Battery replacement time?

[LisaLannister]

A few weeks ago, I went to start my Z4 and it would not start, with the only electrical current being the dull red light coming from the top down button.

I called roadside assistance who came and boosted my car and it started right away and I drove it for about 30 minutes.

A week later, I went back to take it for a drive, and again, it would not start and it was if it was not boosted the week before.

Is it time for a new battery? Any other issues I should consider?

Thanks

[racerbruce]

How old is the battery?

How often do you start the car and drive the car?

How many minutes is the car being driven?

[chickdr]

I will tell you my rarely driven z4 needs a new battery about every 4-5yrs.

[LisaLannister]

Thanks for the responses.

I drive the car for a an hour or two, once every weekend or sometimes once every two weekends.

I think the battery is original.

[racerbruce]

Originally Posted by LisaLannister

Thanks for the responses.

I drive the car for a an hour or two, once every weekend or sometimes once every two weekends.

I think the battery is original.

Original battery....what model yr is the car?

[LisaLannister]

2007

[Emmrbee]

I would suggest that you use a battery tender to maintain your battery during storage and down time between your weekend driving. I used a battery tender on my last Z4, a 3.0si, and had the same battery for 8 years with no problems.
A battery tender does not overcharge the battery like a trickle charger will. Can be purchased at Costco, Canadian Tire, or Walmart for about $50. I bought mine on sale at Canadian Tire in the West Island.
I have my Z4M in storage now with the battery tender hooked up for the winter.
I would also suggest you replace your battery as it sounds like it will no longer hold a charge and it's at the end of its life. Costco has some good deals on batteries for your Z4 and they won't be overpriced like at the dealer.

[jmillet]

I drove my 2007 Z4M for ten years on the OE AGM battery keeping it on trickle charge when not driven for extended periods of time. I experienced the same symptoms and did a load test to determine the battery was used up. Here is a good list of battery options https://www.zpost.com/forums/showpos...03&postcount=1
I went with the Duralast Platinum Battery H6-AGM Group Size 48 which is an exact replacement for the OE battery.

[colb]

Sounds like you need to replace the battery given its age but would be best to use a volt meter on the battery terminals and see what charge the alternator is putting into the battery with the engine running. You should see in excess of 14volts, if its less then that will be an indication that the alternator is failing to charge the battery and in need of replacement. I had a problem with my Z3, if run at night using headlights the next day the battery was flat. Checked the alternator output and it was below 13volts, running with headlights drained the battery hence the no start next day. It provided enough voltage for daylight running but using the headlights was too much for it. Following this I fitted a small usb socket with built in volt meter in the dash so I can monitor the state of the battery and the charging rate the alternator is producing. Fitted a similar volt meter to my Z4 as well.
https://www.ebay.co.uk/itm/5-12V-Car...cAAOSwn4hfUz89
If you don't want to fit a permenant voltmeter buy one that plugs into the cig lighter socket like this https://www.ebay.co.uk/itm/Dual-USB-...kAAOSwAE9fhBw6
Good idea to put a battery tender on the car as suggested earlier given the infrequent use the car has.

[KevinC]

Definitely put it on a Battery Tender or similar if only driving it weekly.

I use the Noco One, which is TINY, has temp compensation for AGM batteries, and is dirt cheap - $30 from Amazon. Extension cable available too if you need a bit more length. Easy to attach under the hood.

https://amzn.to/33tmctZ

[bosstones]

For the age, that battery has had a really good run. Personally, I would just replace it as it likely doesn't have a lot of life left even if it weren't root cause right now.

Back in the day, there was some speculation that the battery lived longer by routinely locking your doors when the car was parked (for the non-battery tender crowd). I always lock my doors when I park in my garage (incl annual winter storage). My original battery lasted 9-10 years but I did start using a tender after approx year #6.

[maupineda]

I have an H5 battery for a lower weight benefit. and is not much different to the H6, plus mine does not have CIC (Nav) and I dont spend time inside the car listening to radio, and I have a battery tender too. It saves 5 kilos or 11 pounds

[Big Hawk]

Probably a dead or very weak cell. Have it load tested either at dealer or parts store.

[LisaLannister]

Hi everyone,

Thanks to all of you for your helpful responses. I purchased a Bosch H6-48 battery and had it installed yesterday. The old one had reached the end of its useful life.

[Emmrbee]

Originally Posted by LisaLannister

Hi everyone,

Thanks to all of you for your helpful responses. I purchased a Bosch H6-48 battery and had it installed yesterday. The old one had reached the end of its useful life.

Don't forget the battery tender for winter storage

https://www.costco.ca/battery-tender...100695600.html

[wdb]

Battery tender. I swear by CTEK. I have a 2007 328i, which is a model notorious for getting wonky when the battery is low. I put it on my CTEK for 10 days and the car has been perfect ever since. (I do keep it on the tender when not in use.)

[SD ///M4]

Originally Posted by wdb

Battery tender. I swear by CTEK. I have a 2007 328i, which is a model notorious for getting wonky when the battery is low. I put it on my CTEK for 10 days and the car has been perfect ever since. (I do keep it on the tender when not in use.)

The CTEK model (Multi US 3300, 56-158) that I've used on my Z4 M Roadster for almost 8 years has been discontinued but I believe that this model is very similar: https://smile.amazon.com/dp/B006CQ9B...ype=automotive. This is roughly the same price as the Battery Tender brand sold by Costco, but is much easier to use.

The CTEK charger includes both clamps and eyelets, either of which plug into the power cable is connected to the charger. I have the eyelets permanently attached to the positive and negative connections in the engine compartment. The power cable can be conveniently led out by the left front headlight so that the hood can be closed. If the supplied power cable is not long enough, CTEK sells an 8' extension cable. Since my Roadster sits in the driveway, I have the extension cable plugged into the eyelets attached to the battery which then runs into the garage and plugs into the power cable attached to the charger so there are no connections out in the open.



My Roadster sits in the driveway most of the time but after having the battery run down once and having to have a bunch of codes cleared it's permanently hooked up to my charger and has never failed to start since then. With the unique plug connecting the battery leads to the power cable, the power cable can easily be unplugged and removed from the engine compartment whenever you drive it.

[3798j]

Originally Posted by Emmrbee

Don't forget the battery tender for winter storage

A very good suggestion. Even when your Z is asleep, it's still using the battery. Invest in a battery maintainer. I've hardwired my CTEC to the positive underhood jump terminal and a ground stud on the firewall...positioning the hookup at the base of the windshield. I always plug in as soon as I get out of the car.

[LisaLannister]

I stored my car a few days ago and took out the battery out and is now sitting in a box in a warm room. Do I need to buy a battery tender if it has been removed from the car?

Do I hook the tender up to the battery and leave it plugged in and attached to the battery all winter long?

Thanks

[chickdr]

I would use a tender even if the battery is out of the car, but you really don't need to remove it when you use a tender either (saves you some time in the spring). I would recommend the Noco one listed above for 30 bucks. Great product.

[kyriian]

Originally Posted by LisaLannister

I stored my car a few days ago and took out the battery out and is now sitting in a box in a warm room. Do I need to buy a battery tender if it has been removed from the car?

Do I hook the tender up to the battery and leave it plugged in and attached to the battery all winter long?

Thanks

Everyone does it differently, I take mine inside to charge, i wouldn't close the lid on the box though, just leave it somewhere that has some amount of ventilation

[Emmrbee]

Winter storage in Montreal
Currently minus 10.5 degrees C outside, 12 degrees C inside.