popsracer

In past experiences with the common silver plated Battery Bars, they will tarnish at the cell contact point if the cells are not pre-tinned before soldering. I would think that tarnish would create more resistance at the joint than solder.
Also, the way that most pack building Jigs hold the cells, the bars will not lay perfectly flat unless they are re-bent to do so. Either way, the tinning of the cells helps fill the slight gap that may occur with the installation of the Bar(s).

Anyone else have some thoughts or comments on this?

koabich

jeepnyy,
I run a TC3 on a road course. I really don't have a brand preference between the two. Both have been extremely good cells. I have ran cells by alot of different matchers and these have suited me the best.
It's hard for me to tell which battery is better because of many different factors and I am always tring different stuff...testing different motors, springs, brushes. Different car set-ups and track configurations. So it's hard to tell which is better than another.
I do know that I have never had a problem with any of their (SMC or Fuku) packs I have bought. Numbers are always true. Cells can take a lot of abuse and they both last the entire qualifier or mains without fading.
I will give Fuku one slight advantage over SMC...with Fuku, you call them and tell them the numbers you want. If they don't have them at the time you call, they will call you when they do. Where with Fantom/SMC you basically have to take what your LHS get in stock or you can ordcer then through the web and play a guessing game...the cells you ordered will be between the voltages of 1.170 and 1.190 (Stormer Hobbies does that and it sucks...they won't even try to help you get better cells...you get what you get).
Hope this helps, let me know if you need anything else!
Joe

seaball

iTrader: (9)

yeah, pops, i think you're right. i prefer to tin the cells. while solder may not conduct heat or electricity as well as silver, gold, or copper, the loss should not be comparable to that associated with poor contact area. not to mention the propensity to physically break the connection durring a mean impact.

for those interested, i know the audiophiles out there use high silver solder for their hand built crossovers, impedence networks, etc. the point is, check out the hi-fi audio industry for silver solder. that's the way to go. it's probably already out there in rc somewhere. i never payed any attention.

Evo_Uk

what are the best battery bars in terms of condution and performance and everything?

EddieO

iTrader: (6)

really, I've never seen any proof that one is better than they are other, assuming they are the top bars a company makes.

I stick to either copper or silver bars.....gold or platinum is just a COOL factor.

You can get great bars from trinity, peak, dan's, and many others.


Later EddieO

dtm

A friend gave me a few (24) of these short cells to run through the matcher (I'm running Gas at the moment, so I haven't been keeping in touch!).

Anyway, without much abuse to the cells I was getting around 1.14x-1.16x v and around 35xx mah on 30A discharge. Overall all the figures improved over the older cells and all heading in the right direction.

Note- These where randomly picked loose cells.....

rayhuang

iTrader: (5)

The new "shorty" pack I ran last Sunday was from Tony Carrubba (Power Push).

It ran great, really strong punch. I ran stock. I also only got 1400 seconds of charge in it for first qualifier and it ran 4:47 minutes strong!!! Not bad for ony a 3/4 charge.

The new "shorty" cells I ran the previous weekend were from Pole Position Batteries and they too (like the Power PUsh) had better punch than anything but my "BEST" long cans.

It doesnt really matter though because the reality is: This is the only cell you can get now and I bet a 1.170 voltage "shorty" will outperform your 1.185 long can youve run since October!!!.

New cells almost always outrun old cells in many cases.

jeepnyy

Thanx for all your replies...this is great...were getting much needed info on a "new" item in our ever growing number of "toys".

Not to shy away from the topic..in fact i think this is important battery assembly question.

How would you assemble a pack if you have a not so "matched" numbers of cells. For example :

cell # 1 406 sec 1.17v 200 IR
cell # 2 404 sec 1.17v 203 IR
cell # 3 404 sec 1.16v 205 IR
cell # 4 402 sec 1.15v 210 IR
cell # 5 400 sec 1.16v 208 IR
cell # 6 401 sec 1.16v 210 IR

In assembling a saddle pack 3/3 for road course 280 ft drive line tight to medium corners asphalt TC3 c/f chassis. Which cell will you put on the positive lead and which one will follow in succesive order up untill the negative lead?

How about 6 cell straight pack for oval high bank concrete oval with 17 degrees of banking in the corners and 5 degrees down the straights. The run line is 350 ft. How will you assemble the pack? Which cell go to the positive? ADX/L4 chassis.

Thanx

robk

iTrader: (22)

"In past experiences with the common silver plated Battery Bars, they will tarnish at the cell contact point if the cells are not pre-tinned before soldering. I would think that tarnish would create more resistance at the joint than solder. "


As an interesting aside, silver contacts are used in motor starters and other switching devices in the electrical industry. They do this not only for the resistance, but for the fact that the "corrosion" that develops on the contacts actually helps the conduction. Sounds really weird, but it is true. I am not sure if this only occurs on electrically conducting surfaces, or if the normal tarnish on silver has this property..........

popsracer

robk;

Your really talking about 2 completely different types of applications for the metal Silver.

Battery Bars use Copper for a base metal, then are plated with silver, gold or platinum. In theory each one offering less resistance than the previous, though I doubt it would be measurable with your standard DVOM.

Electrical contacts are sometimes made from solid Silver (90+%). This is to reduce welding when the points arc as they contact and release in high current/voltage applications.
I have personally seen Silver contacts tarnish in a Motor Starter after months of non-use and need to be cleaned before the device would operate properly.

dtm

Virgins always better than old dogs......in batteries....experience don't count!!

jeepnyy

No amount of experience will get you across the finish line if your batteries " DUMPED" because of some poor contact between battery bars & the battery itself or an unforseen "desoldering " or worst.... when batteries get "un-matched" by maybe reverse polarity....I've seen them "fall-off" after only a couple of runs. Thats why I checked them on a regular basis, just about after every weekend races.

RL Junior

wow jeepnyy.. I had no clue that order mattered at all when building a pack.... Do you actually get different performance by having your stronger cells on the outside (pos/neg wires) ?

Speedo

No, the pack is only as strong as the weakest cell.

Rory

i might be completely off here, but i thought i heard somewhere that the outside cells on a pack discharge slightly "more" or "faster" than the ones closer to the middle. if that's true, then it would help to put the stronger cells on the outside, because as the outside cells discharge slightly faster than the middle ones, all the cells would be closer to equal over the time that the pack is discharging, so the "weakest cell" wouldn't be as weak as it would if the pack was assemble randomly.

that said, i doubt even the highest level pro drivers would notice any difference