Have a redtop optima--drive almost everyday but only 6-8 miles--should i put a Battery Tender on everyday after driving or once a week or so--its usually around 12.60 volts next morning--Whats best for the battery? Thx.

 

Having a battery tender connected can never hurt.

 

I'd be more concerned about the oil not getting to temp on those consistently short drives then I would be about the battery. Although 12.6 V. seems very low.

 

Take the long way home...for the batt and the lubes.

 

A fully charged 12v battery after sitting overnite and settling down and showing 12.6v is fine. Fully charged is 12.66 -12.70v.

My Schumacher 1.5v charger from WallyWorld and costing a whole $24.00 will charge my battery up to about 14.70v before it automatically switched over to trickle/maintain mode.

I just connected it this morning to my C6. My batt showed 12.54V and has sat for 7 days without charging or driving car. Took about 3-4 hours to bring it to full charge of 14.70v then, maintain shows it at 13.05v. Disconnect charger and it begins slowly dropping. Took 7 days to drop from 13.05 to 12.54 without charging or driving car.





The short drives are what kills batteries. The alternator doesn't have a chance to recharge battery enough in that short a time.

 

IMO, if you drive your car daily, there is no need for a battery tender. If I go 5 or more days without driving, I then try to put a tender on the battery. The daily drivers for me and my wife never get a tender and my wife's SUV is all short trips.

 

You probably won't get much benefit from a battery tender since you drive your car daily. If your commute is 3 - 4 miles each way and that's all you do on a daily basis, you've got more to worry about than a battery. As pointed out earlier, condensation in your exhaust, crankcase and moisture in the brake master cylinder are bigger problems. "Take the long way home", two or three times a week and you, your Corvette AND your battery will be happier. OBD

 

Also to point out, if you are going to put a tender on a AGM battery, make sure the tender is designed for the AGM battery.

Hence most tenders are designed for wet cell standard batteries that take a lower voltage to mantain them, and will do more damage then good trying to use a non agm rated tender on the agm battery instead.

 

Let's start with the Red Top. That is a specialty battery for high compression vehicles that need lots of power to turn them over. It is also an AGM battery that can be mounted in unusual positions. To make those and other difference between "normal" batteries possible it has a lower capacity which means it will discharge faster. You've heard of the "Corvette tax". Optima specialty batteries are a battery tax for all but custom built vehicle applications.

Now for your question. EVERY lead acid battery loses some life when it is discharged ANY amount. For the maximum battery life you should put it on a maintainer and never connect it to a car. I've seen batteries last over 20 years if they are constantly on a maintainer and never used. But, getting realistic, if you drive the car every day in a moderate climate (you don't say where you live) the advantage the maintainer is probably not going to be amazing especially with an AGM battery which is less prone to shorting out with sulfate.

Some interesting reading - http://batteryuniversity.com/learn/a..._glass_mat_agm

As far as the type of maintainer, there is a small difference in full charge voltage but most maintainers work with either just fine. It isn't the charge level that is important as much as not changing the level by charging and discharging. It is that physical chemical reaction that causes "wear". If the ACM charging voltage were a problem then you would have an issue with the GM alternator in the car being designed for a wet cell battery.

 

Great information. do you know of any product that will allow a 12 volt battery to be equalized?

 

No need to put it on a tender since you drive it everyday. If it sits for more than 3 or 4 days, then I would put the tender on. Make sure its for a AGM battery.

 

An equalizer circuit is not required when there is only one battery. Now if you are talking about that snake oil chemical additive scammers try to sell...

 

12.60v is really good, I am lucky if I see 12.1-12.2v

 

You are roughly 50% discharged at 12.10. Should have already been on a tender before it got that low. Should not be that low if that reading is after 1 night after driving the previous day.

 

I think my car has a slight drain since new - some dudes here report that they can park their car for 3 weeks and it will start - mine the max it will go (and that too in warm weather) is 10-12 days.

 

Yea, that's been the discussion on here forever. Battery drain, what is normal and what is too much. This forum is literally flooded with battery drain posts and I think I read all of them going back as far as the C5's.

Normal parasitic drain for most cars is less than 50ma. That is still too much unless you drive it every day. Our Corvettes are supposed to be in the 17-25ma drain range. Again, if you drive it often this is not a problem. The problem comes in when the car sits for weeks and is not driven or charged. Even at say 20ma drain 3 weeks is all it can go without being on a tender/charger.

I installed a knife style battery disconnect switch on my neg batt post. I connect my DVOM in amp mode to read the draw. I connect the meter on the neg side, turn meter on to read amp then flip knife handle up/disconnect. That way I am reading the draw without breaking the battery connection which will usually clear, reset any abnormal draw I was trying to see in the first place. The vehicle current is now going thru the DVOM. Not starting or doing anything of course. The DVOM only has a 10amp fuse on that circuit.

My old 05 6 speed after shutdown which is about 15-20 minutes shows 20ma draw. Thats fine and I can live with that. This is not a DD so after about 7-10 days I connect my tender. My drain at 20ma is about 3-4ma in a 24 hour period. Just checked it this morning. Yesterday morning it read 12.79v. This morning it read 12.76v. It was off the tender 2 days ago.

 

Me thinks the battery threads are like a lot of other ones. Way to much battery "Techno - overload" info thrown out there. It really seems pretty easy. If you drive it every day, don't worry about it, you'll know when it's going bad cause it will start spinning slow or won't start....lOL. If it sits for more than 7 - 10 days put a tender on it from time to time. Lots of info overload on tenders too. No need to have a tender on it for 24 - 7. I've been "tendering" my cars and Harleys for many, many years and while I keep the tender hooked up, I only plug it in about 3 - 4 days a week for a few hours at a time and never had any issues. I don't like leaving electrical things plugged in all the time, esp with how cheaply things are made these days. Guess its kinda like if you tender it 24 - 7 then you'll get 60 months out of said battery, but if you only tender it 3 - 4 times a week then you'll only get 59-1/2 months.....EOS.....

 

This is what I use if i leave the car more than a week. Think this is the best I’ve used. To date. Works great. With an awesome readout.
Thanks Richie lol
It hangs on the wall right next to the battery. And i have the supplied pig tails connected for east on and off at anytime.



DIGITAL 400
12V PERFORMANCE CHARGER and BATTERY MAINTAINER

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