Idling an engine
Discussion
What nobody has mentioned already, is the length of time it will take to fully/properly charge a lead acid battery (and that includes AGM, etc). It will be around 18-24 hours to properly charge it. Sure, during the bulk phase, the battery will accept whatever the alternator can output, but once into absorption it will only accept charge at a certain rate, until this drops to - and this is a reasonable definition for fully charged - a tail current of 1.5% (in Amps) of the battery capacity (in Ah) for 15 mins.
A "dead" battery can often be revived using a smart battery charger (at least something that knows what bulb-absorption-float is) but often they can't, because it is sulphated and to at least try and fix this, needs an equalisation charge which will inevitably lose some electrolyte, which would need to be topped up again. And with sealed batteries, while they have a facility to vent gas over a certain pressure, have no facility to be replenished with electrolyte.
What I would do is:
1) fully charge using a smart battery charger (takes ~24h)
2) test with a proper battery tester that can evaluate state of health too.
3) if it fails 2, replace the battery.
A "dead" battery can often be revived using a smart battery charger (at least something that knows what bulb-absorption-float is) but often they can't, because it is sulphated and to at least try and fix this, needs an equalisation charge which will inevitably lose some electrolyte, which would need to be topped up again. And with sealed batteries, while they have a facility to vent gas over a certain pressure, have no facility to be replenished with electrolyte.
What I would do is:
1) fully charge using a smart battery charger (takes ~24h)
2) test with a proper battery tester that can evaluate state of health too.
3) if it fails 2, replace the battery.
ruggedscotty said:
Smint said:
If the battery is completely flat and you jump start the engine its best to switch something on to give the electrical system something to power, hazard lights (bulbs because leds might not take enough power) are ideal because you're less likely to not notice the vehicle is still running.
I've known cars be jump started and left running for hours on end (sometimes several days unnoticed until the fuel finally ran out) in compounds, only for the battery to still be flat if nothing was switched on.
If the battery was still flat, its a battery issue. Once engine is running it will charge the battery, no need for other loads... the flat battery would be enough load. I've known cars be jump started and left running for hours on end (sometimes several days unnoticed until the fuel finally ran out) in compounds, only for the battery to still be flat if nothing was switched on.
An alternator is not man enough to charge a flat battery totally, not at idle anyway. It would take many hours of running above idle to even make a dent. Its job is to replace the power used when starting and any load used while driving.
Plus once really flat most batteries are hard to recover and most likely will never be tip top.
A trickle charge can help, but often a new battery is a better solution.
Plus once really flat most batteries are hard to recover and most likely will never be tip top.
A trickle charge can help, but often a new battery is a better solution.
richhead said:
An alternator is not man enough to charge a flat battery totally, not at idle anyway. It would take many hours of running above idle to even make a dent. Its job is to replace the power used when starting and any load used while driving.
Plus once really flat most batteries are hard to recover and most likely will never be tip top.
A trickle charge can help, but often a new battery is a better solution.
What an abolute load of rubbish.Plus once really flat most batteries are hard to recover and most likely will never be tip top.
A trickle charge can help, but often a new battery is a better solution.
Alternator will push 40 to 100amps into a battery and take it to a third/half full (sufficient for starting multiple times) in 10 - 20 mins. It'll make a "dent" in around 3-5 mins. No one, other than a workshop, has a charger that will exceed much more than 6 amps. Alternators are more than "man enough".
"really" flat is below 11v, and as long as it's not left there for days on end, will recover almost entirely. Trickle charging simply allows the cells to balance at the top end of the charging cycle.
"very" flat batteries, like 9v or less, will recover but be somewhat damaged, expecially if left in that state for days.
FiF said:
Indeed the battery is very accessible. See photo 2022 C3. OP it's the thing on the RHS of the photo. The +ve terminal has the red cover over the terminals. The one at the other end is the -ve.
If you apply a charger or conditioner you will need to clip the +ve lead onto the battery, obviously you will have to remove the red plastic shield to get access and the -ve onto a metal piece of the body. This is how I connect the ctek onto my daughter's C3 and it's easy.
Come on things are not that difficult. Get it started per your other thread and run it for a while, see what happens.
