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Lets talk about batteries and cranking power 6V vs 8V for 346 flathead.

Started by gary griffin, October 31, 2017, 09:29:39 PM

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TJ Hopland

It just seems like going to 8 gives you all the issues of going to 12 with none of the convenience.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

C Gorgas


Janousek

I'm with TJ.  If your going to have a dual system just go all in and go 12 volts.

I've converted and service a 41' 75 series with A/C.  That 12 volt battery sings the starter almost as fast as a running motor.   We did the conversion for 2 reasons.  1.  6volt compressor clutches are nonexistent
2.  Car is driven at night and the 6volts just couldn't make the headlights safe at speed. 
Everything is easilly converted back.  The conversion wasn't done to make it starter faster.  6volts done properly was used for over 50 years.   

I'm converting our 67' series car right now to 12 volts.  Starting speed isn't the reason.  Those headlights are so nice on the 75 series that we decided to have safe headlights since our car will be driven at night.   

dochawk

The only 6V i ever really dealt with was my father's 64 bug.

no reason to convert *those* to anything.

If you had trouble starting from the battery, you just open-end the door and started running down the street with it, then jumped in and popped the clutch. 

I did that so many times, and watched him so many more, that I can't even guess at the number; it always worked (and also on my brother's 74).

it didn't work on my super beetle (also 74), as the seat was placed enough differently that you couldn't hop in fast enough from the run.

OK, so this isn't practical an a cadillac for *so* many reasons, without even getting to dignity . . .

:)

hawk
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

Jim Miller

I made certain my grounds were clean and never had a cranking issue. However, I was concerned about lights at night when stopped at intersections. They do dim down at a slow idle, so I spent the money and had the generator converted to a GenerNator. Nice bright lights and remain 6 volts.
Jim Miller
Jim Miller

1941 6219
1949 6237X
1970 CDV
2021 XT6
Past:
1991 SDV
1999 DeElegence
2006 DTS
2013 XTS
2016 SRX

vttinkerer

I bought my 1940 series 60 a little over a year ago with an eight volt battery in place.That battery tested out as weak and after some research I decided to get a good six volt battery and a new regulator.The car started perfectly well with the good battery, but shortly afterI put it in the starter relay failed.I was fortunate to find another one, as they are rare. I cannot be certain that the exposure to 8 volts led to the failure of the relay, of course, but that certainly was a possibility.While I had the starter out to replace the relayI had a local electrical shop go through the starter and I had them install the new relay.It cost me all of 48 bucks to get that job done and the refurbished, reinstalled starter spins the motor like all get out.





Omarine

Hello and Merry Christmas to all from FL,

Reviving this old thread , been doing some reading 6 or 12 volts. I have no complaints of the 6 volts in my 52 coupe de ville.

I think the only 12v item i may want is a radio, and maybe an electric vacuum for the windshield  wipers.

Questions:

1. would it make more sense to use one of those 6 to 12 volts converters at each 12 volt item?

2. Or, could i wire two 6 v batteries in series and still feed the car 6 volts at the regulator while simultaneously pulling 12v from battery #2?

3. If so, i guess i would need a 12v charging system?

Either way, i think the one thing i will do is install a 6 volt alternator,as i do drive at night and sit in traffic....

Thanks gentlemen!

Cheers
Oscar

1949 Harley Davidson FL
1952 Cadillac Coupe de Ville
1961 Chevy Impala 2 dr hardtop

dochawk

If it's only for an accessory or two, a 6-12v converter mint be less expense or trouble than a second battery.  Come to think of it, you'd need one to charge a second 12v battery, and something even stranger to charge a second  6v in series with your power system
1972 Eldorado convertible,  1997 Eldorado ETC (now awaiting parts swap from '95 donor), 1993 Fleetwood but no 1926 (yet)

las39

No need for extra battery just for radio etc.

This model can draw 10 Amp. Enough for most.
I have one in front for radio, phone charger etc and one in the rear to feed hitch socket via solid state relays.

https://www.ebay.com/itm/DC-6V-5-11V-to-12V-10A-Step-up-Converter-Regulator-Waterproof-Boost-Power-Module/123675203164?hash=item1ccb9dd65c:g:SX4AAOSwkmJcfeLk

Our low compression engines do not need a fast revving starter.
1939 LaSalle 5027
1941 Chrysler Royal Coupe
1934 Oldsmobile F34
1976 Moto Guzzi Convert

Omarine

Thanks for the replies. That converter looks like the way to go.

Now that lights are mentioned, 12 volts at the headlights and tail lights would be nice.

Is that asking for too much out of a step up converter?
1949 Harley Davidson FL
1952 Cadillac Coupe de Ville
1961 Chevy Impala 2 dr hardtop

jdemerson

Quote from: TMoore - NTCLC on November 01, 2017, 11:42:00 AM
Gary -

Before you take the 8 volt route, you should really consider giving the 6 volt battery a chance.  I honestly believe that if you follow all the tips in the (multiple) hard starting threads, you should have no problems using 6 volt batteries with the flathead.  It will save you a lot of grief (gauges, fan motors, radio, generator, regulator) and keep your car original.

