How to install seconday battery?

[///Sniper535]

I have a spare battery and I was curious how to go about doing this. Anyone have any write ups?

[BMWDriver]

Gosh, I'm learning new things here. I think some big rigs like 7 series and other bigger vehicles would need some, especially with all the electronics you can shove in there : screens for all passengers, satellite navigation, cel, Bluetooth items, what-not.

I wonder that this would also warrant a more powerful alternator. I'll let the experts speak, and perhaps you could be more specific about the needs and potential use, or perhaps is it you just want backup.

My 2 cents ($0.016 US 'cause I'm Canadian).

[BennyM]

Interesting...
I know the gauge cluster has status lights for battery #1 and battery #2, but the bulb for #2 is not installed. I wonder what factory configuration warranted a second battery. It just seems like unnecessary extra weight and more charging resistance for the engine.

[tim eh?]

I have a spare battery and I was curious how to go about doing this. Anyone have any write ups?

i want to do this too, just a tiny one. i would like to install it so that it is only connected with the ignition on, mayybe with a switch to bypass this and connect directly.

few reasons for this.

1- my manual unlock doesn't work (really, it doesn't - must be busted) and i don't want to ever rig into the license plate lights ever again just to open the doors.

2- would be really handy for a boost if i kill my primary battery somehow.

3- mini fridge going in this summer i hope and i would like it to be powered after i shut the engine off but not from the primary battery.

[BMWDriver]

The e34 shares many items with the 7 series siblings, like the cluster. So it's likely that the lights are there for that super luxurious 7. Unless it's for the unusual fridge-in-the-armrest option... seriously !

[shogun]

The E32 7 series had as optional extra a 2nd battery, or it was standard when certain options were ordered such a phone preparation. 1 battery is the main battery under rear seat, the 2nd battery is in the trunk right side behind the cover. There is a separating relay to separate the 2 batteries, the main battery has priority to start the engine. Use the E32 7 series wiring diagrams, then you can see it.
Needs quite some wiring.
My 750 Highline even has 2 alternators + 2 batteries. See online ETK E32, select a E32 750iL in ECU specification from 1992 for example, U.S. never got Highline E32 cars.

[632 Regal]

find a spot as showgun mentions behind pass side in trunk. Wire it up in parallel and go on with it. The alternator will be good enough as long as both are not dead. and last of all I dont think you need 2 batteries... I mean there are a couple of us on here getting away with one battery. ;)


I have a spare battery and I was curious how to go about doing this. Anyone have any write ups?

[shogun]

2nd battery retrofit, the detailed instructions here, various languages, 21 pages
http://www.e32-schrauber.de/bmw/daten/einbauhilfen/zusatzbatterie-1961.pdf



and if you need parked heating retrofit, here
http://www.e32-schrauber.de/bmw/daten/einbauhilfen/e32_standheizung_eba.pdf

[Paul in NZ]

my 535 had a second (auxilary)battery when i got it.It is a 25 AH (i think) and it was installed as shogun said behind the boot lining on the lh side,with a metal tray and clamp,probably a specific boot liner too.As far as i know i didnt have a phone,but i know i have the 10 spker stereo and "boosted power output',which i always thought applied to the second battery...The battery was as dead as a dodo when i got it so i have since removed it.It did have some sort of relay or switching associated and a 6mm or so cable went round the boot to the main battery terminal.I have posted a link to the parts before too

[shogun]

original installation, (battery removed in the pic)
http://img165.imageshack.us/img165/3386/zweitbattarie2rr6.jpg
My replacement battery is from a mini truck. As it did not have a hose for the drain of the gases, I made it DIY with parts from the pet shop, connections and hoses from a fish tank, the original BMW battery is pretty expensive, this I could buy in the local battery shop

[E34-520iSE]

I fitted a second battery under my rear seat (my main battery is next to the engine). I took a feed from the unloader relay (blue wire I think) to a lovely illuminated switch on the sunroof panel, which switches a 30A fused relay under the rear seat. This relay connects the 2nd battery to the main live cable as shown is Shogun's diagram above. The great thing about doing it like this is the 2nd battery can only be charged when the engine is running and the overhead switch is illuminated. Pure genius!