I'll look at this tomorrow. Cheers !!!If you apply a charger or conditioner you will need to clip the +ve lead onto the battery, obviously you will have to remove the red plastic shield to get access and the -ve onto a metal piece of the body. This is how I connect the ctek onto my daughter's C3 and it's easy.
Come on things are not that difficult. Get it started per your other thread and run it for a while, see what happens.
Panamax said:
There's often a clutch on the alternator pulley but it's not for disengaging the alternator, it's to allow the alternator to spin more quickly than it would be driven by the belt. Without that clutch the alternator, which is quite hefty, will be trying to push the engine when you lift off the the throttle, knackering the drive belt etc.
Yes, the whole point of an alternator is that it's generating a decent amount of electricity even at very low rpm and easily enough to charge the battery as well as running other systems - unlike an old-fashioned dynamo. At tick-over a dynamo car will be slowly draining its battery, hence the enthusiasm for revving as soon as they've been jump-started or bump-started.
Leaf-blower has neither alternator not dynamo. Its magneto is another permanent magnet device which combines the function of coil and distributor, delivering immediate HT direct to the spark plug.
I've not seen an alternator with a clutch or a gear multiplier, no idea why you would make a gearbox inside one to do that. The drive pully size on the crank and alternator is already specified to work the alternator at the correct speed. Smart alternators use internal electronics to manage charge rate.Yes, the whole point of an alternator is that it's generating a decent amount of electricity even at very low rpm and easily enough to charge the battery as well as running other systems - unlike an old-fashioned dynamo. At tick-over a dynamo car will be slowly draining its battery, hence the enthusiasm for revving as soon as they've been jump-started or bump-started.
Leaf-blower has neither alternator not dynamo. Its magneto is another permanent magnet device which combines the function of coil and distributor, delivering immediate HT direct to the spark plug.
Some need a minimum load to switch on at idle, putting the lights on will do that.
The A/C pump has a clutch to disengage it when not required.
732NM said:
I've not seen an alternator with a clutch or a gear multiplier, no idea why you would make a gearbox inside one to do that. The drive pully size on the crank and alternator is already specified to work the alternator at the correct speed. Smart alternators use internal electronics to manage charge rate.
Some need a minimum load to switch on at idle, putting the lights on will do that.
The A/C pump has a clutch to disengage it when not required.
I was told about an alternator clutch on a car I owned with the same reaction ..Some need a minimum load to switch on at idle, putting the lights on will do that.
The A/C pump has a clutch to disengage it when not required.
Eh? What they should've said was "Undirectional", OR "Overrunning Alternator Pulley". Intrigued I checked it out.Maxdecel said:
I was told about an alternator clutch on a car I owned with the same reaction .. Eh? What they should've said was "Undirectional", OR "Overrunning Alternator Pulley". Intrigued I checked it out.
Cheers, no wonder cars are so stupidly expensive now. Talk about engineering in more complex crap. Eh? What they should've said was "Undirectional", OR "Overrunning Alternator Pulley". Intrigued I checked it out.732NM said:
Cheers, no wonder cars are so stupidly expensive now. Talk about engineering in more complex crap.
My thoughts exactly ! ..However it saves fuel .. Apparently Reduces NVH and Blah, blah, blah.
When it fails (It no doubt will) you find the battery's flat or suddenly the MPG increases and the car becomes impossible to use due to vibration
how did we manage before they re invented the wheel.732NM said:
I've not seen an alternator with a clutch or a gear multiplier, no idea why you would make a gearbox inside one to do that. The drive pully size on the crank and alternator is already specified to work the alternator at the correct speed. Smart alternators use internal electronics to manage charge rate.
Some need a minimum load to switch on at idle, putting the lights on will do that.
The A/C pump has a clutch to disengage it when not required.
They won't be alone, but VW cars and vans with Bluemotion have alternators with clutches. Its their "regen braking" solution.Some need a minimum load to switch on at idle, putting the lights on will do that.
The A/C pump has a clutch to disengage it when not required.
When the battery gets to 80% the alternator clutch releases. Now you are driving with better economy as that load has been removed. When the battery dops below a certain voltage it kicks back in. Which seems pointless.... untill you go down a hill. The alternator re-egages, using itself as a "brake assist", dumping the charge into the battery utilising that 20% buffer it has. Then, it'll disengage and you've got until the battery is down to 80% until it engages again.
