PSA - Don't use a Battery Tender Jr. on your Z
 

Hello everyone. Just got off the phone with Deltran who makes the Battery Tender smart trickle chargers. These are the chargers I've seen recommended for people storing their car over the winter. I store my Z for about 3 months every winter and the last 2 years I have hooked up a Battery Tender Jr. to my battery. The first year after storage this way I went to start the car and it started very rough - like the battery barely had enough voltage. However I checked the battery later after driving it and it appeared fine so I just forgot about it.

Last year I again stored my Z with the Battery Tender Jr. connected. This time something odd happened. I store my car at a relative's house and asked him to check up on the tender every once in a while. He reported back that the Battery Tender Jr. was always flashing the green light. This indicates that the battery is >80% charged but not fully charged yet. All winter long it was flashing green and I didn't have access to the car so I didn't worry about it too much. When I went to pick up my Z in the spring, the battery was totally dead. Nothing. I had to jump charge it for a long time, probably about 30 minutes before it had enough charge to start up.

At this point I thought my battery was probably just old and nearing the end of its life (although that seems strange since it's only a 2009). I also tried searching the forums and google for anyone who had problems like this and I didn't come up with anything conclusive. Nor did I find any information from Deltran that said there would be an issue with a Battery Tender Jr. on a sports car. I had the battery tested after driving it for a while and sure enough the battery was fine and didn't need to be replaced, so I started to suspect the charger was at fault.

Fast forward to this winter and I just put my car into storage a couple weeks ago. The same thing is happening again. The charger is just blinking green again and never lights solid. I called up Deltran and told them the situation and they told me right away that the problem is that you can't use a Battery Tender Jr. on a sports car. They said cars like the Z have very high parasitic draw and this basically confuses the algorithm in the Tender Jr. and it can't keep up with all the electronics in the Z. They said I would need a Battery Tender Plus since it charges at a higher current. I had suspected as much, but until now I couldn't find any information confirming my suspicions.

TL;DR: Don't use a Battery Tender Jr. on your 370Z because it can't keep up with the high parasitic draw on the battery from the Z's electronics. It will make your battery die during winter storage and probably shorten the life of your battery over time. Spend the few extra dollars on the Tender Plus instead.

been using battery tender on my G for the last 7yrs, Z for the last 4yrs with no issue. :D

this one:

http://www.amazon.com/Battery-Tender...battery+tender

i would check your car for abnormal parasitic draw before blaiming it on the battery tender.

:iagree:

Or get the battery tested. If it's a 2009, and it's now 2013, that's a pretty good run from a battery. I never had a problem with my Battery Tender Jr. And it seems odd that the solution from the manufacturer is "The cheap one won't work. The expensive one will. You should buy the expensive one."

my G is 2004 and factory battery. :icon17: my G is less polluting than a f-king prius.

Wow. Probably climate related. I get three years out of a battery. It's like clockwork.

yah, im not in a super hot climate and dont drive the car in really hot weather anyway since i only motor them on weekend motrnings. :D i do add distilled water though when needed.

You're right. The heat will kill em!

There's nothing on my car drawing unnecessary power and the intelligent key battery is pulled as well so the car isn't communicating with the key. Car is stock and nothing is plugged into the adapter ports. There's really nothing it could be and the battery tested solid. I'm still going with the manufacturer on this one. Otherwise what would I even do? I'm not buying a new battery because there's nothing wrong with the current battery. I agree it sounds convenient for the manufacturer to recommend the more expensive model, but the Plus charges at twice the current so it makes perfect sense. She also told me how to troubleshoot the Tender Jr. to make sure it isn't defective (which I did, and it isn't) but she said that won't matter because the Tender Jr. wasn't designed for sports cars. If you guys don't want to listen to me that's fine, but I'm going on my third winter now and I'm sick of having a dead battery in the spring on a relatively new car. It may be 2013 now but I bought the car in fall 11 with only 4K miles. There's no way the battery should be dead this fast.

