The basic about Heng Long RC tank battery packs

[keilau]

My first magnetization project for the HL tank is a complete failure. I picked the Pershing as my first experiment because it had 7 attachment points. I choose the rear center and 2 middle forward for initial installation. Mechanically, it worked perfectly. The tank closed tight with perfect alignment. When I turned it on, I first noticed the engine sound to be strange. It fired up (RC link) ok. Then, the head light started flashing. When I ran the tank, it moved slowly and the turns were intermittent. Something is NOT right. And I have a suspect.

The right magnet is very close to the speaker. Both magnets are too close to the 6.0S MFU.

I removed both of these magnets (upper and lower), but left the rear center one in place. I close the tank and it runs normally. I am greatly relieved. No permanent magnetization of the MFU!

Some of you may remember that this 2005 HL Pershing has undergone a series of upgrades. I removed the original speaker to make room for the MFU at the tank front. A new smaller speaker was put to the middle side.

Now, feeling confident about installing the magnets, I plan to do it on the Leopard 2A6, T34 and Sherman where I do not expect the same problem as the Pershing.

[keilau]

I had a small cylindrical piece of plastic I shoved up the post from the bottom that the screw from the top bit into. They were made from model airplane push rods.

My retired engineering brain just does not work very well. The creativity has left me since retirement. Thank you very much for the tip.

[Evan D]

I had a small cylindrical piece of plastic I shoved up the post from the bottom that the screw from the top bit into. They were made from model airplane push rods.

[keilau]

I only removed the "rim" from the bottom post. The top post was shortened to make room for both magnets.

I have been looking at my Pershing for 3 days and still couldn't figure out a good way to attach the magnet to the lower post except using CA glue. The hole on the magnet is for M3 screw which is too small for the pre-drilled hole on the bottom post. The long bottom post also exclude the use of machine screw and nut. Your tip on this?

[tank_me]

I only removed the "rim" from the bottom post. The top post was shortened to make room for both magnets.

[keilau]

You can see from the pic mine are completely flush fitting with each other once installed. In the second pic it shows the lip on the bottom that gets removed (says "make flat").

It sounds like that you do not remove any material of the top post. The magnets total 6 mm can flush fit with each other when the bottom post is made flat?

[tank_me]

Thank you for sharing. Very, very helpful information. I assume that the counter sink part will face each other so I need half in N pole and half in S pole. 25 pieces of each kind are $30 total with free shipping. Can you confirm that. (The polarity part.)

I found similar neodymium magnet at Amazon for much cheaper. Not knowing how good they are, I decide to get them from your supplier. I know that those magnet you got work very well.

As others have said, yes the countersunk heads of the screws then mate up with each other. I bought mine from JC in bulk (like 50 of each pole north and south) because they get cheaper the more you buy and I knew I would use them on a bunch of tanks. That purchase has magnetized the Bulldog (body and turret), Pershing (body and turret), IS-2 (turret only), T34/85 turret, Hooben ZTZ-99A (body and turret), HL ZTZ-99 (body and turret), and the T-72 turret so far. I still have some left. Can you get away with using less magnets than I do? I'm sure you could, but I like to make sure I have solid connections. Most of my tanks are pretty heavy and I can lift the tank by the magnetized upper hull without them separating. The closer and flatter the magnets fit together, the stronger they hold. I like connecting them with screws rather than CA glue or epoxy so that I can remove them if one breaks and they don't come off during use. I have some other magnets that are epoxied or used CA and it seems there are a few of them I'm always having to reattach. I only shorten the upper screw boss and the great thing is that if you accidentally cut off too much, you can install a washer under the magnet to fix it.

You can see from the pic mine are completely flush fitting with each other once installed. In the second pic it shows the lip on the bottom that gets removed (says "make flat").

[Evan D]

Sorry, eBay... 5-100 N52 Super Strong Block Round Hole Hook Fridge Rare Earth Neodymium Magnets | eBay

Whose magnet did you get? I am getting the JC-Magnetics one for sure and they are not expensive. I am curious about how an Amazon seller's will compare to them in strength. Yours is a good candidate for comparison since it works for you.

[keilau]

I recommend K&J Magnetics; great selection, quick shipping, good prices. ick your size and quantity, none of the "assortment packs".

Thanks. I already ordered from the JC Magnetics. Both JC Magnetics and K&J Magnetics identify their strong N52 magnet. On Amazon, it is a jungle out there. Seller won't tell buyer what their magnet are.

[SoCalBobS]

I recommend K&J Magnetics; great selection, quick shipping, good prices. ick your size and quantity, none of the "assortment packs".

[keilau]

Yes to half N half S. I got mine from Amazon and they work perfectly. BUT... they were supposed to be half N and half S and they gave me more of one than the other...

