Thanks. Those figures look pretty 'standard', and give or take look very reasonable. I assume they are for a new off the shelf battery though.
As an experiment I connected mine to a stabilised 14.4V supply for a couple of hours and was surprised to see the current fall off rapidly to around 0.4A.
Does that mean it is in fact almost fully charged ?
Anyhow, the terminal voltage after 15 hours is now 12.65V which to me seems a big increase for so little energy put back.
What I can't find info on is how aging affect the measured terminal voltage.
As an experiment I connected mine to a stabilised 14.4V supply for a couple of hours and was surprised to see the current fall off rapidly to around 0.4A.
Does that mean it is in fact almost fully charged ?
Anyhow, the terminal voltage after 15 hours is now 12.65V which to me seems a big increase for so little energy put back.
What I can't find info on is how aging affect the measured terminal voltage.
I have no scientifically measured data to cite, but what I've observed is a substantial increase in battery internal resistance as it ages.
This has the effect of making the terminal voltage rise substantially during charging (Eterminal = Einternal + Icharging x Rbat), more than you'd see in a young and healthy battery.
It also has the matching effect of making the terminal voltage fall substantially when the battery is loaded (Eterminal = Einternal - Iload x Rbat). Which is the symptom we usually notice (dim headlights during cranking, etc.)
But the unloaded terminal voltage seems to change little as the battery ages. Which is why you can't tell if a battery is good or bad by just measuring it's terminal voltage with a DMM - instead, auto mechanics use a "battery tester" which puts a beefy resistive load on the battery under test, drawing a large current from it, and then measures the terminal voltage in this loaded condition.
-Gnobuddy
My current car is an '09 Hyundai Sonata. On cold days (near freezing, either above or below), the accelerator becomes incredibly touchy, with the car jerking forward at the slightest touch on the pedal. The surge of power only lasts for a fraction of a second, then it drops back to idle.
The maddening part is that this happens exactly on those days when you have snow or ice or slush on the road - and that brief surge of power lasts just long enough to break the front tyres loose from their precarious grip on the road, spray mud, snow, and slush around, and make me look like an idiot.
-Gnobuddy
There is a threshold of what the voltage drop should be during cranking the starter, 9.6 volts is what I have used as an indicator of a battery that needs help or replacement.
Don’t ignore the connections too, usually are a few that will tie everything together.
Fords and older British cars had starters that were known as “inertia starters”, they didn’t have a solenoid to engage the gear onto the flywheel. Instead, they relied on a jolt to spin up the starter quickly and engage the gear using a helix under the small gear on the starter. Those cars had to have a really good connection (and batteries) or they wouldn’t kick the gear out enough to engage.
The surging when it’s cold is probably just the fuel to air ratio having been affected by the cold air. The ecu may adjust itself with a few days of driving that would include all of the requirements to make up what is called a “drive cycle”. This usually includes hitting 55mph, a couple full stops, the radiator fan cycling on a couple times, something that may not be in the cards during nasty cold weather.
Also, the ecu throws in more ignition advance when very cold, before the engine gets warm, that may make it hard to drive with a delicate throttle in the ice.
Don’t ignore the connections too, usually are a few that will tie everything together.
Fords and older British cars had starters that were known as “inertia starters”, they didn’t have a solenoid to engage the gear onto the flywheel. Instead, they relied on a jolt to spin up the starter quickly and engage the gear using a helix under the small gear on the starter. Those cars had to have a really good connection (and batteries) or they wouldn’t kick the gear out enough to engage.
The surging when it’s cold is probably just the fuel to air ratio having been affected by the cold air. The ecu may adjust itself with a few days of driving that would include all of the requirements to make up what is called a “drive cycle”. This usually includes hitting 55mph, a couple full stops, the radiator fan cycling on a couple times, something that may not be in the cards during nasty cold weather.
Also, the ecu throws in more ignition advance when very cold, before the engine gets warm, that may make it hard to drive with a delicate throttle in the ice.
I have a 2008 Honda Element. It is also touchy on cold days. I notice a quick blink of the traction / stability light followed by a surge of power as the light goes off. This tends to force my foot to lift reducing power. Occasionally it can result in two or three cycles of power followed by loss of traction and a reduction of power. Shutting the stability system off usually eliminates the whole situation, but it must be done on entry to the vehicle since I can't reach the switch from the driver's seat.
I believe this is exacerbated by the very slippery conditions pulling out of our dirt road onto the paved main road. Frozen mud is some slick stuff.
Watch for the little yellow triangle to flash when it usually happens. I have noted that pre warming the car for 15 minutes or so helps the old car shift better on cold days, but does not affect the surging when pulling out onto the main road.
I believe this is exacerbated by the very slippery conditions pulling out of our dirt road onto the paved main road. Frozen mud is some slick stuff.
Watch for the little yellow triangle to flash when it usually happens. I have noted that pre warming the car for 15 minutes or so helps the old car shift better on cold days, but does not affect the surging when pulling out onto the main road.
In the past I have done rough and ready checks by turning on headlights, fog lights and heated rear window. That must pull around 30 to 40 amps at a guess.
