Light weight Braille battery swap DIY

[doba_s]

Originally Posted by lucid

Yes, but I said the stock battery lasted 2 weeks without a problem. I am comparing that to the Braille having issues with the car sitting around for 2 days as an example, which is a scenario I am willing to live with.

Swamp, Doba, what is the longest period of time your car was parked?

As I remember it was parked for 3 days ... It started with no problems but a few seconds after i got "Low Battery" light ...

[HP Autosport]

Originally Posted by ButterzM

I have already replaced mine twice and on my third one right now. So far it has been problem free compare to the first two.

It may be a combination of problems, because we haven't had any issues with the Braille battery sold to date installed on the 1 or 3-series non-M cars. Even on Audi/VW and MB applications, which use the same Braille battery.

[808MGuy]

Why is it not obvious to everyone that this is not a quality control issue with Braille but more of a wrong application. I mentioned early on that you guys are reducing your electrical capacity by over 66% and now you wonder why your batteries are dying?

[swamp2]

Originally Posted by 808MGuy

Why is it not obvious to everyone that this is not a quality control issue with Braille but more of a wrong application. I mentioned early on that you guys are reducing your electrical capacity by over 66% and now you wonder why your batteries are dying?

Definitely do not agree with this. This is the easy, knee jerk type of reaction. You have found a shred of evidence supporting your early guess and now you have "validation". Perhaps you can explain why we have two new batteries that have 12.7 and 12.3 VDC? This is far from normal variation.

Keep in mind that BMW's minumum spec is something like 12.3-12.5 (wish I could quote the exact number).

All of us doing this mod realize we won't be able to sit parked at freezing temperatures, listening to an aftermarket sound system with the lights on for hours. This is more or less the extra capacity the OEM battery has. For those in warm climates, despite its reduced extra capacity, this battery should be a perfectly workable solution.

That being said I am waiting for an official reply from HP as to whether or not this battery is fully certified for Comfort Access equiped cars. HP??

[808MGuy]

Originally Posted by swamp2

Definitely do not agree with this. This is the easy, knee jerk type of reaction. You have found a shred of evidence supporting your early guess and now you have "validation". Perhaps you can explain why we have two new batteries that have 12.7 and 12.3 VDC? This is far from normal variation.

Keep in mind that BMW's minumum spec is something like 12.3-12.5 (wish I could quote the exact number).

All of us doing this mod realize we won't be able to sit parked at freezing temperatures, listening to an aftermarket sound system with the lights on for hours. This is more or less the extra capacity the OEM battery has. For those in warm climates, despite its reduced extra capacity, this battery should be a perfectly workable solution.

That being said I am waiting for an official reply from HP as to whether or not this battery is fully certified for Comfort Access equiped cars. HP??

I assume you mean you received it from Braille with a reading of 12.3V. Did you try charging it? Does it ever come back to 12.8V (fully charged)? How long does it hold that voltage before it's down again? A few days? Weeks?

Someone mentioned above that the low battery indicator comes on after 3 days. That tells me that either something is wrong with the charging system, which is unlikely because its not a isolated incident, or the battery is being taxed so much that its being discharged to the point where it can't make a full recovery. Once that happens, your only solution is to replace the battery. It seems that our cars have a pretty large electrical load so to try and support that from a 31A/h battery seems to be asking a lot.

[swamp2]

Originally Posted by 808MGuy

I assume you mean you received it from Braille with a reading of 12.3V. Did you try charging it? Does it ever come back to 12.8V (fully charged)? How long does it hold that voltage before it's down again? A few days? Weeks?

I am not sure what my battery voltage was from the factory. I can tell you that according to support folks there the output it has now ~12.3 is not normal nor within spec. I did not charge the battery. The only charging it gets in my case is from the car itself. The alternator output runs at about ~14.X volts, which should be perfect for charging any 12V nominal battery. Mine simply never gets to 12.7-12.8. It is 12.3 after hours of driving and at more or less the same level after being parked over night.

