Offshore Blue

My charger doesnt have .33, it only has .3 Is that ok? What about mv? My charger is from 1-20. The manufacuwar reccomends 6 for nicad and 8 for nimh I use mine at 7... Is that also ok?

O and about the charging at night.... Would it be safe?

Orange Crush

I wouldn't say it will "hurt" tehm, so to speak charging them at 4.5-5.0 amps. I just wouldn't do it every time. Ever heard the story about the old bull and the young bull standing on top of the hill looking down on a heard a heffer's... Uh..wait, nevermind. PM me if you have't...

As for the slow .33 amp charge, I do mine on a day when I'm home all day. weekend..doing chores, etc. I don't exaclty stand over them all day, but I check them for over temp when I think about it. I can't say it would be a good thing to charge batteries overnight-unattended. Common safety pracitce would say "no".

Wheelnut

My Feedback: (81)

I have always charged my 3300 packs with 5 amps and have never had trouble with it. I learned that from the racers at the hobby shop Iused to hang out at. We also use to charge 3000mah packs at 5 amps.

Offshore Blue

Ok, great! Thanks for the quick replies. Im trying to get this figred out as soon as possible. But I dont think I heard you mention the peak sensitivity question??

Could you please help with this? :What about mv? My charger is from 1-20. The manufacuwar reccomends 6 for nicad and 8 for nimh I use mine at 7... Is that also ok?

Thanks jallen and everyone else!!

Wheelnut

My Feedback: (81)

Better performance out of end to end configuration??? never heard of that. care to explain? There is only a very short battery bar that has like 0 resistance for side to side configuration. How do you figure better performance.
PS. that would be impossible on like a carpet knife 1/12 scale pan car and those cars perform incredibly.

Orange Crush

If the manufacturer recommends "8" for NiMh, then I would use that for a baseline. I doubt "I'm" smarter than their electrical engineeers....maybe some GM engineers, but I don't know....maybe not.

jfruge

My Feedback: (1)

"Better performance out of end to end configuration??? "

I agree... All of the car racer guys that I have ever ran across want the best performance and use Side by Side packs.

John Fruge

Speederson

Yes

Speederson

No you are not wrong. I think you already been edumacated and lernded from those guys that over analyze.

Lone sv27........... you can charge anyway ya want just watch the temps. You should have an IR thermometer. The race guys use high amps on top of the line Matched and Balanced cells and you can be sure they are watching the temps. 120 to 130F max when charging. 140F or less after a run.

Read up on this thread. Lots of info here.
http://www.rcuniverse.com/forum/m_4835667/tm.htm

CadillacDTS2001

Last i check boys, carpet races do not pull 120 amps+ on a regular basis. ( but then nither do most of you guys )
every watt bar on a battery is resistance. sure the bar it self may have like 0.0000111ohm's but how good is your soldering job ? with out a good one then your very low resistance watt bar is not good.
end to end: there is one 1 watt bar and it on the end. and the battery's are joined rite to the battery. there is less area for the power to go threw. You want to have your wires as short as possible, well the more bars is like more wire.
the only good i see with side bye side is the fact its super easy to discharge.

Got RPM

Modern NiMH cells (3700 mAh and above) have a high self-discharge rate and will go out of balance just sitting on the shelf. It is very important to periodically balance your packs to make certain that every cell is fully charged. Your charger does not know if every cell is fully charged, it just shuts off when the pack peaks. Four cells out of six can peak and trip the charger, leaving the two cells undercharged. Run the pack in your boat and the two cells can over-discharge, ruining them. Periodic balancing of any NiMH cell is a valuable practice if you want your packs to last.

The two biggest enemies of NiMH cells are heat and over discharging. Any time you get you cells over 150F you have damaged them. The damage is cummulative, the more often you overheat the cells the worse they will get. While 120 degrees is a good temperature for cells to come off the charger, if you put them into the boat right away and run them down they can get too hot.

Cells sitting on the shelf will discharge themselves - you must recharge them at least once a month if you do not run them. If their voltage drops too low they will lose capacity and power. Follow these guidelines and your expensive packs will last longer and perform better. Want cred? The fastest R/C boater in the world treats his packs this way.


.

Offshore Blue

Ok everyone! I did the charge at .3 amps they were barely warm. It took them about 5 hours. So I don't see anything diffrent with them. My gp 3300's are putting out 8.6-8.8 volts. Each cell is putting out about 1.4 volts. Is this ok?? My chepo ebay tenergy batteries are putting out like 1.6 ea. hmm. So now my batteries are all ready to go right? Now I discharge them in my boat, and from now on at 3.3 amps.

(Correct me if I am wrong)

Blackjack52

We've already noticed from the performance standpoint many different factors about the NiMh packs. Charge at a higgher mAh and you get more heat and less mAh into the pack. Not good. Do recon every month at c/10. Lone SV.....check the SV Batt threads. All the info is there from us.

Also, a very good recomendation from a vet of 15 years was to charge the packs and run them right away. Grimracer made this suggestion and we all improved ETs. We also decreased our battery heat using this method. This was further backed up by PINZA..but the pic is posted in the RCU Gallery. Here it is.
http://www.rcuniverse.com/gallery/ga...0%26pageon%3D4

Joerg uses the following charging option:
I don't know if you guys have noticed it, but in Europe many people had trouble with the lifetime of the latest NiMH cells, IB3800, IB4200, GP4300 and Grepow4500. People used to store packs empty (or more or less empty) or even worse - discharged them on a discharge tray over night.

Recently some people have tested a new treatment with great success.