My engine has been rebuilt, and so far, the only thing that I have done is to make sure the starter mating surface to the block was cleaned up before mounting, and I have had no issues with the 6 volt battery.  When the time comes, I will swap out the cables for properly sized 00 wire, and perhaps move or add a ground to the starter, but for now, there have been no real issues - this is using an 8 year old Optima 6 volt (I know, not original, but good enough for a restoration project).

I am assuming that your LaSalle is still on six volts, so you have a battery nearby that you can test with - give those old threads a good read and some consideration.

Tod

+1
John Emerson
1952 Cadillac Sedan 6219X
John Emerson
Middlebury, Vermont
CLC member #26790
1952 Series 6219X
http://bit.ly/21AGnvn

las39

Quote from: Omarine on December 26, 2019, 07:03:54 AM

Is that asking for too much out of a step up converter?
Yes too much for incandescent headlight bulbs but not for LED headlights.
Or swap you reflector to H4 type and use H4 6 volt halogen bulbs. This is what I did.
1939 LaSalle 5027
1941 Chrysler Royal Coupe
1934 Oldsmobile F34
1976 Moto Guzzi Convert

bcroe

My experience is those low priced converters will work when battery
and load voltages are both positive in respect to ground.  That because
many low cost voltage changer/regulators are NOT ISOLATED, the input
and output negative leads are tied together internally.  Fine if ALL
negative leads go to ground. 

The problem comes if you have a positive ground (6V, etc) battery.  If
the reg/conv neg input lead is tied to the hot battery neg, and the neg
output lead is grounded, you have created a short on the input source. 
The problem can be avoided by not grounding anything on the output
side, but all 12V transistor car radios I have seen have a neg ground. 
In this case a voltmeter will read + 6V on one output lead, and - 6V
on the other, to ground. 

Some possible fixes are to change the 6V system to neg ground, or
find a converter that has completely ISOLATED output leads, ground
either lead.  Bruce Roe

Jay Friedman

My '49 is 6 volts.  I installed a 12 volt AM/FM radio/cassette tape deck from the 1990s under the dash to replace the original AM radio so I can hear FM stations and play my favorite music.  (I never threw out my old cassette tapes after the switch to CDs.)   It is powered through a Trippe 6 volt to 12 volt inverter, which not only powers the radio perfectly but also drives the tape deck at the correct speed.  There is no need for an 8 volt battery to merely power a radio, nor for starting if the grounds are good, etc.

In fact, my experience with 8 volt batteries is that eventually they will harm sealed beam headlights, other bulbs and accessories, even if their specifications say they are for 6-8 volts. 

In addition, the only need I can see for a conversion to 12 volts is to power an AC system.

1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

bcroe

Need for more energy is a good reason for changing to an alternator,
but driving at higher speeds my generator put out enough for my add
on AC.  Later an alternator was installed to eliminate failures (mostly
brushes) every year, and it also eliminated a source of radio interference. 

Anyone know if 6V Cads were + or - ground?  Bruce Roe

35-709

1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Jay Friedman

Quote from: 35-709 on December 26, 2019, 09:14:51 PM
All 6 volt Cads were positive ground.

That is incorrect.  From 1946 through 1952 six volt Cadillacs were negative ground.  (In '53 Cadillac switched to 12 volts, also negative ground.)
1949 Cadillac 6107 Club Coupe
1932 Ford V8 Phaeton (restored, not a rod).  Sold
Decatur, Georgia
CLC # 3210, since 1984
"If it won't work, get a bigger hammer."

bcroe

Quote from: Jay FriedmanFrom 1946 through 1952 six volt Cadillacs were negative ground.  (In '53 Cadillac switched to 12 volts, also negative ground.)

Based on that I believe most any 6V to 12V converter may be used on
46-52 Cads to generate some limited power for newer radios, etc with
both the input and output neg converter leads tied directly to ground. 
Also most any 12V to 6V down converter could be used on these years
after a conversion to 12V, to supply things like gauges. 

Incandescent lamp voltage is somewhat critical.  The voltage must be
high enough so they are bright enough, but avoid the slightly higher
voltage where they very soon burn out.  I would think an 8V system
is acceptable only when no driving is done with lights on.  Bruce Roe

35-709

Quote from: Jay Friedman on December 26, 2019, 10:39:26 PM
That is incorrect.  From 1946 through 1952 six volt Cadillacs were negative ground.  (In '53 Cadillac switched to 12 volts, also negative ground.)
Thank you, Jay, I stand corrected.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

Omarine

Thank you gentlemen for all the insight. Just to clarify i started this thread back up, to talk about voltage, but 8 volts was never part of my plan.

Sounds like it’s easier to keep 6 volts and use a step up converter for radio, and vacuum pump. Maybe toy with different head light bulbs too.

I guess one could convert to 12 v and use the step down converter to 6 volts for the gauges, but for now i will stay on 6 v.

I think a 6 volt alternator is the first thing i will do.

I like the idea of grounding the starter.

Is it as simple as pulling a bolt out and attaching a think ground wire to the block or frame? Or could i use the same spot on the intake manifold that the battery is grounded to?

Thanks again everyone!
1949 Harley Davidson FL
1952 Cadillac Coupe de Ville
1961 Chevy Impala 2 dr hardtop