Originally Posted by 808MGuy

Someone mentioned above that the low battery indicator comes on after 3 days. That tells me that either something is wrong with the charging system, which is unlikely because its not a isolated incident, or the battery is being taxed so much that its being discharged to the point where it can't make a full recovery. Once that happens, your only solution is to replace the battery. It seems that our cars have a pretty large electrical load so to try and support that from a 31A/h battery seems to be asking a lot.

Do you disagree with my contention that the only thing that should be lost with this battery is the ability to really push it and push it when cold? Leaving the car parked for a couple days is inconsequential compared to lights+stereo+cold weather starting.

Let's do some math. Lets say HP was right about 50 mA to keep CA and other idle processing going. Heck, let's double that just to be conservative. 100 mA x 72 hours (3 days) ~ 7 Ah. What does 7 Ah mean to a 30 Ah battery. Well at such a low current draw over a longer period of time (the 31 Ah spec is at 20 hours) the battery will have even a greater Ah rating probably 25% higher meaning effectively ~39 Ah. 7 surely isn't anywhere close to 39. As I see it the issue here is voltage as delivered, voltage stability (possible QA issues as lucid pointed out) and perhaps the voltage standard from the factory.

[HP Autosport]

Originally Posted by swamp2

That being said I am waiting for an official reply from HP as to whether or not this battery is fully certified for Comfort Access equiped cars. HP??

Braille didn't designed their batery to be CA certified nor do they plan on doing that.

We don't know the exact amp draw when all modules are in the sleep mode. We will need to get a car in with CA to validate the current draw.


Note: Unless your daily commute is 20-30 minutes or longer on the highway, don't expect your battery to be at 100% charge. A 135i that was just at my shop with an oem battery driven from SF to SB, 70% charge! My personal 335i with the Braille 15 lb battery sitting for 2 weeks, 60% charge. The only way to get close to 100% charge is to charge it with a smart battery charger, then do your test.

[lucid]

Originally Posted by HP Autowerks

A 135i that was just at my shop with an oem battery driven from SF to SB, 70% charge!

Are you sure about this? If such a long trip does not charge the battery, I don't know what would. Seriously, how else would the OEM battery be charged? Then all the people commuting short distances to work in city traffic (like myself) should end up with dead OEM batteries within weeks...

[lucid]

Originally Posted by swamp2

Let's do some math. Lets say HP was right about 50 mA to keep CA and other idle processing going. Heck, let's double that just to be conservative. 100 mA x 72 hours (3 days) ~ 7 Ah. What does 7 Ah mean to a 30 Ah battery. Well at such a low current draw over a longer period of time (the 31 Ah spec is at 20 hours) the battery will have even a greater Ah rating probably 25% higher meaning effectively ~39 Ah.

Yeah, I was trying out a similar calculation. Things just don't add up. If the Braille battery indeed has the advertised specs, it should not have problems because of CA over 2-3 days.

I also agree that reducing the OEM reserve capacity of the battery does not explain what we are observing here. That should only be a factor if the car sits around for too long or one demands current with the alternator off. Other than that, the alternator should just charge the damn thing like it charges the OEM battery. UNLESS there is something wrong with the Braille battery and it doesn't like the way the M3's system tries to charge it.

I'll swap mine in soon and see what happens...

[swamp2]

Originally Posted by HP Autowerks

Braille didn't designed their batery to be CA certified nor do they plan on doing that.

Hmmm, maybe I should have been more specific. I should have asked if Braille or HP specifically suggests not running a 3121 in an E9X with CA. All you website says is the lower capacity 2015 is the minimum for the E9X.

[HP Autosport]

Originally Posted by lucid

Are you sure about this? If such a long trip does not charge the battery, I don't know what would. Seriously, how else would the OEM battery be charged? Then all the people commuting short distances to work in city traffic (like myself) should end up with dead OEM batteries within weeks...

Your alternator will mantain a proper charge on your battery. An alternator is not a battery charger by any means, unless you can turn off all power consumer with the engine running, it's not going to charge the battery at a fast enough rate nor will it likely to reach full capacity.

