I know many engineers here work on cars, so ... I am debugging my wife's Lexus ES300. The problem is that the OEM alternators (original and replacements) are not charging at idle. At idle speed, the alternator put out 8V to 10V, which is insufficient to charge the battery. At high speed, it does put out 14V. People suggested speeding it up by changing the front pulley (65mm) to a smaller one. I found a 45mm pulley that might work. But would that cause problem at high speed, including burning out the alternator, or worst?
Alternator problem
Started by ●June 18, 2011
Reply by ●June 18, 20112011-06-18
On Sat, 18 Jun 2011 17:41:07 -0700 (PDT), linnix <me@linnix.info-for.us> wrote:>I know many engineers here work on cars, so ... > >I am debugging my wife's Lexus ES300. The problem is that the OEM >alternators (original and replacements) are not charging at idle. At >idle speed, the alternator put out 8V to 10V, which is insufficient to >charge the battery. At high speed, it does put out 14V. People >suggested speeding it up by changing the front pulley (65mm) to a >smaller one. I found a 45mm pulley that might work. But would that >cause problem at high speed, including burning out the alternator, or >worst?How are you measuring this voltage? Should be with battery and regulator attached. Keep in mind that an alternator is basically a current-controlled current source. Maybe you have a regulator or battery problem? Or an accessory sucking more current than it should? ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●June 18, 20112011-06-18
On Jun 19, 12:41=A0pm, linnix <m...@linnix.info-for.us> wrote:> I know many engineers here work on cars, so ... > > I am debugging my wife's Lexus ES300. =A0The problem is that the OEM > alternators (original and replacements) are not charging at idle. At > idle speed, the alternator put out 8V to 10V, which is insufficient to > charge the battery. =A0 At high speed, it does put out 14V. =A0People > suggested speeding it up by changing the front pulley (65mm) to a > smaller one. =A0I found a 45mm pulley that might work. =A0But would that > cause problem at high speed, including burning out the alternator, or > worst?Should give out 14v all of the time. Can't understand that. Regulator maybe.
Reply by ●June 18, 20112011-06-18
On Jun 18, 5:53=A0pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- Web-Site.com> wrote:> On Sat, 18 Jun 2011 17:41:07 -0700 (PDT), linnix > > <m...@linnix.info-for.us> wrote: > >I know many engineers here work on cars, so ... > > >I am debugging my wife's Lexus ES300. =A0The problem is that the OEM > >alternators (original and replacements) are not charging at idle. At > >idle speed, the alternator put out 8V to 10V, which is insufficient to > >charge the battery. =A0 At high speed, it does put out 14V. =A0People > >suggested speeding it up by changing the front pulley (65mm) to a > >smaller one. =A0I found a 45mm pulley that might work. =A0But would that > >cause problem at high speed, including burning out the alternator, or > >worst? > > How are you measuring this voltage? =A0Should be with battery and > regulator attached.With the battery disconnected. The battery is 12.4V. Regulator is build-in the alternator. Just replaced the alternator (wasn't the problem).> > Keep in mind that an alternator is basically a current-controlled > current source. > > Maybe you have a regulator or battery problem? =A0Or an accessory > sucking more current than it should?People (web search) have reported same problem. It's a known design issue.