Whose magnet did you get? I am getting the JC-Magnetics one for sure and they are not expensive. I am curious about how an Amazon seller's will compare to them in strength. Yours is a good candidate for comparison since it works for you.

[Evan D]

Yes to half N half S. I got mine from Amazon and they work perfectly. BUT... they were supposed to be half N and half S and they gave me more of one than the other...

[keilau]

I used N52 rated magnets which are very strong. 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 screws (countersunk M3s would work better) are M3 type mated to an M3 brass 5mm standoff since it is smaller than an M3 nut and fits in the plastic screw channels where a regular M3 nut would not. The other countersunk wood screw is a #4x1/2" size. The top screw bosses have to be cut down to allow for the magnets. The bottoms don't, but I do remove the lip from the edge using a nippers.

With all those 10mm N52 neodymium magnets holding the hull on, it only separates when I want it to. I do the same treatment to the turret. You can see from the turret bottom pic how the brass standoff is used as a nut. Since they are countersunk magnets you need to buy a north and a south type for them to stick together:

https://jc-magnetics.com/Magnet-N52-...scription=true

Thank you for sharing. Very, very helpful information. I assume that the counter sink part will face each other so I need half in N pole and half in S pole. 25 pieces of each kind are $30 total with free shipping. Can you confirm that. (The polarity part.)

I found similar neodymium magnet at Amazon for much cheaper. Not knowing how good they are, I decide to get them from your supplier. I know that those magnet you got work very well.

[tank_me]

I used N52 rated magnets which are very strong. 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 screws (countersunk M3s would work better) are M3 type mated to an M3 brass 5mm standoff since it is smaller than an M3 nut and fits in the plastic screw channels where a regular M3 nut would not. The other countersunk wood screw is a #4x1/2" size. The top screw bosses have to be cut down to allow for the magnets. The bottoms don't, but I do remove the lip from the edge using a nippers.

With all those 10mm N52 neodymium magnets holding the hull on, it only separates when I want it to. I do the same treatment to the turret. You can see from the turret bottom pic how the brass standoff is used as a nut. Since they are countersunk magnets you need to buy a north and a south type for them to stick together:

https://jc-magnetics.com/Magnet-N52-...scription=true

[keilau]

Nope. Velcro'd to the bottom of the tank on the inside where ever I want since the battery box is gone. The tank top is connected using magnets. This is an example (my HL ZTZ-99) of a battery box removed resin poured bottom hull with magnets installed on the posts that hold the tank together and the battery mounted in the front to offset the weight in the back. The second pic shows where all the magnets were installed. I always remove batteries to recharge my tanks.

Very interested. What do I need to know to successfully implement the magnetic attachment? The type of magnet and how to mount them on the post? Are there any detailed link or youtube upload?

[tank_me]

Confused! Do you mean you Velcro the battery under the bottom of the tank? I cannot see enough ground clearance there. If the battery is inside the tank, how do you recharge it?

Nope. Velcro'd to the bottom of the tank on the inside where ever I want since the battery box is gone. The tank top is connected using magnets. This is an example (my HL ZTZ-99) of a battery box removed resin poured bottom hull with magnets installed on the posts that hold the tank together and the battery mounted in the front to offset the weight in the back. The second pic shows where all the magnets were installed. I always remove batteries to recharge my tanks.

[Rubicon99]

The 7.0 MFU seems to be pretty smart as it didn't take either of my 3s LiPOs too far down. It cut off at much higher voltages than yours did on a Li-Ion pack. I don't, but I have spitballed a mental doodle about modifying the battery tray to accept loose 18650 cells. Or even 21700s. I can readily get either cell at my local vape shop in good quality, good capacity.
With how cheap they are I'd just retire it if I were you. I have a similar problem with my engine starter for my nitro planes; it's just a big ol' brushed DC motor with a switch in the hot line. No electronics whatsoever. I use 3s2200 LiPOs on it because it needs the punch they provide and on occasion have run one way low. Nickel Trickel revivals seldom last more than a few charge cycles before they start to puff up.

My only qualm about using a LiPO in my tanks is that it's overkill for the demands they put on them. I'll never use nickel though. I have 100% obsoleted all nickel batteries out of my hobby; I don't even use that chemistry to light my glow plugs anymore.

I do all forms of RC, not just tanks, and in doing so I've found myself one of the four flight instructors at my local RC aeromodelling club. You don't have a choice with aircraft. Nickel batteries are too heavy and too weak for flying, LiFE flies as receiver power for fuel burners, and Li-Ion can't supply the current demands. It's....not difficult to teach a total newbie how to handle unprotected lithium batteries without burning their house down.