I don't know the exact number, but there is probably 140-180 amp draw with all electronic consumers running. At that level of draw, all your alternator can do is supply power to the consumers.

[HP Autosport]

Originally Posted by swamp2

Hmmm, maybe I should have been more specific. I should have asked if Braille or HP specifically suggests not running a 3121 in an E9X with CA. All you website says is the lower capacity 2015 is the minimum for the E9X.

No one knew there is such a large current draw on the E9X M cars. And to date, no one can verify what the draw is after all modules go to sleep. If that number is higher than double of the 40-50 milliamps, I would be worried when instaling a Braille light weight battery.

[lucid]

Originally Posted by HP Autowerks

Your alternator will mantain a proper charge on your battery. An alternator is not a battery charger by any means, unless you can turn off all power consumer with the engine running, it's not going to charge the battery at a fast enough rate nor will it likely to reach full capacity.

I don't know the exact number, but there is probably 140-180 amp draw with all electronic consumers running. At that level of draw, all your alternator can do is supply power to the consumers.

What do you mean by "an alternator is not a battery charger by any means"? Of course it is! How else will the battery be charged? Nuclear reactor under the seat? We don't throw away our batteries after cranking the engine many times, or drain the battery after leaving the lights on when parked, do we?

Yes, if you somehow manage to switch on every single current drawing curcuit in your car, you might draw whatever current from the battery the alternator can supply (depending on alternator specs and engine speed), but that is beside the point as that is not a sustainable scenario, with any battery. Over a period of time, if your alternator is not charging your battery, it will die even if it has 200 amp/hr reserve capacity.

You are throwing numbers around and arriving at conclusions (as you did in your referenced post above), but you don't actually have any data as far as I can tell. What are the specs for the alternator in this car and what are some typical and maximum loads on the electrical system?

Again, the point is, if a 90 amp/hr battery can deal with CA for several weeks of parking, a 31 amp/hr battery should be able to deal with it for a couple of days. If that's not happening, the specs on the 31 amp/hr battery are suspect or it has some kind of charging issue. It is possible the Braille battery doesn't like to go through deep charging cycles on a regular basis, but I have no info on that.

I'll call Braille on Monday and try to speak with someone. But you'd think Braille would not have replaced someone's battery 3 times if they thought the problem is in the application as opposed to the product (assuming ButterzM's batteries were replaced by Braille. We do know Swamp's was).

[swamp2]

Agreeing with lucid here. You (HP) are not only providing incorrect information but you are throwing around a bunch of totally unverified numbers.

An alternator in any car absolutely charges the battery and it does so fairly quickly. Ever have a completely dead battery, get a jump, drive around for 30 minutes and have a totally fine battery? I have. No not in my current car but I'd be floored if it wouldn't work in it.

I also fail to believe that will all power consumers on that the battery will not charge. What kind of nonsensical design would that be? Give the huge teams of BMW electrical engineers some credit. Also, how much variation is there in consumption? The only variables are stereo (and stereo volume - that would be a big one) and interior lights. Everything else will be running normally and running always. Of course some consumers will consume in an rpm dependent fashion.

Our points stand: If the OEM battery can support CA for weeks, then the Braille, operating as per specs can certainly handle a CA for for days. There is plenty of empirical evidence just among the few of us posting here that Braille DOES have one or more problems.

I'm not sure how many times I have to repeat it: The reduced Ah specs for a battery such as the Braille should only really be a factor in cold weather or for long periods of using lights or stereo with the engine not running. Or of course the combination of these.

[808MGuy]

Originally Posted by swamp2

Agreeing with lucid here. You (HP) are not only providing incorrect information but you are throwing around a bunch of totally unverified numbers.

An alternator in any car absolutely charges the battery and it does so fairly quickly. Ever have a completely dead battery, get a jump, drive around for 30 minutes and have a totally fine battery? I have. No not in my current car but I'd be floored if it wouldn't work in it.

