Dry Battery

[Scott Pettit]

Just a heads up:

Today, while checking the plethora of batteries that I have on battery tenders, I found one that was bone dry and I am certain that it was checked before it was removed from the vehicle in July. I highly recommend that if you are not driving your car and it is being stored, check the battery every few weeks.

Fortunately, after adding water and putting it on a rapid charger, it was back to 100 % in about 20 minutes and the car started just fine.

[RRZ8]

Scott, isn't our battery maintenance free?

Why a rapid charger?

[Scott Pettit]

Technically yes. Realistically no.

Virtually all maintenance free batteries are simply regular batteries that have been sealed with a label across the fill caps. Calling them maintenance free is a selling point and that is it.

I take the battery, feel for the caps (they are flush) under the label, and then trim around the edge of the caps so that they can be unscrewed. The first time I did this to my Z3, I found a very low cell so I filled it and the battery returned to normal.

I recommend this procedure for all MF batteries. If your battery comes with a warranty that does not allow you to service it yourself, wait until the warranty expires and then do as I suggest.

[RRZ8]

OK, thanks I will!

p.s.: Is there a reason that you charge them with a high current?

[Scott Pettit]

I missed your previous question about the rapid charger. I shouldn't have used that term as I don't like to rapid charge batteries unless they are in a vehicle and have died (lights left on and so forth). Rapid charging involves higher amperage than slow-deep cycle charging.

When I discovered the dry battery, I decided to put it on a charger that would run diagnostics and then switch to auto charge mode. I use a Sears brand for this. Otherwise, I always slow charge batteries.

[RRZ8]

I fully agree, slow charging is what I do too. Even our 90ah Z8 battery at 500mA

[Norcal]

I've never used my tender. Some times I let the car sit two or three months between drives. Replaced the battery once, about a year ago. No reason for me to go through all the trouble. Do you guys leave your alarm on? (I don't) I also have never attached a phone.

[Scott Pettit]

Took the phone out when I bought the car as I have another phone.

The car is in my garage and on a lift so the the doors are unlocked.

[jpklecker]

My phone is only in when the car is being driven, and then only sometimes. The car is unlocked in our locked attached garrage. Currently I am on the second battery (it was replaced under warranty after about 3 years of use) and with the car driven at least twice a week, still going strong after four years. The normal life of batteries here in Phoenix is from 18 months to 3 years if you're lucky.

[RRZ8]

My phone is only in when the car is being driven, and then only sometimes. The car is unlocked in our locked attached garrage. Currently I am on the second battery (it was replaced under warranty after about 3 years of use) and with the car driven at least twice a week, still going strong after four years. The normal life of batteries here in Phoenix is from 18 months to 3 years if you're lucky.


Why so short? The heat? I lived in the Middle East, and can't remember that our batteries had such a short life (?)