computer fans sometimes come with speed signals. maybe one of them could work? 12V also
Overriding a "smart" battery management system
- Thread starter circuitsmith
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I think many cars use an IBS these days as my Hyundai EV does. As best as I understand with just a few milliamps current draw it samples and logs battery voltage, (+) current and (-) current 24/7 and makes that info available whenever the car is powered on. By separately tracking energy both in and out with temperature and age it can evaluate the actual state of charge rather than just rely on open-circuit voltage, which without the IBS is impossible to determine anyway.
In most cases it charges at 14.6 V for 30 min only from the start of each drive, subsequently dropping to 13.1 approx for the remainder perhaps to ensure that the battery is not depleted. It also automatically charges at intervals while parked, sometimes skipping those if the battery is already fully charged.
No doubt if the OP removed the (+) wire to the IBS the car would revert to some default charging schedule, but would probably throw a code as well.
In most cases it charges at 14.6 V for 30 min only from the start of each drive, subsequently dropping to 13.1 approx for the remainder perhaps to ensure that the battery is not depleted. It also automatically charges at intervals while parked, sometimes skipping those if the battery is already fully charged.
No doubt if the OP removed the (+) wire to the IBS the car would revert to some default charging schedule, but would probably throw a code as well.
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Does the OP realize that every time he starts and runs the car it charges the battery? Look up alternator on Wiki.
As I posted earlier, I have no interest in making a "hard" modification.
When I'm making a 15 minute drive to the grocery store I simply flip on the headlights, from the comfort of the driver's seat,
which raises the battery voltage from 12.6V to 14.xV, helping to top up the battery charge.
Some people drive with the headlights on all the time anyway.
Sometimes I get 14.x for a couple minutes, then drop to 12.6V. I wish it would stay up to 13V.
If it's a sunny day and the solar panel has been charging, it drops to 12.6 right away.
On a long drive it will rise to 14.x for a few minutes every hour or so.
One day I must try to make a more careful observation, but a long drive may have to wait awhile, due to COVID.
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I have some of those variable CPU fans in the collection, but they were physically too small.
gathermewool
Site Donor 2023
gathermewool
Site Donor 2023
Proper float voltage for a 12VDC LA battery is in the mid-to-high 13s. For the system to command anything lower is simply for gas savings....what little there will be, considering I see my bench power supply drop to ZERO amps at 13.9VDC when the batter is full. It then cycles between a very, very low current and zero again.
Older batteries, and for some reason my latest group 24 battery, pull a little bit higher amps no matter how full.
Older batteries, and for some reason my latest group 24 battery, pull a little bit higher amps no matter how full.
Any idea what the charge rate when doing the balance mode charge is? I’m interested in knowing the correct charge rate to get a 100 percent fully charged and balanced battery. I’m sure it’s a fairly slow charge rate. I have several RC chargers that allow me to set charging parameters exactly how I want to.
Not much to add to the actual discussion, and I will admit I only skimmed it, however being fairly familiar with the BMS systems on newer vehicles and the PWM or data-line controlled alternators on earlier cars it's actually quite amazing to me that someone would be so concerned with the ability of their vehicle to maintain it's own electrical system.
Up here in MN, it's not unusual to see a normal, brand name battery last 4-5 years. That's going through a 12-month cycle of -25 to +100 degree temps year after year. What's the price of a good battery now, $130? That's $26-$33 a year. Call it $30. Or $2.50 a month. Is it really worth all the agonizing, charging, analyzing, floating, calculating, "reconditioning" what have you over a double cheese at McDonald's once a month?
I realize that a bad battery can prematurely cause an alternator to fail, however in my experience it's been the other way around. I've seen many more batteries fail from a failed alternator than vice versa. Newer Honda J35 alternators love to dead-short internally while running and smoke the battery in short order. I've had them kill a fully charged jump pack in the 45 seconds it takes to pull one in my shop from the parking lot.
One more asterisk: I'm strictly referring to vehicles that are used daily to semi-daily, being used for trips exceeding 10-15 minutes of off-idle time after a cold start, with at least 1 full cool down between starts. Fairly typical daily driver usage. Obviously my logic makes no sense for a stored vehicle, a weekend cruiser, or a short-tripped/2nd/3rd vehicle.
