Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Old February 4th 19, 09:45 PM posted to rec.autos.tech,sci.electronics.repair
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Default Engine run time to keep battery charged

If you turn over an engine periodically to keep it charged, how long do
you run it to make up for the charge lost in starting?

In this case it's my neighbor's 87 Buick Regal while he's in the
hospital.


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Old February 4th 19, 10:56 PM posted to rec.autos.tech,sci.electronics.repair
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Default Engine run time to keep battery charged

Tom Del Rosso wrote:
If you turn over an engine periodically to keep it charged, how long do
you run it to make up for the charge lost in starting?

In this case it's my neighbor's 87 Buick Regal while he's in the
hospital.


5 min once every two weeks should be sufficient assuming the
battery and charging system is good. Turn everything off except
engine. It will need to be run at least 1,000 rpm for that time
period.

OTH, Harbor Freight has cheap little float chargers but 120v power
will be needed. A friend uses one of these when out of the country:
https://www.harborfreight.com/automa...ger-42292.html

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Old February 5th 19, 01:05 AM posted to sci.electronics.repair
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Default Engine run time to keep battery charged

On Monday, February 4, 2019 at 5:57:03 PM UTC-5, Paul in Houston TX wrote:
Tom Del Rosso wrote:
If you turn over an engine periodically to keep it charged, how long do
you run it to make up for the charge lost in starting?

In this case it's my neighbor's 87 Buick Regal while he's in the
hospital.


5 min once every two weeks should be sufficient assuming the
battery and charging system is good. Turn everything off except
engine. It will need to be run at least 1,000 rpm for that time
period.


I've always been told that short run times creates condensation and acid in the motor oil from incomplete warmup - get her good and hot to drive off moisture. I realize the OP was asking about charging times, but he'd be better served by letting that old Buick idle for a good half an hour every few weeks, or better yet, have OP take the old girl for a blast.


OTH, Harbor Freight has cheap little float chargers but 120v power
will be needed. A friend uses one of these when out of the country:
https://www.harborfreight.com/automa...ger-42292.html



NOOOOOOOOOOO!!!!!! Don't suggest a solution (even a cheap one) that comes from a credit card lest Arlen Holder or one of his socks pitches a fit!!!
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Old February 5th 19, 01:30 AM posted to rec.autos.tech,sci.electronics.repair
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Default Engine run time to keep battery charged

On Mon, 4 Feb 2019 16:45:34 -0500, Tom Del Rosso wrote:

If you turn over an engine periodically to keep it charged, how long do
you run it to make up for the charge lost in starting?

In this case it's my neighbor's 87 Buick Regal while he's in the
hospital.


72 seconds

Having said that, here's how I arrived at 72 seconds, bearing in mind
there's a complexity to your question which, outside of the engineering
specs of both the battery & engine (and parasitics), we can only help you
guess at it mathematically, where empirical results would seem to be more
accurate than our guestimates.

Starting with the basics, a quick search for a Buick Regal Alternator nets
https://www.partsgeek.com/catalog/1987/buick/regal/engine_electrical/alternator.html
which says the alternator outputs 100 amps at idle (if needed) and 150 amps
output at max rpm (again, if needed as alternators adjust output based on
"B" sensing).

Running a direct search for the power needed to start an 87 Buick Regal,
it's easy to find the vehicle, but hard to find the power needed to start
the engine:
https://en.wikipedia.org/wiki/Buick_Regal#Grand_National,_Turbo-T,_T-Type,_and_GNX

We're kind of stuck with the "generic" stuff, such as this:
o How Many Amps Does It Take to Start a Car?
https://www.reference.com/vehicles/many-amps-start-car-e35b6f3d4d8bf426
Which says an average car needs 400 to 500 amps but doesn't say how long.

Let's assume it takes five to ten seconds to start it, at 500 amps, where
the maximum power would be 10 seconds times 500 amps, which means you
sucked out 5,000 Coulombs (i.e., 5000 amp seconds) if the math is right.