I bought the BT plus for my Harley's years ago (sold both a few yeras ago) and now use it between my vette, Z and lawn tractor over the winters. No problems ever. The BT junior has a charge rate of 0.75 AH vice 1.25 AH for the plus. It should keep any battery charged. Maybe the BT jr is faulty?

Then the BT Jr died. It's a bad unit if I had to guess.

have them send you a replacement battery tender jr and see. i'd unplug the battery from the car to do this test as well.

you shouldnt have to unplug the battery from the car though when using battery tender.

Long Term Parking
 

I would be more concerned about letting a 370Z sit for 3 months over battery issues.

:confused:

In places that snow, it's very common for people to put their sports cars away after snow starts falling and take them out again in spring. Did I misread your post somehow?

I had to replace my 2009 battery already too. I never used the charger but never checked the fluid level either, and it was low. Tons of heat on track days coupled without maintenance = new battery for me.

naw, troyz's just being troyz. :icon17:

my car hibernates 4months sometimes up to 5-6months depending on weather. no issue. 40psi+ and on flatstoppers.

I'm inclined to believe that you have a bad charger. I'm not sure exactly what the parasitic load is but it's not that much and being a sports car has nothing to do with the situation.

How did you test it? I would use two meters - one measuring volts (with and without the charger) and the other measuring current.

I've been using mine for 2 years and nothing wrong with mine so far.

My town has been spreading salt like it's going out of style, just at the threat of flurries, so the Z is parked and covered for the winter. I have my BT Jr. on my Seadoo battery right now, but I'll swap them and see if I can get the green blinking light instead of the constant green light on my regular BT (not sure if it's the Plus or not). Interesting topic and thanks for sharing the manufacturer's recommendation.

It's possible the charger is bad, however I followed the procedures given to me by the manufacturer and the charger is supposedly fine. I also used the same charger on my other car (97 maxima) and it was working fine and the light changed to solid green after a couple days (and I verified the battery voltage on the maxima had increased). So I really think it would be a waste of time to try another BTJr when it's a substantial annoyance to drive 4 hours just to get access to the car (round trip).

And yes, modern cars these days have lots of processors and computers that are drawing power when the car is off. It's entirely plausible the quiescent draw of these cars is higher than typical. On the phone they told me flat out that the Jr. would not work properly on this car, so regardless of whether or not I buy the Plus version I'm not just going to ignore what the manufacturer says about their own product.

and my G and Z are both modern cars and are floating fine, so as many others who use battery tender on their modern cars. so to me, if it's not the battery tender, and if it's not your battery, then it's your car.

did you say you bought the car used? if so, there might be a reason why the original owner sold the car..

im not sure if doing a PSA from one bad experience on your one car is a good idea or not? :confused: not enough proof or testing when you are probably the only one person with a z that mentioned having problems with the battery tender? i could be wrong but i dont remember reading any other z owner here complaining about the battery tender?

and the sales assciate you spoke to at deltran. :shakes head: probably just wanted to get rid of you.

my suggestion is you check youtube on how to test parasitic drain. some cars (even stock) have more drain than others.

^ I agree with Kenchan. I have 2 Battery Tender JR I bought from Amazon one for my Z and the other for my Supra and both are doing fine on it....so far.

Have to agree, I have not had any issues with mine. I use one on the Z and my GSXR1000

My car goes into storage for 5 months without any battery tender on it and it starts right up on the first crank. You have some sort of larger parasitic draw than normal.

I'm about to put my Nismo to sleep for the winter. I figure if I just start her up every month or so and maybe give it a drive around the block I should be ok. Or would a trickle charger be better in this case?

you will have moisture inside your exhaust system which will sit there for a long time. trickle charger will over charge your battery.

if you're not going to get one of these battery tenders or the alternate black&decker one, you can either unplug the battery, or drive your car every 1-2wks for 10miles+ each time.

All valid points. Plus, at the price of trickle/float chargers nowadays, probably not worth the time/effort to troubleshoot.

