Backup Battery...Yay or Neh?

[Allison]

we never seemed to have a need for the back up battery aside from competition when it is required we don't even plug it in.

and as for turn off the RC we were told at the SLT regional by IFI after the third time we forgot to plug in the battery.

[Ryan M.]

Originally Posted by jimfortytwo

I wonder if those who unconditionally hated the backup battery have had the pleasure of the low-voltage reset before?

Note I don't like the backup much, but that I did mention that.

[jonathan lall]

To all those who are indifferent about the backups, just don't worry about them and you'll be fine. The RC still runs off of the main battery, and a lot of teams will never have to worry.

To us, they are a godsend, considering the current draw our robot has. Two years ago, when we tried six motor drive for the first time, lack of a backup battery was one of two major setbacks; this lack of available power would cut out our RC in pushing matches. In 2003, they fixed the other problem with the nice 120 amp breakers we take for granted (which used to sometimes pop when we stalled our gearbox). Finally this year the second problem was fixed and we no longer have to worry about our RC cutting out after too much pushing.

In the end, there's nothing really that should make you unhappy with the backup batteries; either they are very useful, or they are neither bad nor good.

[dez250]

Originally Posted by MikeDubreuil

Oh okay thanks, 2.5 minutes. Seems unnecesarily long, but it's a step in the right direction.

What i was told about time delay shut down after the main power is cut is for matches. When the power is cut or a main battery is lost during a match, or even if the main battery is never turned on, but the "back-up" battery is still there, the LED's still blink. Other then the LED blocks this year your robot alone has no alliance distinction (red or blue) while on the field. The time length supplies the estimated amount of time it would be from the start of a match until the scoring of that match is completed by the refs, so they know who is red and blue right away. Now also when your bot was under arena control and lost the main battery, the light pace changed if the bot was being powered by only the smaller "back-up" battery.

[MikeDubreuil]

Originally Posted by dez250

What i was told about time delay shut down after the main power is cut is for matches. When the power is cut or a main battery is lost during a match, or even if the main battery is never turned on, but the "back-up" battery is still there, the LED's still blink. Other then the LED blocks this year your robot alone has no alliance distinction (red or blue) while on the field. The time length supplies the estimated amount of time it would be from the start of a match until the scoring of that match is completed by the refs, so they know who is red and blue right away. Now also when your bot was under arena control and lost the main battery, the light pace changed if the bot was being powered by only the smaller "back-up" battery.

Excellent, I forgot about that. It looks like 2.5 minutes was a good choice after all.

[Avarik]

I thought it was a really good idea, and it seemed to help with loss of radio packets. In talking with some of the IFI guys when we didn't have our backup battery plugged in for a match or two, they noticed we had a much larger loss of radio packets then those teams who did have backup batteries!

[Andy Brockway]

I liked knowing the robot would not reset on the field. What I would like is someway to know the voltage level in real time just as we have with the main battery. Several times the IFI person came and told us, just as a match was starting, that our back-up was dead. We had to play with the hope that there was enough juice to power our winch latch servo. Luckily each time it was when we had switched starting positions on the field and it was our partners that had not been plugged in or they never charged it because they did not need it.

[MOEmaniac]

Originally Posted by Andy Brockway

I liked knowing the robot would not reset on the field. What I would like is someway to know the voltage level in real time just as we have with the main battery. Several times the IFI person came and told us, just as a match was starting, that our back-up was dead. We had to play with the hope that there was enough juice to power our winch latch servo. Luckily each time it was when we had switched starting positions on the field and it was our partners that had not been plugged in or they never charged it because they did not need it.

That would be a definate improvement if we the operator could tell what the voltage on the backup batter was.

[MikeDubreuil]

Originally Posted by MOEmaniac

That would be a definate improvement if we the operator could tell what the voltage on the backup batter was.

If you use the 2004 Dashboard Viewer it will tell you how charged the backup battery is.

[Mark McLeod]

I like the time delay operation of the RC using just the backup battery. We used it pretty extensively to test over in the programming corner without having to setup a 12v power supply. It was also handy just dropping new programs in without having to power-up the rest of the electrical sub-systems.

Originally Posted by Andy Brockway

What I would like is someway to know the voltage level in real time just as we have with the main battery.

You can use the User Mode display on the OI (or the dashboard) to display the backup battery voltage, just like the main battery display. You just need to use the matching code. I think the default code was setup to display it.

#define backup_voltage	 rxdata.rc_backup_batt*15.64/256

It does have that floating-point number that you might want to shift out of the way.

[KenWittlief]

I would like to see it become a pure backup battery - not used to power anything unless the main battery droops

AND

I would like to see it charge from the main battery so you dont have to unplug it and charge it separately. We were able to keep the same main battery in our bot all the time at the events this year, and only needed to put the 6A charger on it between matches to keep it topped off (our drivetrain was very effecient this year)

it would be even better if the backup battery had a charge path back to the main battery so it would stay charged all the time - even when the main breaker and the RC are off.

oh, one last thing: I want the letter "M" stricken from the english language!

[Max Lobovsky]

Originally Posted by KenWittlief

I would like to see it become a pure backup battery - not used to power anything unless the main battery droops

AND

I would like to see it charge from the main battery so you dont have to unplug it and charge it separately. We were able to keep the same main battery in our bot all the time at the events this year, and only needed to put the 6A charger on it between matches to keep it topped off (our drivetrain was very effecient this year)

it would be even better if the backup battery had a charge path back to the main battery so it would stay charged all the time - even when the main breaker and the RC are off.

oh, one last thing: I want the letter "M" stricken from the english language!

I agree with everything you said, Ken, except that i bet FIRST won't allow the last part about it charging when the main breaker is off. FIRST wants to be sure that absolutely all possible circuits to the main battery are open when that breaker is off. Logically, it sorta defeats the purpose if you do bypass the breaker with anything.

[MikeDubreuil]

Originally Posted by KenWittlief

I would like to see it become a pure backup battery - not used to power anything unless the main battery droops

AND

I would like to see it charge from the main battery so you dont have to unplug it and charge it separately....
it would be even better if the backup battery had a charge path back to the main battery so it would stay charged all the time - even when the main breaker and the RC are off.

Ken posts and the forum readers go wild!
Excellent idea Ken. IFI, if you're lurking on the boards, this is what I want for Christmas next year.

[Elgin Clock]

Gee Mike, I wonder what gave you the idea to post this thread??

I would like to see it again, but as an optional feature that you are not required to use. If you do not choose to use it, then you take your chances with resets.

[Al Skierkiewicz]

Hello everyone!
The backup battery was a great addition to the new controller. It does cover up faults that would have been obvious in the past. If your drivetrain was so current hungry in the past, the low voltage dropout would have alerted you to something being wrong. Without that big indicator, many teams now are going into competition with problem drivetrains that have no indication of problems until they break or die from lack of main battery voltage. That makes it really tough on your alliance partners.
The backup battery powering servoes is another problem in that teams with many servoes risk losing the backup without any previous indication. Although everything on the robot is running fine, none of the servoes work. I think it might be an easy thing to add a charge path from the main battery to the backup for charging and powering the servoes. Since the guys at IFI are really smart, I am betting they have already started working on this.