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7/03/2019 6:45 AM  #1


How much parasitic drain you got ?

My 65 has 150milliAmps of parasitic drain with car off ...

My alarm system takes 40milliAmps and rest I don’t know ... it’s when I hook up the main harness I know .. I tested that yesterday..

How much do you have ?
I read somewhere 50 or more and your battery will drain in a few days


If it aint broke, I have'nt tried to "Fix" it yet!
 

7/03/2019 7:21 AM  #2


Re: How much parasitic drain you got ?

I bought an inexpensive battery tender that I can plug into the accessory plug (used to be called a cigarette lighter).  Pretty easy to hook up in the garage if it is not being driven every day.  But, a quick and save test is to remove the negative batter cable and install a small bulb like a single filament brake light between the negative terminal and your cable.  This becomes a current limiting device that allows you to disconnect individual items to figure out where your drain is.  Under low currents the bulb will glow.  As you remove drains the glow will diminish.  Common drains might be your radio if it is a modern unit with memory and your alternator/regulator.  These should effectively cause no drain but if there are diode or wiring issues you may end up with a slight drain.  The smaller the suspected drain the smaller the bulb that you can use.  Even if you try the start the car, the worst case scenario is the bulb will shine at full brightness.  I have a bulb that I soldered wired to with clip leads that I always use after wiring to test to ensure that I don't have a dead short somewhere before I hook up the cables to the battery.  A battery tender will work but I would prefer to know what is causing the drain and fix that if I can.

 

7/03/2019 9:31 AM  #3


Re: How much parasitic drain you got ?

Mine is not too bad. She goes along with me on every trip I take.


Money you enjoy wasting is NOT wasted money... unless your wife finds out.
 

7/03/2019 10:06 AM  #4


Re: How much parasitic drain you got ?

MS wrote:

Mine is not too bad. She goes along with me on every trip I take.

if I drive the car every couple days of even after a week its ok.. if I leave it for more, the battery is dead, hence got me investigating


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

7/03/2019 10:33 AM  #5


Re: How much parasitic drain you got ?

I have four "keep alive" circuits in the Heap:  Radio, EEC, alarm, and Vintage Air Gen IV HVAC.  It will handle ten days or so setting but anything over two weeks and the battery is getting weak. If I know it's gonna set that long I always hook up the Battery Minder.
With a 1.5 amp/hr drain you'll be pulling the battery down by 1/2 it's capacity in about ten days so you will need to use the Minder/Tender.  I'd just get in the habit of hooking in up anytime the car is in the garage.  Also do what Gary suggest and see if you can find all the culprits.  Years ago we always disconnected the brake light switch first when looking for a drain.  Those old hydraulic brake light switches were good for a low current drain that would run the battery down but not light the brake lights.

BB


"you get what you pay for, good work isn't cheap, and there are NO free lunches...PERIOD!"
 

7/03/2019 10:48 AM  #6


Re: How much parasitic drain you got ?

I have NO "keep alive" circuits.  I checked (like Gary sez) to insure it, because I KNOW there will be weeks when the old hot rod is not driven.  Like now with 90+ temp and hu-damn-midity to match.
BTW.............you DID have the doors closed(no interior light glowing) when you checked, right?!
Don't ask how I discovered this nugget
6sal6


Get busy Liv'in or get busy Die'n....Host of the 2020 Bash at the Beach/The only Bash that got cancelled  )8
 

7/03/2019 11:01 AM  #7


Re: How much parasitic drain you got ?

6sally6 wrote:

I have NO "keep alive" circuits. I checked (like Gary sez) to insure it, because I KNOW there will be weeks when the old hot rod is not driven. Like now with 90+ temp and hu-damn-midity to match.
BTW.............you DID have the doors closed(no interior light glowing) when you checked, right?!
Don't ask how I discovered this nugget
6sal6

LMAO

I wish that was true for me.. but lets c.. slow and steady work


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

7/03/2019 11:50 AM  #8


Re: How much parasitic drain you got ?

MS wrote:

Mine is not too bad. She goes along with me on every trip I take.

Now that's funny!

 

7/04/2019 7:52 AM  #9


Re: How much parasitic drain you got ?

Are you still using 1G alternator? If so, may want to check your voltage regulator/wiring as well for corrosion to ground or the case of regulator (look on backside of housing too).

 

7/04/2019 8:00 AM  #10


Re: How much parasitic drain you got ?

Nos681 wrote:

Are you still using 1G alternator? If so, may want to check your voltage regulator/wiring as well for corrosion to ground or the case of regulator (look on backside of housing too).

No I am using the 3G one wire setup ..


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

7/04/2019 8:13 AM  #11


Re: How much parasitic drain you got ?

Regarding the old hydraulic brake light switch, a friend's father had a 64 Galaxy back in the day and had this issue of battery drain, one night he could see the taillights were dimly lit, changed the switch and problem solved.