But there does appear to be something wrong somewhere. I'm not familiar with the BTJr but, judging by the comments of those who are, it should do the job. If it's not the charger then I suspect you have an above normal parasitic load for some reason. I'd put a meter on it and check - if for nothing else than my peace of mind.

Please keep us informed as to what you find out. My curiosity is piqued.

The PSA part of my post is because the manufacturer that makes the charger said it isn't supposed to be used on the 370z. Their words, not mine. Take that information as you will but I have already verified my charger is not faulty and neither is my battery/z. Making claims that my Z is somehow damaged from the previous owner is beyond asinine. Especially since "parasitic load" isn't damage in the first place, and there's no way the previous owner sold the car because of that. I actually know the reason the previous owner sold is because they couldn't make the payments. Not that it matters at all.

Those of you who claim your battery tender jr. has been working just fine on your Z - Have you actually verified that with a multimeter? And was this during long term storage or were you also starting up and/or driving the car during the storage period? I have no access to my z in the winter so a tender is my only option (or nothing).

hummmm... in order to make this an actual PSA, can you ask the manufacturer wat the maximum allowed drain amperage is for the jr?

and what is the drain amperage of the 370Z they have on file?

would like to make sound decisions based on data, not based on potential xmas-season-hired-part-timer.. :ugh: :confused:

verify wat with a multimeter? verify the battery's cca using an ammeter you mean?

but why would i need to verify anything if everything is working fine the last 7yrs on one unit and 4yrs on another? :confused:

Will do.

So I guess that's a "no". A multimeter can verify the BTJr is maintaining voltage according to their float curves. It could be you perceive the BTJr to be working but really leaving it off would make no difference. Do you start your car during storage or do you rely solely on the tender? And if you don't start your car at all during storage, how long is it stored for? I'm not trying to prove you wrong/be antagonistic here, I'm trying to figure out the answer.

Good advice right there. I have never used a JR, always the Tender Plus on a number of vehicles without any trouble.

As someone said, I would first verify the parasitic draw with nothing attached, put a digital MM between positive lead of battery and the positive battery cable with the amps on meter set to highest scale then work your way down till you find a readable range. Don't use a clamp on meter unless it has range in the 100's of milliamps. Usually quiescent draw is in the low milliamps. This will tell you the quiescent current draw at rest.
Then I would measure the voltage at the battery terminals after the 'lil tyke charger has been connected say, overnight. If the voltage is within tolerance, I would have to assume some other problem exists.
Lets face facts here, you need voltage and amps to crank the car. If the car doesn't crank easily either you have not enough volts or amps, it's that simple.
(Considering your statement that the car cranks normally after a period of time).
If you were feeling REALLY energetic you could measure the current draw of the 'lil tyke battery charger into the battery when first connected, and then after overnight. See if the current draw is over the device rating.

Take your battery out of the car or just disconnect the negative terminal.

Could be a combination of the JR and your older battery/parasitic draw. The JR's lower amperage design isn't really intended to charge a battery, but rather "top it off" and keep it that way. Give the Tender Plus a shot, or try one of the many other brands with at least 1amp or more. I personally run a 1.5amp Schumacher maintainer.

Nothing is an option. I've done it every year. Mustang GT for years, S2000 for 6 years, Z for 2 years. I haven't had to charge the battery once. Never replaced the mustang battery, replaced S2000 battery in year 4 or 5, still on factory Z battery.

Don't start the car for a few minutes, it won't do any good. Either let it sit the entire 4-6 months or start it and drive it enough for all fluids to come up to operating temps.

well the battery is showing a healthy 12v+ at all times. it's really the cca that tells if a battery is good or not. for that, you can't just use your multi-meter.

i dont start the car at all during the 4-6month hibernation. :)

Hibernating
 

I would think it might be better to drive them around (if possible) to keep the tires round and the gaskets good at least once every 6 weeks even if you can't get out of 2nd gear.

Plenty of people in this very thread seem to disagree.