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-   -   My own NiMh battery observations.... (https://www.rcuniverse.com/forum/rc-electric-off-road-trucks-buggies-truggies-more-147/9552004-my-own-nimh-battery-observations.html)

cummins driver 03-03-2010 04:42 PM

My own NiMh battery observations....
 
I just bought a nice used duratrax onyx 210 battery charger for $20 shipped. I thought that was a pretty good deal, and it has some nice features. It also told me a lot about my batteries though, and I thought I would share. It has a readout that will show you how many Mah the battery has accepted at the end of the charge.

I have two venom 5000's that work well that I bought used with only around 15 cycles on them, and provide around 25 minutes of run time in my stampede. I have been happy with them, but I was curious so after i got my new charger, I made it a point to look at the Mah that the pack accepted. So I ran them down in my MGT, and then stuck one on the charger at 3amps. When it got done, I checked the Mah before I took it off the charger. It had accepted 3340mah. Not so great to be claimed as a 5000mah pack. I wasnt dissapointed at all, because like i said, they work well and provide a nice run time for my stampede, and I bought them used for a great deal. $45 for 2 of them and a Dynamite prophet plus 2 charger.

Next up are my new Duratrax Onyx 3000mah NiMh batteries. They seemed to provide almost exactly the same run time as the Venom's. I bought these new shortly after I bought the venom 5000's. So, I ran one of them down to the point where i usually stop running(before the pack goes completely flat), and then stuck it on the charger. I let it do its thing and came back later and checked on it. I was a little surprised, but it had accepted right about 3160mah. Not shabby at all for a battery rated at 3000mah, and they were only $19.99 a pack.

Anyways, my point is, just because the battery claims this, or that doesent mean its better than one that claims less. The duratrax onyx 3000's cost me $19.99 a piece new. A great deal in my opinion. The Venom 5000's I bought used, but they are about $40 a piece new and provide no better performance in any category than the Duratrax batteries. So, I just thought this info may help someone battery shopping. It proves a cheap 5000mah is not always better than a decent 3000mah battery.

Oh, and id rather not start a venom bashing thread out of this. This was only to help people make decisions and not bash products. My venoms perform good, they just dont have the capacity they claim.

Eric

MCSRacing 03-03-2010 04:46 PM

RE: My own NiMh battery observations....
 
i have some EnerG 4600's that acept around 4700 but then there are my ib 3800 that only take around 3200 or so ... kinda cool to see what your putting back in huh!

SyCo_VeNoM 03-03-2010 04:54 PM

RE: My own NiMh battery observations....
 
yea actually thats why venom batteries have such a bad rap, and gets so much flak. I have a 1800 mah (paid $18 last year just found the bill yesterday) venom for my roto start and it peaks at 1300mah
than I got a chinese 5300mah nimh that I paid $20 for that peaks a tiny bit above 5200 mah

rclugnut10 03-03-2010 09:55 PM

RE: My own NiMh battery observations....
 
it all depends on cell condition in the summer when i run alot, my ep 4200's got into great shape acceping 4900mha but now since i maybe get 2 or 3 cycles per week they're taking 3800 after a run, then i end up lettting it sit which degrades quality and power output.... it all depends on condition, had some ib 3800's took around 4000mha for a while then started going down hill i gave up once they hit 2500mha, i got them used, and clearly well used, (the second layer of shinkwrap was melted away from the cells they'd seen some hard use)

the lug

userjh161 03-03-2010 10:16 PM

RE: My own NiMh battery observations....
 
i have a venom 4000 that'll usually take around 4150. i've had good luck with all the venom products i've had. maybe i'm just lucky

cummins driver 03-03-2010 10:18 PM

RE: My own NiMh battery observations....
 
Maybe mine were used more than I was told when I got them? They work fine, they just only take 3300mah usually.

And yes, it is really nice to be able to see how much of a charge the batteries take. It helps to keep an eye on the batteries and gives an idea of their condition and if they are getting worse or not. Im not used to all this technology:D

Eric

FieroMan121 03-04-2010 09:39 AM

RE: My own NiMh battery observations....
 
yeah, my spc energ4600 race packs accept about 4900+/- when i occasionaly:eek: over-discharge them. (they some mean sukas:D)

just ake sure when you over discharge them to rge them at a low amp rating so you dont permanantly ruin the packs

Lilredmachine 03-04-2010 01:36 PM

RE: My own NiMh battery observations....
 

ORIGINAL: cummins driver

Maybe mine were used more than I was told when I got them? They work fine, they just only take 3300mah usually.

