Guys: Anyone running an optima yellow top? I have an upgraded alternator for the electric fans and need a stronger battery. When the fans draw current, they will drain the battery ifnthencar I not running in a matter of minutes. I think my battery is too small. Anyway , just wondering if anybody has one in the car and what model it is? Looking to order one here soon.
My experience with Optima batteries in the last several years has not been good. Had to replace one under warranty and the replacement failed a couple of years later. So no Optimas are in my future. If you search for Optima, you will find a couple of threads with others having similar experiences.
This is not necessarily a battery issue. If you had an upgraded alternator installed, it should keep up with all electrical loads. I upgraded my GTC to a Delco single wire 55 amp unit and it is definitely sufficient. It originally had a 30 amp alternator. Put a digital voltmeter on a hot (12 V) wire. With the engine running at fast idle, you should see at least 13 volts. Turn on your headlights, cooling fans and A/C. With the engine at running speed (3,000+ RPM), you should still see over 13 volts. If you do not, it's more than likely a defective alternator, not a battery issue. Bob Z.
As all of these "upgrades" are done, is anyone upgrading the wiring to handle the added current? Upgrade one area and you Will identify the next weakest link.
I had very good luck with a yellow top Optima in my Jeep. I had a winch and power inverter that would run off of it and used it pretty heavily - I liked the yellow for that use as it's made to be deep cycled and also used for starting/continuous recharge. If you do that with a red top it will kill it as they aren't made to be deep cycled. It was about 4 years old when I sold the Jeep and was still working fine. I have a red top currently in our Porsche 944 race car that's 3 years old and working fine.
Optima batteries are AGM batteries, their advantage is in being sealed and that they will stand for more abuse ( frequent charge and discharge cycles ) as in heavy use. They, however, do not like to remain discharged or undercharged. Under those circumstances they are prone to earlier failure. An Optima battery does not necessarily mean a greater reserve of power. They are close in capacity to a premium std battery. The other issue with AGM is that the charge profile and voltage is different ( is more than 12v and amperes) which makes it difficult to get a 100% charge and maintain at the 100% level with older charging systems in car and off car not designed to maintain AGM batteries. Check the charging system for output and review the regulator for operation for compatibilty with an AGM . Is the car a daily driver ? If not, any AGM style battery is not appropriate...it does not get used enough to be effective. A standard Gel type of battery would be a better choice and it will hold up better under little use. I think that using a deep cycle ( Yellow top ) is a good idea in low use cars, and has nothing to do with any of the issues experienced
Hi Bob: Alternator is fine at RPM. I was talking about at idle. Like when approaching a stop sign or red light. If i don't tap the gas, lights dime etc
change to a smaller diameter pulley on the alternator, it will allow the alternator to spin faster when at idle and may solve your issue. Initially you can set the idle higher to verify if spinnng the alternator faster helps... Do you know the specs for your alternator output rpm and regulator settings ? This shows where the alternator rpm should be at your idle speed to get the desired power. Typical current alternators like to spin at 1500 - 2500 rpm at idle... if engine rpm is 1000 you would need the drive pulley to turn the alternator 2.5 times for each time the engine turns to get 2500 rpm at the alternator to meet your minimum power needs at idle. One or both of the pulley would need to be changed to get the proper ratio. Also you need to be aware of max rpm you can spin the alternator as well. It may be that you need a higher output alternator to match the power needed at idle. Older cars allowed the car to run off the battery when at idle, the low voltage light was acceptable / normal when at idle. New cars have electronics that need a minimum voltage to operate properly and will not allow the voltage to drop while at idle.
Is there a maxim RPM limit to alternators? If you have a drive ratio of 2.5/1 then at 7000 RPM the alternator is spinning at over 17000! Is that ok, it just sounds a little high.
yes, that's the reason to check the specs and the possible need to change both pulleys... or change to another alternator that delivers the correct power needed over the rpm range of the motor... also the voltage regulator should be matched to the power requirements and charge profile of the battery batteries have become high tech, it used to be we only had the flooded cell battery ( std wet type ), now we have gel, AGM, Lithium etc... each of these batteries has a preferred charge profile and charge voltage, they all can be labeled 12v... any 12v charger / alternator will give them a charge when flat, but to get the most out of the newer high tech batteries they need a compatible charger / system to to get them fully charged and maintain them at full charge.