Up here in MN, it's not unusual to see a normal, brand name battery last 4-5 years. That's going through a 12-month cycle of -25 to +100 degree temps year after year. What's the price of a good battery now, $130? That's $26-$33 a year. Call it $30. Or $2.50 a month. Is it really worth all the agonizing, charging, analyzing, floating, calculating, "reconditioning" what have you over a double cheese at McDonald's once a month?
I realize that a bad battery can prematurely cause an alternator to fail, however in my experience it's been the other way around. I've seen many more batteries fail from a failed alternator than vice versa. Newer Honda J35 alternators love to dead-short internally while running and smoke the battery in short order. I've had them kill a fully charged jump pack in the 45 seconds it takes to pull one in my shop from the parking lot.
One more asterisk: I'm strictly referring to vehicles that are used daily to semi-daily, being used for trips exceeding 10-15 minutes of off-idle time after a cold start, with at least 1 full cool down between starts. Fairly typical daily driver usage. Obviously my logic makes no sense for a stored vehicle, a weekend cruiser, or a short-tripped/2nd/3rd vehicle.
Seems to me he does by virtue of him actually measuring the voltage.
What he is figuring out is that alternators even "smart" factory alternators are by and large - not great at fully charging batteries.
Dumb regular ones can be pretty bad, guys that measure them know this.
No matter the length of the trip the battery will not be fully charged compared to what a manual or actual smart charger can accomplish
This is why a whole dedicated aftermarket for truly smart alternators or kits from companies like Balmar exist.
Another solution is to maintain it properly and you can get something like the 12 years Ive gotten out of the pc-1750 in my titan.
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Another solution in search of a problem.
Which?
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Like when LED's started making enough light for people to think about using them in their cars. All the "experts" were telling whoever would listen that regular halogen or tungsten bulbs are robbing power from the car by making the alternator work harder. Sure, maybe theoretically on a laboratory floor with sensitive instrumentation it might show up as a difference. But in real world a couple of fewer amps on a 60 or 120 amp alternator is not gonna amount to a hill of beans in your car. Same with aftermarket charging systems to replace factory designed charging systems. Looking at a hill of beans. Now if you talking about getting some whiz bang aftermarket car charge system so you can run spotlights and PA systems and otherwise use power well outside the design parameters of the car, then OK.
gathermewool
Site Donor 2023
I maintain my batteries for two reasons:
A. It's EXTREMELY EASY TO DO
2. It's an interesting, practical, and EXTREMELY EASY tech to learn about
-----Battery tech (AFFORDABLE, LA) advances at a snail's pace, so you're not playing catchup WHILE learning
-----In temperate climates, such as NE, batteries need not be replaced every 4-5 years
D. It's good for the environment.
-----Sure, the lead is recyclable, but how much energy and waste can be reduced by taking a few SIMPLE steps to make your battery last, let's say, even a year longer than it would have? Multiply that by every BITOG'er or car enthusiast in general!
That may be true of most vehicles' systems; however, that's not true for all. My new-to-me '15 Legacy had an active TSB for battery charging logic when I purchased it three years ago. Unfortunately, I got it taken care of before I could do some real testing to see how bad the original logic was. Regardless, after the TSB reflash, the alternator is now putting out >14VDC (close to 14.4VDC) for my entire 13-miles commute every day and will remain high enough to maintain the battery about as well as if I hooked up a charger to my vehicle while driving (obviously impossible)
My previous Civic, on the other hand, would drop down to the mid-12'sVDC as soon as the engine warmed up and would stay there unless I added an appreciable load, such as the parking light or A/C; then it would jump up to the high 13's, low 14's, IIRC.
What are you talking about? I read up on automotive-relate articles all the time and nowhere outside of ADS have I seen people hawking LED's. I added LED's to my vehicle to increase lumens, not to help out the alternator. Now, a side benefit of LED's, at least in my Subaru, is that it drains the battery at a lower rate when, say, my wife decides to leave an interior light on. Instead of coming out to a dead battery, which used to be the usual, she's able to start the car and be on her way without any issue whatsoever, except that I have to put the battery on a charger ASAP to minimize damage to the battery.
