I have a red top Optima battery in my 74 and over the last few months, the engine has been turning over slower and slower. What are the characteristics of the Optima when it is going bad?

Lead acid batteries usually just dump and won't start the car.

I haven't checked the voltage at rest or while the engine is running to see if it's the battery or my charging system. I guess that will be tonight's activity.

Can I use an external charger to try to put a full charge on the battery?

Thanks,
Spoke

Yes, you can use a 2 amp trickle charger on an Optima. I put one on the 914s periodically during the winter.

1. Clean your battery posts.
2. Clean & tighten your negative cable ground, transmission strap ground & starter connections.
3. Start your car. Use a multimeter and check the voltage reading while the car is running (charging voltage). Should be about 12.9-13v. Someone will give the correct "book" figure, I'm sure.

If you're not getting the proper charging voltage, the regulator could be suspect, but I'd clean the alternator mounting points first. It's a far cheaper solution.

-Rusty

I'm sure you've cleaned the battery terminals and posts already. right? =-)


a dying battery will hold "voltage" but not carry a "load".

you need a battery load tester.

a harbor freight load tester has been in service at my house for several trouble free years. and at $17.00 it's hard to beat the price.

http://www.harborfreight.com/cpi/ctaf/Cate...4&pricetype

I had an odd problem. My silver car was overcharging. I checked my wiring and it was properly installed. I swapped in three different voltage regulators including a new one and it still overcharged. I checked grounds and they were tight.
I replaced the Optima Red Top and it is fine...

A load test is a good idea. I'd charge it up, then take it to your FLAPS to have them do it.

The Optima is a great battery... but one thing that will kill it is letting it go completely dead. Often, they can't be brought back to life.

So, if you're storing your car for the winter (it's cold in PA), be sure to disconnect it. A center console clock is enough to kill a battery.

Don't ask me how I know.

I have read that the red tops require a different charging sequence. You may want to read what they say before putting on a trickle charger.

Jim

I had my red top die, charged it up with my normal charger, and been using it in my DD for about 3 months now.. cranks 3 times faster than my other battery....

You just have to be careful about overcharging a sealed battery. With a normal battery, if you overcharge, the water will boil off. This is no big deal, since you can top it up. With a sealed battery, the water boils off and is contained in the battery, if only slightly overcharged. This water will be reabsorbed back into the battery. If you severely overcharge the battery, then the water will be vented out. This will reduce the water in the battery, and start to expose more and more of the plates. At the plate area goes down, the battery will lose capacity. Also if the battery sits too long in a discharged state, the battery will become sulfated, which will also reduce capacity. This can sometimes be partially fixed by cycling the battery on a pulse charger, or using a desulfator.

I have an SC34U Red Top Optima.

From Batteries Are Us

Here's their charging suggestions:

Charging an Optima or AGM 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 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
______________________________
Website: www.BATTERIESareUS.com
Email: tech@BATTERIESareUS.com
______________________________
We suggest you print this out and share it with others!

I measured the resting battery voltage to be 12.28V (no load). My charger puts out about 15-16V while dumping in about 2 amps. After about 1/2 hour of charging, the battery voltage with parking lights on was 12.48V.

With a resting voltage of 12.28v, this indicates roughly that the battery is around 50% charged. It should read at least 12.65v to be fully charged. You may want to get a good charger and see if you can charge it up full. Expect to pay $80-100 for a good computerized charger. Most cheap chargers are "dumb" chargers, and wont charge the battery properly. A good computerized charger will use a 3 step process to get the battery to full charge. Also to fully charge a battery int he car, you must deliver at least 13.8 volts from the alternator. You will need around 14.4v to properly "top off" a battery for maximum capacity. If you dont top off a battery regularly, then it will eventually build up sulfate, and will fail.

Also forgot to mention that with the charger on, if you are still seing 2 amps after 1/2 hour, then the battery is not fully charged. Best is to put a voltmeter on the battery while it is being charged. When the voltmeter reads around 14.5-15v then take the battery off of the charger.

Here is a quote from battery university regarding the Optima style batteries (cylindrically wound)

"The cylindrical Cyclone by Hawker requires a very high peak voltage of 2.60V/cell. Failing to apply the recommended voltage threshold causes a gradual decrease in capacity due to sulfation. Follow manufacturer's recommended settings on these lead-acid variations."

This would mean that the battery should be charged to a max voltage of 15.6V to avoid a decrease in capacity.

Did some measurements today with the engine running.

At idle, battery voltage measured:

No lights: 13.69V
Parking lights: 13.37V
Headlights: 13.10 to 13.60

Engine Revving:

No lights: 13.84V
Parking lights: 13.60V
Headlights: 13.40V

After turning engine off, battery voltage after 1/2 minute was 12.70V

I was thinking I should see some voltages in the 14's at least during revving.

I believe that 13.8 is usually wht most regulators are set for. You could also try a solid state regulator, and see if it is a little better.

This is the info from theOptima Battery web site's recommendations on charging.

This is for the red top.
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 - 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.
Alternator: 13.3 to 15.0 volts, no amperage limit.
Battery charger: 13.8 to 15.0 volts, 10 amps maximum, 6-12 hours approximate.
Rapid Recharge: Maximum voltage 15.6 volts (regulated).
Maximum current: No limit as long as temperature < 125°F (51.7°C).
Maximum recharge time: Charge until current drops below 1 amp.
Float charge: 13.2 to 13.8 volts, 1 amp maximum current, time indefinite (at lower voltage).
To charge the OPTIMA 6V-1050, six volt battery, divide the charge voltage setting in half.
All limits must be strictly adhered to.
------------

Optima's website also said not fully charging their batteries to a full 15V will shorten the life of their batteries.
MOST lead acid smart charger" battery chargers cut off at around 14.5V...


additionally..... (taken from the optima red top pages regarding charging red tops....)

Recharge Time: (example assuming 100% discharge – 10.5 volts)
Current
Approx. time to 90% charge
100 amps 35 minutes
50 amps 75 minutes
25 amps 140 minutes

Recharge time will vary according to temperature and charger characteristics. When using Constant Voltage chargers, amperage will taper down as the battery becomes recharged. When amperage drops below 1 amp, the battery will be close to a full state charge.
(All charge recommendations assume an average room temperature of 77°F, 25°C)

****************
Not fully charging a battery can result in poor performance and a reduction in capacity.
****************

I also learned a few things on car batteries here
http://www.gammatron.com.au/datasheets/appnote.pdf

When I bought my fan-inflated storage bubble, I bought a solid state trickle-charging little device that stays on permanently during the winter. My Optima Red Top is out of the car and is connected to this thing.

I'll tell you if the battery (new this past summer) works in the spring!

biz

I have had red tops in my four wheel drive and have noticed that if they go completely dead it is really hard to recharge them. I placed mine on the charger for atleast 2 days on trickle with no success. Also i notice that they usually just fall flat on thier face so you might have some loose wires or bad grounds. JMO

Josh

So I thought my charger was messed up since it cycles on and off about every 2 minutes between "full" and "2 amps" after charging for 10 minutes or less. Should I let it continue to cycle? Am I not letting it reach capacity?