Upsize battery better?

[Mkl22]

9 hours ago, Vratenza said:

Hmm, skimmed through both article... I am trying to guess you are saying that a failing/failed voltage regulator will mess up the charging of the battery and the electrical system? 

 

I quote:

"The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. Amperage or current is regulated by the state of charge of the battery.When the battery is weak, the electromotive force (voltage) is not strong enough to hold back the current from the alternator trying to recharge the battery. As the battery reaches a state of full charge, the electromotive force becomes strong enough to oppose the current flow from the alternator, the amperage output from the alternator will drop to close to zero, while the voltage will remain at 13.5 to 14.5."

 

a weak battery will not be able to hold charge and constantly require charging from the alternator. a good battery once full charged will only need very little current and thus load on alternator will drop. so a weak battery does add an additional load on the electrical system and you need more energy. this energy to charge to battery comes from the engine.

[JanM]

21 hours ago, Vratenza said:

If you understand how a car alternator works, this statement is false or misleading.

Car alternator is linked to the engine via a belt. As long as the engine is running, the belt will turn the alternator and it will be constantly be "working" so to speak. Even when the engine is idling, the alternator is "working".

Only difference will be the alternator will be forced to work harder whenever you ram your engine (ie. RPM increase). That is why after a flat battery is jump started, the advice is always to drive the car around for a distance to allow the battery to charge up. Even when idling, the battery is being charged, just more slowly as part of the generated electrical power from the alternator needs to be diverted to run the car's electrical system.

Correct me if I am wrong, I do not know of any engine management system that will increase the engine RPM just to work the alternator harder as to charge a larger capacity battery faster?

So the talk of saving or increasing fuel consumption due to battery sizes/failing battery/alternator does not hold water.

\When the alternator is spun by the engine drivebelt, it generates current which goes onto to charge up the battery.  This current flows within the copper winding of the alternator and that in turn give rise to a reverse torque that opposes the drive of the engine.  The battery itself has a voltage that opposes that generated by the alternator.  The alternator voltage is slighly higher than that of the battery and it is this difference that drives the current into the battery and charges it.  This current is the same current as that flowing through the copper winding mentioned earlier.  As the battery charges up, its voltage increase and thus also the difference between the alternator voltage and the battery's.  The charging current consequently falls and and with it the reverse torque. This translates into lower tension in the drive belt which means less strain on the belt and the bearings.  The lowered current also mean less heat generated in the coil.

So in summary, the alternator may be turning but with little load when the battery is already fully charged.

[Vratenza]

5 minutes ago, JanM said:

\When the alternator is spun by the engine drivebelt, it generates current which goes onto to charge up the battery.  This current flows within the copper winding of the alternator and that in turn give rise to a reverse torque that opposes the drive of the engine.  The battery itself has a voltage that opposes that generated by the alternator.  The alternator voltage is slighly higher than that of the battery and it is this difference that drives the current into the battery and charges it.  This current is the same current as that flowing through the copper winding mentioned earlier.  As the battery charges up, its voltage increase and thus also the difference between the alternator voltage and the battery's.  The charging current consequently falls and and with it the reverse torque. This translates into lower tension in the drive belt which means less strain on the belt and the bearings.  The lowered current also mean less heat generated in the coil.

So in summary, the alternator may be turning but with little load when the battery is already fully charged.

 

26 minutes ago, Mkl22 said:

 

I quote:

"The voltage regulator controls the field current applied to the spinning rotor inside the alternator. When there is no current applied to the field, there is no voltage produced from the alternator. When voltage drops below 13.5 volts, the regulator will apply current to the field and the alternator will start charging. When the voltage exceeds 14.5 volts, the regulator will stop supplying voltage to the field and the alternator will stop charging. This is how voltage output from the alternator is regulated. Amperage or current is regulated by the state of charge of the battery.When the battery is weak, the electromotive force (voltage) is not strong enough to hold back the current from the alternator trying to recharge the battery. As the battery reaches a state of full charge, the electromotive force becomes strong enough to oppose the current flow from the alternator, the amperage output from the alternator will drop to close to zero, while the voltage will remain at 13.5 to 14.5."

 

a weak battery will not be able to hold charge and constantly require charging from the alternator. a good battery once full charged will only need very little current and thus load on alternator will drop. so a weak battery does add an additional load on the electrical system and you need more energy. this energy to charge to battery comes from the engine.

Hmm...So the question is how much "resistance"/"load" imposed by the activated field current applied to the alternator by the voltage regulator to have real world significant effect on the FC?

Mind you, we are talking about easily 150NM of torque minimum from the smallest of engine.

[Mkl22]

21 minutes ago, Vratenza said:

 

Hmm...So the question is how much "resistance"/"load" imposed by the activated field current applied to the alternator by the voltage regulator to have real world significant effect on the FC?

Mind you, we are talking about easily 150NM of torque minimum from the smallest of engine.

you go google and clarify then.

