charging woes part V "The Search for Spark"

[bubba966]

Your ten minute trip with all your electrical loads would tax any charging system..its that simple .Get the best battery you can get that is the proper size.See if you get the 150 amp alternator too next time

+1

Your battery was on it's way out because it isn't getting a good enough charge. The voltage dropping like it is when you've got that many things electrical running is telling you that the alternator isn't putting out enough juice to run everything and charge the battery.

Get yourself a good battery (like an Interstate, or anything else with at least a 7 year warranty). And get the bigger alternator. Shouldn't have any problems then. That battery you had only had a 1 year warranty? And I thought that a 3 year warranty battery wasn't worth buying. Didn't know someone makes/sells a 1 year warranty battery...

Interstate is listing this battery as a fitment for an '89 525
http://www.interstatebatteries.com/e...%7C%7CRank%7C1

This is the size for the seat mounted batteries
http://www.interstatebatteries.com/e...%7C%7CRank%7C1

And the MTP-93 is a bit bigger than the MTP-91 that's listed for your car. So I'd guess that a battery that's the size of the MTP-91 is about the biggest size that you can stuff under the hood. And it lists the dimensions on the links so you can know what size to pick up should you not go for an MTP-91.

Johnson Controls makes Interstate/Costco/Sears/Autozone batteries (and probably a few others I don't know about). So any battery you pick up from them with a 85-100 month warranty is going to be an excellent battery. I just put a new battery in my M-Sport (on it's 13th birthday even!). Went with the Interstate branded MTP-93 (85 month) from a local Firestone for $99. Costco unfortunately doesn't have that size. And the Sears 100 month model was $140, so didn't go with that as it cost 40% more than the MTP-93, yet didn't provide 40% longer life.

Wonder how complicated it is to retrofit the battery location to the trunk?

[Ross]

+1

Your battery was on it's way out because it isn't getting a good enough charge. The voltage dropping like it is when you've got that many things electrical running is telling you that the alternator isn't putting out enough juice to run everything and charge the battery.

Get yourself a good battery (like an Interstate, or anything else with at least a 7 year warranty). And get the bigger alternator. Shouldn't have any problems then. That battery you had only had a 1 year warranty? And I thought that a 3 year warranty battery wasn't worth buying. Didn't know someone makes/sells a 1 year warranty battery...

Interstate is listing this battery as a fitment for an '89 525
http://www.interstatebatteries.com/e...%7C%7CRank%7C1

This is the size for the seat mounted batteries
http://www.interstatebatteries.com/e...%7C%7CRank%7C1

And the MTP-93 is a bit bigger than the MTP-91 that's listed for your car. So I'd guess that a battery that's the size of the MTP-91 is about the biggest size that you can stuff under the hood. And it lists the dimensions on the links so you can know what size to pick up should you not go for an MTP-91.

Johnson Controls makes Interstate/Costco/Sears/Autozone batteries (and probably a few others I don't know about). So any battery you pick up from them with a 85-100 month warranty is going to be an excellent battery. I just put a new battery in my M-Sport (on it's 13th birthday even!). Went with the Interstate branded MTP-93 (85 month) from a local Firestone for $99. Costco unfortunately doesn't have that size. And the Sears 100 month model was $140, so didn't go with that as it cost 40% more than the MTP-93, yet didn't provide 40% longer life.

Wonder how complicated it is to retrofit the battery location to the trunk?

I'll no longer buy Interstate because of the warranty policy.
A failed battery is pro-rated as any other, the difference with Interstate(and Sears as I remember) is that the basis used to calculate is a percentage against full retail. If the battery is more than a year old the warranty is worthless as a new battery can be bought over the counter anywhere at a discount for same or less than the "adjusted" price with a warranty claim.
Wal mart and such(Autozone?) use the actual sale price to calculate an adjustment.
I know this from personal experience

[bubba966]

I'll no longer buy Interstate because of the warranty policy.
A failed battery is pro-rated as any other, the difference with Interstate(and Sears as I remember) is that the basis used to calculate is a percentage against full retail. If the battery is more than a year old the warranty is worthless as a new battery can be bought over the counter anywhere at a discount for same or less than the "adjusted" price with a warranty claim.
Wal mart and such(Autozone?) use the actual sale price to calculate an adjustment.
I know this from personal experience

Not sure what your saying. I paid $99 for my MTP-93. Full retail on it is listed as $124.99-$149.99. So if they're using MSRP rather than the $99 I paid for it to use as the basis of replacement cost then it sounds like you'd be coming out ahead.

Like I said, I'm not getting what you're trying to say...

