What in the ....?????? Low voltage reading, yet full battery and alternator working.

Topic: What in the ....?????? Low voltage reading, yet full battery and alternator working. (Read 19609 times) previous topic - next topic

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #105 – July 04, 2014, 12:24:23 AM

We've really beat this thread to death.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #106 – July 04, 2014, 07:31:21 AM

Quote from: Haystack;435434

I wouldn't be surprised to see a 70 amp peak load if you have electronic goodies.

each bulb pulls a constant 1 amp load.how do i know this? I use extra tail light bulbs to discharge my model airplane batteries. 12v's. = 12 watts. guess what happens at 14.8? Its well over 20 watts. your car should run at 13.5-14.2 ish.

so, 8 tail lights bulbs. there is 8-14 amps. Two 55 watt head lights, another 4 bulbs in front. interior lights, gotta be 10 of those, plus your map lights, sun visor bulbs, dash cluster, lets say you have a 200 watt radio, might only pull 25 watts, but could spike quite a bit highet.

fuel pump, mine said it required 10 amps minimum, power seats, power recline, lets say you use your cigarette lighter to actually light a cigarette as i do frequently, that's well over 20 amps.

and we haven't even started te car yet, just adjusted seats, turned on the key and headlamps.

now why did these cars have a alt with a single 10 guage feed and an alt that puts out about 35 amps at idle? My guess is the same reason why they melted wires.

for some reason i feel compelled to etch this^ in stone .... well said.

have you noticed the single yellow that enters the fire wall yet at the steering column it is split out into two wires feeding one common ignition switch terminal?

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #107 – July 04, 2014, 07:39:04 AM

Quote from: TheFoeYouKnow;435441

I don't know what you've got, Tom, But when I'm running on a cool night, I'm pulling a constant load of 58-66 amps. I've made a few electrical upgrades along the way, sure, but my night-time load is greater than the max of the stock system. Winter before last when I drove the car, my loads were higher still, averaging in the upper 70's and low 80's (in fairness, after 25 minutes or so defrost shuts off and the EATC spins the blower down). .

WOW~!!! 66amps x 1.2 = a pretty decent over current protection size in your case.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #108 – July 04, 2014, 07:55:10 AM

Quote from: V8Demon;435448

Hmmmm...Voltage sensor across the battery terminals built into the car and letting the PCM know when and when not to power up the alternator..... Would a type of clutch or an electrical switch be more efficient/durable? Better yet, will alternators even need to be belt driven in the future? Electric water pumps, EPAS....... I would think an electrically driven alternator would be a logical progression. I'm not alone apparently: http://www.vanner.com/vanner%E2%80%99s-hybrid-beltless-alternator-released-by-vanner-for-allisonhybrids/

Packaging/size will need to be addressed for passenger car applications.

this has been going on in telecom for a long time now.........
http://www.phoenixbroadband.com/bms-system-description

drivers for the alternator would be firmware / software controlled.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #109 – July 04, 2014, 04:52:29 PM

Foe trhings like auto shutdown a stop lights and charging systems that will be controlled by the ecm. By the way some already are. Will weed out all the novice and Saturday morning wrenches. Our new scan equipment put me back a pretty penny. And we still have issues with re-flashes. The dealers will be busy that is for sure. But in time people will learn the ropes but the future will be interesting for sure. Well have a good holiday guys. It is raining a bit here so our cook out will be tomorrow. Be safe

By the way the duel alternator fords are plentiful. We service a fleet of 19 350 Super Duties all with 2 130A Alternators. So one has to think why does ford install 2 130 units when these so called MAGIC alternators claim to be 250 Amp units. Ford would just buy them from those vendors you would think. But Ford knows those units are BULL shiznit and any mechanic worth his weight also knows as well !! Good article guys

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #110 – July 04, 2014, 06:34:31 PM

Amps is only part of the question, not the answer.

watts is actual work performed. think of it this way, a water pipe or fuel pump. amps and volts are the size and pressure of the pipe. watts is the actual end product, lets call it gallons per hour. you could have a ton of pressure in a small pipe without moving a lot of water, or you could have a fire hose with very little pressure and we will get a ton of water.