I also fail to believe that will all power consumers on that the battery will not charge. What kind of nonsensical design would that be? Give the huge teams of BMW electrical engineers some credit. Also, how much variation is there in consumption? The only variables are stereo (and stereo volume - that would be a big one) and interior lights. Everything else will be running normally and running always. Of course some consumers will consume in an rpm dependent fashion.

Our points stand: If the OEM battery can support CA for weeks, then the Braille, operating as per specs can certainly handle a CA for for days. There is plenty of empirical evidence just among the few of us posting here that Braille DOES have one or more problems.

I'm not sure how many times I have to repeat it: The reduced Ah specs for a battery such as the Braille should only really be a factor in cold weather or for long periods of using lights or stereo with the engine not running. Or of course the combination of these.

The alternator should charge the battery but if its totally dead (12.3V is pretty close to that) it will take much longer than a 30 min drive to charge it. Being an AGM battery, the Braille battery should be able to come back from pretty much dead. I mistakenly said it wouldn't before because I thought it was lead acid. While the car is running, the battery is being charged by the alternator and the battery voltage should match the charging voltage of the alternator which is typically somewhere around 14V. What is the voltage reading with the engine on? If it is below 12.5 or so, that means the battery is supplying some of the current and its not being charged.

Has anyone tried using a battery tender or something similar to try and keep the voltage up during long periods (more than a few days) of not driving? Does this help? I still think such a large reduction in capacity has to have its effect on the system but without knowing the actual idle current draw of the system, it's really hard to say for sure.

[Cleveland]

Originally Posted by swamp2

Agreeing with lucid here. You (HP) are not only providing incorrect information but you are throwing around a bunch of totally unverified numbers.

An alternator in any car absolutely charges the battery and it does so fairly quickly. Ever have a completely dead battery, get a jump, drive around for 30 minutes and have a totally fine battery? I have. No not in my current car but I'd be floored if it wouldn't work in it.

I also fail to believe that will all power consumers on that the battery will not charge. What kind of nonsensical design would that be? Give the huge teams of BMW electrical engineers some credit. Also, how much variation is there in consumption? The only variables are stereo (and stereo volume - that would be a big one) and interior lights. Everything else will be running normally and running always. Of course some consumers will consume in an rpm dependent fashion.

Our points stand: If the OEM battery can support CA for weeks, then the Braille, operating as per specs can certainly handle a CA for for days. There is plenty of empirical evidence just among the few of us posting here that Braille DOES have one or more problems.

I'm not sure how many times I have to repeat it: The reduced Ah specs for a battery such as the Braille should only really be a factor in cold weather or for long periods of using lights or stereo with the engine not running. Or of course the combination of these.

You and Lucid are now experiencing the same problems I did on previous M3's. (E36 & E46)

I was determined to fit a small lightweight racing battery into these cars in order to shed some weight. I tried and failed many times to buy 'the right' lightweight racing battery (thinking that actually mattered )

I realize NOW how foolish that was...

When I attempted to swap my heavy OEM battery, with a smaller D50 battery from Optima, it lasted all of three months before the trouble began. It took several trips to the dealer to find out that I simply couldn't use that battery in that car. The electronic circuits that monitored and controlled the factory alarm system was draining that battery too much. (not kidding) I thought the tech at the dealership was kidding...but apparently he wasn't. After charging it all the way back to 100%, just one week without driving the car, and it was dead as a doornail. (again!)



It didn't have the reserve capacity or cranking amps, and it was charging too slow in between trips to make up the difference. I suspect that is what you are experiencing now.

I ended up killing 2 alternators (actually just the VOLTAGE REGULATOR) because of the overload induced by simultaneously trying to charge the battery up and operate every other electrical device while the car was moving. At first, I thought it was just my E36 M3, but I got similar lackluster results on my E46M3 as well. It wasn't the cars, it was my insistence on shoving a square peg into a round hole...

The battery is simply too small man. (regardless of what the specs may lead you to believe)

I have done exhaustive research, and I can share some details that you may not be aware of in regards to these small racing application batteries. There are quite a few differences between the battery you have now, and the OEM battery. The typical automotive battery that you normally buy at the Auto parts store is a different animal. Trust me when I tell you this...

