Alternator, battery or is it all fine?

richardpope50 · Post by **richardpope50** » Tue May 05, 2015 2:51 pm

1997 RV8 5.l (TVR Griffiths 500) Original starter motor but engine little used – 46,000m
Unipart battery (rated 60 amp/hour, EN 540, RC 105) about six years old. Most of its life left on CTEK conditioning charger otherwise used in car for last summer’s weekly type trips.

I always feel that the starter does not turn over my engine that well. Doesn’t always struggle but it’s never ‘crisp and fast’. I’ve noticed a few times recently that when pressing the starter button (that connects a relay) there’s a mild click but pressing it again and it turns OK. This may mean nothing as it could be the switch.

Yesterday I did a 280m (2 x 3hr) round trip almost entirely on motorways at a steady 65mph.
- First start button push = mld click.
- Second push and all OK
- Stopped at service station after an hour’s driving for 10 mins and it seemed that there was no juice in the battery. The voltmeter registered about 9v and simply went down to less so push started engine. I could not tell if the rad fan was on so this may have been the problem.
- Stopped for afternoon and engine re-started OK for trip home.

My TVR / CAI voltmeter usually registers 13v but could well be accuracy of meter. Minor drop under load such as fan or lights on.

1.) Today’s battery tests.
1a) Battery disconnected = 12.57v on multi-meter
1b) Battery connected to car but no load = 12.57
1c) Started engine OK and noticed about 10v whilst cranking
1d) Running at 1,000rpm tick-over = 13.97v
1e) Running at 1,000rpm tick-over with lights and rad fan on =13.66v
1f) Running at about 2,000rpm = 14.01v
1g) Running at about 2,000rpm with lights and rad fan on =13.64v

2.) Alternator voltage drop tests running at 1,500 > 2,000rpm:
2a) MM –ve to battery –ve and MM +ve to
2b) Alternator casing = -0.00v > 0.02 fluctuating.
2c) Alternator bracket = -0.01v
2d) Engine block = -0.01v

All advice says these readings should be -0.05v or above and NOT -0.01v. Hmm

2e) MM +ve to battery +ve and MM –ve to alternator B+ terminal. Showed values of 0.75, 0.196 and 0.2. All advice says readings should not be above 0.3 so inconclusive, I suggest

Finally, the battery’s magic eye seemed to say it needed charging but when put on CTEK charge, it immediate showed it was full. All cells in battery had water covering the plates.

I’m puzzled so any suggestions, please.

Thanks.

Spongo · Post by **Spongo** » Tue May 05, 2015 3:17 pm

I am sure that a bettery should read in excess of 13V when fully charged, 12.5 V would indicate a somewhat lack lustre battery, also charging should be around 14.3 V I think, but I would check that battery first as it may not be doing too well.

Also check all thee main connections both 12V and earth as you may well have a slightly dirty connection that is giving some false readings as well.

stevieturbo · Post by **stevieturbo** » Tue May 05, 2015 4:03 pm

Batteries really dont last long these days.

What sort of voltage are you seeing at the battery, engine running and with a decent electrical load ?

ie all lights, heaters, anything you can turn on ?

But it does sound like alternator is charging ok.

Although the 10v during cranking doesnt sound terrible, sometimes you just never know though.

IMO, for sake of price of a new battery, just get one if there is any doubt. But do check all wiring and connections etc a little dirt or corrosion can make a big difference

DaveEFI · Post by **DaveEFI** » Tue May 05, 2015 4:27 pm

I have an accurate LED voltmeter wired across the actual battery but switched by a relay from the ignition, so no voltage drop through any other loads on its wiring.
Its normal reading is 13.8v. Goes up to 14.1v after a cold start and will drop below 13.8 when idling with lights and so on. When I first switch on in the morning, it reads around 12.5v - unless the car has been unused for a while and the alarm etc has run it down slightly. The battery is old, but has no problem starting the car, which lives outside.

I was never that happy with the original Lucas starter on my SD1 which seemed to struggle. Fitted a high torque type ( high speed permanent magnet motor with reduction gearing) which whizzes it round.

I've a feeling older charging systems may not fully charge modern 'calcium' batteries, which is what mine says it is, but then you don't need a 100% charge to start a car. Hopefully. But a bonus is the battery never needs topping up, and has lasted well at getting on for 10 years old.

I do have a clever battery tester made by ACT. It's the size of a DVM and gives a read out of the actual battery capacity in amp.hours. A decent battery place should have similar. If a charged battery reads less than 65% of the stated capacity, it's time for a new one. Seems this is a more reliable way of testing a battery than the older high current method.

ChrisJC · Post by **ChrisJC** » Tue May 05, 2015 5:25 pm

It sounds like the charging is OK.

I suspect either the earth connection (you could try jumping the battery -ve terminal straight to one of the starter fixing bolts), or the battery itself maybe knackered.

