Rescued Abrams build

[Meter Rat]

The real things can fly.

[Meter Rat]

Just in case you are not aware the 7.1 has two power options a "low" and a "high". Low will only allow for 70% of the max battery voltage to be used. 11.1v at peak is ~12.1v of output.

Running on the low power setting you will be equally to an 8.4v battery output and will have much better overall control of the tank with none of the motor overheating that comes with running at 12v.

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Just ordered a 3S battery to experiment with in my Challenger after reading this.
Metal tracks, road wheels, idlers, and sprockets. Check.
Braced chassis. Check.
Red motors. Check.
Ball bearings in everything. Check.
What can possibly go wrong?

[Handy Lance]

Just ordered a 3S battery to experiment with in my Challenger after reading this.
Metal tracks, road wheels, idlers, and sprockets. Check.
Braced chassis. Check.
Red motors. Check.
Ball bearings in everything. Check.
What can possibly go wrong?

If you don’t crash or keep the throttle pinned, probably nothing. Wear might increase because of power, but I like the slow speed control of 3s, 3s should last longer mah for mah because you keep the throttle down less. 2s requires more throttle so the batteries die faster.

[Rubicon99]

Just ordered a 3S battery to experiment with in my Challenger after reading this.
Metal tracks, road wheels, idlers, and sprockets. Check.
Braced chassis. Check.
Red motors. Check.
Ball bearings in everything. Check.
What can possibly go wrong?

Actually there is a lot that can go wrong when you run at the full power output of 12v (full throttle). Stripping stock steel gears so you have to be easy on the "throttle ups" and burning up motors especially if you happened to get a set of the "fake red" 390 motors as these are not rated for 12v and the internal cooling fans melt. I have a post about that somewhere on HS with photos.

You absolutely will throw tracks in hard over high speed turns especially with the Challenger running rubber padded tracks (the top speed improvement is crazy.). This will cause other huge issues especially if it happens while at full throttle. Expect parts to break.

I have learned to not use the full power of a 3s Lipo except for straight speed run and easy high speed turns unless I am running "non" rubber padded tracks.

So as long as you accept that running in the 12v range with high torque motors is going to break something then you will have lots of laughs in the process.

[Meter Rat]

Actually there is a lot that can go wrong when you run at the full power output of 12v (full throttle). Stripping stock steel gears so you have to be easy on the "throttle ups" and burning up motors especially if you happened to get a set of the "fake red" 390 motors as these are not rated for 12v and the internal cooling fans melt. I have a post about that somewhere on HS with photos.

You absolutely will throw tracks in hard over high speed turns especially with the Challenger running rubber padded tracks (the top speed improvement is crazy.). This will cause other huge issues especially if it happens while at full throttle. Expect parts to break.

I have learned to not use the full power of a 3s Lipo except for straight speed run and easy high speed turns unless I am running "non" rubber padded tracks.

So as long as you accept that running in the 12v range with high torque motors is going to break something then you will have lots of laughs in the process.

Tongue in cheek comment.
I have perused most of the treads that have been written, and taken on board what has been said, on previous posts. This is a fun experiment to see what the speed differences will be between 2S full power, 3S, low power, and 3S full power. Not an attempt to destroy it. Most of the time I am happy with a 2S battery, plenty fast enough for an old codger like me.

[Rubicon99]

Tongue in cheek comment.
I have perused most of the treads that have been written, and taken on board what has been said, on previous posts. This is a fun experiment to see what the speed differences will be between 2S full power, 3S, low power, and 3S full power. Not an attempt to destroy it. Most of the time I am happy with a 2S battery, plenty fast enough for an old codger like me.

I caught what you were saying, but others unfortunately may not have. Keep in mind this forum mostly draws very new people to the RC tank world and will in their minds possibly read it as "its safe to use 3s Lipos". I have seen it happen a number of time on this forum. So what I wrote was more intended as a caution to the wider reading audience.

I recently received a PM related to this thread asking about how I jump my tanks, is it safe to do and does it break things🥴🥴? I sometimes too forget who reads this forum.

[MrChef]

The real things can fly.

annnnnd thennnnnn

[MrChef]

Tongue in cheek comment.
I have perused most of the treads that have been written, and taken on board what has been said, on previous posts. This is a fun experiment to see what the speed differences will be between 2S full power, 3S, low power, and 3S full power. Not an attempt to destroy it. Most of the time I am happy with a 2S battery, plenty fast enough for an old codger like me.

Ohhhh you go with your bad self Mr. Rat! I totally look forward to your experiment, hopefully cool pics and vids and of course the obligatory results/repair posts...😉

[Meter Rat]

I caught what you were saying, but others unfortunately may not have. Keep in mind this forum mostly draws very new people to the RC tank world and will in their minds possibly read it as "its safe to use 3s Lipos". I have seen it happen a number of time on this forum. So what I wrote was more intended as a caution to the wider reading audience.

