I've actually killed a red top using a standard charger. Just Any auto parts store should have a battery charger that will charge an AGM battery. Or go to Sears and pick up a charger that will charge Standard and AGM's for about 70 bucks.
My Red top lasted 8 years driven daily and my Yellow top which I charge with a normal charger is 4 years old and is drained all the way before charging. Good Battery Great Life.
the autozone fast charger is hell on batteries...it charges at 70 amps and 17.5 volts...I know, I hooked up the ARBST tester to it...gel cells have top be trickle charged when there down sometimes...I used to have a red top and a yellow in a 300zx......they are very picky batteries
The following is directly from the Optima Battery Website
OPTIMA RedTop Charging Information
The following charging methods are recommended to insure a long battery life - always use a voltage-regulated charger, with voltage limits set as described below.
RedTop Type: 34 & 34R - 34/78 - 78 - 6V - 25 & 35 - 75/25
These batteries are designed for engine starting applications. They are NOT recommended or warranted for use in deep cycle applications.
Recommended charging information:
Alternator:
* Maximum voltage 15.6 volts (regulated), no current limit as long as battery temperature remains below 125°F (51.7°C). Charge until current drops below 1 amp.
Float Charge:
* 13.2 to 13.8 volts, 1 amp maximum current, time indefinite (at lower voltage).
All limits must be strictly adhered to.
Safety Information:
* Always wear safety glasses when working with batteries.
* Always use a voltage regulated battery charger with limits set to the above ratings. Overcharging can cause the safety valves to open and battery gasses to escape, resulting in premature failure. These gasses are flammable! You cannot replace water in sealed batteries that have been overcharged. Any battery that becomes very hot or makes a hissing sound while recharging should be disconnected immediately.
* Failure to fully charge a battery can result in poor performance and a reduction in capacity.
Info from BatteriesareUS.com
Charging a DEAD Optima Battery:
After handling the Optima product for 15+ years we would like to share the following:
See our NEW line of OPTIMA recommended Chargers (Battery Accessories)
Facts:
- Batteries are designed to store electricity.
- Batteries do not make electricity.
- Batteries must be charged before any testing is accurate or effective.
- Alternators ARE NOT battery chargers!
- Seldom to batteries discharge / re-charge on their own.
- Deep Cycle batteries will take much longer to charge.
- Battery chargers need to be tested and amperage and the voltage checked manually.
- Sitting a battery on concrete does NOT discharge it!
Battery charging instructions:
* Voltage at the battery terminals when vehicle is running should Be from a minimum of 12.8 volts to < 15.0 volts
* Battery chargers should charge 13.8 ? 15.50 volts,
Never charge a battery at > than 15.6 volts.
We recommend the following charging procedure for a 34, 34/78, 75/35, and 6v:
1) Charge the battery A MINIMUM OF 100 amps ( I'm not too sure about this ) for 15 mins ( @ 14.5+ volts)
a) Let battery and charger cool for 15 mins
2) Repeat step one at least four times - after letting battery cool 15 mins after each charge
3) Charge at 2-10 amps (trickle / automatic) for 24 hours minimum
4) Test the battery
5) D31 batteries: repeat each step again
--> WE ALWAYS RECOMMEND CHARGING TWO BATTERIES AT A TIME- CONNECT THEM POSTIVE POST TO POSITIVE POST ? negative post to negative post) AND PUT THE CHARGER NEGATIVE CABLE ON ONE BATTERY AND THE POSITIVE ON THE OTHER BATTERY! (and DOUBLE CHARGING TIMES)
ALL Optima's need Charged up if they have been discharged, before testing!
We compare charging an Optima to waking a teenager up on Saturday morning, or filling an empty 55-gallon drum with water ? it?s going to take some work!
Charging 10 amps on a drained 31 series battery is like filling a 55 gallon drum with an eye dropper!
Charging 10 amps on a drained 34/78 sries battery is like filling a 55 gallon drum with a 10oz cup - it can be done; but why?
Your alternator will not (and should not be used to) charge an OPTIMA up - unless you have a 100 amp alternator and less than 100 amp draw, and charge it for A long period of time with the car running. (and this will only ruin your alternator)
Experience indicates most batteries thought to be defective may have been discharged, and just need woke up ? and recharged,
Questions to ask before having battery tested:
How many amps is the alternator charging at full output?
How many volts is the alternator charging at full output?
How many amps draw is there on the battery, when application is NOT running?
(Put an amp meter between (+) cable and the (+) post of the battery)
Always use a voltage regulated battery charger with limits set to the above ratings. Overcharging can cause the safety valves to open and battery gases to escape, causing premature end of life. These gases are flammable! You cannot replace water in sealed batteries that have been overcharged. Any battery that becomes very hot while charging should be disconnected immediately. If the safety valaves have popped, warranty is void!
Thank you,
Technical assistance
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Website: Batteries Are Us
Email: tech@BATTERIESareUS.com
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From the Optima Battery website:
Specs & Tech - Technical Specifications
If you Optima battery is totally dead, then you must do this (read instructions carefully):
Charging an Optima Battery [Optima Charg] - $0.00 : Batteries Are Us