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BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH

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BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH #1 This topic is about my 1972 MG MGB
NH72MG Don Lavoie Merrimack, NH, USA Sign in to contact 1972 MG MGB	Topic Creator (OP) Apr 26, 2015 04:39 PM Joined 16 years ago 327 Posts

How do you tell if your battery has just gotten old or if there is a battery drain somewhere?
Battery is a cheap Walmart 26R 540 cranking power, approx 6-8 years old. Car will start
up to 3 days without being used, on the 4th day, I just get the click, click, click.

Thanks...............Don

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Re: BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH #2
ohlord Rob C A tiny Island off the coast of Washington State, N.W., USA Sign in to contact 1957 Land Rover Series I "EYEYIYI" 1957 Land Rover Series I "OVRLND" 1971 MG MGB 1971 MG MGB "Bedouin 2" & more	Apr 26, 2015 04:47 PM Top Contributor Joined 12 years ago 28,878 Posts

Charge it fully to 12.7v disconnect it test it in a few days
or borrow a hydrometer
voltage drops below 12.1v time for new battery
6-8 years is due.

LNDRVR4X4.COM
Home of Project "INCARN8'

1957 Series 1 Land Rover electric VEHICLE CONVERSION

FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED

RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972

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Re: BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH #3
dickmoritz Dick Moritz Philly 'burbs, PA, USA Sign in to contact	Apr 26, 2015 05:20 PM Top Contributor Joined 14 years ago 26,273 Posts

Charge battery, remove negative terminal from battery, insert a simple 12 volt test light or voltmeter between the post and the terminal. If your readings show current, something is drawing electricity. Make sure courtesy lights, trunk light, etc., are all turned off. There should be no current indicated.

Dick

Errabundi Saepe, Semper Certi
(Often wrong, but always certain)

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Re: BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH #4
Rick Fawthrop Richard Fawthrop Langley, WA, USA Sign in to contact 1960 Austin-Healey Bugeye Sprite 1974 MG MGB 1994 Mazda Miata	Apr 26, 2015 06:34 PM Top Contributor Joined 12 years ago 6,725 Posts

Get the battery load tested, and do the test that Dick suggests.

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Re: BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH #5
Fogliner Mark Vanherd Port Clements, BC, Canada Sign in to contact 1974 MG MGB	Apr 27, 2015 12:39 AM Top Contributor Joined 13 years ago 2,298 Posts

X2 on the load test. Napa or any parts store that sells batteries should have one.

Should tell the tale on a questionable battery.

Regards

Mark

load tester.jpg 10.7 KB

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Re: BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH #6
ErnieY Ernie Y Albatera, Alicante, Spain Sign in to contact 1976 MG MGB GT	Apr 27, 2015 02:16 AM Top Contributor Joined 12 years ago 19,528 Posts

If it's as predictable as you say then it sounds more like you have a drain.

It's impossible to define or measure a batteries life in terms of time as there are too many other influencing factors, not the least of them being weight and the old adage of you get what you pay for.

Weight is significant because driven by profit and the fact that cars today are expected to start at the very first turn of the key the plates in many if not most modern batteries have been thinned to the point where they simply cannot cope with anything else, such as an MGB being cranked to death because it isn't starting.

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Re: BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH #7
ddubois Dave DuBois (RIP) Bremerton, WA, USA Sign in to contact	Apr 27, 2015 02:25 AM Joined 18 years ago 7,282 Posts

I second (or is it third) on the load test. A 6 - 8 year old battery in a car that is not driven at least a few times a week will form sulphate on the plates that decrease the battery capacity by a considerable amount. If you are not driving you car regularly, should be hooked up to a battery tender while it is sitting in the garage.
Cheers,

Dave DuBois
1953 MGTD
1966 MGB
http://homepages.donobi.net/sufuelpumps/

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Re: BATTERY DRAIN OR HAS BATTERY JUST HAD ENOUGH #8
willie3051 William Leong Brooklyn, NY, USA Sign in to contact 1974 MG MGB GT	Apr 27, 2015 06:30 PM Joined 19 years ago 1,232 Posts

Wanted to talk about battery drain some more; mine is also draining and I did the test Dick described above. Seems like with the alternator plugged in, there's a 12.4 volt reading across the negative post and terminal. With the alternator unplugged, the voltage reading drops to around 7V. What is this saying about the alternator and the rest of the system regarding battery drain? Thanks.

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