Savage Conversion

Hey all,

I'm getting really sick and tired of Nitro. All the hassle of lugging around fuel bottles, ignitors, rotostarts, buying fuel at 40 bucks a gallon, tuning, which i suck badly at, etc. I want an electric

But I've invested so much into the chassis of my Savage that I don't wanna get rid of it I wanna convert it.

For example I have:
FLM TVP
FLM hybrid bulks
Alu diff cups
FLM skid plate
FLM steering brace
and bunch of other stuff here or there.

STS .28 engine with pipe, stock engine with pipe

I want to get rid of the engines and do a conversion but I'm sorta confused.

Do electrics use the 2 speed transmission or not? If they don't, what do I need instead? Also, do I *have* to go to brushless? Will regular brushed motors provide enough power since this thing is pretty darn heavy...

I have 2 6 cell nimh 3000 MAH battery packs which prolly wouldn't last very long in this thing i suppose...

Or should I just keep the savage how it is and buy an E-Savage since I don't have any electronics except the savage radio, the 2 3000mah batteries and a nice charger that i got off ebay that charges 4-8 cell nimh/nicd and 1-3 cell lipo's dynamite ultra somethin or other.

I saw an electric conversion kit for the savage online by Kershaw Design but they say it takes a month to build etc etc and I could probably just make it myself for cheaper it has 2 700 size deWalt drill motors or something like that.

plus lipo's are expensive...do you really NEED to run lipos are they really that much better?

[Serum]

Hi FLMavage;

I'm getting really sick and tired of Nitro.

And so is Nitro when they got beaten by the third brushless truck in a row.. :O

Keep that savage, check my website i did several savages, perhaps you'l get an idea on what to do with yours.

what is your website?

If you just mean your photo album sure its nice to see pics but it doesn't really tell me a whole lot

And judging by your album it looks like you have a aloooootttt of money...I am not so blessed.

[Serum]

You can either use the 2speed or make it stuck into 2nd gear. if you use the 2speed you need the mechanical brake. The good thing of the mechanical brake is that it's less stress on the controller.

So how does that work then, does the mechanical brake just work WITH the speed controller to slow down the truck?

[Getter Robo]

No, normally you can just shut off the brakes on any good ESC.

[suicideneil]

If the truck is that heavy, I would say lock it into 2nd, but keep the mechanical brakes. That way you can use the motor for reversing and soft braking, but when you need to stop in a hurry use the mechanical brakes to take the load off of the esc.

Depending on your budget I would say BL was infinately better than brushed, plus you already have all the neccessary upgrades to run BL pretty much.

Good Nimh batteries are perfectly fine, you want some IB4200 matched packs or something similar.

Dont whatever you do buy an E-savage; junk.

The converiosn its is fairly straight forward, you just need a mount for the motor and batteries, and find somewhere to mount the esc, radio and rx pack- Some photos would be great to that end. How much does this thing weigh, that will help determine the motor/ esc choice.

I have no idea how much it weighs...If I take the hump pack, motor, pipe, gas tank, etc all off it probably weighs a lot less...I'd guess it weighs between 12 and 15 pounds right now with everything on it and an empty gas tank. I don't have a scale though so I can't say for sure. But a lot of NIMH batteries, a BL motor, and ESC will weigh more than the engine/pipe, fuel, and hump pack, for sure.

I've got pictures of what the truck currently looks like on my photobucket.

http://s88.photobucket.com/albums/k161/naossoan/

I can't take anymore recent ones though because the camera has left the building (it was my ex gf's and we split up)

What do you think the minimum amount would be to convert it would be? Or if you know some sites where I can get reasonably priced stuff I'll take a gander for myself - Keep in mind I'm in Canada though, sorry, forgot to mention that :P. eBay may be the best place if it's cheap enough but I kinda need to know what to look for.

How many of those 4200 MAH cells would I need d'ya think? 14/16.8v? 16/19.2v? And approx how much runtime would that give me? Would I be able to make separate packs and run them in series? like 2 7 cells for a 14 or 2 8 cells for a 16? My charger only handles up to 8 cell nimh's, or 3 cell lipos.

