| Author |
Message |
James Selevan (Jselevan)
New member
Username: Jselevan
Post Number: 48
Registered: 6-2002
| | Posted on Saturday, July 20, 2002 - 3:10 am: | |
Ken - the voltage regulator compares the battery (line) voltage against a reference (defined by a zener diode and resistance bridge). If the voltage of the battery falls below this reference, the field voltage to the alternator is increased, which results in greater current output. If the current produced by the alternator exceeds that necessary to provide spark, lights, fans, etc., then the excess current charges the battery. When the field voltage to the alternator increases, the strength of the magnetic field swept by the coils increases, and this requires more work. (It is a bit more complicated when one introduces the concept of back EMF - not germane). Thus, when the alternator produces more current, it resists turning to a greater degree, and requires more horsepower to turn, and increases the tension in the belt.
Your mechanic friend is fundamentally correct. A low battery voltage will lead to more tension in the belt. However, this is rather negligible, and modern belts should not whimper at the chance to produce more current.
Batteries prefer slow trickle charges to slam-bam-thank-you-ma'am current inrush. The electrolyte and lead plates in your battery get warm and fuzzy with slow charging. They become real irritable with big amperage. Nonetheless, they are designed to accept large charging current during normal driving. Happens all the time when the fans go on with the wipers on a rainy night in Georgia (with the AC and lights on) while at a traffic light. Once you get moving, you will charge 40 + amperes for a few minutes. Those that recommend trickle chargers are on the right track. So is your mechanic. It's a stretch, however, to suggest that the belt will suffer the consequences of a low battery voltage.
Jim Selevan
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david handa (Davehanda)
Junior Member
Username: Davehanda
Post Number: 119
Registered: 5-2001
| | Posted on Saturday, July 20, 2002 - 12:44 am: | |
This mechanic is wrong. Yes the alternator WILL work a little harder, but let's face it, most 308's are not driven that much, and most are probably started with batteries that are down on power, yet I have never heard of an accessory drive belt breaking because of this. Yes, he may have seen it happen, but that has got to be a rare occurance. Simple cure, drive the car more, it's way more fun than plugging in a charger. :-) |
Ken Ross (Kdross)
Junior Member
Username: Kdross
Post Number: 86
Registered: 2-2002
| | Posted on Friday, July 19, 2002 - 7:51 pm: | |
James:
From what my mechanic told me, I should never start the 308 with a battery that has a low charge. The result is that the alternator belt will snap because it is so small and tiny and it is not easy to replace. Here is the reason. If you have a battery that is low when you go to start the car, something in the car (real technical term) will sense the low charge and the alternator activates. For some reason, the combination of the alternator coming on and starting the car is too much stress for the tiney alternator belt and it will snap. I am not mechanically inclined, so that is the best I can do in explaining why a 308 QV should never be started with a low battery.
As to the quick disconnect, yes my car has one and I do use it. Ferrari did something right when the design that feature. |
James Selevan (Jselevan)
New member
Username: Jselevan
Post Number: 47
Registered: 6-2002
| | Posted on Friday, July 19, 2002 - 7:38 pm: | |
Ken - can you elaborate on "starting a low powered battery can cause the alternator belt to snap (too much stress on the belt)." If I do understand the sentence correctly, you have been ill advised. While charging at high ampere rate will require more work, the belt should be designed to tolerate this. Has anyone experienced alternator belt failure as a result of charging 40+ amperes for a few minutes?
I ask this question only because I recently rebuilt my alternator, and when first starting the car, the battery charged at 40+ amperes for approximately 30 minutes of driving. I was worried, not about the belt, but about heat in old, corroded connectors at the alternator fuse box.
Jim Selevan |
Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 208
Registered: 5-2001
| | Posted on Friday, July 19, 2002 - 3:14 pm: | |
BTW, When I read the thread title, my initial reaction was "use your credit card"(heheheh...). |
Verell Boaen (Verell)
Junior Member
Username: Verell
Post Number: 207
Registered: 5-2001
| | Posted on Friday, July 19, 2002 - 3:07 pm: | |
1) If your car has it, use the 'battery disconnect switch' to the left of the spare tire well. It's really just a large plug/socket that disconnects the negative battery terminal from ground. Most of the '80s 308/328s have it. See your owner's manual.
2)The Schumaker automatic charger is nice. They're sold by Walmart, Menards, JCWhitney, & others for $25 to $45. Sears sells it under their lable. The shape is very distinctive. See the JCWhitney one below:
http://www.jcwhitney.com/productnoitem.jhtml?CATID=5454&BQ=jcw2 |
JPM (John_308qv)
New member
Username: John_308qv
Post Number: 41
Registered: 4-2001
| | Posted on Friday, July 19, 2002 - 9:54 am: | |
I use the Schumacher Mity Mite Battery Charger that I found at my local Menards for $25. It is a "smart" charger. I strapped it to my battery and ran the chord out to the front grill. Plug it in for winter storage. Works great. John |
Matthew J. Morgan (Kermit)
New member
Username: Kermit
Post Number: 22
Registered: 8-2001
| | Posted on Friday, July 19, 2002 - 9:34 am: | |
You may wish to make sure that the charger is a "smart" charger. These differ from the old style trickle in that once they reach optimum volts, they shut completely off. The old tricklers keep a low charge going. This will harm the battery in the long run. Believe me, I ruined a good battery learning this one! |
Dave Penhale (Dapper)
Junior Member
Username: Dapper
Post Number: 129
Registered: 4-2002
| | Posted on Friday, July 19, 2002 - 4:54 am: | |
I use an 'Optimate' from these guys
www.accumate.co.uk
You affix a mini loom to the battery, it then stays on the car. Whenever you aren't using the vehicle you plug to the charger and it trickles the battery. Its relatively cheap and ensures that whenever you want to use the vehicle the battery is in tip top condition. |
Erik R. Jonsson (Gamester)
New member
Username: Gamester
Post Number: 32
Registered: 3-2002
| | Posted on Friday, July 19, 2002 - 1:15 am: | |
www.performanceproducts.com or griotsgarage.com
they have a neat charge system that attaches to the battery then has a molex plug so it can be undone easily. |
Paul Newman (Newman)
Member
Username: Newman
Post Number: 273
Registered: 12-2001
| | Posted on Thursday, July 18, 2002 - 10:10 pm: | |
If you use the car regularly, the battery wont need to be charged. If you use it once a month, the battery should still hold a charge if its any good. Where I live, in the winter, you might consider removing it and putting a trickle charger on it but thats about it. I didnt even do that this past winter and had no starting problems. |
Ken Ross (Kdross)
Junior Member
Username: Kdross
Post Number: 85
Registered: 2-2002
| | Posted on Thursday, July 18, 2002 - 9:47 pm: | |
My mechanic has suggested that I keep the battery in my 308 constantly charged. Supposively, starting a low powered battery can cause the alternator belt to snap (too much stress on the tiny belt). Because the battery is located under the spare tire it is a PITA to charge. Does anyone have any suggestions as to how I can connect some type of wires or connectors that will make charging easier? TIA. |