They don't have a choice these days. Heng Long is including a 2s1800 Li-Ion pack in their tanks now, alongside one of those god awful USB balance lead chargers. And it's not like it's difficult to teach newbies how to handle Lithium batteries without burning their house down. It isn't some mystical long-lost art that only 20+ year RC veterans who's houses smell of castor oil and look like hobby shops know. It's pretty simple really.

* Never over-discharge
* Never over-charge
* Store at half charge if not being used for >2 weeks
* ALWAYS balance charge on a smart charger set to the correct lithium profile
* Charge in a fireproof location.

There. That's it. That's all they need to know. So rather than fearmongering and trying to promote terrible, obsolete, and frustrating battery chemistries, how about just educating newbies on proper lithium battery care so they can enjoy the objectively better in every way performance that comes right there in the box when they buy their new tank?

I've seen the same arguments you put forth when it comes to monster trucks and foam airplanes and it's always countered by 'well just teach them then'. It's not even an option with the aircraft because NiMHs are just too heavy to fly.....and as I'm one of the flight instructors for my local club I'm often teaching total novices who've never run anything more advanced than a crappy WalMart toy grade how to run hobby grade electronics. It legit takes about 15-20 minutes to do it.



You get far better results just practicing driving the thing than you ever will fiddlefarting with battery voltages, especially with such an inferior chemistry as NiMH and its terrible discharge curve. Was half the reason I took my KV-1 to the local park yesterday after work; just get some time on the sticks driving the thing. The more I drive it the better I get at making it do what I want it to do.

The next biggest upgrade would be radio. I'll grant the radio Heng Long includes is useable...hell it's better quality than what Traxxas includes with 100MPH supercar RTRs shockingly enough...but it leaves a lot to be desired. Maybe I'm spoiled by all the Futaba radios hanging on my wall...4YF student box, 6J, 10J, 16IZ...but I could see a LOT of improvement in performance of one of these tanks by ditching the Heng Long electronics entirely and moving my tanks to my 16IZ. Indeed, that is a future plan for my KV-1E alongside any future tanks I buy. Clark control board, Futaba S-FHSS receiver.

Next upgrade is battery capacity. The included pack is pretty good, performance wise....driving it I can't really tell where the remaining capacity is which means a nice and flat discharge curve as one expects from a Lithium battery...but 1800mAh is pretty pathetic and that tiny little pair of 18650s leaves a TON of unused space in the battery tray.

HL switching to Li-Ion had simply to do with economics and supply then achieving better running performance or ease of use. It also has lead to a higher battery failure rate and warranty claims that are still continuing. In fact HL is considering stopping supplying batteries with their tanks do to these and other issues. Recently several HL tanks ordered did not even come with batteries and had addendums in the instructions manuals regarding batteries. This would seem to indicate that HL might have started deleting the once included battery.

Now it is clear you don’t know me, thats ok and what I have done in the hobby and RC tank industry. So I am going to be little arrogant about it here for the moment. I know 1/16 rc tanks not just HL better then the vast majority of people here and can only sit back and be entertained at this point by what is being written on this thread and others threads of recent by what is to me RC tank beginners. All making the same mistake that have been being made for years by others (myself included) and ending up with the same mediocre results over and over and over. It’s only when stepping away from the pack that real gains are made. Sometimes this means taking a step back to take three steps forward. New is not always best.

So believe what you like about batteries for RC tanks and be happy with the overall mediocrity results that come from a one size fits all way of thinking that new is best. Not saying Lipos and Li-Ion aren’t good batteries, just that they are not as good as NiMH for tuning a tanks performance and getting the most out of the basic HL or Tamiya control systems.

[Evan D]

I’m sure inside. Many use magnets to make removing the top easier.

[keilau]

I don't care that they don't fit in the stock battery box as I normally cut the battery box out and pour resin in the bottom of my chassis to stiffen it up after removing the battery box. I then use velcro on the battery and on the bottom of the tank to hold them in place.

Confused! Do you mean you Velcro the battery under the bottom of the tank? I cannot see enough ground clearance there. If the battery is inside the tank, how do you recharge it?

[JennyC6]

Very useful information. I have not tested my HL 7.0 LVC yet. Last week, I found out that the 6.0S LVC tripped at 6.2 volt when the tank is on flash mode with a Li-Ion pack.

The 7.0 MFU seems to be pretty smart as it didn't take either of my 3s LiPOs too far down. It cut off at much higher voltages than yours did on a Li-Ion pack.

I use only DIY Li-Ion packs with the HL tanks.

I don't, but I have spitballed a mental doodle about modifying the battery tray to accept loose 18650 cells. Or even 21700s. I can readily get either cell at my local vape shop in good quality, good capacity.

