Battery Charger?

On May 3rd, there were rules changed regarding battery charging:

So are we not allowed to use Fast Battery Chargers either?
So does that mean my team’s large set of both batteries and chargers are now useless?

Does the Fast Battery Charger not have over-current protection, automatic shutoff, and is safe?

EDIT: Mods please move this thread to the Q&A section, I didn’t find it until now. :facepalm:

This is the intent of the rule:

It seems to me like this rule is pretty clear. They can’t monitor 700 teams at the world championship and their battery usage, and local tournaments can’t all be expected to keep up with battery charging checks either. Looks like they decided to simplify the issue by saying that vex teams at a vex competition can only use the vex battery charger. Any battery charger other than the vex smart charger would be illegal to use.

And Cody, Karthik spelled out your idea at the drivers meeting at worlds. He was very adamant that teams who attempted to cheat would be thrown out. Obviously it didn’t do as much in the way of scaring them as he thought, or he encountered many people doing things accidentally, and they’re just trying to make sure things stay fair.

Even the Fast Charger?

The smart charger IS the fast charger…

It has settings “safe” and “fast”

What on earth are you talking about? VEX only sells one charger for the 7.2v batteries.

Use this.

I think he might mean the fast setting. Yes of course the fast setting is allowed, just no other charger.

There was a fast charger but had been discontinued.

My team used this “old” version of the chargers all year, I highly doubt they would illegal since it was made by vex.

Huh. I’ve never even seen one of these before.

Defiantly worth asking if you have them, I guess.

I’m talking about these chargers:

Only work with these:

Our team has about 20 batteries and 6-7 chargers that are not compatible with any of the new chargers or batteries.

Right, those. Post a question on the q and a. My prediction is that they make it legal to use old batteries with the old chargers and new batteries with the new chargers, but no mix and matching because the page clearly states that the old nicd chargers are not to be used with the new nimh batteries.

I’m not sure what you mean by this, but to clarify, VEX has made these technical recommendations ever since replacing the NiCad batteries with NiMH:

Old NiCad batteries (black bands on the ends) can be charged by either the old 2-slot “Fast Charger” or the newer “Smart Charger.”

Newer NiMH batteries may only be charged on the “Smart Charger” but NOT the old 2-slot “Fast Charger.”

This has nothing to do with VRC game rules – these are technical standard practices from VEX. Since starting to switch over to the NiMH batteries, I know of several VEX programs that have retired (or are phasing out) their old 2-slot Smart Chargers to make sure no student ever accidentally tries to charge a NiMH battery on the old-style charger.

If you want clarification on the rule for VEX Toss Up, please post a question in the official Q&A forum.

A couple teams I know have been consistently getting significantly over 8 volts with vex chargers. Are they really supposed to max out at 7.2? I think a voltage limit would be better than controlling the types of chargers, but I guess that could also penalize teams who are unintentionally overcharging.

Yes every single battery I pulled off my legal vex chargers at worlds ranged from 8.4 to one that was 8.9. These were all charged in fast mode.

Yeah, Fast charging makes them go above the 7.2 volts. Everyone runs into that.

Have you guys had good results using the ‘fast’ mode on the smart chargers? Our batteries always seemed to approach a temperature that made the battery too hot to comfortably handle when charging them on fast, but in safe mode they never had this issue (they’d be warm, but not ‘ouch I can’t hold this warm.’)

When we charge nimh batteries on the fast setting of the smart charger, are they safe to leave on for long periods of time or are we supposed to pull them off as soon as they go green? I know in the safe mode it trickles them or whatever it needs to do to keep them charged, but what about in fast mode?

This old version of charger is capable of overcharging, because it was designed to for both the 9.6v and 7.2v batteries, whereas the new charger is only designed for the 7.2v batteries. The old cradle could detect which battery was placed in the charger and adjusted itself accordingly, but the new batteries apparently don’t trigger the automatic limit. This is why old 7.2v batteries can be charged in a new charger to the correct limit, but new 7.2v batteries can be overcharged (and ruined) in the old cradle.

Again, official clarification is needed, but it sounds like old chargers are now out. Yet another item to put on the “wish list.”

1 Like

I’m telling you all, ask on the q and a if you can use old chargers with old batteries. I doubt the intent of the rule is to make a vex produced charger and vex produced batteries illegal.