m1cojakle

I have a XXXT team losi car, a D6 motor, a SC-1 JR speed control, and a futaba T2PH, 75.550MHZ. When I take the car out to drive,initiallythe velocity is fine but then the car starts slowing down until it wont go at all. Everything seems to be hooked up correctly and the battery is charged, so I am not sure what is wrong. Thx

A.T.

initiallythe velocity is fine - for how long? much depends upon actual capacity of battery, may have just run flat. or
1. Battery defective or insufficient power rating for the motor and/orgear train use
2. Motor overheating - add heatsink.
3. Wiring defective - any heating or hot spot?
further information available at
Alan's Hobby, Model & RC FAQ Web Links

Regards
Alan T.

safeTwire

My Feedback: (2)

What type of battery and charger are you using? Is the battery new?

m1cojakle

- battery is 6 trinity (GP NIMH) 4300's

safeTwire

My Feedback: (2)

According to the chemistry of NiMH batteries, they require "Formatting", which is several charges and discharges at a low rate.

Until a NiMh is formatted, it can be charged, but the battery will peter-out in a short period of time. I dont know why this happens, I am not a Chemist!

After a NimH is formatted, you will be very pleased about how long they put out!

I am no authority, this information is what I have learned to be true from experience.

The format rate of charge is suggested to be 10% of battery capacity. In your case: 10% of 4300= a charge rate of 430milliamps(ma).

The discharge rate should be low enough as to make certain that battery never gets HOT. Slightly warm to the touch will probably happen, but you will not do damage.

Can your charger put out the required 430ma? (or more for future, higher rate charges?)

Enclosed is some information that I hope will help. Good Luck!

m1cojakle

Problem seems to be fixed. I was previously charging the battery at 2amp. Switched to four and it worked great. Thx or now.

Rafael23cc

My Feedback: (6)

[X(] [X(] Did you read the post that you quoted? He said 430mAh Not 4 amps. you potentially just fried your battery. 430mAh is about 0.4 amps. You need to leave it on the charger until it gets warm (approx 10-14 hours depending on remaining charge). Then you need to discharge it at a low setting, and complete that process a few times. A good charging-discharging device like a Triton or similar is great for this task. i normally do it 3 times, but I don't use my batteries as primary power supply. That is what fuel is for. My batteries power my control systems only. [8D]

Rafael

Brendan Lugo

A 4300mah 6 cell pack for a car is a sub-C cell which is fine to charge at 4 amps. [8D]

Rafael23cc

My Feedback: (6)

Although I might agree with you, you need to go back and read the entire post before posting something like that and confuse people further. He was having trouble with a brand new pack, and a suggestion was given to "break-in" the battery. To "break-in" a battery you do several charge-discharge cycles at 0.1C. On a 4300mAh pack, 0.1C is 0.43amps.

Rafael

BuschBarber

My Feedback: (2)

Forming the cells of NiMh packs requires several cycles at .1c or less. This is supposed to yield Better Performance and Longer Life.

Brendan Lugo

True that several cycles will yield a small gain but in his application it's not necessary. [:-]

safeTwire

My Feedback: (2)

Brendan, The reason for formatting a NiMH battery is not to obtain a "small gain" in performance. Formatting is to properly prepare and condition a NiMH battery for use and to function at its full capacity!

m1cojakle charged his battery at a higher rate, and probably brought it up close to it's highest possible voltage. (Even testing under load would confirm this). At first, the car will go like a rocket, but will begin to taper off rather quickly. However...after formatting, his battery will deliver the most power, for the longest period of time.

The actual gain in performance after a format is quite profound.

Brendan Lugo

No where does he state he is using a new battery. "Formatting" is not a necessity for him to get his vehicle running properly or for more than the 10 seconds he stated it worked for.

safeTwire

My Feedback: (2)

And...nowhere did he say the battery was NOT new.

Thats' the first thing you establish before telling someone to "nuke" their NiMh at the maximum allowable rate of charge.

jaka

Hi!
Those car NiMH batteries don't hold up long when charged with 4Amps! But car people perhaps don't care as we airplane people do...?[]

Rafael23cc

My Feedback: (6)

This will be a little off topic as 90% of my experience is with fuel powered RC "stuff" rather than electric powered RC "stuff"......

For those of you that "play" with multiple facets of this hobby answer if you have noticed this.....

Manufacturers place important precautions on the equipment used for aircraft applications. Not always is the same for surface applications. For example: helicopter fuel wiht a nitro content of 20% also has an oil content of 20%. For airplanes the oil content is still pretty high at about 18%. But have you seen how much oil is in a car nitro fuel at 20% nitro? Pretty darn near 8%. That is right, helis have cooling fans, airplanes have the propeller blowing air over the engine for as long the prop is spinning. But cars, that have the engine buried inside a body, have the least amount of oil.....

Then we go into the battery powered realm. Airplane and heli pilots use 80% of the rated capacity of a battery pack. Then re-charge them at 1C or 1 x the rated capacity of the pack. That is after the pack has been broken-in or formatted, as described above. But car drivers, charge their batteries at 2 or 3C since day one. It makes me glad that very few car people actually use Lipos, could you imagine what would happen if they did?

Rant over, good luck to m1cojakle and his battery pack. I'm outta here!

Rafael