I recently received a PM related to this thread asking about how I jump my tanks, is it safe to do and does it break things🥴🥴? I sometimes too forget who reads this forum.

Point taken. I too, forget that others, less experienced than myself may be reading what I have written.

[Meter Rat]

Ohhhh you go with your bad self Mr. Rat! I totally look forward to your experiment, hopefully cool pics and vids and of course the obligatory results/repair posts...😉

We seem to be hijacking Handy Lance’s post. Sorry.

[Handy Lance]

Point taken. I too, forget that others, less experienced than myself may be reading what I have written.

We assume no responsibility for broken toys because someone reads what we do! Everything is at the readers own risk. 3s is always better if done correctly. I get stripping gears and what not, but I would apply “done correctly “ here. There’s a lot that goes into getting these heavy tanks properly setup for 3s. It took me an hour and a half to shim and regrease the trannys. 3s would’ve torn my tank apart or burned it up stock. Plus fuses are even more important at higher voltages. I do think all the functions act better now on 3s then the oem 2s battery. I know the get same voltages but it’s a crisper movement and sound now.

I work in a hobby store when I’m not building furniture. I deal with goofballs all the time. I help them, laugh at them and move on. I like helping genuine knowledge seekers, not ….”duh….. what’s the fastest ya gaht” customers.


Side note
blew a motor fuse 10a with some sucked up carpet. Replaced with 15a prob hang at 15a no more.

[Handy Lance]

We seem to be hijacking Handy Lance’s post. Sorry.

it’s on topic👍🏻

[Meter Rat]

We assume no responsibility for broken toys because someone reads what we do! Everything is at the readers own risk. 3s is always better if done correctly. I get stripping gears and what not, but I would apply “done correctly “ here. There’s a lot that goes into getting these heavy tanks properly setup for 3s. It took me an hour and a half to shim and regrease the trannys. 3s would’ve torn my tank apart or burned it up stock. Plus fuses are even more important at higher voltages. I do think all the functions act better now on 3s then the oem 2s battery. I know the get same voltages but it’s a crisper movement and sound now.

I work in a hobby store when I’m not building furniture. I deal with goofballs all the time. I help them, laugh at them and move on. I like helping genuine knowledge seekers, not ….”duh….. what’s the fastest ya gaht” customers.


Side note
blew a motor fuse 10a with some sucked up carpet. Replaced with 15a prob hang at 15a no more.

Ah! A child’s favourite question. ‘Ow fast is that go mister.
That may be so. But I would hate to think I might be partially responsible for destroying an inexperienced, or young person pride and joy. I have read a lot of information on here and on other sites. I am also an engineer, so I am able to make logical calculations. These are “toys” and if I break it, I am able to repair it, others might not. Strengthen one part, and the next weakest link will break. I didn’t just rush into this experiment, others might. Hence why I took Rubicon 99 point.
As I said I am enjoying this build and will employ some of what you have built, and lessons learned from my Challenger. I still haven’t worked out how your latching mechanism works.

[Handy Lance]

Ah! A child’s favourite question. ‘Ow fast is that go mister.
That may be so. But I would hate to think I might be partially responsible for destroying an inexperienced, or young person pride and joy. I have read a lot of information on here and on other sites. I am also an engineer, so I am able to make logical calculations. These are “toys” and if I break it, I am able to repair it, others might not. Strengthen one part, and the next weakest link will break. I didn’t just rush into this experiment, others might. Hence why I took Rubicon 99 point.
As I said I am enjoying this build and will employ some of what you have built, and lessons learned from my Challenger. I still haven’t worked out how your latching mechanism works.

ill get better pics if it helps.

It’s an adjustable (attached to another L welded to upper hull) L shape piece slotted to grab lower screw towers (preventing any lateral movement) , and another ABS piece with notches to accept the notched L tabs (described above) and attached to lower towers,sides and bottom. I used the oem screw towers on the chassis upper hull and lower as reference points, then cut them off upper as they interfere when sliding forward.
Think 2 L back to back one slides on the other

2x upper hull L attachment pieces welded to inside of upper hull (slotted on side with M4)
2x upper hull adjustable L pieces, with slots wide enough for lower towers,
attached with M4 hardware to L attachments welded to hull
2x M4 bolt/nylock combo
1x lower chassis plate to accept L tabs from upper
welded to oem towers, bottom of hull, and sides of hull

put top hull down 1/2” back from normal position . Gentle pressure down to hold top down and a firm push forward. Tabs engage lower towers and L fits under plate . Holds perfect



I apologize if I’m not making sense.

[Handy Lance]

hope this helps understand

[Meter Rat]

Thank you for the pictures. And the explanation. It now make a bit more sense.