Reply by ●June 18, 20112011-06-18
On Sat, 18 Jun 2011 17:59:30 -0700 (PDT), linnix <me@linnix.info-for.us> wrote:>On Jun 18, 5:53�pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- >Web-Site.com> wrote: >> On Sat, 18 Jun 2011 17:41:07 -0700 (PDT), linnix >> >> <m...@linnix.info-for.us> wrote: >> >I know many engineers here work on cars, so ... >> >> >I am debugging my wife's Lexus ES300. �The problem is that the OEM >> >alternators (original and replacements) are not charging at idle. At >> >idle speed, the alternator put out 8V to 10V, which is insufficient to >> >charge the battery. � At high speed, it does put out 14V. �People >> >suggested speeding it up by changing the front pulley (65mm) to a >> >smaller one. �I found a 45mm pulley that might work. �But would that >> >cause problem at high speed, including burning out the alternator, or >> >worst? >> >> How are you measuring this voltage? �Should be with battery and >> regulator attached. > >With the battery disconnected. The battery is 12.4V. Regulator is >build-in the alternator. Just replaced the alternator (wasn't the >problem). > >> >> Keep in mind that an alternator is basically a current-controlled >> current source. >> >> Maybe you have a regulator or battery problem? �Or an accessory >> sucking more current than it should? > >People (web search) have reported same problem. It's a known design >issue.Measure the current with the battery connected. Clamp-on thingie maybe, or just DVM the voltage drop in the wires. John
Reply by ●June 18, 20112011-06-18
On Sat, 18 Jun 2011 17:59:30 -0700 (PDT), linnix <me@linnix.info-for.us> wrote:>On Jun 18, 5:53�pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- >Web-Site.com> wrote: >> On Sat, 18 Jun 2011 17:41:07 -0700 (PDT), linnix >> >> <m...@linnix.info-for.us> wrote: >> >I know many engineers here work on cars, so ... >> >> >I am debugging my wife's Lexus ES300. �The problem is that the OEM >> >alternators (original and replacements) are not charging at idle. At >> >idle speed, the alternator put out 8V to 10V, which is insufficient to >> >charge the battery. � At high speed, it does put out 14V. �People >> >suggested speeding it up by changing the front pulley (65mm) to a >> >smaller one. �I found a 45mm pulley that might work. �But would that >> >cause problem at high speed, including burning out the alternator, or >> >worst? >> >> How are you measuring this voltage? �Should be with battery and >> regulator attached. > >With the battery disconnected. The battery is 12.4V. Regulator is >build-in the alternator. Just replaced the alternator (wasn't the >problem). > >> >> Keep in mind that an alternator is basically a current-controlled >> current source. >> >> Maybe you have a regulator or battery problem? �Or an accessory >> sucking more current than it should? > >People (web search) have reported same problem. It's a known design >issue.Battery should be around 13.2V with no load (6 x 2.2V) My #2 daughter (the chemist) has a Lexus ES-something-or-other. They'll be here tomorrow for Father's Day. I'll ask if she's had any charging system issues. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●June 18, 20112011-06-18
On Sat, 18 Jun 2011 17:59:30 -0700 (PDT), linnix <me@linnix.info-for.us> wrote:>On Jun 18, 5:53�pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- >Web-Site.com> wrote: >> On Sat, 18 Jun 2011 17:41:07 -0700 (PDT), linnix >> >> <m...@linnix.info-for.us> wrote: >> >I know many engineers here work on cars, so ... >> >> >I am debugging my wife's Lexus ES300. �The problem is that the OEM >> >alternators (original and replacements) are not charging at idle. At >> >idle speed, the alternator put out 8V to 10V, which is insufficient to >> >charge the battery. � At high speed, it does put out 14V. �People >> >suggested speeding it up by changing the front pulley (65mm) to a >> >smaller one. �I found a 45mm pulley that might work. �But would that >> >cause problem at high speed, including burning out the alternator, or >> >worst? >> >> How are you measuring this voltage? �Should be with battery and >> regulator attached. > >With the battery disconnected. The battery is 12.4V. Regulator is >build-in the alternator. Just replaced the alternator (wasn't the >problem). > >> >> Keep in mind that an alternator is basically a current-controlled >> current source. >> >> Maybe you have a regulator or battery problem? �Or an accessory >> sucking more current than it should? > >People (web search) have reported same problem. It's a known design >issue.Whoa! I just realized what you said... without battery. Where's it deriving field current ?:-) Certainly it can't be a PM-type. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
