BMW Advanced Battery Charging System

[SEVEN40iL]

So I just picked up this unit from my Stealer, actually at a great price , part number 82 11 0 406 881.



The instructions say to use the positive and negative terminals in the engine bay. My question is, can this be hooked up to the battery in the trunk directly instead?

Reason why I ask is I have a power outlet close to the battery rather than the engine bay, and the instructions also note not to use an extension cord if possible.

Anyone have any insight into this?

TIA

Hardeep

[Qsilver7]

Just change the direction of how you pull into your garage....that way the engine bay will be closer to the electrical outlet.

(my e38 hooked up to its float charger)

[spazzboy]

Just change the direction of how you pull into your garage....that way the engine bay will be closer to the electrical outlet.

I loled.

[Xephius]

+1

[Timm]

Yes, it can go directly behind the battery (my BMW charger fits nicely there). My mains lead runs under the carpet and pops out right at the back of the boot ready to be plugged in. I run a thin extension cable into the boot when a charge is required.

[hpbongers]

Is that battery minder for a stored car. I use one from Canadian Tire i got for $12 for my winter storage. Hope the stealer didn't burn you for to much.

It's just a 12-14 vdc low current cheap charger that turns on only when the battery needs power. Doens't matter on an extension cord or were you connect it. I don't even leave mine on. I switch it back and forth with my Porsche ever other month.

[SEVEN40iL]

Just change the direction of how you pull into your garage....that way the engine bay will be closer to the electrical outlet.

(my e38 hooked up to its float charger)

I loled.

+1

Car is parked for winter and I do not want to pull it out to turn around!

Yes, it can go directly behind the battery (my BMW charger fits nicely there). My mains lead runs under the carpet and pops out right at the back of the boot ready to be plugged in. I run a thin extension cable into the boot when a charge is required.

Any diagrams as to what to hook up where? So there should be no problems connecting directly to the battery then?

[Timm]

Mine is permanently wires to the battery terminals - RED to the +ve battery terminal (nearest the front of the car) BLACK to the -ve treminal (nearest the back of the car).....

[SEVEN40iL]

Thanks Timm!


P.S. got the charger for $20 at the Stealership, which I thought was a steal on its own!

[E38740]

Mine is permanently wires to the battery terminals - RED to the +ve battery terminal (nearest the front of the car) BLACK to the -ve treminal (nearest the back of the car).....

Need to do the same..



Hardeep,

I have the same unit and I attach the leads directly to the battery, have been using it since late fall, works like a charm!

Did you pick it up from Mike@maranello?

[jmiseo2008]

Wow, $20? I picked it up for $40 and was pleased. Nice deal.

[SEVEN40iL]

Hardeep,

I have the same unit and I attach the leads directly to the battery, have been using it since late fall, works like a charm!

Did you pick it up from Mike@maranello?

Yes, it was from Mike! Great guy to deal with.

Wow, $20? I picked it up for $40 and was pleased. Nice deal.

[IcemanBHE]

Car is parked for winter and I do not want to pull it out to turn around!

How about a longer extension cord....

[01740ISP]

How about a longer extension cord....

and the instructions also note not to use an extension cord if possible.

Hardeep

I have the same one but I use an extension cord at times and never had a problem. I tend to use it mostly under the hood so most often, it is straight up to the wall. The cord is quite long.

-Messan

[SEVEN40iL]

I have the same one but I use an extension cord at times and never had a problem. I tend to use it mostly under the hood so most often, it is straight up to the wall. The cord is quite long.

-Messan

I checked the length, it is long, but not long enough for me. I was going to use an extension cord, but then the instructions said not too if you don't have too.

I'm gonna try hooking it up directly to the battery this weekend, if it doesn't work, then I'll use an extension cord.

[shled]

It draws 1.2 amp so if you NEED an extension, go for it.
Just use a sensibly thick (and grounded one).
Also be sure you battery is well charged before you try. Its too small to fix a flat battery.

[Route 66]

Assuming that your battery is good, meaning there are no parasitic drain problems and also assuming that there are no unnecessary draws from the battery when the car is in "sleep mode" and the car does not have the security systym "Armed" could an E38 sit for 2-3 weeks like that without a trickle charger? The other factor is that the car would be in an insulated garage but not heated.

[DenisMcG]

The only reason that this would be recommended to use under the hood, is that the unit will heat up as it charges the battery. The battery will also offgas while charging. The gasses are highly flammable, and quite corrosive. As long as your battery is propery vented, and it should be, there should be no problem. Don't place the charger on anything flammable.