[Ross]

Mini-fridge? One of those electronic jobs without moving parts?
I have one, it SUCKS power. If you want this thing to run 24/7 be prepared to install a fork lift battery.
I bought one for a road trip thinking it would be nice to have a little food, okay beverage, available without stopping. Ever look to jump start a German car in the hotel parking lot that is hosting the Buick GS club national meet?

[ladiesman217]

whatever you do do not just wire it up in parallel.
anything large enough to be worth the effort will 'fight' the primary battery.
in essence they will take turns dragging each other down in voltage (or trying to charge up the other one) when the car is off, and you'll kill both of them (although maybe if lucky just the secondary) in short order.

Been there and even matched twins don;t last more than a couple of years or three, even with daily driving.

Use an isolator wired to ignition. Then the battery is only connected when the key is on, ie driving, starting, etc. IF you drain the primary and the secondary is large enough you'll get a couple of chances to start the car when you flip the ignition on which connects them together again.
Ignition lead on alarm prewire cars is in the 12 pin alarm connector, and readily accessible.

Again this is only useful if you are going to be having a lot of key off accessories ( like the lighter/power port always in use, the BMW phone or the vent timer) running, or plan on running a large load in accessory (large amp draw amplifiers for example).

It is kind of a built in jumper cable. it isn't for more key off time.

[ladiesman217]

Ross, some e32s had an actual refrigerator option. coils, condensor, freon, i forget if they ran off an electric compressor or the engine compressor. Leaning towards engine compressor, but been a while since I read the install .pdf

Probably still archived on AE's .pdf collection.

[shogun]

yes, BMW had them for the E32, even one for the center concole, maker was WAECO. that was with compressor and run by electricity. See here pics from Herby under der Kuehlschrank
http://freenet-homepage.de/Herbie01/
That was a standard accessory from WAECO, and there should be a TI = technical info or EBA Einbauanleitung = installation instruction for that in the CD.
http://www.7-forum.com/forum/14/neuanschaffung-2006-a-65258.html

The Highline version is different, that has a complete separate cooler system driven by compressor
http://bmwe32.masscom.net/johan/ihka/ihka.html

and if you have 2 batteries, do the installation of that system as per the TI I posted earlier.

you can't do parallel or else the secondary and primary will discharge each other as they try to find a common voltage and amperage float point.

You must have an isolator.

[tim eh?]

Mini-fridge? One of those electronic jobs without moving parts?
I have one, it SUCKS power. If you want this thing to run 24/7 be prepared to install a fork lift battery.
I bought one for a road trip thinking it would be nice to have a little food, okay beverage, available without stopping. Ever look to jump start a German car in the hotel parking lot that is hosting the Buick GS club national meet?

understood... that is why i want a second battery that is isolated from the main system but that will charge. i like 520ise's unloader relay rig thing but i don't know if i ever want to go anywhere near the unloader relay again... (charge trek VII (http://www.bimmernut.com/forum/showthread.php?t=39885)) i have one that plugs into the lighter socket and the draw isn't so bad, but it's tiny. that's the idea... not 24/7 but just enough for milk in my coffee if i am camping, maybe a bevvy or 2, stick o' butter, u get the idea.

main purpose is to switch it on to unlock the doors when batt#1 dies (methinks it's dead right now) so i can pop the hood and boost... or just a straight boost... i seriously never want to do that license plate light thing ever again and i hate crawling under the car to get to the starter. believe it or not i hate working on cars.

heyyyy... what happens when the obc alarm is set and the battery dies enough to get no start but still power the obc? i think i will find out soon...

great link shogun u r like god to me. (but i am an atheist :D)

[tim eh?]

heyyyy... what happens when the obc alarm is set and the battery dies enough to get no start but still power the obc? i think i will find out soon...


oh man i am so dumb sometimes

[632 Regal]

Tim you have to sort this problem soon, you have like 3 more months of winter hell there, this is mind numbing that your battery dies this fast. As a temporary solution have you considered a battery tender or such to keep it topped off so you can get in and start every day?


oh man i am so dumb sometimes

[632 Regal]

Amazing theory except the E31 comes factory with 2 batteries. Problem is that the E31 drains so much upon being parked that the need to charge within a month is required whereas the E34 does not. Batts are matched and "at least" 5 years old so that part holds no grounds on my personal vehicle.

whatever you do do not just wire it up in parallel.
anything large enough to be worth the effort will 'fight' the primary battery.
in essence they will take turns dragging each other down in voltage (or trying to charge up the other one) when the car is off, and you'll kill both of them (although maybe if lucky just the secondary) in short order.