Bullet Bob wrote:

I have four "keep alive" circuits in the Heap:  Radio, EEC, alarm, and Vintage Air Gen IV HVAC.  It will handle ten days or so setting but anything over two weeks and the battery is getting weak. If I know it's gonna set that long I always hook up the Battery Minder.
With a 1.5 amp/hr drain you'll be pulling the battery down by 1/2 it's capacity in about ten days so you will need to use the Minder/Tender.  I'd just get in the habit of hooking in up anytime the car is in the garage.  Also do what Gary suggest and see if you can find all the culprits.  Years ago we always disconnected the brake light switch first when looking for a drain.  Those old hydraulic brake light switches were good for a low current drain that would run the battery down but not light the brake lights.

BB

 


65 Fastback, 351W, 5-speed, 4 wheel discs, 9" rear,  R&C Front End.
 

7/04/2019 10:56 AM  #12


Re: How much parasitic drain you got ?

Raymond_B wrote:

MS wrote:

Mine is not too bad. She goes along with me on every trip I take.

Now that's funny!

Glad to see someone else got it.
 


Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
 

7/04/2019 11:19 AM  #13


Re: How much parasitic drain you got ?

rpm wrote:

Raymond_B wrote:

MS wrote:

Mine is not too bad. She goes along with me on every trip I take.

Now that's funny!

Glad to see someone else got it.
 

I just got it!! And I feel so stupid while LMAO!!! Wow


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

7/04/2019 11:59 AM  #14


Re: How much parasitic drain you got ?

Funny!  Can’t be that bad if you had four a/c vents cooling you off.  Oh, back to subject.  I have only 2 keep alive ckts: KAM and radio memory. Total current = 5.42mA

 

7/04/2019 12:46 PM  #15


Re: How much parasitic drain you got ?

Nos681 wrote:

Funny!  Can’t be that bad if you had four a/c vents cooling you off.  Oh, back to subject.  I have only 2 keep alive ckts: KAM and radio memory. Total current = 5.42mA

Just my viper alarm  system takes (0.04A) 40mA ... rest I am gonna figure our .. let’s c

Last edited by Gaba (7/04/2019 3:17 PM)


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

7/04/2019 3:31 PM  #16


Re: How much parasitic drain you got ?

An alternator with a bad diode can cause the battery to drain fairly quickly.  One thing to try in looking for the drain would be to disconnect the alternator. 

 

7/04/2019 3:49 PM  #17


Re: How much parasitic drain you got ?

I can let my car sit for weeks (which I try not to do) and it will still crank over no problem. If sitting for a long time, only drama I have is pumping the fuel back up through the lines, but that just means more cranking.
With my taillights, I went to LED. Will never look back as it has lime 10X the brightness at a fraction of the current draw.


1964-1/2 D Code Coupe - 289 V8, 4 Speed Toploader, 3.00 ratio rear, Autolite 4100 Carb, 15" tires, Pertronix ignition
 

7/04/2019 3:51 PM  #18


Re: How much parasitic drain you got ?

MS wrote:

Mine is not too bad. She goes along with me on every trip I take.

You might get a bit more drain happening if she reads this (ha, ha)


1964-1/2 D Code Coupe - 289 V8, 4 Speed Toploader, 3.00 ratio rear, Autolite 4100 Carb, 15" tires, Pertronix ignition
 

7/04/2019 5:08 PM  #19


Re: How much parasitic drain you got ?

Gaba wrote:

Nos681 wrote:

Are you still using 1G alternator? If so, may want to check your voltage regulator/wiring as well for corrosion to ground or the case of regulator (look on backside of housing too).

No I am using the 3G one wire setup ..

 
3G is three wires. You either have 3G or 1 wire, not both. The choice of one or the other is the subject of many heated discussions in the Sparky community.

 

7/05/2019 7:03 AM  #20


Re: How much parasitic drain you got ?

Hornman wrote:

Gaba wrote:

Nos681 wrote:

Are you still using 1G alternator? If so, may want to check your voltage regulator/wiring as well for corrosion to ground or the case of regulator (look on backside of housing too).

No I am using the 3G one wire setup ..

 
3G is three wires. You either have 3G or 1 wire, not both. The choice of one or the other is the subject of many heated discussions in the Sparky community.

Sorry I have 3G not one wire .. I wrote that wrong


If it aint broke, I have'nt tried to "Fix" it yet!
     Thread Starter
 

7/05/2019 7:56 AM  #21


Re: How much parasitic drain you got ?

I have used this process in the past. I connect my ammeter ( I start on 10amp scale jic I turn lights on) in series with my battery. Then methodically remove fuses one at a time to see if current changes to lower value or goes to zero.  If you have a suspected problem, try flexing wiring and see if values change as well. Might want to look on backside of fusebox to body for any corrosion or pinched wires.  A wire can be pinched and drain battery without necessarily shorting to ground. As mentioned earlier, take a look at courtesy lights and I’ll throw in exterior lights such as turn and parking.  Possible corrosion tracking to metal housings or between terminals in light sockets. Hope this helps.

 

7/06/2019 12:20 PM  #22


Re: How much parasitic drain you got ?

Gaba wrote:

rpm wrote:

Raymond_B wrote:


Now that's funny!

Glad to see someone else got it.
 

I just got it!! And I feel so stupid while LMAO!!! Wow

Sherry doesn't read this forum, does she....? :-)
 


68 coupe - 351W, 4R70W, 9" 3.25 -- 65 convertible - 289 4v, C4, 8" 3.00
 

Board footera


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