anyone leave their battery tender on when car is covered?

[Steve 00RT/10]

Re: What\'s the best battery tender?

My battery is original and almost 5 years old/44,400 miles. The only time I have ever drained the battery is when I left a door ajar...triggering the interior lights or locked the car by mistake...security system active.... in our garage and not run it for several days. Any car battery would be drained by doing either of the above. I only use the tender when I store the car for the winter.

I agree with Joe that the current draw from our cars should be very very minimal and a battery tender should not be needed unless not running for an extended period.


Steve

 

[joe117]

Re: What\'s the best battery tender?

Thank you Shelby. Having others agree that I am right always makes me feel warm inside.

By the way, looking closely at your avitar, I can see the wires running across the lawn feeding power the three battery tenders you hooked up while you were taking that picture.
Better safe than sorry.

 

[FlyBryViper]

Re: What\'s the best battery tender?

That was the impression I got yesterday!!
We need guys like Joe constantly questioning, analyzing and debating other people's decisions, even though it has no bearing on Joe whatsoever.

 

[joe117]

Re: What\'s the best battery tender?

Mr Fly,
#1 I don't care if you act in an illogical un scientific manner.

#2 I don't see any reason to allow your superstitions to pass as good advice on a forum for the exchange of knowledge.

#3 Your ridicule of someone who actually knows something about this topic does not enhance your reputation.

 

[Shelby3]

Re: What\'s the best battery tender?

Ok, we all agree that Joe is right, now move along, nothing more to see here.

 

[joe117]

Re: What\'s the best battery tender?

Mmmmmm, warm.

 

[Cris]

Re: What\'s the best battery tender?

1 month is about the max I can go without a tender. More than that and I need to jump or recharge it to start the car. That is both with a Gen I and a Gen III. And I have heard the early Gen II's were much worse due to the security alarm.

So Joe, sorry to burst your bubble, but that is my real world experience. This is with moderate mileage cars (circa 4000-6000 miles per year). For a few week period there is no need to do anything though.

 

[joe117]

Re: What\'s the best battery tender?

Ok, I'll buy your one month limit. I said two months but one month sounds reasonable.

The gen1 maintenance manual says twenty days. I don't know what they base that on and I know from my experience that twenty days is very conservative.

Here's what I based my statement on.

The book says a 94 should have an IOD, that's "Ignition Off Drain" of 5 to 30 milliamps.
30 milliamps is .03 amps.

The book also says the battery, I suppose the factory battery, has a reserve capacity of 115 min @ 25 amps.
If you use less current the reserve is longer.

25/.03= 833x115= 95,833 minuets that's the reserve capacity at .03 amps.

95,833/60= 1597 hours, 1597/24=66 days.

Now, keep in mind that we use the max drain of 30 milliamps in this calculation. The book says 5ma to 30ma is acceptable.
The book also says that over 30 milliamps mean that there is an electrical problem.

So, there you go. That's how long your Viper should be able to sit without needing a battery tender, 66 days.

Also, 5 to 30 milliamps is the same as most other cars. The Viper doesn't draw any more from the battery when it is sitting than other cars.

 

[95Viper]

Re: What\'s the best battery tender?

So it takes 66 days to drain the reserve capacity.

At our now agreed upon 1 month limit
Even at 33 days, does it make sense to drain your battery 50% of it's reserve because you don't want to take the 5 seconds to plug in a tender?

Isn't it harder on the battery to go down 50%, then back up? Why not leave it at 100% all the time? Isn't that better for the health of the battery?

 

[Ulysses]

Re: What\'s the best battery tender?

If you use up your reserve capacity (your 66 days), you will have a dead battery (depleted battery).

A battery is considered depleted when it goes below 10.5 Volts.

Why would Dodge say 20 days when you just calculated 66 days? We all know that the Viper electrical system is finicky. When the battery gets low, it refuses to run correctly or run at all.

Let's start with what we know. We know that a fully charged battery reads 12.6 Volts. We also know that a depleted battery is 10.5 Volts. We also know it takes approximately 66 days to go from 12.6 to 10.5 Volts. Let's assume everything is linear. 12.6 - 10.5 is 2.1 volts. Let's say that the Viper is finicky at say 12 Volts or below. That's just a guess but a good number to start.