Try measuring the voltage drop between battery negative and engine block with your multimeter whilst the engine is cranking. You would expect to see much less than 1V.

Chris.

SimpleSimon · Post by **SimpleSimon** » Wed May 06, 2015 2:09 pm

Could be a cell dieing in the battery and usually intermittent too basically you have to check it as the fault is occurring

like suggested already check ground/earth security/continuity

richardpope50 · Post by **richardpope50** » Thu May 07, 2015 10:29 am

Thanks guys.

I think it is not the alternator so decided to buy a new Varta battery. To my surprise it is a bigger capacity one than the current one and £15 less than I paid for it 6 years ago. Just £64 all in delivered.

Will see what happens when fitted.

richardpope50 · Post by **richardpope50** » Wed Jul 01, 2015 1:13 pm

Still a problem after installing a new battery. Haven't been able to use the car much however after leaving for two and a half weeks after a long run so battery well charged, on starting all I got was a 'clunk' from the cog hitting the flywheel. Battery was reading low at about 9v.

Jumped with fully charged battery and all OK. Only drove about 25 miles then garaged car. Today (3 days later) same problem on first and second press of starter. Battery showed about 12v via gauge. Then started OK (as normal) and drove about three miles home.

Just at the moment out of 5 or 6 tries, half the time I get a clunk and half it all starts OK.

1.) Could this be the starter's solenoid? Probably gets hot under there and came out of a Griffith that had done 44,000 so it got hot there too.

2.) Can you repair / replace the starter solenoid? It's a standard starter motor.

3.) Has anyone any experience of PowerLite high torque starters? They seem cheaper than TVR Parts list of £352 as they are £198. Or any other ones?

Thanks.

ChrisJC · Post by **ChrisJC** » Wed Jul 01, 2015 5:00 pm

I guess you could try another starter incase there's a fault with it.

I have only ever used the standard Land Rover ones, the P38 ones are pretty darn good, but I don't know if the solenoid is located in a convenient place for your application.

But it is odd that the battery appears to lose charge suddenly?!

Chris.

DaveEFI · Post by **DaveEFI** » Wed Jul 01, 2015 5:16 pm

It's a PowerLite RAC318 I have. IIRC, one size fits all RV8, unlike the Lucas ones which can be model specific.

I'd check the quiescent current draw when the car is parked up. A good lead acid battery has very low self discharge, so if yours was discharged after a couple of weeks parked, something is causing it.

Generally, you'd expect to see no more than 50mA (0.05A) and hopefully a lot less. Some alarms can be pretty power hungry, though.

Ian Anderson · Post by **Ian Anderson** » Wed Jul 01, 2015 5:27 pm

I have had a similar click when trying to,start

Believe it or not I tracked it back to the power disconnect switch which made contact but not always enough to allow the starter draw.

Easy fix add piece of plastic in hole to pack out the removable key

Ian

richardpope50 · Post by **richardpope50** » Thu Jul 02, 2015 8:29 am

After posting I used the car yesterday and starting was faultless - luckily as once I was in a crowded pub car park with all eyes on my car!

I have to say I'm puzzled on the low voltage - that's only the CAI gauge reading and I did not have my multi-meter to check. I only have an immobiliser that draws a minute current and a (CAI) clock. I tried to measure drain with a multi-meter but negligible amps drain. I thus think it is something else.

Starter switch is actually a savage push button switch triggering a relay to solenoid and do wonder if that's not connecting perfectly as said above but when trying push again I assume it would connect.

I see there are WOSP starters too that seem competitive and are Denso inside. Anyone tried these?

Currently take spare charged battery around just in case.

DaveEFI · Post by **DaveEFI** » Thu Jul 02, 2015 8:55 am

Think you need to do some checks next time it won't start. If the battery is low, something must be discharging it. Low volts somewhere else in the chain would be a different fault. If it always starts normally with a jump start, that would suggest a low battery, or poor connection from the battery to its terminals. Can be a sod to find.

ChrisJC · Post by **ChrisJC** » Thu Jul 02, 2015 5:40 pm

I try (as to motor manufacturers!) to minimise the number of connections between battery & starter. A connection of 10milliOhms is 1volt drop at 100Amps., and 10milliOhms is way too small to measure with a meter!

Chris.

Denis247 · Post by **Denis247** » Fri Jul 03, 2015 5:15 pm

ChrisJC wrote:I try (as to motor manufacturers!) to minimise the number of connections between battery & starter. A connection of 10milliOhms is 1volt drop at 100Amps., and 10milliOhms is way too small to measure with a meter!

Chris.

Put your digital voltmeter between the battery + terminal and the starter terminal, then crank the starter. That will measure voltage drop direct. The lower the better.

Similarly using the meter between the - terminal and any other ground points, engine block etc, will tell you if there's a hr anywhere.