Reply by ●June 18, 20112011-06-18
linnix wrote:> On Jun 18, 5:53 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- > Web-Site.com> wrote: > >>On Sat, 18 Jun 2011 17:41:07 -0700 (PDT), linnix >> >><m...@linnix.info-for.us> wrote: >> >>>I know many engineers here work on cars, so ... >> >>>I am debugging my wife's Lexus ES300. The problem is that the OEM >>>alternators (original and replacements) are not charging at idle. At >>>idle speed, the alternator put out 8V to 10V, which is insufficient to >>>charge the battery. At high speed, it does put out 14V. People >>>suggested speeding it up by changing the front pulley (65mm) to a >>>smaller one. I found a 45mm pulley that might work. But would that >>>cause problem at high speed, including burning out the alternator, or >>>worst? >> >>How are you measuring this voltage? Should be with battery and >>regulator attached. > > > With the battery disconnected. The battery is 12.4V. Regulator is > build-in the alternator. Just replaced the alternator (wasn't the > problem). > > >>Keep in mind that an alternator is basically a current-controlled >>current source. >> >>Maybe you have a regulator or battery problem? Or an accessory >>sucking more current than it should? > > > People (web search) have reported same problem. It's a known design > issusSounds like a shit battery and possibly a body ground strap problem.. I don't know how you are measuring your voltage from the alternator but you should not be getting two different readings between the battery post and the back of the alternator output. A good battery should hold the output of the alternator up... Sounds to me that you are some how getting two different readings Lets see.. Lets assume you are reading the alternator at some point where the battery isn't influences it. 8 Volts* 1.414 = > 12 volts. And 10 Volt reading you have should be ~ 14.4 volts.. because the alternator generates AC into DIODES that give you peaks not seen otherwise with a DMM unless you have a battery at that point.. So, take the readings at the battery post instead of the alternator when it's running.. Jamie
Reply by ●June 18, 20112011-06-18
linnix wrote:> On Jun 18, 5:53 pm, Jim Thompson <To-Email-Use-The-Envelope-I...@On-My- > Web-Site.com> wrote: >> On Sat, 18 Jun 2011 17:41:07 -0700 (PDT), linnix >> >> <m...@linnix.info-for.us> wrote: >>> I know many engineers here work on cars, so ... >>> I am debugging my wife's Lexus ES300. The problem is that the OEM >>> alternators (original and replacements) are not charging at idle. At >>> idle speed, the alternator put out 8V to 10V, which is insufficient to >>> charge the battery. At high speed, it does put out 14V. People >>> suggested speeding it up by changing the front pulley (65mm) to a >>> smaller one. I found a 45mm pulley that might work. But would that >>> cause problem at high speed, including burning out the alternator, or >>> worst? >> How are you measuring this voltage? Should be with battery and >> regulator attached. > > With the battery disconnected. The battery is 12.4V. Regulator is > build-in the alternator. Just replaced the alternator (wasn't the > problem). > >> Keep in mind that an alternator is basically a current-controlled >> current source. >> >> Maybe you have a regulator or battery problem? Or an accessory >> sucking more current than it should? > > People (web search) have reported same problem. It's a known design > issue.I know this is a silly question but, "what does the dealer's repair shop say about it?" I'd recommend NOT running the alternator disconnected from the battery. inductor, voltage spikes, electronic regulator... you get the point. Changing the pulley sounds like a bad idea. It's already running pretty fast at cruising speed. Another silly question. You're attacking a symptom. What's the PROBLEM you're trying to solve?
Reply by ●June 18, 20112011-06-18
On Sat, 18 Jun 2011 17:41:07 -0700 (PDT), the renowned linnix <me@linnix.info-for.us> wrote:>I know many engineers here work on cars, so ... > >I am debugging my wife's Lexus ES300. The problem is that the OEM >alternators (original and replacements) are not charging at idle. At >idle speed, the alternator put out 8V to 10V, which is insufficient to >charge the battery. At high speed, it does put out 14V. People >suggested speeding it up by changing the front pulley (65mm) to a >smaller one. I found a 45mm pulley that might work. But would that >cause problem at high speed, including burning out the alternator, or >worst?There's apparently an issue with the ES300 that involves internal separation of the harmonic balancer, causing slippage at low RPM (alternator torque increases at low RPM). Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