12.6 - 12 V = .6 V

0.6/2.1 ~= .29

.29 * 66 days = 19 days

Let's just say 20 days to be conservative. We need that margin because capacity is also affected by the environment (mostly temperature).

Should you use a battery tender? I'll leave that up to you, but when mine sits for a week or more, it has the tender hooked up.

 

[VPRVENM97]

Re: What\'s the best battery tender?

This thread is cracking me up. It's amazing how a simple question can evolve into such entertainment.

Here's my 2cents FWIW (and I'm by no means an expert). I always have the Viper hooked up to the Battery Tender if its not going to be used for more then a couple days. My understanding is that a lead acid battery operates at peak performance when kept at full charge. My factory original battery lasted 6 years before I replaced it. Still working great when I did. I currently have an Optima Red Top installed and it's on the Battery Tender too.

I believe that its safe to say that a lead acid battery will self-discharge over time. As lead acid batteries are left in a state of discharge, they will sulfate as sulfur in the acid combines with lead in the plates to form lead sulfate. With our Vipers the way they are, taking a couple seconds to attach the quick disconnect and keeping it on a float charge sure can't hurt. The result I've experienced is a reliable long lasting battery. That and a Vipair is worth 55HP!

To answer the original question, no problems with using the Battery Tender with the car cover on.

 

[Shelby3]

Re: What\'s the best battery tender?

To hell with it, we're headed to the four pager minimum I predicted earlier. I think both battery tenders AND Vipair are worthwhile additions to Gen II Vipers. When I use my battery tender before driving, it feels like 50 more horsepower, no sheet.

 

[VPRVENM97]

Re: What\'s the best battery tender?

To hell with it, we're headed to the four pager minimum I predicted earlier. I think both battery tenders AND Vipair are worthwhile additions to Gen II Vipers. When I use my battery tender before driving, it feels like 50 more horsepower, no sheet.

Jim,
You sure it's not the air pump sitting on top of your engine that you're feeling? My SOTP feeling is that the Battery Tender is good for 5 HP and the Vipair is good for 50 HP so that's a gain of 55 RWHP! You might wanna check you numbers again or recalibrate your SOTP Dyno.

 

[Hisserman]

Re: What\'s the best battery tender?

I guess if you keep the car running under the cover, the battery will stay charged!?!

 

[FlyBryViper]

Re: What\'s the best battery tender?

If you guys keep this up, you are really going to piss Joe off!

 

[VPRVENM97]

Re: What\'s the best battery tender?

I guess if you keep the car running under the cover, the battery will stay charged!?!

Or if you're not sure that the alternator is working, you can keep the Battery Tender hooked up while driving and run a really long extension cord. I wouldn't recommend driving with the car cover on though (it might flap in the wind and scatch the paint).

If this thread doesn't make it to 4 pages we need to revive the Vipair thread or the Windbreakers and Zaino thread (unless its been zapped)

 

[FlyBryViper]

Re: What\'s the best battery tender?

O.K. here you go...who uses the Battery Tender Jr. on their Harley, or whatever brand bike you have?

 

[VPRVENM97]

Re: What\'s the best battery tender?

O.K. here you go...who uses the Battery Tender Jr. on their Harley, or whatever brand bike you have?

No Battery Tender Jr. but I use the Optimate III Charger on my 95 Dyna Wide Glide. With and without the bike cover. Felt like .258 RWHP gain with the Optimate.

You must be registered for see images

 

[IEATVETS]

Re: What\'s the best battery tender?

94 Viper, 35,000 on the clock, 2 year old battery, heated storage, NO battery tender, never started during the winter, no problems with a dead battery.......ever!! What do you all think of that? (we will make 4 pages yet.)

 

[Shelby3]

Re: What\'s the best battery tender?

O.K. here you go...who uses the Battery Tender Jr. on their Harley, or whatever brand bike you have?

No Battery Tender Jr. but I use the Optimate III Charger on my 95 Dyna Wide Glide. With and without the bike cover. Felt like .258 RWHP gain with the Optimate.

You must be registered for see images

Damn Dave, I like your taste in bikes too. My 2002 Wide Glide. It came with a battery tender.

