evan-RCU

I want to cut out the bottom of my T-90 to use a full size LiPo and a battery cover from a M-1 or similar. has anyone designed a 3DP battery box to glue in the hull?

Crius

I've never used the battery box like that, I just put in a velcro strap so I can strap the battery to the floor of the tank.

evan-RCU

I assume you pull the top hull off to do this each time?

Looking to make more user friendly by using a "stock" battery hatch. Also since it's minimal clearance to the turret mechanics I'd like to have a "roof" to the box so wires or other things wont snag on the battery. I saw something that would work on thingieverse but can't find it now. Before I try to design one I figured I'd ask.


Also interested in if anyone has 3DP figures , water cans, duffel bags or other things.

evan-RCU

An alternative would be getting a lower hull and battery cover from another tank, say a M-1 and cutting the whole battery box area out and transplanting it. Anyone have a trashed hull?

Crius

Most guys like to make their tanks so they have a lift off top. It's just much easier to get at everything for battery changes as well as routine maintenance.

You should be able to get a stock plastic hull from AliExpress for about $15 or $20. If not, let me know, I have an old Tiger 1 hull that has the battery box with the spring-loaded cover latch.

evan-RCU

I did buy some round magnets with holes thinking about a lift off hill. Any pictures of a good way to do this? Thinking a screw with a nut and a part protruding to act as a pin into the other side.

really thinking to mod the hatch though. I’ll pm you.

bowlman

Once you take the battery box out you loose some of the stiffness of the hull and will have to add some support back in by ether adding some flat stock across the hull or figure some other way to add support or you will have flexing of the hull and could lead to tracks popping off .
Thanks
Jimmy

evan-RCU

Thanks Jimmy, I understand what you're saying. My thought was to not take the BB out but to make it bigger.

I'm new to this, having just started looking at RC tanks only 13 days ago. But I move fast, here is my current fleet. I actually got to "battle" a friend for the first time today with all three and FPV with the T-90. Had a great time.

I have bunch of 5200mAh 2S LiPo's that work great in my Leopard and M-1 and give me almost an hour of run time. The T-90 has the small battery compartment and just fits the stock 1800.
Today I did receive a 5000mAh LiIon that also fits so I think I'll be good to stay with the unmodified compartment.

jarndice

Remove the battery box cover and cut out the battery box BUT DO NOT cut out the uprights,
Reinstall the battery box cover and using "Green Putty" or whatever filler you have available close up any holes in the hull floor then flood the hull floor with epoxy resin 2 centimetres deep,
Leave to set then glue a sheet of "Velcro" to the new floor and sides of the hull,
Glue velcro to the base of the smoker and the speaker and the control board and the battery,
The battery can now be placed against the hull side with the other fittings on the new floor,
Screw Countersunk 5mm Neodymion magnets on the top of the front and rear uprights top and bottom (You will need to adjust how high the uprights need to be to get the hull and body flush),
You now have a Tank with space inside and everything both secure and placed where YOU want them to be rather than where the maker thinks they should.be.

evan-RCU

Thanks. Out of curiosity would you have a picture?

jarndice

Sorry I don't do pictures and I never have.

tankme

You can see from the pic below that I used some aluminum angle to brace the hull sides, removed the battery box completely, added the magnets to hold the top on, and filled the bottom hull with resin to stiffen it up. If you do use resin make sure EVERY hole is sealed up BEFORE pouring as the resin will find every little hole to seep out of. I used a hot glue gun to seal up all of the suspension spring holes from the inside before pouring. I then just mount the battery with some Velcro. All the components are Velcro'd in also. Makes maintenance much easier.

evan-RCU

Thanks. And also for the picture so I can see what you are say, a picture is worth a thousand words as they say and a great way to validate that what I hear is what you are saying.

You have 6, really 12 magnets, and it looks like a metal tracks, drive wheels and road wheels tank so it's 10-11lb. What magnets did you use if you remember? And I assume that not having any pins to set the top hull to the bottom isn't an issue? I assume what you do to attach the magnets is on the left in the picture. What I was thinking about with a locating pin is on the right. Or an outer tube as on the far right.

spinnetti

I don't like any lower hull openings (water) so I just seal up the bottom and mount the battery inside. I never take it out so rarely have to take the top hull off. I just have long leads with deans connectors through the back hatch for charging.

jarndice

Using the screws that come with the Tank to join the hull to the body I screw 1 magnet on the top of each of the 2 rear and each of the 2 front uprights and the same on the opposite facing struts using 10mm diameter x 2mm thick x 3mm countersunk Neodymium magnets with 1.2 kg pull,
They are available in packs of 10 from www.first4magnets.com priced at £6.12 plus postage, You have a choice of north or south magnets,
.I do not glue the magnets in place simply because the magnets will pull themselves free from the glue.

tankme

Yeah, I don't use glue on my magnets either. I do use the countersunk N52 magnets I got from https://jc-magnetics.com/Magnet-N52-...untersunk-Ring . In the pic below it shows the actual hardware used for my builds. The magnets are that far apart or else they will fly toward each other. Each magnet is 10mm in diameter by 3mm high with an M3 sized hole. Pan head (counter sunk M3 screws are preferred, but I didn't have any at the time) screws are M3 type mated to an M3 brass 5mm brass standoff since it is smaller than an M3 nut and fits in the plastic screw channels better than the M3 nut. The other countersunk wood screw is a #4x1/2" size. With six pairs of 10mm N52 neodymium magnets holding the turret together on this tank, the turret only separates when I want it to. You have to level off the bottom screw boss before mounting that magnet with the M3 screw and stand off. Then the screw boss on the top part of the hull needs to be shortened to take into account the height of the two magnets. Top is mounted using the wood screw.



You can see the brass stand offs as I used the same method on the turret.

How they look joined together.

evan-RCU

Cool thanks, as usual I am over thinking it. I have the magnets waiting and since it's snowing here today I can do this. I got N52 12 x 3mm x 4mm hole

mcovalsk

WOW!! I thought my problem was getting the Clark TK22 to work properly, but I see I underestimated the problem (it looks terrible) of battery placement. LOL

sclui

tankme One would need N & S for each attachment point since the countersink opposes each other, right? BTW, very nice mod, much better than epoxy.

evan-RCU

Tank me and others. Thanks for the inputs, magnet mod done on my M-1... Basically what others said and Tank me explained so well but instead of a machine screw into a brass insert for the bottom posts I used a plastic insert and the same sheet metal type screws as the top.

My original question was about 3D printed things and no one has really pointed me towards much in that regards, especially duffels, gas and water cans and things like that... I won't need a 3D printed battery tray as I've found a great 5000 that fits in the small battery box of the T-90.

tankme

Sorry...kinda hijacked your thread. Originally before I completely cut out the battery box in my T-72 which is the same one as the T-90 I used some 18650 based batteries. I just cut off the top of the battery box on the inside so the new 2S2P 7AH battery would fit. Eventually I wanted things mounted in different locations so I did completely remove it. These batteries have a balance plug so you can put a Li-Ion low battery indicator buzzer on them so you don't run them to low, but in my tanks they seem to run a long time. The T-90 and T-72 come with a HL 18650 based battery pack from the factory now, but it is only 2 cells wired in series. The packs I use are two cells wired in series then wired in parallel with another set of two cells doubling the pack capacity.

And yes you need both north and south for each pair of magnets so they attract each other.


Mod to the battery tray to hold the new battery.

Battery pack I use in pretty much all my tanks now.

Crius

Thingiverse has several different files for Jerry cans, both US and German.