These problems will definitely persist going forward. There is no "solution" that will magically appear on the horizon. You and Lucid will continue to fight an uphill battle on this until you finally give up. (that's a promise)

By that time, you will have invested a great deal of time, money, and effort for a mod that has no chance of long-term success.

I HATE TO SEE PEOPLE STRUGGLE WITH SOMETHING, WHEN I KNOW IT WON'T WORK.

Sorry for shouting, but this kind thing bugs me. (a lot)

This battery is all wrong for your application, and it should not be marketed as a legitimate option for this car. It may work well for a smaller import (compact or sub-compact) but that's about it.

And so you don't get the wrong idea here, I really like Braille batteries, and consider their products one of the best out there FOR RACING APPLICATIONS. (not necessarily street cars)

It's not just Braille. I tried Oddyssey, Buddy Club (out of japan), Optima, Exide, and even a Heavy-Duty Motorcycle battery with custom terminals.

None of it worked for more than a year...

When I think of all the time and money I wasted, trying to 'beat the system' (more or less) by screwing around with something that was never going to fly...

I was trying to "out engineer" the BMW electrical enginnering group in Germany...and it didn't turn out well. That's a daunting task...even if you aren't trying to reinvent the wheel.

I did eventually find a more practical solution that worked out extremely well.

If you have any questions, let me know...

[Cleveland]

Originally Posted by 808MGuy

The alternator should charge the battery but if its totally dead (12.3V is pretty close to that) it will take much longer than a 30 min drive to charge it. Being an AGM battery, the Braille battery should be able to come back from pretty much dead. I mistakenly said it wouldn't before because I thought it was lead acid. While the car is running, the battery is being charged by the alternator and the battery voltage should match the charging voltage of the alternator which is typically somewhere around 14V. What is the voltage reading with the engine on? If it is below 12.5 or so, that means the battery is supplying some of the current and its not being charged.

Has anyone tried using a battery tender or something similar to try and keep the voltage up during long periods (more than a few days) of not driving? Does this help? I still think such a large reduction in capacity has to have its effect on the system but without knowing the actual idle current draw of the system, it's really hard to say for sure.

Actually a "dead" battery will usually be in the 10-11 volt range. It could be even lower if a sustained load was applied after the engine was shut off.

Once a battery has been totally discharged once (run all the way down) it typically never recovers 100% of it's capacity. Some manufacturers will tell you this upfront, while others will not.

FYI: It seems that some of you are confused on how these batteries work. They are not "charged" by a battery charger at the factory before they are shipped out to dealers or directly to customers.

The battery shell (plastic casing + LEAD lined glass mat plates) is filled with ACID which starts a chemical chain-reaction that 'activates' the battery right before they ship out to prospective customers. It's ready to go when the box it up for shipping. No power is lost or gained until it's installed up to about one year. If you are reading a low voltage on these Braille batteries, either that's how they come from the factory, or the acid was not filled to the proper level.

Those are the only 2 practical explanations, outside of some serious internal parts defect they have not identified to date.

If needed, these batteries CAN sit on a shelf for about a year without suffering any significant loss in voltage.

These racing batteries have a very low discharge rate if NO LOAD is present.

[lucid]

Cleveland, it sounds like you had an alarm system that was drawing significant current. I don't have an alarm system (I don't know if Swamp or Doba does). In my car, the only possible significant load on the system is CA when the ignition is off (unless the car is performing "significant" functions that I am not aware of when parked; it probably is not completely silent). So, your comparison is off, and how much current CA will draw is unknown at this point.

The specific battery under consideration does have the required cranking amps (per specification).

The specs state that it will last 3100 charging cycles at 10% DOD. It seems like what we need to know is how much of a load CA constitutes exactly, and if that exceeds 10% DOD when the car is parked for a couple of days or not driven enough for a full charge cycle.