They fully charge the pack when it's cold after usage. You can store it now for some weeks (1-4). Then, the day before you want to run, repeak the pack @1A until all cells become warm. This is kind of a forming charge at 0.2C.

On race day, repeak with 2A - to about 50 C (120 F). Recharge and reuse the pack after it cooled down (this time 5-6A charge). You might see slight less punch on the first discharge, but even this can be avoided if you do the first discharge the day prior to race day. Then store about 500-1000mAh for the night and charge the pack normally the next day (5-6A).

Joerg



I personally don'[t use 5-6A on my 4500s because I have enough packs for an 1.5hrs of time at the lake (counting breaks b/w runs). Therefore I don't need to use such a high amperage charge to get the packs back out onto the water.

Also, last week I charged my Elite 4500s at 3A and didn't watch the temps after the last peak of 5100mAh. The temps got to 150F. I ran them past Sat with excellent results. They actually had the punch to get Force 8 on plane best and on loose water. I also have run them in the boat at the threshold of the prop.....right around 140F, some higher, depending on water setup. I still get the 125% into these packs......time and time again. These are great packs IMHO and experience.

But I don't think Joerg is worried about purchasing more packs too. Like Jallen mentioned, keep the heat down, longer life. Charge at C (3.8 for 3800, 4.5 for 4500s) and you're good. I never use more than 2A on race day because the packs sat all week on the shelf with a full charge.

But batt mx is like prop choice. Everyone has there own style. I have tested many alternate charge/discharge/store etc plans and have one that is optimal. I think many others use this same plan with excellent results.

Just a warning though. Discharging NiMh with lights=not good for the packs.

Offshore Blue

Cell Size: SC
Chemistry: NIMH
Capacity: 4500mah
Length: 1.71in. 43.43mm
Diameter: 0.9in. 22.86mm
Weight: 2.45oz. 69.42gm

Available
Price: $6.74


And for the Ib



Cell Size: SC
Chemistry: NIMH
Capacity: 4200mah
Length: 1.72in. 43.69mm
Diameter: 0.92in. 23.37mm
Weight: 2.38oz. 67.44gm

Available
Price: $8.70

Now the question is, elete 4500's or Ib 4200's... (Not considering price)

Blackjack52

That sounds decent 1.4v. Remeber, the more use the batteries have on them, the higher the voltage will get. Newer packs will get around 8.8V and then start climbing with more use. As the voltage goes up during a charge, the mAh will go down. The quicker heat is generated, the more resistance is created, and the less of a charge (mAh) you get. If you have a bad cell in a pack, you voltage might be low also, but the heat will be the giveaway,,,,,really high.

Offshore Blue

The pack is Atleast, 2 years old maby even more like 2 1/2 years. The packs have never gotton above 8.8 volts and they always get consistant run time. My first charge on them I got 8.6, now I occasionaly get 8.8.

Blackjack52

From a performance perspective.....go with the 4200s. Less weight (which is why..........oh I don't believe this........Jallen is getting the quicker ETs). I have 3800s and 4500s. I really like the 4500s. But because of the weight/performance tradeoff, I on;y use the 3800s for true ET testing. Just dorking around, I use the 4500s....like testing new setups/temps/props.

IMHO and seeing how the math doesn't lie.......a resoundingly YES for the 4200s. With 5300mAh of run charge, no difference compared to the 5650mAh on the 4500s. The 4200s will also have lower resistance.

Offshore Blue

If I set my mv all the way down to 3 and I set it at 7 when im fast charging. If I set my mv to 3 I can squeese atleast 9.4 volts out of em. But the second I take them off the voltage drops down to 8.8 again, always High 8.'s

Offshore Blue

How is jallen getting such fast speeds with Ibs? There like a brick! Im leaning twards the Ib4200's but thats because so many people here have them, and I could get lots of help with them since im a total noob when It comes to battery packs. Eletes are lighter there is no doubt, but the resistance is higher??? Isnt that bad? Saying that would you still go with the elete?

Blackjack52

The pack is Atleast, 2 years old maby even more like 2 1/2 years. The packs have never gotton above 8.8 volts and they always get consistant run time. My first charge on them I got 8.6, now I occasionaly get 8.8.

Hold on to those packs. They might have some life in them. Waych the charge mAh in time you charge along with the temps. If you have successive increases in the mAh each charge and temps stay below 120.....you're OK.

I've also heard some of the pros do multiple charge/discharge using their chaarger (not dischaarge tray or lights) to wake thee packs up. If you don't have a charger/dis....just dischaarge them in the boat. And have fun.

What kind of tempss are getting on the packs after a run and whaat size prop are you using? These are critical to the condition of batts/setup. Let us know in the Supertune Youur SV thread.

Blackjack52

Lone
Re-read from post #42 of this thread. The 4200s are lighter and have lower resistance. I think that'll help.

Offshore Blue

4200's it is, they will be shipped today, I will get back to everyone because im sure I will want to know How they should be charged discharged and maintained! Thanks every one for the help and I will let you know how they go!

CadillacDTS2001

yeah and im talking about 3300 packs .
for a guy who doesn't race there will be no benifit.
i change my batteries around 1 or 2 twice a year for racing. a person who runs for fun does not need to.
you always beef on everything

Blackjack52

Jallen,
I think if we were doing something wrong with the batt mx, we wouldn't be in the 36-42mph range.........repeatedly. Hmmmmm.
Speedo....what do you think? Oh.....don't worry, he's hybermating with a 12oz.

Blackjack52

Cool,
Just make sure you post your results in the SV Batt Thread.. Don't start another thread....OK.