Voltage and amperes are just as stated and will charge as required without any trickery, 2 batteries are better than one in a less then adequate environment.

Been there and even matched twins don;t last more than a couple of years or three, even with daily driving.

see above 5 year claim.

Use an isolator wired to ignition. Then the battery is only connected when the key is on, ie driving, starting, etc. IF you drain the primary and the secondary is large enough you'll get a couple of chances to start the car when you flip the ignition on which connects them together again.
Ignition lead on alarm prewire cars is in the 12 pin alarm connector, and readily accessible.

You do know about circuits and my boy would be proud.

Again this is only useful if you are going to be having a lot of key off accessories ( like the lighter/power port always in use, the BMW phone or the vent timer) running, or plan on running a large load in accessory (large amp draw amplifiers for example).
It is kind of a built in jumper cable. it isn't for more key off time.

Agree the vent timer is a big drain but if not used in excess an additional battery should simply not be required in said vehicle.

[tim eh?]

Tim you have to sort this problem soon, you have like 3 more months of winter hell there, this is mind numbing that your battery dies this fast. As a temporary solution have you considered a battery tender or such to keep it topped off so you can get in and start every day?

no it's not what you think... battery is holding charge now. when it gets this cold my starter is really really slow i am amazed it catches but it always does. i am sure it is the corroded wire... it's just i haven't touched the car in 2 weeks and i suspect i will need 100% charge to get it going and it's been sitting in -20'c the whole time. i haven't needed a boost yet this winter, i keep the obc on the voltmeter all the time and make sure it never ever goes below 13.5v. if it gets worse i will borrow a garage for a day but otherwise i'm trying to keep my 'all outdoors' streak going and waiting for spring.

i have considered a solar panel but then i hit the snooze button, besides i blew all my car budget for '08/'09 in '07... have to wait for a sale :D

thanks for the concern :) sorry for the hijack :( man i really am dumb :D

[632 Regal]

LMAO you are not dumb but this problem spread to another member in Manila and I wonder if it is some sort of international virus, thus the questions LOL


man i really am dumb :D

[tim eh?]

LMAO you are not dumb but this problem spread to another member in Manila and I wonder if it is some sort of international virus, thus the questions LOL

:D y i saw... but i would bet more than just we 2 have this problem... just we notice it b/c i use heat, defrost, lights all the time, and bmwrp8 uses a/c (maybe even aux fan is screwed a bit ?) and we both have been keeping an eye on voltage for other reasons.

i think even ferret has it... said something about 12v with rear defrost on.... no?

it's just battery cables! must be one of the most common problems around in old cars. for sure in humid places anyway. what a total beeeyatchie to get to tho... in my case right now at least...

[ladiesman217]

Amazing theory except the E31 comes factory with 2 batteries. Problem is that the E31 drains so much upon being parked that the need to charge within a month is required whereas the E34 does not. Batts are matched and "at least" 5 years old so that part holds no grounds on my personal vehicle.

whatever you do do not just wire it up in parallel.
anything large enough to be worth the effort will 'fight' the primary battery.
in essence they will take turns dragging each other down in voltage (or trying to charge up the other one) when the car is off, and you'll kill both of them (although maybe if lucky just the secondary) in short order.

Voltage and amperes are just as stated and will charge as required without any trickery, 2 batteries are better than one in a less then adequate environment.

Been there and even matched twins don;t last more than a couple of years or three, even with daily driving.

see above 5 year claim.

Use an isolator wired to ignition. Then the battery is only connected when the key is on, ie driving, starting, etc. IF you drain the primary and the secondary is large enough you'll get a couple of chances to start the car when you flip the ignition on which connects them together again.
Ignition lead on alarm prewire cars is in the 12 pin alarm connector, and readily accessible.

You do know about circuits and my boy would be proud.

Again this is only useful if you are going to be having a lot of key off accessories ( like the lighter/power port always in use, the BMW phone or the vent timer) running, or plan on running a large load in accessory (large amp draw amplifiers for example).
It is kind of a built in jumper cable. it isn't for more key off time.

Agree the vent timer is a big drain but if not used in excess an additional battery should simply not be required in said vehicle.


dude, what is your major malfunction? you get shot in the head or something?

