For purposes of setting the charger correctly, are they "AGL" or "GEL" ?

Depends on which optima you have:

https://www.optimabatteries.com/en-us/support/battery-basics/redtop-vs-yellowtop-vs-bluetop-battery

There is a specific charging procedure for recharging/charging a fully discharged 6v red top Optima AGM Battery. It is described on their website.
Recovery Option #2, on the right.

What type/model Optima battery are you referring to?

John,


A gel battery design is typically a modification of the standard lead-acid automotive or marine battery. A gelling agent is added to the electrolyte to reduce movement inside the battery case. Many gel batteries also use one-way valves in place of open vents, which help the normal internal gasses to recombine back into water in the battery, reducing gassing. Generally, gel batteries are less tolerant of high heat and are charged at lower power than traditional or AGM batteries. An OPTIMA battery is neither a gel battery nor a regular flooded battery. OPTIMA is a SPIRALCELL TECHNOLOGY AGM battery.

Or, just drive Charlie more!

One more thing, there are no Dumb questions on this site, Mr Milliman! We just look at the person whom asked the question and take it from there!
See ya soon, in beautiful Morrisville Pa.
Jim

No such thing as a stupid question.

John, if you have a UPS on your computer stuff, they use gel batteries. But like posted above Optimas are not gel, but are AGM (Absorbent Glass Mat).
My charger has an AGM setting. I just use that for recharging my boat Optimas.

6v Optima available from Advance Auto Parts, with a 20-25% off promotion (25% shows up on a pop-up menu).

Thanks for the input everyone -- I'll try Tim's Option No. 2 when I get a chance (which won't be any time soon).

I had a dead 6v Optima that would not charge, using any type of charger (including a heavy-duty big-truck battery-charger at a friend's professional garage).

The technique on the Optima website (that I linked-to, above), got the battery working again.

That was at least 10 years ago.

Tim, Roger that. The hardest part about that trick is finding a second 6-volt battery ... that's charged ... and isn't on the other side of the county

John,

I think the second/traditional battery does not have to be charged.
It just has to be good enough to be chargeable (to take a charge).

I have done it a few times with a dead Optima 6v and an almost dead lead-acid 6v (one that would not crank an engine).

Nonetheless, yes, you need a second 6-volt battery. I keep one around for "old times sake" (and, just in case I forget to put the Optima 6v on a automatic trickle charge during "hibernation").

John,
Since your in no rush, try a trickle charge. I do this during those dry spells when she’s not running a lot.
Oh, Happy New Year to you and Ms Peg.
Jim

I had an Optima in my 1954 for 13 years and only got a new one when it seemed to be getting weak. Replaced with another one from a company named Penn. They make the battery for the Auto Zone. It was slightly cheaper. I keep a maintainer on my truck during downtime. They do make a special charger for gel batteries.

What is the Penn 6v battery part number, Ron?

Is it an "Intimidator"?

Happy New Year

If you've got a 12 volt battery with removable cell caps, it's easy to make it a faux "6 volt" by sticking a piece of copper like a short piece of 1/4" tubing into the 3rd cell electrolyte and attaching a jumper wire to it. Back in the dark ages when cell connectors were lead straps on top of a battery, we just used a sheet metal screw into one of the straps to attach a 6 volt tap if we needed one for some reason.
Jerry

So Jerry, you are saying that you can make two 6 volt batteries, in parallel, out of a single 12 volt battery?
Your Country wisdom amazes me!

Don

Hmmm ... I do not. But .... Hambone does .... hehehehehehehehehehehehehe!

Not parallel, Don, series. With the old style batteries with cell-top connectors, a true 6 volts could be obtained by tapping into the connector strap between cells 3 and 4. A 12V with cell connectors through the battery case walls will be close enough to 6V by simply using the electrolyte as a conductor for a few hours to kick off the charging cycle of a dead Optima battery.
Jerry

I am not sure if they have one Boltergeist but I will check.This is who they make for.. It is actually East Penn. https://www.autozone.com/batteries-starting-and-charging/battery/optima-battery-6v/437833_0

Jerry, Just a little feedback ...

I actually had a 12-volt battery in the shed on the battery tender (my boat battery) with caps. I used some heavy gauge copper wire. Hooked everything up as you said and ... it worked like a champ!! Wow. Very impressive. In fact, it took less than 15 minutes for the optima to come back up to the point where my NAPA charger was happy to accept it for charging. I will go back out there in a little bit to check on it, but I am guessing that the Optima is back on board and RFT. I will be making a Tech Tip out of *that*

Here's a couple of bad images of my "donor" battery and the Optima. Once again, it just proves that "if it's stupid but it works, it isn't stupid."