I saw posts of guys saying they have 8000 MAH batteries that least 40+ minutes. How much would it cost to get one of those? Would they be nimh or lipo d'ya think?

[Patrick]

I use Truerc 8000mah lipo packs in my e-maxx. http://home.comcast.net/~truerc/custom/custompack.htm (8000mah packs about half way down the page)
I use a 2s2p pack (7.4v, 8000mah) ($75) in series with a 3s2p pack (11.1v, 8000mah) ($100) for 5s2p (18.5v 8000mah) total.
They are not the highest quality cells, but I like them so far and most other people that have them seem to as well, especially for the price. I think they're about the same weight as 12 nimh cells.
There is also the maxamps packs that a lot of people have. http://www.maxamps.com/products.php?cat=45

[suicideneil]

That does look like a big truck. Im gonna say go with the 9xl motor (feigao/wanderer/nemesis), 2x 7cell packs, and the MM esc with the bec disabled (remove red wire from rx lead and run your rx pack to power the radio & servos). You should be able to make back alot of money from selling the nitro parts -engine, tank, exhaust etc) to help cover the conversion costs. The only tricky part will be motor mount, but Im sure Serum and several other guys can help you with that.

As for where to buy from- the RCM store has everything you need pretty much, or ebay is a good place too yeah, though there is no after sales help if something goes pop.

ok ok that's not looking too bad. $80 US for one of those 9xl motors is not too bad. I just saw the first page with $280 motors and it kinda scared me a little bit...well, a lot.

What's the difference really? If an $80 will work fine, why get a $280 motor?

How much power will the 9xl motor give me? I don't really care a lot about top speed and all that, I care more about accelleration because I just a basher, no racing what so ever (no where to race)..so I'm just messing around in gravel pits and random places I can find.

Do you think the 9xl will give me as much power as my .28 engine?

I'm trying to find an MM speed controller you mentioned. Do you mean Mamba Max? If so I was trying to find one that supported 14 cells but they all said 12 (the ones on the RCM store). Am I missing something here?

Also, what are these lipoly batteries that cost $300+ it seems awfully extreme for just a battery. Why is it so expensive?

And what do the terms "5s1p" and 25C 125A CONTINUOUS, 50C 250 AMP BURSTS mean?. What does the 25C 50C mean?

[suicideneil]

Originally Posted by FLMSavage

ok ok that's not looking too bad. $80 US for one of those 9xl motors is not too bad. I just saw the first page with $280 motors and it kinda scared me a little bit...well, a lot.

What's the difference really? If an $80 will work fine, why get a $280 motor?

Quality of construction & efficiency. feigao type motors are very good value, but they are not as well built as the expensive neus/ lehners etc, and they are not as efficient, meaning they heat up more. Some people occasionaly get a bad motor where the magnet splits too, but it is quite rare.

How much power will the 9xl motor give me? I don't really care a lot about top speed and all that, I care more about accelleration because I just a basher, no racing what so ever (no where to race)..so I'm just messing around in gravel pits and random places I can find.
Do you think the 9xl will give me as much power as my .28 engine?

The power a 9xl will give you is massive, more than any nitro engine could ever manage, both in terms of torque and speed. if you are just after good acceleration and usable topend, then you would gear down a little, or use 12 cells instead of 14.

I'm trying to find an MM speed controller you mentioned. Do you mean Mamba Max? If so I was trying to find one that supported 14 cells but they all said 12 (the ones on the RCM store). Am I missing something here?

The MM (mambamax) is rated at 12 cells yes, but it can easily run 14 cells if you disable the built in bec (this powers the radio and servos). You simple remove the red wire from the rx lead and tape if back onto the other wires, and use your rx pack to power the radio & servos.

Also, what are these lipoly batteries that cost $300+ it seems awfully extreme for just a battery. Why is it so expensive?

Lipo batteries (lithium polymer) are the next generation of batteries, they have a much greater 'energy density', meaning they can hold many more Mah of power than any Nimh or Nicad. They are also much lighter. The downside is the price as you noticed- the better the quality and higher the mah capacity the more $$$ you pay.