If I did the math right, that's less than 1.5 amp hours, and since we
guessed high, I'd say the amount used is roughly about 1 amp hour to 1.5
amp hours, but since we want to "be safe" and have "easy math", I'd use 2
amp hours as the amount to add back.

If you put back two amp hours (to cover for inherent losses, mostly in
heat), you're back to where you started, where we have to "assume" that the
battery sense circuit allows the alternator to output enough current to
charge the battery after just one start.

At idle, if we assume the battery sense allows you to get those 100 amps we
saw in the spec, to generate 2 amp hours would take only about 0.02 hours,
or about 72 seconds (if I did the quick math right) - which -
coincidentally - is about how long it took to run the quick math.

If that 72 second answer is wrong, I welcome someone who can tell us how to
arrive at the better answer.
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Old February 5th 19, 01:34 AM posted to rec.autos.tech,sci.electronics.repair
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Default Engine run time to keep battery charged

On Tue, 5 Feb 2019 01:30:54 -0000 (UTC), arlen holder wrote:

Let's assume it takes five to ten seconds to start it, at 500 amps, where
the maximum _power _would be 10 seconds times 500 amps, which means you
sucked out 5,000 Coulombs (i.e., 5000 amp seconds) if the math is right.


Ooops... Coulombs ... not power... (power would be via P=IV or I^2R but
not amp seconds)...

(I hacked that out in a minute on the run, so, please correct where I err.)


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Old February 5th 19, 01:43 AM posted to sci.electronics.repair
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Default Engine run time to keep battery charged

On Mon, 4 Feb 2019 17:05:13 -0800 (PST), John-Del wrote:

OTH, Harbor Freight has cheap little float chargers but 120v power
will be needed. A friend uses one of these when out of the country:
https://www.harborfreight.com/automa...ger-42292.html


NOOOOOOOOOOO!!!!!! Don't suggest a solution (even a cheap one)
that comes from a credit card lest Arlen Holder or one of his socks
pitches a fit!!!


First off, neither of you appeared to have _comprehended_ the question,
which was how much time does it take to recharge the battery to compensate
for the charge lost in starting, which I roughly calculated at about 72
seconds, meaning, a couple of minutes "should" recharge the battery if the
assumptions I made were reasonable.

Even if you did _comprehend_ the question, you made no attempt to _answer_
the OP's question, which, is par for the course since all you _can_ do is
off-topic chit-chat drivel.

NOTE: I don't need to prove that statement since you prove it for me.

Moving on though, assuming the OP is satisfied with the 72 second
assumption, there _is_ a question of how often he _needs_ to charge the
battery.

I wonder if you, John-Del, have the brains to answer _that_ question?
(HINT: I don't think you do ... but maybe you'll prove me wrong.)

HINT: I already calculated it in the same minute (or so) that I calculated
the answer I provided - but I didn't post it because, unlike you, I
actually _comprehended_ the question that the OP had asked.

HINT: If you can't take a hint - you always prove to be _stupid_, John-Doe.
DOUBLEHINT: The proof will be in exactly what you write in response.
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Old February 5th 19, 02:59 AM posted to sci.electronics.repair
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Default Engine run time to keep battery charged

On 2/4/19 7:43 PM, arlen holder wrote:
Nothing of interest as usual.

Quack quack quack, ding, reverse direction.

--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com
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Old February 5th 19, 04:11 AM posted to sci.electronics.repair
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Default Engine run time to keep battery charged

On Mon, 4 Feb 2019 20:59:38 -0600, Fox's Mercantile wrote:

Quack quack quack, ding, reverse direction.


Two points which _adults_ will comprehend.

1. Snit here acts like a child _all_ the time, and,
2. Snit here didn't even _attempt_ to answer the OP's question.

We really shouldn't fault him as his brain _is_ that of a child.
o He proves that fact in _every_ post - as he did here.

Meanwhile, I at least attempted to faithfully answer the guy's question.
o And, yet, Snit (aka Fox's Mercantile), calls everyone but himself, a troll.

I don't even have to prove these two statements since he proves it himself.
o What Snit (aka Fox's Mercantile) wries, proves these two facts.