Ironically, it backfires in their camper vans as people arrive on site with 80% leisure batteries as they are all linked when driving. Owners circumvent this by putting on the heated seats to load the battery up, to keep the alternator going... newwer vans can override the system with a boost button.
FiF said:
The problem I've got now with trying to jump start the battery myself with the booster is that the jump start cables are very short and there is no chance that the black cable will reach the other side of the engine as per the instructions for where the earth point is. It's only about 30cm long and clearly designed to be attached directly to the battery itself (like the red one) but the manual says "" The battery's negative terminal is not accessible. A remote earth point is placed on the structure of the front wing"".
So how the hell do I jump this battery if I can't even attach the black cable to the battery OR reach the earth point?
This is turning into a headache. Big time!
1Steve68 said:
FiF said:
The problem I've got now with trying to jump start the battery myself with the booster is that the jump start cables are very short and there is no chance that the black cable will reach the other side of the engine as per the instructions for where the earth point is. It's only about 30cm long and clearly designed to be attached directly to the battery itself (like the red one) but the manual says "" The battery's negative terminal is not accessible. A remote earth point is placed on the structure of the front wing"".
So how the hell do I jump this battery if I can't even attach the black cable to the battery OR reach the earth point?
This is turning into a headache. Big time!
In interests of full disclosure never had to jump start her C3. Though have used a ctek charger / conditioner in which case it's connected as described, +ve terminal and designated earth point. Leads are sufficiently long.
I too have a jump start pack, never used on the C3 obviously, but any vehicle where it's been used just connected it across the battery terminals, switched it on, waited 10 seconds, turn on car ignition and then starter. Always fired first go.
Not sure why your manual says -ve terminal not accessible. She's at work at the moment, will have a look later this evening.
Sorry, not being much help I fear.
FiF said:
If you've got a jump start device then as you say the leads aren't long enough to connect to +ve and the designated earth point.
In interests of full disclosure never had to jump start her C3. Though have used a ctek charger / conditioner in which case it's connected as described, +ve terminal and designated earth point. Leads are sufficiently long.
I too have a jump start pack, never used on the C3 obviously, but any vehicle where it's been used just connected it across the battery terminals, switched it on, waited 10 seconds, turn on car ignition and then starter. Always fired first go.
Not sure why your manual says -ve terminal not accessible. She's at work at the moment, will have a look later this evening.
Sorry, not being much help I fear.
If you can give me some advice that would be appreciated. I'm looking at other boosters/jump starters too but they're all the same with short cables designed to clamp directly on batteries. So frustrating this !In interests of full disclosure never had to jump start her C3. Though have used a ctek charger / conditioner in which case it's connected as described, +ve terminal and designated earth point. Leads are sufficiently long.
I too have a jump start pack, never used on the C3 obviously, but any vehicle where it's been used just connected it across the battery terminals, switched it on, waited 10 seconds, turn on car ignition and then starter. Always fired first go.
Not sure why your manual says -ve terminal not accessible. She's at work at the moment, will have a look later this evening.
Sorry, not being much help I fear.
I reckon even if I got Halfords out to fit a new battery the technician would get confused by this car and not even know how to swap/connect a new battery.
The only other option the manual gives is to connect jumper cables to an external fully charged battery but that's going to be more money wasted as I'll have to buy long cables and a new battery and my current battery might be dead beyond recovery anyway.
The other option has already been covered by another poster, jump start cables connected to another battery that's operating in another car owned by someone willing to help you get a jump start.
Honestly if you already have a jump pack with short cables I'd just connect it across the existing battery terminals assuming they are physically accessible.
By the way have you actually tried to start it and confirmed the battery is flat and it won't start as is?
Honestly if you already have a jump pack with short cables I'd just connect it across the existing battery terminals assuming they are physically accessible.
By the way have you actually tried to start it and confirmed the battery is flat and it won't start as is?
732NM said:
Buy a set of jump leads and use that to extend it.
Would that be safe to do? clamp longer cables onto the shorter cable clamps of the booster/jump starter then clamp the longer cables to the dead battery and earth point of the car? I've never done any tinkering or mechanics on vehicles but that sounds like a botch it spanner monkey idea?FYI the short red cable reaches the battery terminal just fine. It's just the black one that's useless.
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