Defender 2032 battery Lithium mod

Peale

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I did the lithium battery mod on my Defender about six months ago. It worked great. Then I wasn't able to touch it for several months.

Today I fired it up and...yep...dead battery.

About a week ago I remember reading that the mod was useless on a lot of Defenders because they drain a lot more power from the battery than the other Williams games. That's why I fired it up today - to test this theory.

What causes this?

How can I prevent it? Additional mods to the board?
 
What I have done is to buy a sealed plastic battery case (3xAA batteries) then add some extra wire to it so that I can mount the case away from the CPU board. Admittedly a hack, but if any of the batteries blow up, the damage will be minimized by being away from the motherboard and being in a sealed case.

Radio Shack: http://www.radioshack.com/product/index.jsp?productId=2102735
http://www.radioshack.com/product/index.jsp?productId=2062253 (This one has 4 battery slots, I wired around the 4th one).

The AA batteries have a larger capacity than the lithium button cells and should last a year or so.

ken
 
Your battery must have been weak to begin with. I put a 2032 in my defender well over a year ago and its still fine.
 
Your battery must have been weak to begin with. I put a 2032 in my defender well over a year ago and its still fine.

It was brandy-new, right out of the package. Metered over three volts when I popped it in.

I put another one in, I'll meter the voltage on a weekly basis to see how it fares.
 
Lithium Battery Mods only good for Stargate +++.

No. Yes, the 5101 draws more current than an 5514. But all you need to do is use a larger cell. Lithium batteries are never going to leak and make a mess like alkalines, so they are still the best choice. And you don't have to use a button cell... you could use a large cell and be set for 15+ years.
 
You can also buy expensive Lithium AA's from Menards.

I got nothing against you, Riptor, I just feel the Lithium Mod is not worth it for Defender based on other people's experiences.
 
You can also buy expensive Lithium AA's from Menards.

I got nothing against you, Riptor, I just feel the Lithium Mod is not worth it for Defender based on other people's experiences.
I've only had 1 Defender board that's had a lithium cell for a long period of time. That battery was installed in 08/2007, and when last checked a couple of months ago, it was still fine - settings and high scores all intact. That's over *2 YEARS*. Barring nvram, I'll be sticking with lithium.
How long would a battery last if D13 in the attached schematic were shorted? Could that explain the short-lived Defender batteries, or would it drain much faster than the few months we've been hearing about?
 

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I did the Bob Robert's battery upgrade on a Defender cocktail, made sure the limit diode was good, and still lose the battery in about 3 days....
 
I did the Bob Robert's battery upgrade on a Defender cocktail, made sure the limit diode was good, and still lose the battery in about 3 days....

3 *days*?!?! Wow, how long did alkalines last on that board?
 
Forever. I replaced that battery 3 times, and all three times it was dead in a couple days. I checked the diode, replaced it anyway, and no luck. Ken mentioned that Defenders didn't like these batteries....
 
Forever. I replaced that battery 3 times, and all three times it was dead in a couple days. I checked the diode, replaced it anyway, and no luck. Ken mentioned that Defenders didn't like these batteries....
A few days is crazy, I've done this to a few Defenders and none have failed on me yet (but only one has been in long-term). Which diode did you replace - the one that prevents recharging the batteries or the one that keeps the battery from backfeeding the 5v line?
 
Is there a way to swap out the 5101 with a 5114?
It can be swapped for nvram and you can ditch the batteries completely. But AFAIK, nobody is making an nvram adapter for Defender anymore. I suspect some 5101's use less power than others - that and higher quality batteries may explain most of the differences (but not the dead in 3 days bit).
Edit: looks like Matt types faster than me :)
 
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A few days is crazy, I've done this to a few Defenders and none have failed on me yet (but only one has been in long-term). Which diode did you replace - the one that prevents recharging the batteries or the one that keeps the battery from backfeeding the 5v line?

Both. I finally just went back to AAA's...
 
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