With regards to the potential "charging too slowly while driving issue", Braille specifies "daily driving" as a suitable application for this product:

http://www.braillebattery.com/index....s/b3121/specs#

I know every car model car is different, but they should have a good idea of how long it takes a nominal car to charge a 10% discharged battery since they specificed "daily driving" as an application.

A test would be for someone to disconnect the battery terminal every night for a couple of weeks to see if that makes a difference (or log the current when parked overnight), but I'm sure the disconnects will be logged in the computer.

[Cleveland]

Originally Posted by lucid

Cleveland, it sounds like you had an alarm system that was drawing significant current. I don't have an alarm system. The only possible load on the system is CA when the ignition is off. So, your comparison is off, and how much current CA will draw is not determined at this point.

The specific battery under consideration does have the required cranking amps.

The specs state that it will last 3100 charging cycles at 10% DOD. It seems like what we need to know is how much of a load CA constitutes exactly, and if that exceeds 10% DOD when the car is parked for a couple of days or not driven enough for a full charge cycle.

Oh Lucid, I only glossed over one or two of the issues that I went through trying to make this work in both cars.

You don't even know the half of it...

When I tell you that I was determined, I'm DEAD serious. I wouldn't give up, because I really thought I could beat the odds that were stacked against me.

I thought this way for about FIVE YEARS. No one could convince me otherwise.

I had "a plan"...or so I thought...

The E36 Alarm fiasco was just the tip of the iceberg. That was merely one of many road blocks I had to overcome.

Another instance was the Bluetooth/ASSIST module in my E46 M3 that was drawing a load when it was supposed to be in 'sleep mode' when you kill the car. I was surprised to see how even a small amp draw affects these batteries.

It wasn't enough to kill my big OEM battery, but it wiped out my little Odyssey battery in no time. You wouldn't think these batteries would drain so quickly, but I found out the hard way they can and will.

My point is, you and I both know that your margin for error with this particular mod is significantly reduced with a smaller racing battery. (less than half the size) You can't afford to leave anything on in the car for very long, or you will end up stranded somewhere just like I did about four years ago.

I had to flatbed the car because I decided to stop at a mall out of town and forgot to kill the courtesy lights on the car.

I was only inside the mall for about an hour (less actually), but that was enough to drain the small battery past the point of no return. It was late Sunday afternoon (all the auto parts stores were closed) , and I had to call a damn tow truck to flatbed the car back home. That was an expensive and embarrassing situation that could have been avoided. I put myself in that awkward situation. I know it was my own fault, but that just goes to show you how easy it would be to get yourself into a lot of trouble.

Just food for thought, I think the battery size you are trying to use is too small for the electrical demands of the M3, and it will come back to haunt sooner rather than later.

Other members are quick to tell you how "cool" this mod is...well, it's not all peaches and cream. (that's for sure)

But hey, it's your call.

I just thought you might like to know the other side of this story...

[lucid]

Thanks Cleveland. I appreciate the information you are providing. Can you briefly outline the modules that you have discovered to be "active" after the ignition is turned off? So far we have:

1. Comfort Access (if installed)
2. Bluetooth/Assist (if installed)
3. Alarm (if installed)

And what was the reserve capacity of your Odyssey battery?

[Cleveland]

Originally Posted by lucid

Cleveland, it sounds like you had an alarm system that was drawing significant current. I don't have an alarm system (I don't know if Swamp or Doba does). In my car, the only possible significant load on the system is CA when the ignition is off (unless the car is performing "significant" functions that I am not aware of when parked; it probably is not completely silent). So, your comparison is off, and how much current CA will draw is unknown at this point.

The specific battery under consideration does have the required cranking amps (per specification).

The specs state that it will last 3100 charging cycles at 10% DOD. It seems like what we need to know is how much of a load CA constitutes exactly, and if that exceeds 10% DOD when the car is parked for a couple of days or not driven enough for a full charge cycle.

With regards to the potential "charging too slowly while driving issue", Braille specifies "daily driving" as a suitable application for this product:

http://www.braillebattery.com/index....s/b3121/specs#

I know every car model car is different, but they should have a good idea of how long it takes a nominal car to charge a 10% discharged battery since they specificed "daily driving" as an application.