1. Snit (aka Fox's Mercantile) is _never_ purposefully helpful, and,
2. Snit (aka Fox's Mercantile) _always_ proves to own the brain of a child.

The funny thing is that it's not even an ad hominem attack!
o It's simply pointing out what Fox's Mercantile proves himself to be a fact.

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Old February 5th 19, 04:48 AM posted to sci.electronics.repair
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Default Engine run time to keep battery charged

In article ,
says...

I've always been told that short run times creates condensation and acid in the motor oil from incomplete warmup - get her good and hot to drive off moisture. I realize the OP was asking about charging times, but he'd be better served by letting that old Buick idle for a good half an hour every few weeks, or better yet, have OP

take the old girl for a blast.


OTH, Harbor Freight has cheap little float chargers but 120v power
will be needed. A friend uses one of these when out of the country:
https://www.harborfreight.com/automa...ger-42292.html




I am using one of those HF float chargers to hold up a lawn mower
battery over the winter. I really use that battery to power a sprayer
instead of the lawn mower.

My mower is in a shed with out power. I have a small solar cell about
the size of a mouse pad to keep it charged over the winter months.

If starting the mower, I would run it long enough to get the motor and
exhaust system hot. Maybe a 5 ot 10 mile trip to the store and back
once every 2 weeks or so. It will probably do the other parts of the
car some good also.

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Old February 5th 19, 05:03 AM posted to rec.autos.tech,sci.electronics.repair
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Default Engine run time to keep battery charged

On 02/04/2019 08:30 PM, arlen holder wrote:
On Mon, 4 Feb 2019 16:45:34 -0500, Tom Del Rosso wrote:

If you turn over an engine periodically to keep it charged, how long do
you run it to make up for the charge lost in starting?

In this case it's my neighbor's 87 Buick Regal while he's in the
hospital.


72 seconds

Having said that, here's how I arrived at 72 seconds, bearing in mind
there's a complexity to your question which, outside of the engineering
specs of both the battery & engine (and parasitics), we can only help you
guess at it mathematically, where empirical results would seem to be more
accurate than our guestimates.

Starting with the basics, a quick search for a Buick Regal Alternator nets
https://www.partsgeek.com/catalog/1987/buick/regal/engine_electrical/alternator.html
which says the alternator outputs 100 amps at idle (if needed) and 150 amps
output at max rpm (again, if needed as alternators adjust output based on
"B" sensing).

Running a direct search for the power needed to start an 87 Buick Regal,
it's easy to find the vehicle, but hard to find the power needed to start
the engine:
https://en.wikipedia.org/wiki/Buick_Regal#Grand_National,_Turbo-T,_T-Type,_and_GNX

We're kind of stuck with the "generic" stuff, such as this:
o How Many Amps Does It Take to Start a Car?
https://www.reference.com/vehicles/many-amps-start-car-e35b6f3d4d8bf426
Which says an average car needs 400 to 500 amps but doesn't say how long.

Let's assume it takes five to ten seconds to start it, at 500 amps, where
the maximum power would be 10 seconds times 500 amps, which means you
sucked out 5,000 Coulombs (i.e., 5000 amp seconds) if the math is right.

If I did the math right, that's less than 1.5 amp hours, and since we
guessed high, I'd say the amount used is roughly about 1 amp hour to 1.5
amp hours, but since we want to "be safe" and have "easy math", I'd use 2
amp hours as the amount to add back.

If you put back two amp hours (to cover for inherent losses, mostly in
heat), you're back to where you started, where we have to "assume" that the
battery sense circuit allows the alternator to output enough current to
charge the battery after just one start.

At idle, if we assume the battery sense allows you to get those 100 amps we
saw in the spec, to generate 2 amp hours would take only about 0.02 hours,
or about 72 seconds (if I did the quick math right) - which -
coincidentally - is about how long it took to run the quick math.

If that 72 second answer is wrong, I welcome someone who can tell us how to
arrive at the better answer.


https://www.jstor.org/stable/44611429?seq=1#page_scan_tab_contents

It's behind a pay-wall but I can probably get my hands on a copy


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