BimmerFest BMW Forum banner

1 - 20 of 55 Posts

·
Registered
Joined
·
126 Posts
Discussion Starter · #1 ·
Looking for some forum best tips and practices on my E90 328XI. I don't drive this car often but I want to keep it in good shape and not let the battery drain fully. I can go a max of 2 weeks not driving it before the battery dies.


Should I disconnect the negative terminal and stop battery drain and will that allow the battery to survive a month?
I can't charge the battery in its current garage spot. Is it worth removing the battery, bringing indoors and leaving it on a tender for 1 month instead?

Main issue is that I don't have a outlet in the exposed condo garage that I use. Any tips would be appreciated! I think my oil and gas have been ok FYI
 

·
Registered
Joined
·
220 Posts
I'm no expert but I think you should bring the battery inside somewhere you have an outlet and keep it on a battery maintainer such as Battery Tender brand (which is on sale right now at Costco).
Another alternative to consider is, depending upon your weather where you live, placing a solar panel on the roof of your exposed garage and running the output to your battery using some type of solar battery maintainer. I'm not sure how much sunlight you get or what the outpur of these are, but it might be enough to keep the battery charged especially if you disconnect it from the car so it doesn't have the drain from the computers. Disconnection might not be needed. You could do some calculations and/or measure the battery voltage each week or so and see how you are doing. If it stays charged, wait another week and measure again. If it is going down, try disconnecting it and wait another week. And if that doesn't work, then bring it inside.
 

·
Registered
Joined
·
3,385 Posts
The battery should ordinarily last more than two weeks undriven!!! During the shelter-in-place imposed upon us in the SF Bay Area during March-May, I didn't really drive my car during that time, and it still started! I connected the Ctek battery maintainer to top off the battery.

When the E9n is 'asleep', it draws 45mA. Divide 80AHr capacity by .045A, 1777hr or 74 days until the battery is flat.
 

·
Registered
Joined
·
6,110 Posts
Your suppose to charge it from the charge points under the Hood no need to take the battery out . Put a Ctek on it and leave it there for the time unused.
 

·
Resident Curmudgeon
Joined
·
24,181 Posts
Your suppose to charge it from the charge points under the Hood no need to take the battery out . Put a Ctek on it and leave it there for the time unused.
Spot on.

DO NOT remove the battery, that can cause issues. Leave it connected, a Ctek or other will keep it topped off.
 

·
Registered
Joined
·
126 Posts
Discussion Starter · #6 ·
To clarify, this is a Condo garage. There is no outlet for me to link to. I have a CTEK charger, I just have no outlet to connect to. That's the problem.
 

·
Registered
Joined
·
126 Posts
Discussion Starter · #7 ·
The battery should ordinarily last more than two weeks undriven!!! During the shelter-in-place imposed upon us in the SF Bay Area during March-May, I didn't really drive my car during that time, and it still started! I connected the Ctek battery maintainer to top off the battery.

When the E9n is 'asleep', it draws 45mA. Divide 80AHr capacity by .045A, 1777hr or 74 days until the battery is flat.
It's a little colder where I am, but at 2 weeks its barely starting. Its a older battery but I don't want to replace it and re-program it.
 

·
Registered
Joined
·
3,385 Posts
It's a little colder where I am, but at 2 weeks its barely starting. Its a older battery but I don't want to replace it and re-program it.
If 5-6 yr old battery, be prepared for an unpleasant surprise when you try to start the car and the battery is dead, and you cannot get a jump or a replacement in time to get to where you need to get.
E9n batteries last as short as 4.5 year and as long as 7 years, but most batteries (in 50+ years of driving history) fail at 5-6 years...and suddenly.

IMPORTANT: If your E9n is an LCI model with NO trunk keylock, DO NOT DISCONNECT battery from the terminal and then close the trunk lid!!!!!!
 

·
Registered
Joined
·
3,385 Posts
To clarify, this is a Condo garage. There is no outlet for me to link to. I have a CTEK charger, I just have no outlet to connect to. That's the problem.
...which really makes me wonder about the mandate in CA this year, that by 2025 no more gas powered cars will be sold...how about all these condo and apartment dwellers?! :unsure:
 

·
Registered
Joined
·
126 Posts
Discussion Starter · #10 ·
Thats a good point. I tried to get the HOA to install just two ChargePoint stations and they said no. They are also 10grand a pop.
 

·
Brucew
Joined
·
121 Posts
I have no outlet near my parking space also so what I do is to use a CTEK charger powered by the 110v outlet on a Schumacher Instant Power gadget (from Costco!).
When my car is not used for a week or longer I charge the battery every week to make sure the battery is not discharged too much. The jump starter is recharged after every use.
This has worked well for me during the pandemic
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
Joined
·
19,439 Posts
Just a while ago today was chatting with RE agent SiL and he touted the benefits of Section 8 tenants as the best.
 

·
Resident Curmudgeon
Joined
·
24,181 Posts
To clarify, this is a Condo garage. There is no outlet for me to link to. I have a CTEK charger, I just have no outlet to connect to. That's the problem.
Hmmm. Would have been useful in post 1.

;)

Now if only CTek made a cigarette lighter adapter.....
 

·
Registered
Joined
·
1,872 Posts
Is there no solar powered option for trickle charging ? I have the same problem at my vacation condo - no 110V outlet to plug a tender into.
 

·
Registered
E90 : 09 328xi N51 E46: 05 325xi M54
Joined
·
211 Posts
I just bought this

Battery Tender 12 Volt, 5 Watt Solar Battery Charger and Maintainer - Weatherproof Mountable Solar Battery Charger with Windshield Mount and Cigarette Adapter Accessory Cable/AC Adaptor - 021-1171 https://www.amazon.com/dp/B08BFJ12SF/ref=cm_sw_r_cp_api_i_12DNFbT1NKTZZ?_encoding=UTF8&psc=1

I intend on using alligator clamps on the jump posts under the hood, just need to find a way to run the wires inside the car. If it's in a garage just use the plug in type. Use a hood brand as mentioned and use the jump posts under the hood

Sent from my iPhone using Tapatalk
 

·
Nuclear engineer
02/2012 X5 35d M57Y CPO 100K miles NOKIAN WR G3 20K miles
Joined
·
19,439 Posts
12 VDC will NOT charge a battery. Watts = Volts x Amps. 5 Watts / 12 Volts is a really really low charging rate, 400 mA
 

·
Registered
Joined
·
220 Posts
I have no outlet near my parking space also so what I do is to use a CTEK charger powered by the 110v outlet on a Schumacher Instant Power gadget (from Costco!).
When my car is not used for a week or longer I charge the battery every week to make sure the battery is not discharged too much. The jump starter is recharged after every use.
This has worked well for me during the pandemic
That's a great idea.
 
1 - 20 of 55 Posts
Top