A test would be for someone to disconnect the battery terminal every night for a couple of weeks to see if that makes a difference (or log the current when parked overnight), but I'm sure the disconnects will be logged in the computer.

Make sure you don't fall in love with those specs too much...you may be disappointed later on.

The power output of these batteries can be tweaked to a point, but SIZE rules when it comes to making really substantial power in automotive batteries. I love advanced technological breakthrough as much as the next guy but you have to be realistic here. A larger battery case will hold more LEAD plates and a larger volume of ACID. That's what drives the battery power output.

Yes, you can squeeze a few more amp hours, cranking amps, and reserve minutes out of some AGM batteries by using some innovative techniques, but you are still limited to what you can ultimately cram into that small battery case.

Don't fool yourself into believing this battery is the holy grail or something. It's not. It's a good, solid, small form factor, lightweight racing battery. Nothing more...nothing less. That's how i got myself into trouble. I had convinced myself, that these racing batteries were something they were not.

And I got bitchslaped back into reality a few times before I sobered up and stopped drinking the kool-aid...

I suspect you are starting to realize this yourself?

In regards to your quote from the braille website about the charging of these racing batteries...

They ALL recommended daily driving...because that's basically a requirement of ownership. (another thing I found out the hard way)

What they don't tell you is...abosorbed glass mat (AGM) batteries are not very compatible with current automotive charging systems. That's why they recommend that you drive the car around everyday. The CHARGING RATE for that type of battery is slower than that of a conventional wet cell LEAD-ACID battery. (OEM)

Modern alternators are not designed to deal with charging AGM batteries. I'm not saying they CAN'T charge them, they can...although at a reduced rate. The efficiency is reduced, and the alternator has to work harder to charged it back to 100%.

You could do this, but it's not very PRACTICAL though. I know I can't drive my car everyday due to where I work, and my occasional out-of-town business trips.

Every one of the small racing battery brands I bought over the years, told me it would be fine to leave the car sitting for few days. I seem to remember them telling me something like: "It won't hurt anything"

Well that was a bald faced lie!

The only real way to make sure this mod never comes back to haunt you...

...is to install a battery disconnect switch and use it every day.

Now Lucid, lets be realistic here... who the hell is going to go through all that trouble to make sure they never get burned by leaving the console light on?

At that point, this mod is more trouble than it's worth...

Maybe a small percentage of the people with OCD wouldn't mind, and that's about it.

[Cleveland]

Originally Posted by lucid

Thanks Cleveland. I appreciate the information you are providing. Can you briefly outline the modules that you have discovered to be "active" after the ignition is turned off? So far we have:

1. Comfort Access (if installed)
2. Bluetooth/Assist (if installed)
3. Alarm (if installed)

And what was the reserve capacity of your Odyssey battery?

I think it was like 24 Ah or something like that...

I'll see if I can dig that up for you. It's been a while...

Yea, all the modules in his car are supposed to go into 'sleep mode' a few minutes AFTER you lock the car and walk away.

After opening a PUMA case at my local dealer, they found out that the I-BUS com link (internal communication system that runs all the modules) was telling all the different modules to go into 'sleep mode', but sometimes the Bluetooth/ASSIST module was hanging up and it wouldn't power down properly. The tech who worked on my car also said the SIRIUS satellite radio tuner modules, nav, and any other device that is connected to the this com system could potentially hang up and continue to draw a small amp load from the battery.

Well, that was the last straw for me.

I was just too close to the edge on that issue.

I immediately moved up to a 33lb. battery that worked out much better. Still a lighter weight version than stock...but NO DRAMA.

That was a welcome relief, as I was pretty much at the end of my rope. I was trying too hard to push the envelope...and it pushed back!

I wouldn't even think of getting a small lightweight racing battery around the 20 lb. mark (or less) Not after all the headaches I had to deal with over a 5 yr. period. I've had my fill of that nightmare thank you very much!