[Arogab]

39 minutes ago, JanM said:

\When the alternator is spun by the engine drivebelt, it generates current which goes onto to charge up the battery.  This current flows within the copper winding of the alternator and that in turn give rise to a reverse torque that opposes the drive of the engine.  The battery itself has a voltage that opposes that generated by the alternator.  The alternator voltage is slighly higher than that of the battery and it is this difference that drives the current into the battery and charges it.  This current is the same current as that flowing through the copper winding mentioned earlier.  As the battery charges up, its voltage increase and thus also the difference between the alternator voltage and the battery's.  The charging current consequently falls and and with it the reverse torque. This translates into lower tension in the drive belt which means less strain on the belt and the bearings.  The lowered current also mean less heat generated in the coil.

So in summary, the alternator may be turning but with little load when the battery is already fully charged.

All these were probably calculated during the design stage of the car. So adding up or subtracting up might just be negligible. If there is a huge difference, then I suppose the design is screwed up or the car manufacturer is just cheating up on you

[Vratenza]

22 minutes ago, Mkl22 said:

you go google and clarify then.

Yups I did, even go as far as digging into scholar citations and papers.

Conclusion I draw is the induction flux effect on the mechanical load on a alternator is miniscule to have any real world significance. Pumping up the tyres to the proper pressure probably have more detectable FC savings.

[Columbian78]

I would like to add on to the weight adding factor (not insignificant) of upsizing car battery since I have not seen detailed numbers being discussed here. I think some car folks are particular about adding kilograms into the engine bay area in front.

A popular battery like Amaron Hi-Life weighs as follows, ref from Kim Hoe website as below.

35AH = 10.9kg

45AH = 13.2kg

60AH = 17.4kg - 18.4kg

80AH = 22.5kg

 

A typical small car like Vios, Jazz uses 45AH and some will upsize to 60AH --> Add 4 to 5 kg.

A typical car life Sylphy stock batt 60AH and some upsize to 80AH --> Add 4 to 5 kg.

So one needs to consider if there is a need to employ higher capacity batt with the additional weight. Probably some folks really need the higher capacity (camera running off parked cars, audio system).

 

http://www.kimhoetyre.com/Products-Michelin-Pirelli-Yokohama-Continental-Good-Year-Eagle/Batteries

 

 

[Si4dr]

Side track a bit, how often need to change battery?(no extra ICE & car cam no 24hrs monitoring)

WS ask me to change every 2 years......

[Dafansu]

31 minutes ago, Si4dr said:

Side track a bit, how often need to change battery?(no extra ICE & car cam no 24hrs monitoring)

WS ask me to change every 2 years......

I usually change every 2 years to 2.5 years max. 

[Vratenza]

28 minutes ago, Si4dr said:

Side track a bit, how often need to change battery?(no extra ICE & car cam no 24hrs monitoring)

WS ask me to change every 2 years......

You probably have to pay for the battery...😄

this is a good reference and guide:

https://carro.sg/blog/car-battery-still-working/

 

for me practically, I will keep track of how my car cranks up from cold. (this method works even with the modern day push start button, just that you do not have your hand on the key in the ignition to feel the vibration).

if the cranking gets a bit sluggish or laborious, it is usually sign of a weakening battery.

Many newer cars also have self diagnostic warnings that will alert you (it does so by registering quickly reducing voltage each time the engine is turned off)

[Etnt]

42 minutes ago, Si4dr said:

Side track a bit, how often need to change battery?(no extra ICE & car cam no 24hrs monitoring)

WS ask me to change every 2 years......

on a prev alfa, when the dashboard have disco lights, and each change can barely last 2yrs

on a prev bimmer with the batt in boot, there will a warning on the center screen on discharge during startup, changed at 4yrs

imo, heat plays a big part.

[Cheesey74]

40 minutes ago, Si4dr said:

Side track a bit, how often need to change battery?(no extra ICE & car cam no 24hrs monitoring)

WS ask me to change every 2 years......

If u seldom drive, ur battery will last longer, like mine already 4 years cos i drive sparingly and yes, mine a opc car and all my previous opc cars the battery usually last 3 to 4 years 

[Arogab]

Mine is low mileage and I was asked if I wanted to change after 4 years. I just change lor. 

[Vratenza]

apparently most websites state that if you infrequently use your car, the higher chance your battery's lifespan will decrease.

I guess it has something to do with deep discharge cycle that will kill the non-lithium car battery.

For wet cell batteries, it is recommended to keep their charge topped up as frequently as possible.

 

[Sdf4786k]

20 hours ago, Dafansu said:

I usually change every 2 years to 2.5 years max. 

U need a reliable workshop or battery supplier to run a diagnostic or in some case, your car infor system will ping you on SOC state of charge .

doing a estimate is a waste of money. Trying to help everyone save money at this time of inflation worry 

[Columbian78]

Previously I will change around 2 years which is usually when I start to feel regular cranking weakness.

Nowadays with a backup starter like lipo starter, just change when the batt really start failing. Its so easy to get it started again, no need waste a good batt.

 

[inlinesix]

Shopee/Lazada/Amazon has a lot of battery testers.

 

[Kb27]

21 hours ago, Si4dr said:

Side track a bit, how often need to change battery?(no extra ICE & car cam no 24hrs monitoring)

WS ask me to change every 2 years......

a ballpark figure in Sg is 2 yrs. anything more, the risk of not starting your car gets higher.