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Question. My stock 1937 Packard 120 came with two Optima, red top, 6 volt, AGM batteries. With the engine running I noticed that the generator gauge indicates no charging. It does work and shows much discharge when I turn on the headlamps. Will the generator damage the AGM batteries because it's not designed for AGM? Should I disconnect the generator or should I replace the AGM batteries with traditional lead-acid battery? Is there a work-around using AGM batteries? I found myself stranded with dead batteries - no fun...my wife was with me!

Looks like I'm running the vehicle on batteries only. I now trickle charge the batteries when not in use

D.O.

Given that so many of us have the combination of an Optima battery with the original charging system I would say that combination is quite acceptable.

The ammeter indicating ‘no charge’ in itself is also not a concern, but it could be a clue, because once the battery is charged that’s the correct meter reading. Your comment about a discharge with the headlights ON, is a clue that the generator output might be compromised . . . perhaps zero output. Check the battery voltage with the car not running, and again running at a high idle. There should be about one volt difference in the two readings (running would be the higher voltage). If you measure no difference between the two readings I would agree with your observation about running the car on batteries only. I’m assuming the car is a 6+ system and the two batteries are connected in parallel.

dp

Either your generator or voltage regulator is not performing correctly. An easy check is to start the engine, run it at fast idle and remove a battery cable while it is running. If the engine dies, then you are running on the battery alone. If it continues to run, hook your voltmeter between the + and - cables and read the voltage. If it not over 6 volts, the system will never charge a battery.

I suspect the first scenario is the case. The two batteries were an attempt by the previous owner to keep the car going for a reasonable amount of time without repairing the charging system. I have a single optima in my 39 120 and it is more than adequate.

I agree that there must be something wrong with the charging system which could be easily checked with a Volt meter. I am running a single 6V Pos earth Optima in my 38 Twelve and it appears to be entirely adequate. A bonus was that there was sufficient room in the battery holder to put a 12 Volt Gel battery, which I run as Negative earth to the Cigar lighter for GPS, Dash cam and other 12 Volt accessories. I use a 6v and 12 V battery minder for each system and plug in under the running board. Peter Toet

Thanks to David Packard, longjohn and Peter Packard for sharing your wealth of knowledge regarding my Packard electrical issue - I can't thank you enough. My goal is to be a good steward of my 1091 and retain the car in its 1999 restored condition (I'm told it was restored and featured at the Magnum Opus). Keep up the good work, you guys are a treasure!

G'day D.O.,
to PackardInfo.

I invite you to include your '37 One Twenty Deluxe Touring Sedan in the Packard Vehicle Registry.

There's really no chemical difference between a AGM and a liquid cell - both are lead acid. So you won't gain anything switching back.
AGM's are more expensive to make. The AGM stands for Absorbed Glass Mat, which means the electrolyte is held/gelled in a "mat" of fiberglass. It allows higher battery performance and no acid leakage.
Wet cells, always "spritz" acid when the hydrogen is released(bubbling) during charging requiring topping up the water. They're able to seal the AGM cells, so that doesn't happen.
Optima uses a wound AGM cell (round) vs others that are the convention retangular battery shape. No other difference than marketing and among the first.
https://www.batterypete.com/agm-battery-technology/

Concur it's your charging system at fault. Always start at the VR first, it's the cheapest and most likely to fail. It may just need "polarized" also. Some people unfamiliar with gen systems don't know about that jewel.
Not much goes wrong with the generators until the brushes or sleeves wear down.

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That, sir, is a damned fine idea. This very issue has been lurking in the back of my head for weeks. Voila, it is solved. Thank you!!!

Thanks Wat_Tyler and Fish'n Jim for joining the conversation!

I contacted Optima regarding a charger for the AGM battery and have attached their reply below:

"Thank you for contacting Optima Customer Service. Unfortunately, Optima does not offer a 6V charger. Since there are many great battery chargers on the market, we do not have the capability of testing each one. We do not “Officially” endorse specific chargers, yet we will supply information about our charging recommendations.

The best method for consumers to maximize AGM battery performance or to recover a deeply discharged AGM battery is to use a modern AGM specific microprocessor-controlled charger with a conditioning/desulfation mode.



Battery Charger (Constant Voltage): 6.9 to 7.5 volts; 10 amps maximum; 6-12 hours approximate

Float Charge: 6.6 to 6.9 volts; 1 amp maximum; (indefinite time at lower voltages) "

I hope this will help someone else who might have the same question I did.

You're welcome.


I have heard good things about Optimas and may spring for one when time comes.