When I got as far as just the heated window the other day and saw the voltage heading south rapidly (11.75v) I abandoned the check and looked to research actual voltages.
An increase in internal resistance is certainly going to figure into it though.
Modern engines start so instantly that its hard to gauge how low the voltage dips, I would say mine starts from cold in under 1.5 seconds and when doing a restart (the Stop/Start function) it seems well under a second.
The starter can even spin the engine even if the engine hasn't stopped rotating...and that is a valid condition if the Stop/Start cuts in and you suddenly want to move off. It restarts the already spinning motor, apparently it also 'remembers' the last injection cycle under that condition and so picks up from where it left off in the firing order.
I guess at 9 years old I just have to accept the battery is probably well past its best although it is still serviceable at this point in time.
In the UK it is possible to wring out more life from a car battery by connecting a charger on cold nights, but In Canada when the engine turns over too slow to start there is no choice but to replace the battery.
Cold nights in the UK are often 30 deg C higher than most parts of Canada in the winter.
Cold nights in the UK are often 30 deg C higher than most parts of Canada in the winter.
Mine lives a cosseted life in a garage and so never sees sub zero temperatures on a cold start. I would guess +3 to +5C would be the absolute minimum it has to cope with.
Modern batteries can have a nasty habit of failing suddenly and with no warning. That happened to a friend recently. Car was fine to use at 9AM, they came home and wanted to go out again later that morning and the battery was dead. I've known of other cases like that happening as well.
Modern batteries can have a nasty habit of failing suddenly and with no warning. That happened to a friend recently. Car was fine to use at 9AM, they came home and wanted to go out again later that morning and the battery was dead. I've known of other cases like that happening as well.
I think you're attributing symptoms to the battery that probably are really due to the car's computer systems. In a modern car, they do all sorts of things and have all sorts of interlocks. For example, prevent an engine start attempt if voltage is below a certain threshold, or power certain systems even when the car is parked and not running.
The last battery in my Element failed overnight without warning. It was a 5 or 6 year old Walmart battery, so it was on borrowed time, but it had survived last year's winter with zero no-start days. There was one no-start day the previous winter but it was bleepin cold.
Sometime in spring or early summer before the serious heat appeared, I went out for my morning trip to the gym and was greeted by a dim dome light which vanished when I turned the key. My trusty $4 Harbor Freight DVM showed 10 something open circuit volts, and some really low number when I turned on the headlights. I don't remember the exact numbers. I do poke the DVM leads directly into the battery posts to eliminate any possible connection issues. It was DED!
I ripped the battery out and took it with me in Sherri's car to the gym and the Walmart to fetch a new battery. It fixed the problem. As with the Mustang the Element starts with much more enthusiasm than before. The new battery is now 8 to 10 months old and it's still sluggish on days that are 20+ degrees below freezing.....but then, so am I.
The battery in Sherri's Honda Pilot died instantly as well. She had driven to a restaurant to meet friends from church and when she came out after about an hour, the car did nothing. No click-click, nothing. I jumped it with my Element and drove it home. When I get home, still nothing. This was the original Honda battery, and it had the same symptoms, slightly low open circuit voltage, near zero when the lights are turned on. A fresh battery from Walmart made the car fine, and it hasn't acted up again in two years.
Investigation discovered that this car IS started by the computer, turning the key only initiates the start sequence. Apparently the computer will not grant your start request if there isn't enough voltage.
Sometime in spring or early summer before the serious heat appeared, I went out for my morning trip to the gym and was greeted by a dim dome light which vanished when I turned the key. My trusty $4 Harbor Freight DVM showed 10 something open circuit volts, and some really low number when I turned on the headlights. I don't remember the exact numbers. I do poke the DVM leads directly into the battery posts to eliminate any possible connection issues. It was DED!
I ripped the battery out and took it with me in Sherri's car to the gym and the Walmart to fetch a new battery. It fixed the problem. As with the Mustang the Element starts with much more enthusiasm than before. The new battery is now 8 to 10 months old and it's still sluggish on days that are 20+ degrees below freezing.....but then, so am I.
The battery in Sherri's Honda Pilot died instantly as well. She had driven to a restaurant to meet friends from church and when she came out after about an hour, the car did nothing. No click-click, nothing. I jumped it with my Element and drove it home. When I get home, still nothing. This was the original Honda battery, and it had the same symptoms, slightly low open circuit voltage, near zero when the lights are turned on. A fresh battery from Walmart made the car fine, and it hasn't acted up again in two years.
Investigation discovered that this car IS started by the computer, turning the key only initiates the start sequence. Apparently the computer will not grant your start request if there isn't enough voltage.
There are some added computer features that reduce the (charging) voltage in order to reduce the parasitic drag and save gas. This can have a detrimental effect on the battery in the long run, and I always have the headlights turned on in an effort to maintain a higher voltage and circumvent some of that.
Too many engineers trying too hard to appease regulatory agencies. I would much rather use the extra macro amount of fuel myself.
For a Polo stereo that won’t get ripped off, I would get a line level converter, a small amp that’s 70-100 watts per channel, and some decent 6.5” replacement speakers. Hide the amp up under the dash somewhere. Search out how to deaden the door panels, will help a lot.
