net result, battery goes flat.
Remove your battery leads. Clean the battery terminals with boiling water to remove the white crystals if there are any. Rough up the posts and connectors with emery cloth or similar. While the terminal is hot smear petroleum jelly on the contact surfaces. Make sure that the connections are as good as you can get them. Your battery will last much longer.

[RDfella]

A10 - I note you refer to AH rating. That is fairly unimportant, sort of tells you how long you can leave your lights on for. What is important is the cranking amps available. For an average car engine I like over 500A, for boat engines over 750A (their AH rating is 125).

[a10 gf]

^^^ basically agree very much, just my impression a more amps battery would also prolong the max A time somewhat, in addition to the 'lights on' time. 10 or 30 seconds more cranking may make the difference.

[KiwiGF]

I have a Ford Focus 1.8 TDCI which has been a bad starter. It was fitted with a 60 AH battery and the motor always cranked relatively slowly. Most times it would eventually start after many attempts, but not always. Sometimes it would just not start, and inevitably the battery would go flat. The standing voltage measured 12.7v and the alternator is delivering 14.7v. I fitted a new starter motor and new  glow plugs which made no difference. Anyway I have now bought a new battery rated at 70 AH and it has transformed starting. Engine cranks much faster and it starts almost straight away even in cold temperatures. So, can anyone offer an opinion on the battery? Was the old battery US, or simply not man enough for the job? I know nothing about batteries and would be interested to hear from anyone that does. Seems to me that although the old battery seemed to check out OK it was probably on its way out.

Not sure about the uk but specialist car battery sellers here will test batteries for free, they can use a special testing machine (like a std voltmeter) that measures max cranking amps (which is the hundreds of amps) these “little” testers take multiple short bursts of the max cranking current so the leads can be thin and don’t get hot etc.

A few places have better (big) testers that have the really thick leads and that will better replicate the current taken by starter motor.

Either way you can get an opinion on the state of your battery in respect of starting current capability, hopefully for free as it only takes a few seconds to do the test.

[duTch]

 Also check n the connections of the starter,  but may also be a lazy armature- I'm having the same issues with my Gutzzi with 30Ah AGM $240 battery which is 'only' maybe three years old but generally sits at about 12.3/12.4 V but still only bump/ jump starts ok- had better values out of cheap wet acid jobbies....

 On the other hand and of no help, I also had similar with my 3L Hiace (2.8 diesel)- after a fair bit of messing about it finally occurred to me that in a time of need, I'd swapped the starter with the one from my old 2L which doesn't have reduction gears ( or other way round)... bought a used one from a wrecker and immediately all good


 

[Greybeard]

Not sure about the uk but specialist car battery sellers here will test batteries for free...

I feel pretty certain that at least here, they never find a battery that doesn't need replacing by one of their own 'High Capacity', high price batteries.  Cinical about the motor trade, me?

[duTch]

 

....... Cinical about the motor trade, me? .....

 Not at all- but ' cynical ' ;  no more than most of us 

[KiwiGF]

Not sure about the uk but specialist car battery sellers here will test batteries for free...

I feel pretty certain that at least here, they never find a battery that doesn't need replacing by one of their own 'High Capacity', high price batteries.  Cinical about the motor trade, me?

Same here, but with my poor starting ‘96 Land Rover discovery diesel two (surprisingly honest) places said my battery tested out ok, and I didn’t buy a new one, later in desperation I DID buy a new 800cca (up from 650cca) one but it only made a slight difference and after a year of use I was back to square one. If I replace the glow plugs every year I can live with it......and it’s just got got a new 680cca battery after 5 years of the 800cca one, which eventually got killed off by a intermittent current drain so it kept getting completely drained and left for days like that.

Much as I love this old land rover they are a PITA electrically, the intermittent drain was a faulty relay in the heater blower circuit.......I couldn’t find that issue until it became “permanent” and I noticed the blower stayed going when I turned the ignition off!

Actually, I guess it’s worth testing the current drain (with ignition off) on the Ford Focus? To check it’s not excessive? On that, Modern cars often cant be left unused for much over a week cos of the electrics draining the battery even with the ignition off (alarms, immobilisers, remote locking, keyless entry etc etc).

[Greybeard]

I had an early series 2 diesel Land Rover for 12 years. It would start fine from cold but was a right dratsab when hot. The starter just refused to turn the engine over fast enough. The car had two huge 6v batteries, one under the passenger seat and one under the bonnet, (hood). I think the battery connecting leads and their connections were absorbing current. After I changed to one 12v battery starting was good.

[KiwiGF]

I had an early series 2 diesel Land Rover for 12 years. It would start fine from cold but was a right dratsab when hot. The starter just refused to turn the engine over fast enough. The car had two huge 6v batteries, one under the passenger seat and one under the bonnet, (hood). I think the battery connecting leads and their connections were absorbing current. After I changed to one 12v battery starting was good.

I’d have a series Land Rover like a shot, but the wife hates them from when she was young and towed horse floats around with em as part of her job.

My impression of the early discovery like mine is that Land Rover seriously over stretched themselves when designing the wiring for abs, air bags aircon etc, the number of wires in the harnesses defies belief 

It doesn’t get used much nowadays and the battery drain issues are completely solved by disconnecting the battery when in its in the garage 

[RDfella]

For vehicles only used occasionally I usually fit a battery master switch. Done that to my classic cars, though mainly as insurance against fire, given the age of the wiring. Also acts an an anti-tealeaf device and an answer to those hard-to-find electrical leakages that drain a battery over a few weeks. I got tired of buying new batteries because they'd gone flat and been that way for a week or more. Only downside is modern radios lose their memory and take too long to re-programme. Modern technology is taking us backwards in many cases.