E-Maxx cells

Hello to everyone, it is my first time
I am interesting to buy a Traxxas E-Maxx 3905 and I would like to ask about decent batteries packs. I am not looking for something extreme or sophisticated. Of course I would like to exploit the most of the 16.8 V motors, so I am looking for 7-pack cells, but I was concerning about the autonomy and I don’t know how much mAh should I look for. If it has autonomy for about 20-22 min it would be brilliant.

I did a little search and I came up with this: http://www.promatchracing.com/proddetail.php?prod=42007
(Product ID: 42007 - ENER-G 4200 7 CELL FLAT STICK PACK)

Will these cells meet my needs for 20 min autonomy?
Why are they cheaper than the others? (Usually I found cells with the same characteristics at about 45-55 $)
What is your opinion?
Thanks in advance

[Metallover]

http://www.hobbycity.com/hobbycity/s..._15C_Lipo_Pack

Mislabled; actually 20c.

[suicideneil]

Skip the nimh cells, go straight for lipos- for the same performance/ runtime they cost a lot less, just means you need an LVC (Low Voltage Cutoff) and a lipo capable charger (preferably with a built in balancer). Nimhs will struggle to get you the runtime you want, and will overheat if you gear up from the stock 18/68 the emaxx 3905 comes with... that said they overheat anyway in many people's experience, mine included.

[magman]

LI-PO and you will never look back!

Thank you for your reply
I respect your knowledge and your proposals and I read about LiPo predominance over NiMh cells and I feel the same, (Suicideneil your links are fantastic and your level of knowledge is far beyond), but I am novice in RC world and I am afraid to use something else except from these, which Traxxas recommends. I have to point out the lack of technical support of the retailers in my country (Greece), that enforce me not to depend on them.
What about the budget? Ok those T5000.2S.15 - Turnigy 5000mAh 2S 15C LiPos are a great deal, what about chargers? LVC?
…and what about complexity? …are that waterproof? (This is the main reason to purchase E-Maxx)

NiMh its near 80€ (2packs of NiMh 4200mAh 8.4V with TRX connector and a AC twin output charger) …that’s it
http://www.promatchracing.com/proddetail.php?prod=42007
(Product ID: 42007 - ENER-G 4200 7 CELL FLAT STICK PACK)
http://www.modelsport.co.uk/?CallFun...n&ItemID=32524
(Fusion 5ive Delta Peak Dual Output Charger)

I was thinking having NiMh for a year or so and go LiPo or A123 afterwards
So I thing I’ll stay with NiMh simplicity at the moment
…could you please advise me about NiMh products I found or others that I haven’t found out about?
Thanks

Promatchracing.com if you want reasonably priced, quality NiMh pacs. I run 7 cell pacs in my older 3906 Emaxx (have lipo as well, but these pacs just keep on going).

I'd post a link, but their site seems to be unavailable atm.

[suicideneil]

Fair enough, and thanks too.

The promatch site is still down at present, but they are one of the best nimh brands out there, along with SpecPointConcepts (http://www.specpointbatteries.com/), you cant go wrong with either really.

The charger you picked out is very nice, very new too as I check out Modelsport on a regular basis. My only concern would be that it doesnt have an adjustable charge rate, its fixed at 5amps.

http://www.modelsport.co.uk/?CallFun...n&ItemID=32523

I know that version only does one battery at a time, but its adjustable from 0.5 upto 5amps, which would be much better and safer for the nimhs- less chance of overheating due to a high charge rate (nimh should never be hot off the charger, no more than 'quite warm' ideally). So far as I understand anyway, been a while since I had nimhs.

A123s would be a good upgrade in the future, as they dont need an LVC, and are quite simple to look after, plus the power output is comparable to lipos so its the ideal battery for most general users. We'll always be on hand to advise at anyrate- rc-monster is a great website and forum with some of the friendliest, intelligent and funny people you will come across.

I have already found out about these friendliest, intelligent and funny people, thanks to you Suicideneil.
That’s why I will keep asking

I would prefer twin output, so I also found this:
http://www.dynamiterc.com/Products/D...ProdID=DYN4033
(Twin Peak AC/DC Dual Peak Charger)
What do you think?

Can I use a US charger? (AC 110V outlet). My wall outlet is AC 220V. If I use a travel adapter convertor will it meet the charger’s demand for Volts and Amps?
The charger has DC output with alligator clips. Can I change them to car lighting DC socket?
Cheers

....and also can you please tell me about 4200mAh runtime?
Based on your experience are these packs can deliver 15min decent(not a lot of Volts drop) runtime?

I know that I ask a lot, but I want to know, because I will probably purchase 2 E-maxxes(1 for a friend) and I have to know what I am talking about with him

If you see above you will see I make a choice of packs by promatching, but I would like to know the runtime of these packs (15-20 min runtime would be great)

Originally Posted by Duster_360

Promatchracing.com if you want reasonably priced, quality NiMh pacs. I run 7 cell pacs in my older 3906 Emaxx (have lipo as well, but these pacs just keep on going).

I'd post a link, but their site seems to be unavailable atm.

If you see above you will see I make a choice of packs by promatching, but I would like to know the runtime of these packs (15-20 min runtime would be great)

[suicideneil]

4000mah+ should easily get you 15 minutes- the guys on the traxxas forums rave about both brands, and 30 minutes is about normal with titans or hvmaxx systems, so MMM might be a bit shorter; I think you'll have to find out the exact runtime you'll get the hard way.

The 110volt charger wont work from ~220volts, you'll have to locate a version sold in europe or the UK for our different mains voltage- the travel adaptor just changes the type of pins on the plug.

You could power it from the lighter socket if you switched the leads, that wouldnt be a problem.

I think I ve learned everything I had to know at the moment

Thanks for everything mate
keep in touch
ps: the best way its the hard way

[suicideneil]

Aint it just