[Ross]

Not sure what your saying. I paid $99 for my MTP-93. Full retail on it is listed as $124.99-$149.99. So if they're using MSRP rather than the $99 I paid for it to use as the basis of replacement cost then it sounds like you'd be coming out ahead.

Like I said, I'm not getting what you're trying to say...

My example went something like this;
72 mo battery failed at 18 mos.
Retail price of battery was ~$150, let's call it $144 for simplicity sake.
$144 divided by 72 mos. is $2/mo.
The battery was in use for 18 mos. so a $36 dollar adjustment was offered against a $144 battery that can be bought outright for ~$100.
Didn't make much sense to me.

[Tiger]

I hated Interstate batteries for decades... they never last and they are super super expensive.

[bubba966]

My example went something like this;
72 mo battery failed at 18 mos.
Retail price of battery was ~$150, let's call it $144 for simplicity sake.
$144 divided by 72 mos. is $2/mo.
The battery was in use for 18 mos. so a $36 dollar adjustment was offered against a $144 battery that can be bought outright for ~$100.
Didn't make much sense to me.

Ahh, I see now what you're saying. I'm used to the in use for under 3 years 100% of price refunded, 3-4 year in use 80% refunded, 4-5 year use 60% refunded, etc. type of pro-rating. Which would make using MSRP as the cost to pro-rate against much better than the purchase price.

I've used Johnson Controls batteries for around a decade and never had problems with them if they were used properly. Only reason I ever returned one was because my truck had sat for months and the battery died. So I'd take it back and get a new one.

So I wasn't so worried about the warranty as I'm used to getting good product from Johnson Controls. Not to mention every other BMW owner around my area has had good luck with them as well. The M-Sport gets 30+ minutes of driving at least twice a day, so I'm not worried about killing the battery due to lack of charging.

[bubba966]

I hated Interstate batteries for decades... they never last and they are super super expensive.

Well, Johnson Controls has made Interstate Batteries for at least a few years now. And Johnson Controls has made good batteries in my experience over the last decade or so.

I doubt Johnson Controls always made the Interstates. Makes me wonder when they started making them for Interstate as it sounds like your experience with Interstate batteries is from some time back.

[Tiger]

Yes, I stopped buying Interstate since 2001 For the E34, two batteries died within 2 years. Auozone battery after this... one died within 2 years but this current one is going beyond 2 years now.

We had Interstates since 1980's... some last long but in the 90's they were dying left and right in no time.

[tim eh?]

Hmm, I was wondering if you were going to go for a 'search for spark' title or not with your next thread.

If a 100A tester is just wobbling on the good line there could be a problem. Though! I'd be pretty sure its guage is calibrated against specific voltages at 100A pull.

Regardless you're making some progress now.

When you go shopping for a new battery, here's a tip.

The 35mm difference in the battery sizes needs *no* adjustment, you just push the locking plate upto the next bolt hole. When you're shopping for your next battery unbolt the battery tray out of your engine bay and take it with you! (It's like 2 or 3 10/13mm bolts) The guys wherever you go will be happy to let you upsell yourself to a bigger battery

yeah... re: title i do get carried away sometimes don't i...
i blame it entirely on the car that drove me mental.... sorry.


I am having trouble buying a battery. Canadian Tire won't sell me one under warranty because they don't stock the size officially listed for my car, so whatever they sell me becomes a 'non-conforming' battery.

Only major store that I have found that has a size91 is NAPA at $160(!), 700cca.


Still looking around but that is the best bet so far .

Yes, the locking plate moves to the next holes which are 35mm from the other ones, and that is about the extent I want to 'modify' anything. The battery pan is welded to the chassis, and even if I made a custom one there is hardly any space to work with anyway. I measured height again and I don't think I can go up in height more than a cm.

So I can put a 91 in at 175mmx175mmx280mm under warranty or a size 92 if i can find it at 175mmx175mmx317mm probably not under warranty.

Tim... gotta stop this problem!

1. Belt tensioner fault. Not tight enough would cause problem.

2. Bad ground cable at the battery and starter.

3. Bad alternator... Eliminated

4. Bad battery... Will be eliminated

5. Bad starter...

6. Bad fusible link?...

agreed... good list... must get battery first... i was counting on a buddy to bring over a spare bat he has last night... d'oh! bicycles, 5am and -2'c are a bad combination!

actually i think i'll forget shopping around dammit, i'm off to napa to get the 91.

btw if it's the tensioner my bmw specialist mechanic screwed it up too so i won't feel so bad, AND i got him to doublecheck it when he tested the battery. belt is tight at least