You must be registered for see images

 

[joe117]

Re: What\'s the best battery tender?

The experience related by IEATVETS is what I would expect.
I don't think your Viper, sitting in a garage, would need a battery tender for over the winter storage.

I believe that it wouldn't be a bad idea to have a battery tender connected for over the winter storage, I just don't think it is required.

Remember, my comments were not really directed to the folks who hook up a battery tender for a non use period of weeks. The comments were directed to the guy who hooks it up during the week when he only uses the car on weekends.
They were also directed to the guy who says he hooks up the tender between runs on the track.

Again, I have no problem with an owner who connects his tender for weeks of non use. It isn't needed but it isn't a worthless practice.

Ulysses has some numbers to back up his comments, a true man of science compared to those of you who spout myth and pseudo science. ;-)

Ulysses has a point. The fact that the reserve capacity low voltage limit stared in the manual is actually 10.7 volts is a small point and doesn't really taint his calculation.

The problem I have with his calculation is the 12 volt minimum for proper Viper operation. I can't find any science backing up that claim.

Again, looking at the published data, we find that the manual states that the voltage present at the battery terminals in a cranking load test is acceptable at 8.5 volts to 9.6 volts depending on the temperature of the battery during the test.

That means, the Viper will start properly when the voltage during cranking is about 9 volts.
Not the 12 volts that Ulysses uses in his calculation.

After the car starts, the alternator will cause the voltage to rise to well over 12.6 volts.

These numbers show that the claim that the Viper needs 12 volts to start are false and have no basis in fact.

So Uncle Joe, what the heck, why not connect the tender any time the car isn't being used? It takes no time, it's easy.
What's the downside?

Well kids,
If you connect the tender whenever you park in your garage, your battery will be held at a decent state of charge. That's a good thing.
But,
when you take the little trip over a weekend and leave the car in a nice safe parking garage, without the tender. You may find that the problem you have been masking by the use of the tender, comes back to bite you on your tender butt.
Get it? Tender? Butt? Ok, no more jokes.

All I'm saying is, you shouldn't need the tender. If it does anything to help you keep the battery up in short term periods of non use,
You have an electrical problem or a battery that needs replacing.

 

[Steve 00RT/10]

Re: What\'s the best battery tender?

"Let's start with what we know. We know that a fully charged battery reads 12.6 Volts. "

I thought a fully charged battery was 13.2 volts...2.2 volts/cell? That's what I remember from school many years ago.

"All I'm saying is, you shouldn't need the tender. If it does anything to help you keep the battery up in short term periods of non use,
You have an electrical problem or a battery that needs replacing."

This a true statement.

Steve

 

[VPRVENM97]

Re: What\'s the best battery tender?

Damn Dave, I like your taste in bikes too. My 2002 Wide Glide. It came with a battery tender.

You must be registered for see images

Nice bike Jim. I see you also have one of those Kuryakin Hyperchargers. That's gotta be the Harley version of the Vipair. Did you notice any SOTP HP gain?

 

[Shelby3]

Re: What\'s the best battery tender?

Feels like bout fiddy..........

 

[THOR]

Re: What\'s the best battery tender?

I keep my Battery Tender on at all times. I have enough extension cords plugged that I can drive my car the six miles to work if desired. I have never had a battery issue!
Oh yeah, and I always cover my car - no problems in doing that either.

 

[redlightrich]

Re: What\'s the best battery tender?

I guess if you keep the car running under the cover, the battery will stay charged!?!

wow! this thread really morphed!!!! if i keep it running under the cover, what is the best way to vent the exhaust:O) as an added bonus i can use it to heat my garage!! i just didnt want to create a mini hindenburg.

 

[joe117]

Re: What\'s the best battery tender?

Dang Rich,
There was a guy a few posts back with a six mile extension cord who drives it to work with the cover ON!

And you are worried about venting exhaust........

 

[redlightrich]

Re: What\'s the best battery tender?

Dang Rich,
There was a guy a few posts back with a six mile extension cord who drives it to work with the cover ON!

And you are worried about venting exhaust........ i guess youre right joe, i am turning into a bit of a wuss. the real solution is make my gts my daily driver, then who needs a stinkin tender