New main battery connectors allowed

According to R25, the main battery connector is allowed to be any of the connectors from the SB series. This is a great change, and I am happy they did this.

That’s an entirely reasonable change. Of course, it does make inter-team logistics potentially more difficult, but I’d recommend that if you’re using a non-red/non-SB50 connection for main power, that you build and carry an adapter to the quasi-standard red SB50 connection.

There are also clones of the SB connector available from other vendors (like the AMP Power Series from TE connectivity). It might be nice for FIRST to permit those as well—consider asking on the Q&A. (If FIRST doesn’t grant permission, the brand markings on the connectors will make clear who the manufacturer is, for inspection purposes.)

The Anderson SB Smart, SBS, SBE, SBO and SBX connectors may remain illegal, even if only 2 poles are installed. The Q&A should clarify this for greater certainty.

Also, as a public service announcement, note that the SB connectors (and AMP clones) are keyed: the traditional red ones won’t work with anything except red and black (universal) Edit: and apparently pink also.

Please be aware that SB50 connectors will continue (as of this date) to be supplied on the batteries in Spare Parts at events.

Would an adapter to conver from SB50’s to any new connector be legal? It doesn’t look like it according to the rules, but it would be much easier if it was. We could just make a few adapters and solve that problem.

Your adapter is only going to be useful for charging batteries. R25 sounds very much like only one SB connector pair is allowed between the battery and the breaker/PDP.

In other news, the bigger connectors and larger wire that goes with them will be great for dealing with high current draws from pushing matches, etc. Next year. (Crosses fingers)

R25 does say “connectors”, but there are two connectors in the drawing.

(Of course, any adapter (if legal) is part of the ROBOT, not the battery assembly, for weight purposes.)

It’s unclear enough (given the use of the plural) that the Q&A can fill us in. I’d lean towards permitting it, since there are no new hazards caused or major advantages conferred.

(Thought experiment: if we assume that in the absence of a written quantity, the quantity depicted in R25’s figure is mandatory, does that imply that we would have to prohibit a team from doubling up the wire running from the 120 A circuit breaker to the power distribution panel? What purpose would that serve, particularly since teams can use wire of arbitrarily large gauge? Alternatively, what if a team doubled up the SB connectors in parallel? Would that be permissible?)

One connector and one set of wires. This rule is primarily for those teams wishing to use the SB120 series with the larger wire for the primary supply wiring on their robot. As have been discussed in many previous threads, there is very little improvement using this method. Adapters from SB50 to SB120 will be allowed should the need arise to use a Spare Parts battery. Adapters will not be provided and modification of Spare Parts batteries will not be allowed.

Many people have asked over the years about failures in the SB50 connectors due to over current. I have inspected more than 20 failures of these connectors, including one of our own. Not one failed due to the current. Every one I inspected failed due to mishandling, modification or failure to engage. About half were caused by team members bending the contact springs to make insertion easier. Most of the remainder were due to severe wear and/or severe corrosion on the contact surface.

Sounds like a solution looking for a problem.

I had a service truck with an SB50 mounted to the front bumper, I did bad things to that little connector, hard jump starts, an electric winch in the front tow receiver, never melted it.

How can an adapter be okay when R25 clearly says:

R25 The one (1) ROBOT battery, Anderson Power Products (or APP) 2-pole SB type connectors, the one (1) main 120-amp (120A)circuit breaker (Cooper Bussman P/N: CB185-120), and the one (1) Cross The Road Electronics Power Distribution Panel (PDP,P/N: am-2856, 217-4244) **shall be connected with 6 AWG wire or larger as shown in Figure 4-2. **

(emphasis mine)

I don’t see an adapter anywhere in figure 4-2. If they specifically show the wiring layout they want and the lead of lead inspectors says we can ignore that, how are we to know what other rules won’t be enforced at events?

Practically speaking, an adapter is ok because Al is the chief robot inspector of FRC. CD isn’t a official information outlet, so a brief clarification question in the Q&A would be wise, of course. But at least we can take Al’s word here that SB120 teams won’t be left out to dry regarding spare parts batteries.

I expect small adjustments will be made to allow teams that need to use a battery from Spare Parts. My recommendation to those teams would be to convert their robot to the SB50 connector if the need to use Spare Part batteries arises.
And while I am Chief Robot Inspector, I am not GDC and this will still require clarification in the Q&A.

Here comes my first of many warnings…
The 2015 motor rules that allow unlimited numbers of some motors does not imply that the electrical system can support multiple motor designs. A fully charged battery can supply more than 500 amps but at a vastly reduced voltage for a short time. Continuously demanding large currents from this system will lead to early battery discharge (and shortened life) and/or main breaker trips. Your mileage will vary.

This question is only tangentially related to this thread, but it didn’t seem that my question really warrants a new thread, either…

Is there any difference between the (old) red SB50 connectors and the (new) pink SB50 connectors in the 2015 KoP other than the color?

Two of our new battery cables (with pink SB50 connectors) from the 2015 KoP, when connected together, require herculean force (needed to mount one in a vice) to disconnect. We don’t see anything immediately wrong with either of them. We’ve never had this happen with two of these before.

Any suggestions on what to look for to see what is wrong? The contacts appeared to be properly oriented and in the correct position.

I didn’t look at ours yet but the kids mentioned they were hard to get apart. If they are high force contacts they take about 15 pounds minimum to separate.

You can get grips for the SB series to aid in connection and disconnection if it’s an issue.

Ours are definitely taking more than 15 foot-pounds of force! We’ve tried with all three combinations of pairs for the three cables that came in our KoP and they are all very difficult to get apart - way too difficult to separate in the typical confines of a robot. One pair we passed around at the meeting, and nobody could separate them by hand. It was like “The Sword in the Stone” with everybody thinking it should be easy to get them apart, but nobody could! (We did manage to separate them in a vice).

Maybe the contacts are made of uru?

How many regular pounds of force would that be?

Oops I meant pounds, not sure why I put foot in front.

But that is just the minimum spec. Every power pole I’ve ever installed took a great deal more when new.

Oops! That’s what I get for hastily using the same terminology from the prior post without thinking about it…

Of course, they should be “pounds” (lbf) of force, since foot-pounds are not a unit of force, but of energy or work. Oops!

There should be no difference in the pink connectors. We have not tried mating yet, but I will put that on the list for tonight’s meeting. When I inspected out KOP last week, the pink had the same contacts used in previous shipments of the KOP. The standard reel supplied, machine terminated terminals.

Can confirm, had the same problem. On the Andymark website it states that the pink connector mates with the red SB50, nothing mentioned about the pink one.