Too many engineers trying too hard to appease regulatory agencies. I would much rather use the extra macro amount of fuel myself.
For a Polo stereo that won’t get ripped off, I would get a line level converter, a small amp that’s 70-100 watts per channel, and some decent 6.5” replacement speakers. Hide the amp up under the dash somewhere. Search out how to deaden the door panels, will help a lot.
I've been noticing the chasing of energy efficiencies in designs as well, not cars yet thought.
We have a dishwasher that's less than a year old. If you want it to actually get the dishes clean, you have to press the high temp water "option" button. I looked, there's no way to make it a default. You have to press the button every load.
My old fridge, still in use, had this pesky water leak problem. After a LOT of digging on my part, I found that the manufacturer makes a repair kit that solves the problem robustly. The head scratcher is that the replacement parts look cheaper to manufacture and install than the original parts, and judging by Youtube the problem was known long before my fridge was ever manufactured. Does the fix lower efficiency? You betcha.
The newly renovated washroom toilets and automated paper towel dispensers at my work place are more "efficient", meaning one flush releases far too little water to do its job, and the towel dispenser grudgingly spits out so little paper that you can barely dry your fingertips with it, never mind the rest of your hands.
So when I'm in the washroom area, I now hear the average user flush two or three times before he/she leaves the stall. And then he/she will wave his/her hands three times under the stingy towel dispenser to get enough paper to be useful.
I bet that's saving a whole lot of water and paper towels.
-Gnobuddy
That’s bad engineering by fools trying to make “technology” conserve energy.
Instead of actually making something better, just cut it short right?!!
Typical short sighted approach, happens everywhere unfortunately.
Cracked me up the other day when a tank-like suv stopped politely to allow us to cross the street, and the engine shut off. Didn’t see that coming.
Wouldn’t it have been more economical to just not commute in a 4,000 pound vehicle?
Instead of actually making something better, just cut it short right?!!
Typical short sighted approach, happens everywhere unfortunately.
Cracked me up the other day when a tank-like suv stopped politely to allow us to cross the street, and the engine shut off. Didn’t see that coming.
Wouldn’t it have been more economical to just not commute in a 4,000 pound vehicle?
Speaking of efficiency, anyone remember the days when a "sports car" didn't weigh as much as a large hippopotamus (i.e., two tons), and feel like a large hippopotamus going round every curve?
The '73 Datsun 240Z I owned for a while in the 2000s weighed not much more than half that ( 1973 Datsun 240Z technical and mechanical specifications .) But even that 240Z was a porker compared to a '69 Volkswagen beetle's sub-1800 lbs weight. And that was a family car, not a two-seater.
Nowadays we have 8-speed automatic transmissions, gasoline direct injection, variable valve timing, and lots of other complicated bits of machinery to try to improve gas mileage. But the vehicles have become gradually heavier, and heavier, and heavier, for at least fifty years now.
When an auto manufacturer revisits the old formula, spectacular results are possible. A 1986 Honda CRX weighed about as much as the old Volkwagen Beetle, and the EPA rated it at 52 miles per gallon. Some users reported getting 60 mpg or better on the highway. No tricks, just a small light car, a small efficient engine, and a manual transmission.
Now a new Honda Accord Hybrid weighs nearly twice as much as the old CRX, and it needs two powerplants and a large lithium battery pack to barely manage a little worse fuel mileage than the '86 CRX. ( 2018 Honda Accord Hybrid First Drive | Review | Car and Driver )
Two steps forward, one and a half steps back...
I miss the way those much lighter old cars handled.
-Gnobuddy
I agree, and it’s the safety requirements along with any passenger capacity that is driving the weight increases.
I did have a 3800 pound Lexus that would pound through corners, holding to over 1 g before breaking loose. Was fun, but the 1800 pound Tercel that I had after ($100 vs $18,000) was more fun, especially around town. Now the only way to get a proper lightweight sports car would be to get a lotus, and then you are basically outcast from the rest of the typical cars.
I guess the SUVs are indeed much more than 4K lbs, pretty nuts...
The Datsun Z always let you know there was a heavy engine up front, required a very aggressive driving style to balance it out, and even then...
My mom had a ‘73 VW squareback, had fun with that car, put a sway bar on back, lowered the front a bit, put some stiff shocks on it. While I’m sure it wouldn’t be any super handling car by today’s standards, it was nicely balanced for sure.
I did have a 3800 pound Lexus that would pound through corners, holding to over 1 g before breaking loose. Was fun, but the 1800 pound Tercel that I had after ($100 vs $18,000) was more fun, especially around town. Now the only way to get a proper lightweight sports car would be to get a lotus, and then you are basically outcast from the rest of the typical cars.
I guess the SUVs are indeed much more than 4K lbs, pretty nuts...
The Datsun Z always let you know there was a heavy engine up front, required a very aggressive driving style to balance it out, and even then...
My mom had a ‘73 VW squareback, had fun with that car, put a sway bar on back, lowered the front a bit, put some stiff shocks on it. While I’m sure it wouldn’t be any super handling car by today’s standards, it was nicely balanced for sure.