R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 02-05-2009, 01:50 PM   #1
Tech Elite
 
Zerodefect's Avatar
 
Join Date: Apr 2008
Location: Underground, Ohio
Posts: 4,305
Default 4 cell NIHM

New to onroad, I went from nicad to lipo. Was out of rc for the time offroad was using NIHM.

Do these have a memory like NICAD and need discharging before charge, or can you just "fill 'um up" like LiPos.

Can you recharge them throughout the day. I'd like to get into 4 cell pan car, and unfortunatly Lipo rules aren't here yet.
Zerodefect is offline   Reply With Quote
Old 02-05-2009, 02:01 PM   #2
Tech Elite
 
Trips's Avatar
 
Join Date: Aug 2001
Location: 360 Speedway
Posts: 2,251
Trader Rating: 16 (100%+)
Default

NIMH cells don't have the same memory effects of nicad, but you do want to discharge them before charging. I discharge the pack as a pack at 30 amps down to 3.6v, then put the pack in a tray that slow discharges each cell too .9v before charging. You can run the same pack more than once a day, but on a typical club race day I find there's not enough time to properly dfischarge before charging for the next run, so two packs would be ideal... run one in round 1 and round 3, the other for round 2 and the main.

Between race days you want them stored with some charge in them, I hit each pack with 6 amps for fifteen minutes when I get home from the track and leave them til the next weekend.
__________________
MARSHAL!!
Trips is offline   Reply With Quote
Old 02-05-2009, 02:21 PM   #3
Tech Elite
 
Zerodefect's Avatar
 
Join Date: Apr 2008
Location: Underground, Ohio
Posts: 4,305
Default

Thanks. Looks like I'll need a discharger tray and another battery added to my onroad race list.

I wish we could just run single cell lipo 17.5. Might just wait it out.
Zerodefect is offline   Reply With Quote
Old 02-05-2009, 03:35 PM   #4
Tech Elite
 
SpraydbySprague's Avatar
 
Join Date: Jun 2008
Location: Conducting aggressive board meetings at my local track
Posts: 3,301
Trader Rating: 64 (100%+)
Default

As far as discharge trays go. I own 2 of these.

http://www.muchmoreusa.com/dischargers/mmrp1020.html

It's not cheap at 200 a pop, but they discharge at 30 amps pulse and 5 amps linear. The 30 amp pulse keeps the cells from gettin hot. The 5 amp linear will ensure the cells are fully equalized.

The biggest reason to equalize before charging is the extreme difference in the rate of self discharge in a pack. In the best of matched packs the difference in rate of self discharge can be as much as 50% between any given cells.

I equalize my packs on race day before charging. First at the 30 amp pulse, then at the 5 amp linear. Cells never get above 90 degrees. I let them sit for a few mins then charge the cells. Making sure they peak off about 10 mins before I go to race. After the race I simply put them away with whatever charge is left in them until next week. At 4600 mah capacity running 17.5 brushless, the cells still have plenty of charge left in them for a week to week storage.
__________________
How would I describe my holeshots?

Three words...

Ready... Steady... Confetti!!!! (gonna need a new one of those)
SpraydbySprague is offline   Reply With Quote
Old 02-05-2009, 03:58 PM   #5
Tech Elite
 
Zerodefect's Avatar
 
Join Date: Apr 2008
Location: Underground, Ohio
Posts: 4,305
Default

Got to love the MMR stuff. I got a lipo rx pack from them,and it has a shutoff built in! I'll check out thier tray. $200 is alot! Thats more than my charger!

Nihm is kind of a bummer if we are about to switch from NIHM to lipo.

Thanks for the help.
Now I have to choose between simple xray or complicated serpent or crc cars....
Zerodefect is offline   Reply With Quote
Old 02-05-2009, 04:01 PM   #6
Tech Elite
 
SpraydbySprague's Avatar
 
Join Date: Jun 2008
Location: Conducting aggressive board meetings at my local track
Posts: 3,301
Trader Rating: 64 (100%+)
Default

I've owned several different discharge trays. The Muchmore trays are the best. No need to babysit them. Just turn them on and let them do their thing. What kinda charger do you have?
__________________
How would I describe my holeshots?

Three words...