And yes, it is really nice to be able to see how much of a charge the batteries take. It helps to keep an eye on the batteries and gives an idea of their condition and if they are getting worse or not. Im not used to all this technology:D

Eric
They don't necessarily have to be 'used' more. Generally a NIMH battery that has been well cycled lots of times will be in better condition than one that has been poorly cycled (ie run down to 50% then recharged repeatedley) a few times. The cells in your Venoms are damaged, think of it in terms of amp draw, if the batteries were in peak condition they would provide decent motive power to your truck for as long as it took you to use 5000mah of power. The fact they are crapping out at 3300mah does not necessarily indicate that they have physically lost the capacity, just that the cells no longer have the ability to maintain a decent voltage under load after 3300mah have been used. In NIMH cell performance and capacity are one and the same, you lose one, you lose the other.

It can be difficult to get your head round if you're new to electric. As an experiment you could try cycling the cells on your charger if it has that function. You may find that when gently discharged at say 1 amp they give you the full 5000mah capacity, however they would never be able to actually give you that full capacity under load in an MT. For example I have an old 3000mah pack I use in a roto start, didn't use it for a year (NIMH self discharge over time) so I knew it was flat, charged it at 1 amp and it took 3300mah. Tried to use it in the roto start and it barely turned the motor. The capacity was there but the ability to hold voltage under amp draw was not. If I was to run it until it appeared to be flat and then recharged it I'd only probably get 1000mah back into the cells, however if I was to gently discharge them on a charger I'd probably see my 3300mah back out of them.

Ps Lipos solve just about all of this, no self discharging, no break in, no cell degradation over time. Nimh need careful looking after, not many realise this.

cummins driver 03-04-2010 02:12 PM

RE: My own NiMh battery observations....
 
My venoms still perform perfect though. Dead on the same as my Duratrax 3000's. I dont think they are on their way out. I just doubt that they ever held the advertised capacity.

LiPo's are better for power delivery obviously, but they have problems all of their own also, and are not without their flaws IMO. Im still pretty darn keen of nitro in these heavier vehicles.

Eric

Lilredmachine 03-04-2010 02:50 PM

RE: My own NiMh battery observations....
 
The flaws being running them too low and knackering a cell? The only one I can think of really. Hardcases render them invincible, they don't need balancing, superior voltage holding characteristics, no self discharge, massive capacities available and now cheap lipos are cheaper than cheap NIMHs.

You just gotta try them man... Night and day. Seriously. Especially on the system you run on the MGT.

qoisdhc oqina 03-04-2010 02:57 PM

RE: My own NiMh battery observations....
 
i get about 45 min out of my venom 5000 in my slash, dont have a nice charger to detect mah though [:o][:o][:o]

cummins driver 03-04-2010 03:29 PM

RE: My own NiMh battery observations....
 
Lipo's have plenty of their own faults, most people just dont want to admit it.

Im pretty sure im just a nitro head anyways. Just went out and ran my Savage since it is nice out today, and I just have a blast with nitro. I think im just gonna sell this MGT, buy another stampede to modify so me and my fiance both have a cheap, quick electric to run, and call it good. I just have so much fun with nitro's and i really dont burn a whole lot of fuel anyways, so it'll take a long time to get to the cost of me going lipo and brushless in this MGT..... Plus I already have enough batteries and chargers to keep 2 stampede's running for an hour or so which is usually more than enough running for me, her, and her dad. I just dont think it makes sense for me to spend a lot of $$ on this thing to make it how I want it when my Savage does it all now. Not bashing electric, it is very nice in some ways, and i love almost everything about my stampede, but my savage is just so much fun to drive for when i want a 4wd 1/8 scale truck.

Eric

Lilredmachine 03-09-2010 01:06 AM

RE: My own NiMh battery observations....
 


ORIGINAL: cummins driver

Lipo's have plenty of their own faults, most people just dont want to admit it.

Eric
Fair enough you're not that into electric, however I wouldn't rag on lipos in quite such a way if you've never used them... Which it would appear you have not. There would be a lot less misinformation about lipos if people who just read things on an internet forum and had kneejerk reactions to them didn't form opinions based on no personal experience.

Just something to think about.

I'm into nitro too, however I'm not particularly fond of it. I'm fairly well voiced on here with a heavy bias to electric running, however I have been running both for around 10 years, been in the BRCA racing etc. I only run nitro today as my local track is nitro, they were initially acceptive of me running an electric 1/8th until I began thrashing them so I ended up having to back down to nitro. I've had my fair share of nitro fuel swallowed blowing down the pressure pipe :)

cummins driver 03-09-2010 01:33 AM

RE: My own NiMh battery observations....
 