This in no way justifies the ENORMOUS cost of QUALITY LED's today, but that's not the point, is it.
Anyway, I like some of your funny posts (whether they were intended to be funny or not), but what you have to say about batteries makes it obvious you haven't fully accepted the dark side of automotive maintenance and, therefore, will never truly be accepted into our cult.
A. It's EXTREMELY EASY TO DO
2. It's an interesting, practical, and EXTREMELY EASY tech to learn about
-----Battery tech (AFFORDABLE, LA) advances at a snail's pace, so you're not playing catchup WHILE learning
-----In temperate climates, such as NE, batteries need not be replaced every 4-5 years
D. It's good for the environment.
-----Sure, the lead is recyclable, but how much energy and waste can be reduced by taking a few SIMPLE steps to make your battery last, let's say, even a year longer than it would have? Multiply that by every BITOG'er or car enthusiast in general!
That may be true of most vehicles' systems; however, that's not true for all. My new-to-me '15 Legacy had an active TSB for battery charging logic when I purchased it three years ago. Unfortunately, I got it taken care of before I could do some real testing to see how bad the original logic was. Regardless, after the TSB reflash, the alternator is now putting out >14VDC (close to 14.4VDC) for my entire 13-miles commute every day and will remain high enough to maintain the battery about as well as if I hooked up a charger to my vehicle while driving (obviously impossible)
My previous Civic, on the other hand, would drop down to the mid-12'sVDC as soon as the engine warmed up and would stay there unless I added an appreciable load, such as the parking light or A/C; then it would jump up to the high 13's, low 14's, IIRC.
What are you talking about? I read up on automotive-relate articles all the time and nowhere outside of ADS have I seen people hawking LED's. I added LED's to my vehicle to increase lumens, not to help out the alternator. Now, a side benefit of LED's, at least in my Subaru, is that it drains the battery at a lower rate when, say, my wife decides to leave an interior light on. Instead of coming out to a dead battery, which used to be the usual, she's able to start the car and be on her way without any issue whatsoever, except that I have to put the battery on a charger ASAP to minimize damage to the battery.
This in no way justifies the ENORMOUS cost of QUALITY LED's today, but that's not the point, is it.
Anyway, I like some of your funny posts (whether they were intended to be funny or not), but what you have to say about batteries makes it obvious you haven't fully accepted the dark side of automotive maintenance and, therefore, will never truly be accepted into our cult.
Gamer - Good to hear someone has it close to right although 14V is still 9.5 % short of a full charge of 14.4
Thats about what my ridgelines "smart" system will do. I can come off a 500 mile trip and it will be right around 14V.
Thats about what my ridgelines "smart" system will do. I can come off a 500 mile trip and it will be right around 14V.
My 2005 Silverado does this also. I never heard of it until I started using torque pro after purchasing the truck from my employer (had been driving it for years) and realized the voltage dropped to ~12.6 at times. I had noticed this behaviour on the factory gauge but assumed the gauge was wonky (typical for these trucks). When I replaced the alternator it still read low voltage sometimes. Then I did my research and found out it was normal.
I honestly believe it's the only reason the original alternator was still working on 200k miles and ~8750 engine hours.
I would leave it active. It could even increase battery life by not pushing it to the max all the time. You're already doing good by keeping a charger on it when it sits.
I've seen an OEM battery last 11 years in a 2002 GMC truck, 10 years in my mom's 1999 Olds sleep and I got a hand me down battery from my ex's mom's 94 Lumina Van with 350k miles on it, that battery went 10 years too.Sure, and get my oil changed at Iffy Lube every 3000 miles too?I don't think so.
Get it tested before winter (in cold climates) or before a long trip if you're concerned about it, or every year once it gets to 4-5 years old. Most of my batteries have lasted 6-7 years.
I replaced the original battery in my previous 2006 Toyota Matrix after 9 years.
It was still working okay, but I didn't trust it for a 10th winter.
Back then I connected the battery to an adjustable power supply overnight every 3 months, set to 14.5V.
I do let it do its thing when I'm driving more than 30 minutes.
On return trip to home I bump the voltage up (with the headlights) for the last 30 minutes.
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