Ready... Steady... Confetti!!!! (gonna need a new one of those)
SpraydbySprague is offline   Reply With Quote
Old 02-05-2009, 04:02 PM   #7
Tech Regular
 
Parnelli's Avatar
 
Join Date: Nov 2008
Location: Minnesota
Posts: 341
Trader Rating: 13 (100%+)
Default 4 cell nimh batteries

What is the normal voltage for these packs when fully charged. Mine show 6.8 volts, is this right? Thanks.
__________________
Parnelli

Drives like a Washburn monkey
Parnelli is offline   Reply With Quote
Old 02-05-2009, 04:20 PM   #8
Tech Elite
 
SpraydbySprague's Avatar
 
Join Date: Jun 2008
Location: Conducting aggressive board meetings at my local track
Posts: 3,301
Trader Rating: 64 (100%+)
Default

Quote:
Originally Posted by Parnelli View Post
What is the normal voltage for these packs when fully charged. Mine show 6.8 volts, is this right? Thanks.
4, 5, or 6 cell pack? What's a Washburn monkey anyway?
__________________
How would I describe my holeshots?

Three words...

Ready... Steady... Confetti!!!! (gonna need a new one of those)
SpraydbySprague is offline   Reply With Quote
Old 02-05-2009, 06:14 PM   #9
Tech Elite
 
Zerodefect's Avatar
 
Join Date: Apr 2008
Location: Underground, Ohio
Posts: 4,305
Default

Quote:
Originally Posted by SpraydbySprague View Post
I've owned several different discharge trays. The Muchmore trays are the best. No need to babysit them. Just turn them on and let them do their thing. What kinda charger do you have?
I have a Hyperion 6010 ac/dc charger and the Hyperion model thats one step higher than that as well (250watt if I remember right). I'm set for chargers so I don't have to worry bout that.

Are the Trinity matched team packs still good. Looks like I'll need two of them.
Zerodefect is offline   Reply With Quote
Old 02-05-2009, 06:42 PM   #10
Tech Regular
 
Parnelli's Avatar
 
Join Date: Nov 2008
Location: Minnesota
Posts: 341
Trader Rating: 13 (100%+)
Default 4 cell nimh

SS they are 4 cell packs for VTA. A Washburn monkey is a mythical Autox creature from Wisconsin, kinda like a Jersey devil.
__________________
Parnelli

Drives like a Washburn monkey
Parnelli is offline   Reply With Quote
Old 02-05-2009, 07:51 PM   #11
Tech Elite
 
SpraydbySprague's Avatar
 
Join Date: Jun 2008
Location: Conducting aggressive board meetings at my local track
Posts: 3,301
Trader Rating: 64 (100%+)
Default

Quote:
Originally Posted by Zerodefect View Post
I have a Hyperion 6010 ac/dc charger and the Hyperion model thats one step higher than that as well (250watt if I remember right). I'm set for chargers so I don't have to worry bout that.

Are the Trinity matched team packs still good. Looks like I'll need two of them.
Myself along with many other fellow drivers, are pleased with the EnerG4600 cells. There are several companies who match them. SMC, ProMatch, OHP(Ohio Hobby Plus? I think). I'm not sure if Trinity uses the EnerG cells.

Quote:
Originally Posted by Parnelli View Post
SS they are 4 cell packs for VTA. A Washburn monkey is a mythical Autox creature from Wisconsin, kinda like a Jersey devil.
Never seen a 4 cell pack hit 6.8. What are your charger settings; amp rate, cut off settings, temp? Do the cells come off the charger at an even temp? Most of my packs get to 6.5 volts, this is charging at a 7 amp charge rate.

I like the comparative refrence to my home state's own mythical mascot.
__________________
How would I describe my holeshots?

Three words...

Ready... Steady... Confetti!!!! (gonna need a new one of those)
SpraydbySprague is offline   Reply With Quote
Old 02-06-2009, 04:00 PM   #12
Tech Regular
 
Parnelli's Avatar
 
Join Date: Nov 2008
Location: Minnesota
Posts: 341
Trader Rating: 13 (100%+)
Default 4 cell nimhs

S by S, I have a Vision Peak 2 charger I run at 2 amp rate. Yes I need to upgrade. I no longer discharge my nimh packs since I cannot control the cutoff point (old rack of 1157 auto bulbs). Last night I changed the connector (removed the Tamiya to Deans adapter) and recharged. Today my 4 cell packs after charging and cool down read 7.2 volts. They are 4000MAH packs from CBP.com. I thought they would peak out at about 5.6 volts. Thanks for your help.
__________________
Parnelli

Drives like a Washburn monkey
Parnelli is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
1/12 forum ovalnator Electric On-Road 46189 Today 08:13 AM
Associated Factory Team TC5, Brushless, LiPo, Li-ion Nanophosphate, Tips and Tricks John Stranahan Electric On-Road 839 11-01-2011 04:31 PM
For Sale: 4 x NiHM 6 cell saddle packs and Team Wave discharger Rorynw Australia For Sale/Trade 9 02-07-2008 09:59 PM
Lipo vs Nimh Racing and Minimum Weight yyhayyim Electric On-Road 91 09-20-2007 05:56 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 01:09 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net