Eh, I think LiPo's can be dangerous just because people forget things sometimes, and you just cant afford to do that with Lipo. However if you are always careful and treat them right, then i'd say they would never cause a problem.

Im actually 1 nitro shorter now, putting me at having 2 electric, and my nitro savage. I needed to get rid of something and so I sold my nitro buggy. My savage will have to take care of my nitro needs for now I guess:) I run my electrics more now anyways since my fiance has laid claim to my stampede, and my father in law has an e-maxx so we all have something electric to run now. Its a lot of fun for sure[8D]

Oh well, i like both, and have fun with both, so that is really all that matters.

I just bought two Turnigy NiMh 3800mah batteries, so I will see how they do soon. They were a good price, so im anxious to see how they are. Ill have to see how many Mah they accept while they are still pretty new after i cycle them a few times.

Eric

black mamba 03-09-2010 05:03 AM

RE: My own NiMh battery observations....
 
Just get lipos and be done with it. $20 2S 20C 5000mah Turnigy hardcases from hobbycity await you. lol



SyCo_VeNoM 03-09-2010 08:18 AM

RE: My own NiMh battery observations....
 

ORIGINAL: black mamba

Just get lipos and be done with it. $20 2S 20C 5000mah Turnigy hardcases from hobbycity await you. lol



Personally I got the $23 2s 30C 5200mah Turnigy hardcases from Hobbycity ;)
Prefer the extra discharge rate buffer room (even though I'm more than certain I won't need it just like the extra wiggle room just in case;))

Lilredmachine 03-09-2010 08:30 AM

RE: My own NiMh battery observations....
 

I just bought two Turnigy NiMh 3800mah batteries, so I will see how they do soon. They were a good price, so im anxious to see how they are. Ill have to see how many Mah they accept while they are still pretty new after i cycle them a few times.
Cool, I look forward to seeing how they do. I haven't heard of anyone using the Turnigy nimhs yet.

cummins driver 03-09-2010 12:07 PM

RE: My own NiMh battery observations....
 
Yeah, Im sure if im in electrics long enough that I may eventually try LiPo's. We'll see i reckon:)

I read a couple reviews on the turnigy NiMh's. They arent supposed to be top of the line, but I have heard they are great basher batteries, which is all im doing anyways, so hopefully they do alright[8D]

Eric

blank916 03-09-2010 12:17 PM

RE: My own NiMh battery observations....
 
Love the promatch cells......i've had good luck with tenergy as well.

black mamba 03-09-2010 12:54 PM

RE: My own NiMh battery observations....
 


ORIGINAL: cummins driver

Yeah, Im sure if im in electrics long enough that I may eventually try LiPo's. We'll see i reckon:)

I read a couple reviews on the turnigy NiMh's. They arent supposed to be top of the line, but I have heard they are great basher batteries, which is all im doing anyways, so hopefully they do alright[8D]

Eric
Once you use lipos, you'll never touch a nimh pack again. Same for brushless....you'll never touch a brushed can ever again. lol

isaacstaco 03-09-2010 01:25 PM

RE: My own NiMh battery observations....
 


ORIGINAL: cummins driver

I just bought a nice used duratrax onyx 210 battery charger for $20 shipped. I thought that was a pretty good deal, and it has some nice features. It also told me a lot about my batteries though, and I thought I would share. It has a readout that will show you how many Mah the battery has accepted at the end of the charge.

I have two venom 5000's that work well that I bought used with only around 15 cycles on them, and provide around 25 minutes of run time in my stampede. I have been happy with them, but I was curious so after i got my new charger, I made it a point to look at the Mah that the pack accepted. So I ran them down in my MGT, and then stuck one on the charger at 3amps. When it got done, I checked the Mah before I took it off the charger. It had accepted 3340mah. Not so great to be claimed as a 5000mah pack. I wasnt dissapointed at all, because like i said, they work well and provide a nice run time for my stampede, and I bought them used for a great deal. $45 for 2 of them and a Dynamite prophet plus 2 charger.

Next up are my new Duratrax Onyx 3000mah NiMh batteries. They seemed to provide almost exactly the same run time as the Venom's. I bought these new shortly after I bought the venom 5000's. So, I ran one of them down to the point where i usually stop running(before the pack goes completely flat), and then stuck it on the charger. I let it do its thing and came back later and checked on it. I was a little surprised, but it had accepted right about 3160mah. Not shabby at all for a battery rated at 3000mah, and they were only $19.99 a pack.