Without know what your amps and volts are, you have no idea what your actually getting. having an oversized alt vs a underside one will not hurt anything. the actual load placed on the alt is based on load. low load equals a very long lasting and way understressed charging system.

another thing to consider is that a large alt at idle will likely far out perform a small one at max output. for instance, my 55 amp alt may only put out 35 amps at idle, but it will be really stressed compared to a standard 3g that will put out more then 70 amps at idle. the 3g will also take less power to spin and be a lot more efficient.

your battery size doesn't matter one bit as long as it can start.the car. once its started it becomes a load just like the rest of your electrical. at idle while stressed, our cars essentially run off the battery while at idle. this destroys the battery and puts a large load on the alt for no reason. I'm really tempted to see what comes out of the battery while the car is running at idle. ill bet its more then 20 amps.

a well designed electrical system will not draw any power from the battery. instead it should charge it back up. once its charged, it will no longer be a load and your amp draw will raise/drop as needed. an oversized alt will not take more power, it will not wear things out, and it will not melt wires if done properly.

has anyone ever played with the resistance of wires or voltage drop? Its not uncommon for me to see more then a full volt of power loss at the ignition switch. The tail lights themselves get down to 10v's or lower because of how long the feed wires are and the amount of voltage that is lost. this in turn increases amp loads to get the same amount of wattage to power the lights, and in turn eats up the wires as amp loads increase.

for the most part, as long as you have over 12v's your charging system is fine. the higher the voltage, the lower your amp load, the happier and less stressed everything will be (within reason).

The larger fuse and wire you run, the less voltage loss you will have, and the less stressed all parts of your electrical system will be. if your calculating voltage on the tail lights by grounding to the chassi, your only getting part of the voltage loss. even though its low as the entire chassi is energized, you still have to factor in the voltage drop between your power.feed and the negitive ground. you really sould mesure voltage.by connecting to the ground cable of the battery to get an accurate reading. this is basically pointless though, because if you used a jumper wire from to your tail light, then you have to factor in the losses of the jumper wire.

the only point of a fuse to an alt is to prevent a direct short between the charging cable and battery. as long as the fuse trips before your battery maxes out, you will not damage anything and it will cut power like its supposed to.

this is why i would recommend a 6 guage or larger wire and a 175-200 amp fuse.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #111 – July 04, 2014, 11:30:30 PM

Ford's first PCM controlled alternator was on 2000 Focus. That's 14 years, and I can confirm that by 2012, every Ford had one. The depth of computer controlled function now is amazing, and Auto Start/Stop and PCM controlled charging systems, and multiplexed high-speed networks, gateways and so on makes sure that as a dealer tech, I stay needed. And that's just the tip of the iceberg. Anyone wanna talk about Hybrids?

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #112 – July 05, 2014, 06:43:46 AM

Yep try some of the BMW or MB circuits. We deal with HYBRIDS all the time and our state says you have to be a CERTIFIED DEALER ONLY. So if we need to mess with some of the batterys we have to tow then to the dealer to power them down or properly disconnect the propulsion battery. Of course there is a state tax associated with it and licensing fees. The insurance companies are forking out millions on these cars. This in turn costs us more to buy insurance. So much for the TREE HUGGERS. I hate TREE HUGGERS WITH A PASSION!!!!! There ECM REFLASH takes 18 hours compared to a chevy 1/2 hour. Or how about auto Headlight circuits that set a service code if they fail. Or if they blow a lamp. Like i said the novice saturday wrench is going to be a stretch at best. But working in the collision business we have to deal with it all. Now how about 1234yf on some new cars. All new equipment gauges and procedures. Have a great weekend. The future is not for the NOVICE.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #113 – July 05, 2014, 08:06:46 AM

and to my 9 year old post ,,,,
the technologies will generate more garbage in the planet because at a certain point, a piece of equipment becomes cheaper to dispose of rather than repair.
Factor in todays range of upward/downward compatibility , i see this also causing vechicles to become garbage sooner.
Technologies change so fast just lookat how long someone kept thier cell phone 20 years ago vs today.

