Hyper ST Pro Conversion Advice Please

[Arct1k]

I'm opening myself up for some advise (abuse) on options for a new Hyper ST Pro Conversion.



I wanted to do a conversion from scratch so just purchased a new Hyper ST Pro kit - I have a Neu 1515 2.5D/F (1650kv) to go in it with a MMM (sadly the monster escaped and it is back with castle) hence I have a modded MM in the interim. Steering will be provided by a 5595TG...

I'm really only intending to use this at the track and maybe a little bit in the garden - The G3R would be reserved for the bashing duties...

The question is what to do about batteries and hence chassis layout and battery mounts.

OPTION 1 - I have some A123 packs 2x 2s2p and 3s2p that I could use in saddle formation at the rear of the truggy for 7s2p with the motor opposite the steering servo - for this I would make some custom battery mounts from Kydex.

I also have 2 x 3s2p Maxamps 4200 batteries that would fit this config...

OR

OPTION 2 - Buy a a FlightPower 6s1p 5000mah 25C for $245! This I would mount as normal position next to the spur with an RCMonster battery tray.

I'm torn... considerions

Option 1
+ No additional cost for batteries
- Weight and impact on truck balance
- Complexity of wiring
+ Potential for reuse of 4200 batteries but will they cope with MMM
+ Option to run 5s2p A123 on MM

Option 2
+ Simple clean layout
- Cost of battery
- Battery won't run on MM (although I have a 4s Polquest i could use)


Last night I leant towards 1 figuring I could always do 2 later - but then woke up and thought about biting bullet on 2 and cancelled the order for kydex...

Did I mention I might be bipolar!

[lincpimp]

My only issue with all of the batteries on the back of the chassis is the jumping performance. That is alot of weight at the back, and I have forund that I prefer the batteries at the front of the chassis. I am going to use a neuenergy 6s 3900 pack in my st, mounted across from the steering servo, in the area where the nitro fuel tank used to be. It will go from the steering post to the back of the center diff assy. That will give ne some room to mount the MMM behind the battery, or behind the motor if I want to.

I played with alot of battery configs with my hv savage, and ended up with the batteries as far forward as I could get them. Otherwise the truck would fly nose high after a jump.

[Arct1k]

Obi-Wan spoke...

I run my 1515/2.5d on a 5s Lipo pack and couldn’t be happier with the performance. Plenty of power, but tractable as well and great temps. Lipos have a big weight advantage over the A123 packs for sure – my truck weighs 10 pounds even with a 5s 5000mah pack – with your A123 setup, it would be a full pound heavier, which puts a lot more stress on the parts, as well as makes it more challenging to set up the truck for track duty(getting the proper shock dampening and spring rate for an 11 pound truck with parts designed for a 9.5-10 pound truck will be tricky at best, and you may not find a suitable spring rate available). 10 pounds or less is the best plan in my opinion.
Once you have the truck and motor mount, setting up the ST should be pretty quick and easy. You need to make a decision on the batteries before getting a battery tray, though.


I ordered!

[Finnster]

I know your pain, I've tossing similar options in may head. :)

The problem w/ all the A123s (14cells) is its going to be insanely heavy, esp in the rear. I raced around w/ 10 A123s, and at the last little bash 9 (tho I barely gotto run it, seemed pretty decent.) 14 cells is over a kilo. Going to 1P won't give you enough amps or runtime.

If this is a dedicated racer I think it will be a bit disappointing.

The single batt is easiest, but I would say you can cut the Mah down to save some weight. How long of mains do you want to run? If its mostly vs elecs (like at the barn) you really only need 10 min. Seems like a lot of nitro mains are only 15, maybe 20. A 5000 mah pack would give you over 25 min realistically.

To make a lipo saddle pack would be tough. Most higher Mah packs are too long based on the measurements you sent me.

[Finnster]

Read the other post that was up while I was typing.. Yeah I think you are better off w/ 5S on that motor. My 1100kv on 8S was a bit much on the track, so the 1670kv on 6S would be overkill.

I really liked my 2Y on 9S A123 (~27K rpms) actually. Doesn't sound like much, but was a bit easier to control and not overpower.

[Arct1k]

I picked up a cheap 4000 5s 20c pack (sub $90) and an RCM battery tray.

I might split the tray in half to make longer to enable be to try the 6s2p 4200 maxamps.

[lincpimp]

Originally Posted by Arct1k

I picked up a cheap 4000 5s 20c pack (sub $90) and an RCM battery tray.

I might split the tray in half to make longer to enable be to try the 6s2p 4200 maxamps.

I knew that you would not be able to pass up that deal...

6s2p 4200 should be fine.

[Arct1k]

I just got an email saying order shipped! I just got one for now but it is very tempting you can get 2 X 4000 5s 20c bats for under 165 with free shipping - thats a lot of battery...

I'm hopeful that the 6s2p 4200 should work too to give me a couple of options...

[Finnster]

Originally Posted by lincpimp

I knew that you would not be able to pass up that deal...

6s2p 4200 should be fine.

Arct1k is the deal master

That batt should be great. I would think you could sneeze a 15min main on it, depending on how you drive. 10min should be easy. Nice find!

[Arct1k]

Come to Papa!

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[jayjay283]

[Arct1k]

ha ha - the box is in front me

[Finnster]

Originally Posted by Arct1k

ha ha - the box is in front me

luuuucky

I saw that you got your st for 390 in another thread. Was that the shipped price and from where? I plan on doing this exact same conversion in the next couple weeks.