Anyways, my point is, just because the battery claims this, or that doesent mean its better than one that claims less. The duratrax onyx 3000's cost me $19.99 a piece new. A great deal in my opinion. The Venom 5000's I bought used, but they are about $40 a piece new and provide no better performance in any category than the Duratrax batteries. So, I just thought this info may help someone battery shopping. It proves a cheap 5000mah is not always better than a decent 3000mah battery.

Oh, and id rather not start a venom bashing thread out of this. This was only to help people make decisions and not bash products. My venoms perform good, they just dont have the capacity they claim.

Eric
you may need to charge your battery twice. somechargers stop charging and go into trickle after 90min as a safety feature. so after 90min its only charged about half way.i have to do this with my duratrax charger to charge my 5000mah DTX

cummins driver 03-09-2010 01:39 PM

RE: My own NiMh battery observations....
 
Well you know, I thought about that. I dont think it was timing out, but maybe it was? Im going to try again soon to be sure. I may be surprised. haha

Eric

Slo-V Flyer 03-09-2010 03:38 PM

RE: My own NiMh battery observations....
 


ORIGINAL: cummins driver

Well you know, I thought about that. I dont think it was timing out, but maybe it was? Im going to try again soon to be sure. I may be surprised. haha

Eric
What amp rate do you charge the 5000 mah Nimh at? There are a couple of possibilities I can think of that are causing you to not get a "full" charge, barring any defects in the battery.

1) The charge rate you're setting is high, something like 4-5 amps, and the batteries are heating up being fed at that high rate, and/or causing false peaks due to internal resistance or some other phenomenon. Try something like 2-3 amps instead? Which leads to..

2) As suggested above by someone, you're setting the charge rate to something like 3 amps.... while your battery is 5ah (5000 mah = 5 ah). That means it will take more than an hour to charge it full (assuming it's drained first), closer to 2 hours. BUT your charger has a safety feature where it shuts down the charge after only an hour and half... See where that would be a problem making it seem your battery is "done"? Depending on what charger you have, either press start again, or disconnect the battery, and then reconnect and start the charge again, which should allow the battery to finish up. I have this issue when charging my 5000 mah lipo, and my charger only goes up to 2.5A rate, so it takes ~2 hours to charge it.

FairTax4me 03-10-2010 12:05 AM

RE: My own NiMh battery observations....
 
What charge is put back in varies and depends greatly on what is discharged from the pack during running. Maintenance and charge habits can also affect how well a battery charges or discharges.

A lot of times, especially with high draw motors (brushless, low turn or modified brushed) battery performance will drop greatly at a certain point and it can be perceived that the pack is fully discharged, when in fact it may not be. If your charger is capable of discharging, cycle the packs a few times at low rates (1.0 - 1.5 amp range). Discharge to .9vper cell, and charge with 3-5mv per cell peak detection. After about 3 or 4 cycles you should see a difference in performance.

I had a Duratrax 3600 mah stick pack that regularly charged well over 4000mah on my ICE charger. Didn't have a ton on the power end, but it would run for 18-20 minutes on a mild motor setup.

cummins driver 03-10-2010 12:28 AM

RE: My own NiMh battery observations....
 
Thanks for the tips guys... I did think about the fact that my charger could be timing out. Next time I charge I am going to be sure and check that out before unhooking the battery. I have been charging on 3 amps, so its possible it could have timed out, and I didnt pay attention to that.

I usually stop running when i see a noticeable difference in performance since I have heard its best to not really drain the packs. Or at leas that is what I thought? Is that correct?

I actually just bought another Stampede tonight. Its a nice XL-5 roller with a body that is a little beat up, but I am going to put my electrifly S-600 in it, and my Fiance will have it to run.

Then, I am going to take my E-Savage ESC, and 1 of the GT550 motors and run that setup with 2 batteries in my other stampede for me to run. I think I will probably sell my MGT, but we'll see. I think a stampede on 14.4v will be a lot more fun to bash than the big MGT that is slower and wont run half as long on the same batteries. The stampede with 2 batteries on 14.4v should run for 30-40 minutes with gobs of power, so im pretty excited to try it out. [8D]

The only thing I really do with the MGT that could possibly slow down the stampede is hill climbing. And I think the stampede will be as good at that as long as the surface is somewhat smooth, its just the rougher dirt with clods Im afraid it may not do as well on, but hill climbing will probably only be 20% of our running, and my Savage is real good at that if I need to bring it out:D

Eric


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