and im not a tree hugger but i do love my planet and understand how she feeds and houses us.\
litterally everyone back then (maybe it was 2004) posted and disagreed.
we are generating more garbage now per capita than just a short 20years ago, and the trash we are generating is becoming more and more in the hazmat catagory.

tom & Foe,
let me know what you see if a hybrid has a low voltage situation in the charge system.
meaning~ if you measure a voltage at point A,,, what is the current on that conductor with the low voltage.
then~ tell us what is the current reading after the voltage problem was repaired.
--i am suspecting there are going to be a boat load of switch mode power supplies inside those cars within the various sub assemblies and if so, then this is where tom will see the impossible happen,, ohms law will get broken right before his very eyes :)

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #114 – July 05, 2014, 09:32:53 AM

Scott, it's not just cars. Look at the packaging some of your kids stuff comes in now so as to be tamper resistant. Some of it is so ridiculous that the kitchen scissors won't cut through and I have to resort to a pair of tin snips. For PLASTIC.

My Dodge Nitro has started exhibiting an issue where the sat/nav screen stays on after the ignition if off and key removed. These vehicles have almost every electronic component controlled by a single power unit that isn't cheap...... Looks like I might have to spring for one... This isn't rare for them to go bad either.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #115 – July 05, 2014, 11:22:57 AM

Quote from: V8Demon;435517

Scott, it's not just cars. Look at the packaging some of your kids stuff comes in now so as to be tamper resistant. Some of it is so ridiculous that the kitchen scissors won't cut through and I have to resort to a pair of tin snips. For PLASTIC.

So I'm not the only one who wants to stab the person who came up with those packages?

Prior to my current phone (Galaxy S3) I had my previous phone for 5 years. I've had the S3 for a year now. I'm going to try and keep it another 4 years, just to prove that a smart phone can last past it's contract.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #116 – July 05, 2014, 06:35:28 PM

I don't understand the point in a hybrid. 52 mpg at an averagre speed of 48mph. i get 60 mpg at 55 and 50mpg at 65mph in my fiesta.
They can build more fuel efficent cars. they just don't want to.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #117 – July 05, 2014, 07:29:13 PM

Every time they increase the mileage they increase the emission standards and cars loose mileage. But there is only so much energy in a gallon of gas and you can not make that any more. Making the cars lighter is the only way now. Car companies are always trying to increase Mileage. That sells cars. Do you think if GM could pick up another 5 MPG they would not do it?? Of course they would mileage sells cars. By most standards engines are clean and fuel efficient today. And i do not think a prius is fuel efficient at all. As the matter of fact cradle to grave fuel numbers are better in a H3 hummer than a PRIUS. My LS3 Gets 20 MPG at 70 MPH all day long and it dynoes at well over 850 HP have a good evening guys.

52 MPG from a Fiesta. I am not buying that one bit. The AVEO is one of the best mileage cars right now and they do not get anywhere near 52 MPG at any speed

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #118 – July 05, 2014, 11:02:38 PM

My point in making the hybrid comment was to illustrate how stupidly simple even a PCM controlled charging system is when held against some of the highest tech currently widely available in the industry. I've got advanced Hybrid training at Chicago Training Center next month, I'll tell you how it goes.

What in the ....?????? Low voltage reading, yet full battery and alternator working.

Reply #119 – July 06, 2014, 05:52:34 AM

Tom, on an almost all highway trip in my Focus I got 44 MPG. The highway rati g for the car is 38. To be fair it gets around 28 around town.....