And what do the terms "5s1p" and 25C 125A CONTINUOUS, 50C 250 AMP BURSTS mean?. What does the 25C 50C mean?

Basically lipo cells have a voltage of 3.7v, so a '5s' pack is 5 cells in series, giving 18.5v in total. The 'p' stands for parallel, meaning a 1s1p pack is 3.7v & 4000mah for example, a 1s2p pack is 3.7v & 8000mah, and 2s1p is 7.4v & 4000mah, and 2s2p is 7.4v & 8000mah etc etc. The idea is wiring cells in series gives more voltage, but the mah capacity stays the same, but wiring in parallel give the same voltage, but double or triple the mah capacity.

With escs you have 2 ratings normally, continuous and burst. The continuous rating is the amount of amps the esc can supply continously, without buring up. The burst rating is the maximum amount of amps the esc can supply for a short period, usually something like 10 seconds; this is useful because under hard excelleration the motor draws alot more amps from the batteries & through the controller than it does under normal running. For example, just driving along you will draw about 20-30 amps say, but when you nail the throttle from a standstill the motor may draw up to 120-150 amps, but only for a split second or two.

With lipo (and nimh) batteries they generally have 3 ratings; Mah, continuous and burst/peak.
The Mah (milli amp hours) is the packs capacity- the more mah, the longer the batteries will run for (exactly like fuel tank size).
The continuous rating, 25c for example, is how many amps the battery can supply continuously without overheating (puffing in the case of lipos, venting with nimh packs). 1c is equal to the packs capacity, say 4000mah = 4amps, which is 1c. 25c would be 25x4 amps = 100amps. Different packs have different mah capacity, and also different 'c' ratings, again down to quality and intended purpose really.
The burst/peak rating refers to the maximum amount of amps a battery can provide for a short period (10-30 secs depending) before it puffs or vents, and that is rated the same way as the sustained or continuous, say 50c, which for a 4000mah would be 50x4amps=200amps. Again, the motor only draws that much current for a split second so the battery will be fine.
The problem alot of people have is that they get a cheap lipo battery that can only provide a limited number of amps (low c rating), say a 10c 2000mah pack, and when the motor continuously sucks 20-30 amps, the battery cant keep up and so puffs, or bursts into flames (rare, but it does happen with older lipo packs).

For bashing, I think you will be perfectly happy with some good quality Nimh packs, with 4000mah or more- deans plugs are a must though, and side by side packs are better than stick packs if you can help it.

[MTBikerTim]

That's a huge post suicideneil. I have to say FLMSavage that lipo batteries are great. My experience with them has been completely positive. Lipo batteries prefer to be charged more often then run dry and just that makes me love them. I run a 2s lipo in my brushless and brushed mini t's. The difference in power though is incredible between my 7.4v lipo and 7.2v nimh. The 7.4v lipo makes the crappy brushed motor pop wheelies whereas the nimh packs are so slow and gutless it's not even fun.

[BrianG]

+1 ^. The voltage with NiMHs drop more under a heavy load. So instead of 14.4v, you're only getting, say, 12v. Maybe a primo zapped/matched NiMH set can do better, but the price starts to get close to that of a decent lipo pack. Lipos are also lighter.

[suicideneil]

That is the most important factor to concider when choosing which batteries to run, since a couple good 2s lipo packs will provide as much run time as 4 or 6 6cell Nimh packs. Some people even say they get bored after 45minutes or more of running from a single charge ( I would never get bored though ). The only thing to think about is the need for a lipo balancer (balances the voltage between cells in a pack), an lvc (low voltage cutoff device) which stops the lipo cells from over discharging- very very bad, and a specialised charger capable of charging lipo batteries safely & properly.

Depends on your budget and how serious you are about your bashing. That said, only hard cased lipo cells are really safe for bashing with, and on a savage conversion the batts would probably have to be mounted on the outside of the tvps, which makes them a little vulnerable for my liking. Much to consider.....