Charging newer batteries

[wmcwings]

How long should it take to charge 3300 NiMH batteries? I realize that the type of charger may make a difference, but just give me an average idea please. Last time I charged them I think it took like 30-45 minutes! Seemed like a real long time. I'm new to this newer stuff. I raced back when 1700SCRs were da bomb. Now getting back into it for my son.

Thanks for your input.

[Jay Dub]

Well, it is a directly proportional to how many amps you charge the batteries at. 3300mah is 3.3 ah. If you charge them at 3.3 amps, it will take 1 hour. 6.6 amps will take 30 minutes, etc. etc.. However, most of the cells have limits to the amount of current (read amps) you can charge them with. Consult the manufacturer about their charge rate (read amps) and that will (with a little math) tell you how long your charge should be. -Jeff

[wmcwings]

Well that makes sense! Thanks Jeff

[iVTEC4LIFE]

I'm also new to nimh, but Jay Dub seems very reliable..... Check this quote....

Well, if you have your heart set on NiMh batteries, then what you really need to do is rather complicated. First, figure out what type of cell you have, and then find out what care regimine is prescribed (most manufacturers had this available at one time). It really does vary for every type of cell. There are some general guidelines, but to get the best from your packs you need to do some research.

Basics: Never discharge your cells past .9 volts per cell (very difficult to do with pre assembled packs) -it will ruin the cells (you spoke of inconsistency in run time and perfiormance ). After every run (remember you can't run your packs all the way down), tray your packs with a discharge tray (Rayspeed made an excellent one).

Then you need to charge them before storage (if you don't they will be damaged). They need to be stored with a 1000 Mah per week of storage. 3 weeks = 3000 Mah of charge. If they are 3800 Mah packs, then they can't sit for 4 weeks without damaging the packs (providing they were in perfect shape to begin with). Then they need to be discharged before they are charged for a run.

To charge them' you need to find a charger than has the peak detection fcn adjustable, and it need to be adjusted for each type of cell, and pack configuration (eg. 4 cell, 6 cell, 7cell etc.) -Ip cells, Ib cells, Powers, GP etc.

Next you really can't run them more than once a week, or you

will damage the cells. Some cells can go 4 days, but you should find out which ones (research). And, if you do everything correctly, you should get 20 or so runs in tip top form. If you missed anything, then you can count on reduced performance -Yaaaayyy! Now you know the basics of caring for NiMh cells! -Jeff

I've got Onyx 3000mah nimhs and they take about 40-45 min at 4.5-5 amps.

So far I've heeding this advice pretty well. Mostly due to life getting in the way of r/c. Even so, I'd like to bash a little more so I'm going to get a bunch of Tower 1800mah nicds since they charge faster and can be used over and over during the day. Plus they are cheap!

[Coelacanth]

NiMH battery packs should only be run once per week?? I've never heard that before...

[iVTEC4LIFE]

Yeah, I thought it was a little crazy too but jay says he used to be (still is?) a team driver and the suppliers told him that. Once a week helps maintain peak charge and capacity longer. From what I gathered, nimh can lose around 30% of it's charge/capacity if it is cycled too much.

Nicds are near limitless in cycles as long as you care for them.

[iVTEC4LIFE]

I also started doing this to keep track of my peak mAh's (painters tape) so I know when they start to lose their edge.

[tommykart]

this stinks, i thought they were basically the same as nicd, as far recharability. so is ithe decease in battery life compounded each time you charge it more then once per week? So for optimum care = charge - run - charge - wait a week - repeat how depressing

Side note look what my Novak Ionic peak charger just did to a 2100nimh in just under 20 min set at 4amps

so hot i almost burned myself .... think its still good???

well luckily it was not new

[tommykart]

Ok my stupid self had it on 7 cell didn't have my reading glasses on, and the charger goes to 8 cells wasn't paying attention plus old mind set of just 6 or 7 cell.

On a positive note the other 2100 used pack that i charged on the millennium pro charger shows 1300 mAh and that ran pretty good with a vintage trinity Monster stock motor, i was cold by the time it was loosing power.

ok having read this topic i realized i might be running too many amps so i am going to err on the light side

I don't know the name brand i have but Onyx batteries cant be the best and the info on the charge rates are on tower hobby descriptions http://www3.towerhobbies.com/cgi-bin/wti0093p?&C=CGD
2000 mAh nimh battery = max charge 4.0 A
4200 mAh nimh battery = max charge 4.2 A

1800 mAH nicd battery = max charge 3.6 A

with this said i'll let ya know when my 5300 mAh get here and post some results

[tommykart]

Don't buy these batteries they are a waste of money.... 5300mAh nimh $12 shipped

old saying " you get what you pay for" holds true here as well

[kaiser]

When I got out of Rc 20 years ago nimh's weren't even out yet.
I'm glad I missed that phase of Rc.
I can't see any reason to ever voluntarily use them.

Lipo is so cheap now, chargers too.

I am forced to run nimh's when I race legends, but that's not often and
Sooner or later that rule has got to change.

[longboardnj]

3000nimh at 4 amp takes 35-50 min charge ..thats really all i run is 3000nimh . alot of people love lipo and think nimh is dead cause you can buy china lipo packs for $20 and you can get something that works good. if you have a honest hobby shop owner im sure they can tell you alot of bad stories about lipos.. i was just told lipos are not good to use in the cold..aaahhh funny stuff . the real problem with nimh is almost all cheap (noname) nimh packs are a waste of $$.i even hear venom nimh packs are a waste of $$ and they are a name brand. (you would think they would deliver a better product now i know there packs were junk in the past.) get a duratrax charger (get a onyx 200 or better) and some duratrax 3000nimh packs (i get them with traxxas connector 2 for less then $39 at tower hobbies)and you should be fine . have fun

[tommykart]

yeah i got 2 used 3800 packs they charge to 3300+ for cheeeeep and they are awesome( compared to 1200 nicd pack or yesteryear, still takes a charge btw) and i got an novak ionic charger for $12 shipped, both from the bay, Radio Shack is selling 3300 nimh packs for $13 reg $31. I might have to try one

the reason i didn't do the whole lipo change over because i still run old novak esc. They are rated at 100A but i would be afraid to fry them, even if i got 3000mAh 20c lipos =60A i guess i would be safe but not willing to invest in all that right now.

[longboardnj]

yeah i got 2 used 3800 packs they charge to 3300+ for cheeeeep and they are awesome( compared to 1200 nicd pack or yesteryear, still takes a charge btw) and i got an novak ionic charger for $12 shipped, both from the bay, Radio Shack is selling 3300 nimh packs for $13 reg $31. I might have to try one

the reason i didn't do the whole lipo change over because i still run old novak esc. They are rated at 100A but i would be afraid to fry them, even if i got 3000mAh 20c lipos =60A i guess i would be safe but not willing to invest in all that right now.

i dont trust radio shack stuff the battery maybe over 5yrs old..see if you can find a date on the box $13 for a bad battery is not a deal.

[Russ Winn]

I ran Venom 3000Mah Nimh in my cars for a while. Some packs are crap, and others worked pretty well. I stayed away from Lipo because of all the horror stories of explosions I was hearing. Now I'm running Lipos in my bomber class car, and it's a world of difference. They even make my brushed cars more powerful.
I picked up a Tenegy Eco Six balance charger, and two Gens Ace 5000Mah 50C Lipos for about $100 shipped. The charger is idiot-proof (which is what I need), and was a great deal compared to some things out there.