I accidentally fully discharged the 2S2200 on an older MCU. It was dead. I revived it using trigger charge to holding 1700 mAh. I am not sure how long it can last.

With how cheap they are I'd just retire it if I were you. I have a similar problem with my engine starter for my nitro planes; it's just a big ol' brushed DC motor with a switch in the hot line. No electronics whatsoever. I use 3s2200 LiPOs on it because it needs the punch they provide and on occasion have run one way low. Nickel Trickel revivals seldom last more than a few charge cycles before they start to puff up.

I feel more secure with the Li-Ion packs. Don't use NiMH anymore due to its nonlinear discharge curve.

My only qualm about using a LiPO in my tanks is that it's overkill for the demands they put on them. I'll never use nickel though. I have 100% obsoleted all nickel batteries out of my hobby; I don't even use that chemistry to light my glow plugs anymore.

I do all forms of RC, not just tanks, and in doing so I've found myself one of the four flight instructors at my local RC aeromodelling club. You don't have a choice with aircraft. Nickel batteries are too heavy and too weak for flying, LiFE flies as receiver power for fuel burners, and Li-Ion can't supply the current demands. It's....not difficult to teach a total newbie how to handle unprotected lithium batteries without burning their house down.

The issues most are missing here is that the vast majority of those buying HL tanks have little to NO RC EXPERIENCE and telling them to use Lipos is not good advice. Lipos and Li-ion batteries are best left to those with moderate to advanced RC skills. Hence why I only recommend NiMH batteries, I have to assume from experience that most readers are relatively new to RC. NiMH are the safest and easiest for a new to RC person to handle and abuse. As there experience level grows then they can branch out should they find the need to.

They don't have a choice these days. Heng Long is including a 2s1800 Li-Ion pack in their tanks now, alongside one of those god awful USB balance lead chargers. And it's not like it's difficult to teach newbies how to handle Lithium batteries without burning their house down. It isn't some mystical long-lost art that only 20+ year RC veterans who's houses smell of castor oil and look like hobby shops know. It's pretty simple really.

* Never over-discharge
* Never over-charge
* Store at half charge if not being used for >2 weeks
* ALWAYS balance charge on a smart charger set to the correct lithium profile
* Charge in a fireproof location.

There. That's it. That's all they need to know. So rather than fearmongering and trying to promote terrible, obsolete, and frustrating battery chemistries, how about just educating newbies on proper lithium battery care so they can enjoy the objectively better in every way performance that comes right there in the box when they buy their new tank?

I've seen the same arguments you put forth when it comes to monster trucks and foam airplanes and it's always countered by 'well just teach them then'. It's not even an option with the aircraft because NiMHs are just too heavy to fly.....and as I'm one of the flight instructors for my local club I'm often teaching total novices who've never run anything more advanced than a crappy WalMart toy grade how to run hobby grade electronics. It legit takes about 15-20 minutes to do it.

I hear often “Hey Rubicon why does your tank run so much better then mine when they are set up similar”. Because I run a tune of battery to tank to optimize handling and performance. NiMH being available in more voltage options (7.2 / 8.4 / 9.6) have a few advantages with the 6.0-7.1 HL MFUs (and with Tamiya DMD/MFUs) that the others do not. These advantages come into play once a given level of understanding of how to set up a tank (overall weight, weight balance, metal suspension, track type and patterns , road wheels, motors and gearboxes ...) for achieving smooth performance (fast and slow) and handling (turning/climbing) come into play. Having the right voltage range, not to much, not to little makes the difference between a good handling tank and a great handling tank. NiMHs simply are superior for tuning/making great handling tanks

You get far better results just practicing driving the thing than you ever will fiddlefarting with battery voltages, especially with such an inferior chemistry as NiMH and its terrible discharge curve. Was half the reason I took my KV-1 to the local park yesterday after work; just get some time on the sticks driving the thing. The more I drive it the better I get at making it do what I want it to do.

The next biggest upgrade would be radio. I'll grant the radio Heng Long includes is useable...hell it's better quality than what Traxxas includes with 100MPH supercar RTRs shockingly enough...but it leaves a lot to be desired. Maybe I'm spoiled by all the Futaba radios hanging on my wall...4YF student box, 6J, 10J, 16IZ...but I could see a LOT of improvement in performance of one of these tanks by ditching the Heng Long electronics entirely and moving my tanks to my 16IZ. Indeed, that is a future plan for my KV-1E alongside any future tanks I buy. Clark control board, Futaba S-FHSS receiver.

Next upgrade is battery capacity. The included pack is pretty good, performance wise....driving it I can't really tell where the remaining capacity is which means a nice and flat discharge curve as one expects from a Lithium battery...but 1800mAh is pretty pathetic and that tiny little pair of 18650s leaves a TON of unused space in the battery tray.