Spal PWM controller
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I generally won't answer unless I know for sure but I will make an exception in this case because of my experience in designing electronic equipment. It would have to be a very poorly designed controller not to have a battery backup of the user program stored in a eeprom or similar component in case of power failure 
Last edited by MotorHead; Sep 10, 2006 at 07:19 PM.
Safety Car
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From: Raleigh NC
Originally Posted by MotorHead
I generally won't answer unless I know for sure but I will make an exception in this case because of my experience in designing electronic equipment. It would have to be a very poorly designed controller not to have a battery backup of the user program stored in a eeprom or similar component in case of power failure
Team Owner
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From: Columbia Missouri
Originally Posted by PhotoVette1
I just wish they would design car stereos to hold memory when the battery gets disconnected.
That's an easy fix even for someone with limited experience. A 9 volt battery taped to the back of the stereo. Run pos to pos and neg to neg. Just tap into the wires. The battery will never get used unless the main battery is disconnected and then it just slides into main control until main battery power is restored. If the controller loses memory with battery failure...the same principal should apply.
Team Owner
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From: Springfield MO
St. Jude Donor '07
Originally Posted by Durango_boy
That's an easy fix even for someone with limited experience. A 9 volt battery taped to the back of the stereo. Run pos to pos and neg to neg. Just tap into the wires. The battery will never get used unless the main battery is disconnected and then it just slides into main control until main battery power is restored. If the controller loses memory with battery failure...the same principal should apply.
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Generally speaking backup/safety features are designed into equipment based on, in laymans terms, how much damage would be done if the equipment fails.
For example you have double or even triple redundancy on medical equipment, there is most likely triple everything on the space shuttle. Redundancy/backup should used all the time in critical equipment where people could get hurt or injured. It is used most of the time where equipment failure can result in other equipment being damaged or left out of service. This one covers the Spal controller as your motor could overheat it the fans don't come on.
There is very little damage that can be done ( to anyone over 16 ) if you lose your radio station presets
For example you have double or even triple redundancy on medical equipment, there is most likely triple everything on the space shuttle. Redundancy/backup should used all the time in critical equipment where people could get hurt or injured. It is used most of the time where equipment failure can result in other equipment being damaged or left out of service. This one covers the Spal controller as your motor could overheat it the fans don't come on.
There is very little damage that can be done ( to anyone over 16 ) if you lose your radio station presets
Team Owner
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From: Columbia Missouri
Originally Posted by I'm Batman
It would be good to put a diode in the main power input line so that the 9v can't discharge into the main system.
Yeah, that's a good safety catch. I haven't tried doing that, or have seen any effects caused by a 9V on the system. I've used it once or twice.
Team Owner
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From: Columbia Missouri
Originally Posted by MotorHead
Generally speaking backup/safety features are designed into equipment based on, in laymans terms, how much damage would be done if the equipment fails.
For example you have double or even triple redundancy on medical equipment, there is most likely triple everything on the space shuttle. Redundancy/backup should used all the time in critical equipment where people could get hurt or injured. It is used most of the time where equipment failure can result in other equipment being damaged or left out of service. This one covers the Spal controller as your motor could overheat it the fans don't come on.
There is very little damage that can be done ( to anyone over 16 ) if you lose your radio station presets
For example you have double or even triple redundancy on medical equipment, there is most likely triple everything on the space shuttle. Redundancy/backup should used all the time in critical equipment where people could get hurt or injured. It is used most of the time where equipment failure can result in other equipment being damaged or left out of service. This one covers the Spal controller as your motor could overheat it the fans don't come on.
There is very little damage that can be done ( to anyone over 16 ) if you lose your radio station presets
That's all very true, but my $9 alarm clock has a battery backup so when the power goes out it doesn't lose the time and can still wake me up.
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
There is no reason other than cost to prevent someone from designing in a battery backup to anything, so you paid more for that clock than the same one that doesn't work when the power goes out 
Team Owner
Joined: Oct 2004
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From: Springfield MO
St. Jude Donor '07
The Shuttle is, I believe, quadruple redundant on all main systems. It's been a while since I did the space camp thing as a kid, so I don't remember the details too well.
Team Owner
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From: Columbia Missouri
Originally Posted by MotorHead
There is no reason other than cost to prevent someone from designing in a battery backup to anything, so you paid more for that clock than the same one that doesn't work when the power goes out
And it's worth every penny. Just like someone installing a battery backup for their car stereo. Saves them the hassle of re-entering all their presets and the time and date and tuning and what-not. I liek the idea of things having their own redundant system. Liek PC motherboards have a small battery to hold the bios in place for extented periods of powerless stand-by.
Drifting
Joined: Oct 2003
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From: VetteMOD
St. Jude Donor '05-'07
Originally Posted by MotorHead
There is very little damage that can be done ( to anyone over 16 ) if you lose your radio station presets
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Originally Posted by I'm Batman
The Shuttle is, I believe, quadruple redundant on all main systems. It's been a while since I did the space camp thing as a kid, so I don't remember the details too well.
Safety Car
Joined: Aug 2001
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From: North Easton Mass
Originally Posted by Gordonm
No it does not. I have had my battery disconnected many times and it stays at the original settings.
I disconnect the battery every time I pull into the garage and the controller works the same every time. I'm using the SPAL sensor and factory presets. I assume there is a NVRAM in the controller to store the settings so I wouldn't worry about disconnecting power.
Rick B.
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From: Columbia Missouri
Originally Posted by Corvette Engineering
Battery backup is so 1980's. You can get a microprocessor now with EEPROM for under a $1.00.
Yeah, that's a lot cheaper than a 9V battery. Kudos.
