Red Top Optima Batteries 6 Volt??

[Guest jimstulga]

Does anyone know if Optima Red Top 6V batteries have changed recently?  Here's my frustration; I have a '41 Cadillac. Back in 2010, I installed two Optima batteries in parallel to help with hot starting. They worked great and being narrow, both fit side by side in the cars battery compartment taking up the same room as a normal type battery.  To my knowledge Optima is the only brand that makes this size in 6 volt. For six years they maintained a strong charge, but started to weaken, so I changed them last month for a new set.  I charged the new one's to 100% with my plug in charger, took the car for a long ride. When I got home, hooked up the charger to check strength and they were down to only 25% charged.  Took over 4hrs to recharge. Another ride to a car show, home and same thing again. Just had my generator rebuilt and voltage regulator checked at the same time with it.  My brother brought over his Sun Vat40 to test charging system and put a load on it. It is charging 7 1/2 volts.  All is responding. Put a fluke meter across batteries while running and it's charging, so batteries were not responding to the charge, I guess.  Took them back to Napa and explained all of this.  They were very nice and ordered me two fresh batteries with recent date codes.  Now, it's the same thing again; new batteries charged to 100%, take a ride and they show about 50% charged with hours to bring them back up. The car is stock with no accessories like a/c or sound system, just ignition and turn signals.  Ideas? 

Jim

[Grimy]

I've been using 6V Optimas exclusively for at least 12 years and have had excellent service.  I have 9 years on a pair in my 1934 Pierce, and last year changed out the 14-year-old pair in my 1930--they were getting tired. On my 8-cylinder cars I, too, run a pair in parallel.  For me in a no-freeze climate, Optima(s) will hold a charge for four months or more without any charging. I try to avoid using external chargers on Optimas unless absolutely necessary.  If an Optima is really flat, one needs to charge it in parallel with a higher-charged battery.

 

You seem to have covered the testing waterfront, but I suggest you check for a parasitic draw which may pull down the Optimas when the car is not running. You might also refresh (clean) ALL battery cable connections.

[Guest jimstulga]

Thanks for reassuring me with the quality of the Optima's.  The Napa rep mentioned that same thing about charging them, but the generator in the car should be compatible for doing that, no?  Am I doing harm by using an external charger? 

Battery connections are perfectly clean and tight, proper gauge wires. I use a heavy duty battery cut off switch on the plus side (ground) that is always off when the car is not in use. My brother checked that switch with a gauge for any draw or open. It's fine. 

I did have another thought. After these batteries are charged up again. I could install one in another 6V antique car that I have to see what happens. 

Jim

[Grimy]

Hi Jim, agree with trying one Optima at a time in *another* car.  Also, try one Optima at a time in your Cad and see if you get the same results.  Another option is to try a wet cell battery in the Cad--if that suffers the same fate as the Optimas, I'd conclude the issue is in the car, not the battery.  All of these ideas are time-consuming but non-invasive==and inexpensive!

 

I run a pair in parallel primarily for the reserve capacity; the Group 3 wet cell furnished with my cars has 140AH reserve capacity, and the Optimas are 90-100 AH each.  The 1930 and 1934 Pierces have 25 amp generators whose output drops to 17 amps max when warm, and that's not enough to carry the ignition and all the lights at night--especially because I use higher-output (and higher amperage draw) bulbs in my tail and stop lamps.

 

Please continue to keep us posted!

[edinmass]

I have installed them six times, and removed them six times. I run regular Napa 6 volt workaholic batteries, last one lasted nine years. I have seen and suffered charging issues with the optimias and don't want to deal with the hassle that they than cause. Ed

[Grimy]

To each his own, Fast Eddie!  :-)  I'll stay with Optimas because they work for me, and I really dislike pulling out the seat cushion and/or floorboards to check the electrolyte level in wet cell batteries.  The battery location in Jim's 1941 Cad (the same as in the 1939 75 I owned for 42 years) is not pleasant to deal with, unless you're putting in an Optima with one hand. 

[Spinneyhill]

I am not familiar with Optima batteries. But I have come across charging problems with non-lead acid batteries in our modern heap. The 12 V versions need a higher charging voltage than lead acid to fully charge them. Is it gel or ACM or something that needs the higher charging rate?

 

Is you car compatible? Is your plug-in charger compatible?

[Robert Street]

Optima's have a specific charge voltage which is generally lower than lead acid and at a specific amp rate.  Driving a vehicle with them could be an issue depending on the voltage output of the generator.  Yes, they use a specific aux charger or an electronic smart charger that can be set for their application.  the old conventional wet or lead acid models can hurt them

Robert

[Guest jimstulga]

After doing more research, I think Spinneyhill hit it, the car is not compatible nor is my charger.  Back in 2010 those Optima's were great and worked fine and lasted more years than I would have thought. Something has changed with either the new Optima Batteries or the generator rebuild.  For now, I'm going back to a 975 cold cranking amp wet battery that's available in 6 volt. Too bad nobody makes a narrow wet 6V battery the size of those Optima's.  Jim

[rsb]

Those Optimas are like 800 CCA which is higher than most wet cell batteries. If you need two of them to crank your car, then you have other issues. Possibly bad starter, bad ground, or cable size too small. The power density of two 6-volt Optimas in parallel is probably too much for your poor little generator to keep up.

[DavidMc]

I once fitted 2 Optima's in parallel because we were going on a long tour in an untried newly restored 1920's car that had been having starting difficulties.  The 2 batteries allowed for much longer cranking time before the batteries were flat, (which never looked like happening).  Doubling the number of CCA  made no difference to the speed of the starter motor as one Optima puts out more amps than the starter motor can draw.  In other words the extra battery is just like having a bigger fuel tank.

As it happened our starting problems resolved and we were able to lend a battery to another of our group when their battery died.

  

[John_Mereness]

I went with an Optima in my 41 Cadillac 60 Special - a wet cell is just not a fun battery to get in or out of the case.  I put a new one in the car when I sold it two years ago - prior one lasted about 8 years and went countless 1000's of miles.  The mileage was 17,500 when I bought it in August 1979, at age 14, and I drove it to 97,500 miles.  I never ran two Optima in parallel - I always just focused on the car itself.  You need to ground the battery to the frame and the frame to a bolt on the starter,  You need clean connections *ie grind some paint off your frame),  And, you need an original or a decent sized battery cable - no toy stuff.  1935/1936 Auburn friends have been talking about how to rebuild a starter - metal to metal to metal - no pretty paint on the mating surfaces and they are also reworking all the rivets in the end plate (rust under a rivet does not help the cause).  It is still a process of ear coordination (you have to be one with the car sort of a YODA thing) and it will give you one chance to start it when hot - muff it and you will sit.   Carry an  extra Optima in the trunk as well as jumper cables.  Also, I never ran an electric pump - I would put a NOS fuel pump (usually then rebuilt by Arthur Gould) on it every ten years or so.    Also, I went with a 7 bladed fan from something 50's GM, replace the metal fuel line with neoprene in the axle hump area (especially helpful for a far with fender skirts).  The blocks are also notorious for rust chips - if running an unrestored car you better think about a serious cleaning out (radiator too).   I am told flatheads have a nasty habit when toaster to develop cracks in the valve area on drivers side rear most cylinder (a good reason to takle the underlying problem).      You may want to move this discussion to the CCCA technical - these are really popular CCCA tour cars.

Edited August 16, 2016 by John_Mereness (see edit history)

[Guest Al Brass]

I've got a few 6V Optima's fitted and their performance amazes me.  I've never had a charging problem either so as my lead-acid batteries fail, I'll be fitting more Optima's.

 

Al