Oh yeah, while I was setting up (and stripping the heavy copper wire) my grandson showed up and watched as I got everything set up. He watched as everything worked as you said it would (I had two different volt meters hooked up monitoring things) He now thinks I am an electrical wizard.


Thank you, thank you, thank you.

"I love it when a plan comes together"! Good job of "observe, adapt, execute"! I really like doing stuff just a little on the oddball side of things when the results accomplish the objective. Good work!
Jerry

That technique is absolutely insane looking to me! If it were recommended by anyone but HRL, I would have laughed at it.
Too cool for school.
Hey Hotrod, when are you going to write a book with all of the gems that you have aquired over the years? It would be an instant best seller.

Follow up question for Jerry....

On the "donor" battery... does it *have* to be a copper conductor? Are we worried about some type of galvanic reaction happening (that would be bad for the donor battery) if we use something else conductive like, say, an old screw driver or something that isn't copper?

I dont understand what just happened. Can we talk through this using smaller words?

I might try that with my 15+ year old Optima battery, if/when my 20+ year old 6v "spare"/retired lead-acid battery ever goes bad.

John, copper is about the least reactive metal I can think of to be sticking into a strong sulfuric acid solution. Steel would have an immediate, not very pretty reaction, and produce lots of hydrogen gas. Ditto for most other metals such as aluminum, zinc (galvanized), etc. A strip of lead would be the ideal conductor to use, since the negative plates of a battery cell are pure lead. The positive plates are powdered lead dioxide, pressed into a pure lead grid. A big lead (NOT ZINC!) wheel weight, hammered into a long, thin shape that would fit into a cell group fill hole would work even better than copper. We don't want to contaminate the acid in the cell, but sticking a copper conductor in there for a few minutes probably won't do any noticeable damage. One precaution I might mention- - - - -don't stuff the temporary conductor deep enough into the cell to contact the plates- - - -you could short out the cell and damage the battery. That's why I initially suggested flattening a piece of copper tubing, so it can sit flat on top of the insulators between the cell plates and contact nothing but the acid. A flattened wheel weight would be even safer.

Hambone, since most folks don't have a conventional 6 volt battery stashed away to assist in kicking off the initial charge on a dead Optima battery, putting a conductor into the electrolyte (acid) of one of the middle cells of a 12 volt is a sneaky way of simulating a 6 volt battery. Each cell of a lead-acid battery produces slightly over 2 volts, so it takes 3 cells to create 6V.
Jerry

This trick works for dead cordless tool batteries too. Sometimes, the battery can be so completely dead that the charger cannot "see" that there is a battery wanting to be charged. Just like what John did, you can use a good battery to give the dead battery an initial boost so the battery charger can detect it and charge it. People have put up YouTube videos you can watch to see this.

(doesn't work all the time - sometimes dead is dead)

Thank you, Gord

I have an old/spare 6v battery, so I can easily charge my 6v Optima battery, if I ever need to do so.

However, I have many 20v, 36v, and 40v tool batteries. I threw one away when in would not take a charge. Your YouTube revival-technique might save the two batteries that will now not take a charge.

Note: there is a NiCad technique, and, a different Lithium-Ion technique.

If it works, you have saved me around $100 now (and, will save me much more in the future).

I tried this on a drill battery that would not charge .the charger for the drill battery would just flash when it should be a solid red when charging . It worked now I have a extra thanks for the tip

Yes, Gord,

Thank you for the tip.

I recently threw away one 40v “dead” Black and Decker Li-Ion battery.

I have two other “dead” 40v Lithium B&D batteries that I will try that technique on. I will report back here. NiCad and Lithium-Ion batteries have different recharge techniques (both shown on YouTube).

Thank you, again,

To close the loop on this:

The battery took about 24 hours on the charger after removing the booster battery. It reached about 6.5 volts and the green light came on to signal that it was "done." Took me a couple of days to get my act together logistically to run the battery back over to where the truck is stashed and reinstall it. The battery held its charge and started the truck just fine.

Pretty sad when your major truck accomplishment for the past 4 months was "reinstalling the battery." Especially when sitting next to it in the shop is Hambone's project, which in the same timeframe went from a cab and chassis to a street legal and driveable truck with a shiney new paint job.

Anyway, kudos to Jerry (and Gord) for the outstanding hack. It really works!