[632 Regal]

Tim are you in a mostly idle area? lots of traffic and crap? If so maybe it is possible to be so low in voltage in this arena with all the aux items on that this would be normal.. at least without backtracking things would see normal/

[ladiesman217]

Bulletin Number: 611200 Bulletin Date: 20000701 Category: 111000 ELECTRICAL SYSTEM:BATTERY
Summary: SERVICE INFORMATION REGARDING PREMATURE BATTERY DISCHARGE ON 850 CSI MODELS. *TT

Btw no hard feelings about deleting the google stock thread since you say you aren;t familiar with VB software. I am sure someone can show you how to delete your own posts without deleting entire threads. Really isn;t hard, I do it all the time on the boards I mod, and I'm sure others here canteach you how to do it..

In the mean time how about a gesture of sincerity and putting the article back up to fix your mistake.

[shogun]

guys, do not mix up the E31 and E34/E32 system.

The E31 system needs BOTH batteries to be in a good shape, otherwise the car even does not start properly.

The E32/E34 system is completely different, that car has no problem to survive without a second battery, and most of the cars even do not have a 2nd installed.
It was OPTION.

But on E31 is is necessary to operate the car!

If you want to know it in detail, study the wiring diagrams E31, E32, E34, or visit E31 boards, that is daily discussion there if a car does not start, always first thing someone will propose is to check both batteries and have both batteries changed at same time and charged completely.

[ladiesman217]

I don't believe you. I am just being polite.

here is the link.
http://www.nytimes.com/2009/01/23/technology/companies/23google.html?ref=business

Go press
new thread
copy and paste into it,
hit submit.
Title is: Is google well positioned for next quarter?

Make a demonstration to me and to this forum that you are as sincerely sorry as you signed your apology and protest you are in public.

I'm not much inclined to believe you have an honest bone in your body after what I saw yesterday and today.

[ladiesman217]

thanks shogun... appreciate the back up on the electrical system.

[tim eh?]

Tim are you in a mostly idle area? lots of traffic and crap?

...no... when i am driving normal people are still sleeping.

i kept an eye on this last year as it was my first winter with the car and i have had many old cars with charging problems. (and playing with the obc was somewhat of a novelty)

this year i get way less voltage than i did last year...

it's not urgent, i can keep the voltage at a good level if i keep my eye on it.

but i am willing to bet my cabling will look like bmwrp8's ground cables when i get around to pulling them out.

are you sure that it is normal to drain the battery with full accessories on at idle? methinks i am not the only one with old cables...

y'all will have to be patient and wait until spring... don't hold yer breath! :)

[shogun]

but i am willing to bet my cabling will look like bmwrp8's ground cables when i get around to pulling them out.
here you mention a very important point. Since I changed my cable from alternattor to B+, I get measurable +1 volts more out of the system (at the end where it is needed). That cable was so wrotten, that stopped the flow of the power
http://www.bimmerboard.com/forums/posts/560991/



are you sure that it is normal to drain the battery with full accessories on at idle? me thinks i am not the only one with old cables...

that you can measure. But as long as the red light for the battery does not go on, there should be even enough in idle, but needs to be checked, after you checked the ground cables and the battery /alternator cables and connections.

[BMWDriver]

Tim, if your battery runs out and you've got your code in your OBC, you just need to enter your code back in. However, the car will start to honk as happened to me once because of the hood being open.

My bat went dead once because of interior lights - doh! I was able to open my door and pop the hood, and as soon as I connected my charger, the car started honking. Put the code in, and all back to normal.

Somehow the code gets retained. I know there exist memory chips that retain the info entered even without power, as on a hard drive for example. Just not the common thing in the electronics world, except for the now more and more comon Solid State Disks that are beginning to replace laptop hard disks.

[shogun]

The easiest to support a battery when you only drive short distances or park the car for a long time:
1. trickle charge if there is a power socket in the garage or where you park
2. a good solar charger which you plug into the cigarette lighter, when the car is parked in an open area. It will not charge an empty battery, but it will keep it on sam elevel. There are also larger solar panels which can be folded. When checking on Ebay, buy only one which states somthing about the output, lthough this is also optimistic
3. Portable Jump Starters & Car Battery Jump Starter Solutions
http://www.autobarn.net/jumpstarters.html
solar

http://www.autobarn.net/solarbatterychargers.html