Battery tender question

[doctorjay61]

Newbie question here. I just got my 94 zr1 back in February. I just replaced the battery with an odyssey battery and bought and odyssey charger as well to maintain the battery. The directions for the charger say to ground the negative terminal cable. I wasn't sure where to place the terminal and I connected directly to the battery. Is that Ok? I just didn't want to cause any electrical issues.

Thanks for your responses. I look forward to meeting some of you guys at carlisle next month.

Dave

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[GOLDCYLON]

Yes that's OK. Just like the old school days black goes to negative and red goes to positive that's where I attach my Battery tender to as well when needed. GC

[We Gone]

That should work fine, or any frame bolt.

[doctorjay61]

Thank you both for your quick responses. I never had an agm battery before and the odyssey charger is way more complex then the basic tender i use on my lawn mower so I just wanted to make sure I wasn't hurting anything. Looks like it already fully charged the battery and is now in maintain mode. Thanks again.

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[George Maz]

No, Odyssey & AGM mode chargers put out much higher charge cycles due to these batteries having low resistance. My Odyssey Optimizer (25amp) charging instructions state to disconnect battery from vehicle. The concern is that higher currents can backfeed into the car's older electronics.

Now, have I connected, charged, and gone for a drive without following those directions exactly...well yes, but I just want to point out recommendations that I've read.

Deltran Battery Tender is safer, less amperage, but doesn't have conditioning charge capabilities like the $180 Odyssey charger.

Best option is usage of Quick Disconnect ($5) that eliminates parasitic draw altogether.

I have Odyssey Batteries in everything I own, and the rebranded AGM Die-Hard that Sears disappointingly no longer sells. Worth the money.

[doctorjay61]

Thanks for the info George. I have the 20 amp version. The directions didn't state to disconnect the battery but just not to hook up directly to the n battery terminal. I was unfamiliar with this requirement and so I was confused.

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[ssrszz4]

Buy a cheap battery disconnect and use it when car will be sitting for any length of time. I actually disconnect mine even if it sits over nite.

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[Dynomite]

Buy a cheap battery disconnect and use it when car will be sitting for any length of time. I actually disconnect mine even if it sits over nite.

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The Battery Disconnect Switch TIPS (https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-8.html#post1587653767)

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite11/9b113ff3-2c27-4600-aba8-a9f3456647a4.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/Dynomite11/04ee613c-938d-4097-8632-8ae82f07897f.jpg

[Paul Workman]

After extensive dealings with lead-acid batteries as part of my profession (in a previous life) I feel some axioms are helpful:


Batteries (including AGMs like the Optima) intended as direct replacement for flooded lead-acid batteries, must operate in the existing (charging/discharging) environments.

Performance is optimum when battery condition is maintained at peak levels

Battery capacity is better preserved when not being charged if external drain is eliminated.

Temperature is inversely proportional to the rate of chemical reaction.

Steps taken to support these truths will serve to preserve battery life, barring other practical factors/limitation.


As these (above) apply in the automotive application, these are some other things i find to generally be true as well...

Special instructions/recommendations posted by specific battery (type) chargers are focused in order to optimize the performance of a particular charger/battery combination, without interference from external circuits: i.e., circuits which may alter sensor readings and thus interfere with optimum results.

The output (voltage and current) characteristics produced by various chargers are constantly varied via inherent design, selected delivery rate, and the state of the battery as it reaches full charge.

Hopefully, somewhere in all of this one can find some tools to assess the virtues of various chargers and their practical (charger vs. cut-off switch) decision. :cheers:

[Hog]

You are powering down the ECM everytime you switch off the power. Fueling must be relearned everytime this occurs.


Even with a disconnect, an automotive battery will still discharge. Lead /acid batteries are designed for frequent shallow discharging/charging. Exactly what an often used daily driver will supply.


Sulphation occurs anytime a lead/acid isn't 100% charged.


A disconnect along with a low current tender is the best option for long term storage. This all gets worse for you guys in the warmer latitudes. What does help the warmer latitude guys is that there typical winter storage is shorter than us Northeners. 5 months is normal up here.
Keep em cold and keep em charged.


Its not an either or option, use a battery cut off AND use a trickle charger.

[Paul Workman]

You are powering down the ECM everytime you switch off the power. Fueling must be relearned everytime this occurs.


Even with a disconnect, an automotive battery will still discharge. Lead /acid batteries are designed for frequent shallow discharging/charging. Exactly what an often used daily driver will supply.


Sulphation occurs anytime a lead/acid isn't 100% charged.


A disconnect along with a low current tender is the best option for long term storage. This all gets worse for you guys in the warmer latitudes. What does help the warmer latitude guys is that there typical winter storage is shorter than us Northeners. 5 months is normal up here.
Keep em cold and keep em charged.


Its not an either or option, use a battery cut off AND use a trickle charger.

If, for example, a "Battery Tender" (or any such "smart charger") is in parallel (which it would be) with a battery left connected to the car's circuits, one could argue too the need to disconnect the battery from the car's circuit is unnecessary IF the the charger's output current is substantially greater than the tiny (.25mA) parasitic draw.

FWIW, even the very small "smart" chargers, e.g. Battery Tender, provide ample current to maintain the memory and pre-sets while servicing the battery too. In my experience with (Battery Tender brand) chargers, plain old flooded lead-acid batteries have gone no less than 7 years, and as much has 11 years and counting - and still cranking like it was new.

[ssrszz4]

Except for long storage a disconnect always has been easier for me and have had batteries last 6 years never on a charger.

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[lfalzarano]

Downside is the security alarm is not functional.


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[Dynomite]

Except for long storage a disconnect always has been easier for me and have had batteries last 6 years never on a charger.

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I disconnect for 4 months at a time or even for two days at a time.....batteries last and last and seem always fully charged.

Security???? Battery is disconnected :p
Never on a charger :thumbsup:

[gbrtng]

Newbie question here. I just got my 94 zr1 back in February. I just replaced the battery with an odyssey battery and bought and odyssey charger as well to maintain the battery. The directions for the charger say to ground the negative terminal cable. I wasn't sure where to place the terminal and I connected directly to the battery. Is that Ok? I just didn't want to cause any electrical issues.


The reason for connecting the negative lead on the frame or some place other than the negative battery terminal is to prevent a possible spark from igniting any hydrogen gas at the battery ... Connect the positive lead to the battery first and then connect the negative lead. Safety first.

[Hog]

If, for example, a "Battery Tender" (or any such "smart charger") is in parallel (which it would be) with a battery left connected to the car's circuits, one could argue too the need to disconnect the battery from the car's circuit is unnecessary IF the the charger's output current is substantially greater than the tiny (.25mA) parasitic draw.

FWIW, even the very small "smart" chargers, e.g. Battery Tender, provide ample current to maintain the memory and pre-sets while servicing the battery too. In my experience with (Battery Tender brand) chargers, plain old flooded lead-acid batteries have gone no less than 7 years, and as much has 11 years and counting - and still cranking like it was new.


I agree and think that so long as you are overcoming the parasitic charge, you "should" be golden.

[Hib Halverson]

Hog's comments elsewhere in this thread on smart chargers vs. battery disconnect switches is spot on.

AGM, gel cells and flooded cell batteries will last just as long or longer if they are connected with a smart charger rather than being disconnected. Plus, they will hold a charge indefinitely, whereas, if they are just disconnected, they will eventually go dead.

I've used the AutoMeter Battery Extenders for more than two decades. I have them for all of our Corvettes. To charge batteries at higher rates, I use the new Odyssey chargers which are smaller, lighter and less expensive than the previous Odyssey Ultimizer chargers.