[darkstarmedia]

Mine is permanently wires to the battery terminals - RED to the +ve battery terminal (nearest the front of the car) BLACK to the -ve treminal (nearest the back of the car).....

What if you have the dual battery setup... ? I'd like to get one but I want it to take care of both batteries...

Richard

The only reason that this would be recommended to use under the hood, is that the unit will heat up as it charges the battery. The battery will also offgas while charging. The gasses are highly flammable, and quite corrosive. As long as your battery is propery vented, and it should be, there should be no problem. Don't place the charger on anything flammable.

If you have your vent hoses hooked up properly, off-gassing should not be a problem. Also, it will off-gas no matter where you charge it from.

Richard

[Qsilver7]

1. If you have your vent hoses hooked up properly, off-gassing should not be a problem. Also, it will off-gas no matter where you charge it from.

2. What if you have the dual battery setup... ? I'd like to get one but I want it to take care of both batteries...

Richard

1. Yes, the battery will off-gas no matter where you charge it from...but the distance between the engine bay & the trunk's battery compartment allows for greater dissipation of those off gases in the event that there is a spark ...versus the spark occurring in near proximity to the off gases. That's why there's no need to vent a battery that is located in the engine bay...there is enough air movement that there is no build up of off gases...unlike when the battery is inside the cabin under the rear seat (e32/e34), or in the trunk.

2. If you use an aftermarket float charger OR the BMW charger like the OP purchased...and you hook up to the jump start locations as indicated in the documentation...both your batteries will be charged/maintained (priority goes to the starter battery) if the hood is closed.

Here's a link to the BMW TIS for the e38 with dual batteries...which is almost word for word the same as the info in the image below for the dual setup in the e32. Click link & scroll down to where the write up begins about "Vehicles with a two-battery system ": http://tis.spaghetticoder.org/s/view.pl?1/00/09/57

[darkstarmedia]

1. Yes, the battery will off-gas no matter where you charge it from...but the distance between the engine bay & the trunk's battery compartment allows for greater dissipation of those off gases in the event that there is a spark ...versus the spark occurring in near proximity to the off gases. That's why there's no need to vent a battery that is located in the engine bay...there is enough air movement that there is no build up of off gases...unlike when the battery is inside the cabin under the rear seat (e32/e34), or in the trunk.

2. If you use an aftermarket float charger OR the BMW charger like the OP purchased...and you hook up to the jump start locations as indicated in the documentation...both your batteries will be charged/maintained (priority goes to the starter battery) if the hood is closed.

Here's a link to the BMW TIS for the e38 with dual batteries...which is almost word for word the same as the info in the image below for the dual setup in the e32. Click link & scroll down to where the write up begins about "Vehicles with a two-battery system ": http://tis.spaghetticoder.org/s/view.pl?1/00/09/57

Normally I do use the underhood for charging.... but... if I wanted to add a built in charger in the trunk for maintenance charging I was wondering if there is a point somewhere that would be the same as if I were hooking to the charging posts.

Richard

[Qsilver7]

Ahh...I see what you mean. I don't know...but what has me slightly curious is this "isoloating relay"...and how does opening the hood disconnect the starter battery from the equipment battery? Hmmm.

[darkstarmedia]

Ahh...I see what you mean. I don't know...but what has me slightly curious is this "isoloating relay"...and how does opening the hood disconnect the starter battery from the equipment battery? Hmmm.

The isolating relay in not really a relay in the classic sense... it's actually a computer module attached to the side of the upper battery tray. AFAIK it is all solid state. You can actually query it in inpa and see it's sttus.

When you pop the hood it is likely reading that the hood is open and disconnects the batteries from each other.

Now this does not mean that it can jump it's self for starting the car (but you can do it manually if you have a big enough cable). I remember reading somewhere that the battery isolator is limited to about a 60A crossover.

When you charge the batteries from the posts under hood it will charge one battery (starting battery) till it comes up to a given level then it will connect them so you are charging both..... I think....

Richard

[Qsilver7]

The isolating relay in not really a relay in the classic sense... it's actually a computer module attached to the side of the upper battery tray. AFAIK it is all solid state. You can actually query it in inpa and see it's sttus.

When you charge the batteries from the posts under hood it will charge one battery (starting battery) till it comes up to a given level then it will connect them so you are charging both..... I think....

Richard

Cool, thanks for the info about the isolating relay and its location etc. ...I learned something new...gotta add that tidbit to my "mental rolodex".

And you're correct about using the engine bay jump posts & charging...the starter battery charges first, then the equipment battery will then be charged after the starter batt reaches a certain level. That detail is discussed in the dual battery info in the TIS (see post #20 above).