Hi all, I will be getting my 2 sons 2WD Traxxas Stampedes for Christmas. I have had nitro in the past, but never electric and don't, as much research as I have done thus far, quite know what battery I need to be getting. I have pretty much narrowed it down to either An 8.4V 7 cell 5000mAh NiMH or a 7.4V 5800mAh 2 cell 20C or 25C. Traxxas or Venom were the 2 I've been thinking about. I am a total newb when it comes to electric. I can't seem to find the info I need as far as general run times, performance in these trucks, etc. Thanks in advance for any help!



Edit: Also, I was thinking about getting the Venom Pro Quad 100W X4 AC/DC 7-amp 4-port charger, has anyone used this? If yes how do you like it?

Run time is going to be dependent on how hard the throttle is being used. You can safely assume a 2s or 7 cell pack of ~5000mah will get you anywhere from 10 to 25 minutes of run time.

LiPo's generally require additional steps to care for them. They don't like to be left fully charged or discharged, they don't like to be over-discharged, and you need to use a balance charger to charge them. They have a risk of fire hazard as well, though this is typically avoided entirely with proper usage techniques. However, they can be recharged quicker, have more consistent power output, and can offer longer run times than a nickel cell counterpart. I'll let others comment on the quality of Traxxas and Venom packs, I have no experience with them.

I can, however, recommend you a good charger that will last you a long time. I would suggest the Hitec X2 Black Edition, it has 2 charging ports to let you charge 2 packs at the same time, can be used at home or out at the track, and is fully programmable for any hobby chemistry type out there.

Which batteries do you run and why?

You definitely want to go with with the 2S Lipo over the NiMh. However, here is the thing about Traxxas. A bunch of guys in my flying club have Traxxas vehicles. Traxxas seems to have a proprietary connector on their batteries that includes a third wire for balance. Most standard batteries have two different connectors; one for power and another for balancing. This video shows the situation

So without some adapters, you won't be able to balance charge a Traxxas battery on the Venom charger. The Traxxas chargers may be underpowered and take a long time to charge a 5800mAh . Even 100W Venom is a bit underpowered for a 5800mAh size battery. It will just take longer to charge than a charger with more power/current. I thnk 200Watts is a good size for 2S 5000-6000 mAh batteries.

This is all probably more than you wanted to hear but there is are some traps out there and some stuff to learn about batteries, connectors, and chargers.

If it were me, I would change the connector on the ESC to something more standard and then use a battery with the mating connector. There are numerous connector choices. Deans is popular with cars. Maybe also XT60. I have all my stuff on EC3 or EC5. But I am comfortable with soldering so changing connectors is not a big deal for me.

Thanks for the heads up on charge time, I was aware of the special plug and needing adapters, I am an automotive technician by trade so I'm cool with soldering. All info is helpful and never too much. roughly how long will a 2s take to charge on a 200W charger like you mentioned? With such a short run time and long charge time I suppose it would be wise to get 2 batts for each of em. I am getting a truck too so we can share the experience, I was going to get a 1/10 Summit but have shifted to a TRX4. Hence the need for a 4 port charger. Great informative vid!

so here is how to estimate charge times with Lipo batteries. It helps if you read up on the term "C". You will probably always see a discharge C-rating but not as often a charging C-rating. C is current normalized to the capacity. So for a a 5000 mAh hour battery (5 Ah), 1 C is 5 amps, 2 C is 10 amps, etc. 20C is a typical lowish discharge C. 30-50C is a decent rating for discharge.

On the charging side of things, the C's are much lower. Standard charging is 1C which by definition would take 1 hour. Most LiPo hobby-type batteries can be safely charged at 2C or even 3C. 2C would charge a battery in 30 minutes and 3C in 20 minutes. So a 5800mAh (5.8 Ah) at 2C requires 5.8x2=11.6 amps. 3C would need 17.4 amps.

Power is amps times volts. A 2S battery like for that truck is about 8volts (8.4 fully charged) so the power required for 2C charging is about 8V* 11.6A=92Watts or for 3C 8V times 17.4amps= 139Watts.

So with a 5800mAh battery and a 100W charger, you can just manage 2C but not 3C.

The actually times vary because you should never fully discharge a Lipo (50-80% is a good stopping range) but the chargers tend to only balance at the end of the cycle so balancing can take a while. So time is reduced for the battery being partially charged but increased if the cells are out of balance.

I have this charger
https://www.amainhobbies.com/protek-...k-8519/p578442
It is two channels and 200Watts per channel. If is great for LiPos up to about 4S. It is underpowered for my 6S 5000mAh helicopter batteries. I have a 1000W system (iCharger i306B with 1000W 24 VDC powersupply) that I use for those.

You can buy whatever cables and adapters you need from various places, or make your own. Progressiverc.com is a great shop for all things related to charging.

Most of my batteries I buy from Hobbyking or GensTattu https://www.genstattu.com/

Both Hobbyking and Gens batteries tend to come with XT60 connectors which are easier to work with than Horizon Hobby style EC3 or EC5. So if you change your ESC connector to XT60 you will be out of the Traxxas ID issue.

I did see that Venom sells their batteries with a universal connector system. This is a nice idea but adds an extra adapter. Each connection point adds a little more resistance.

There are lots of decent chargers out there. Not too many with higher power have built in AC to DC power supplies. When you look at chargers, make sure you look at the max current and max power per channel. Either can limit how fast you can charge. Generally, I think 200W is good for up to 4S batteries and you want 500-1000W for 6S. So as long as you are using 2S batteries, 200W is fine.