Lithium Ion Battery Mod 300+ MAH

[LBRC]

Supplies and tools
Battery Pack
2 x 10430 lithium ion cells with tabs, or 10440’s
3/16” heat shrink for battery wires.
37mm shrink wrap
Team Losi Micro-T connector set.
Soldering Iron and solder

Chassis Mod
Rotory tool with ¼” drum sanding wheel.
½ round or rattail file.
Glue, either epoxy or CA

I recommend building at least two battery packs one 2s 7.4 volt pack for all out speed and one 2P 3.7 volt pack for extended runtimes and control, you wont be disappointed

10430 Lithium Ion cells are 10mm x 43mm’s or 10 x 44mm for 10440’s, AAA size. I recommend getting cells with tabs to keep the packs as short as possible since the ends of the pack will stick out a couple of millimeters on each side of the chassis.



When building the packs insure that the connector and wire are at least 1 ¾ inches long,

by using cells with long tabs this is easy since you just solder the wire to the tabs and use the 3/16” heat shrink to cove the wire connection and tab as it runs along the side of the battery. After soldering the connecting tabs together it doesn’t hurt to use a piece of tape to insulate them as you fold them flat. You will need to make sure your wires and tabs fit in the V-groove between the cells so that the pack with heat shrink is no more than 11mm thick and 21mm wide.

After you have your battery pack, glue and screw the battery cover permanently in place. Then use the rotor tool and file to cut out ovals exactly the size of the battery pack on each side of the battery compartment, which is why I recommend making the battery packs first, so you can insure you get a snug (not loose) fit.

I also recommend using the file when you start cutting through the metal posts since the rotary tool will heat them up enough to melt the plastic. As an easier option you can take the posts out and not screw the bottom cover on but the glue alone will not be as strong.

Once you have your holes you’re done, it’s that easy.


The great thing is that the battery packs can be changed in seconds since they slide right in and push back out.

Cheers from lbrc

Edit:
The weather cleared so I finally got in some good rough terrain, hilly, off road battery sucking tests. I managed to overheat the 7.4 volt 2s pack fairly easily in the stock car causing it to turn into a slug, however the 3.7v 600mAh 2p pack was amazing, just picture a Micro-T pulling a little road kill action on the Energizer Bunny. In the ball bearing equiped brushless car the same 7.4 volt 2s pack did not overheat under identical conditions. So the success and your enjoyment of a 7.4 volt 2s Li-Ion pack will depend heavily on your car and the driving conditions.

[Keono]

Li-Ion Cells in a AAA size? where'd you buy those? Am I just out of "the loop"? I've seen countless LI-ION batteries in flatpacks... hrm...

[LBRC]

I got the one’s I used through my work, but you can order 350mAh 10440’s from batteryspace.com I recommend spending 25 cents more per cell and going with the tab option.

I have ordered from the site several times and can vouch for batteryspace.com as far as reasonably quick delivery and overall honesty goes, it is a reputable discount battery site. The only problem is that their shipping tends to be a bit steep (UPS only) so just in case you are like me an usually opt to throw in other items to spread out the higher initial shipping cost a bit and haven’t tried their NiMH cells before a word of caution about the Powerizer’s; you get exactly what you pay for no more no less, and aside from Xmod circles mentioning the name will usually cause the experienced to groan or laugh depending on what was said. This does not mean that there is anything particularly wrong with them they are simply just cheap cells and you should not expect anything more from them than the price implies. I have bought several sets over the years when I needed large quantities of low cost cells and some of them even still work but they are not high end and consistency is not one of their strong points they vary a great deal from cell to cell.

I too have purchased from batteryspace with good interactions.

LBRC, I was wondering if you have noticed any heating issues or failure points running with the 2s pack. I've seen some videos of a 2s pack on youtube, and that thing flies. I have to imagine you'll find the weak points with it. How long have you run it with them?

[Namuna]

If LBRC has some personally tested info, I'd take that as the most reliable info...But so far I've been reading on the different Forums that the stock ESC has NO problems handling the extra juice of 2s packs ("stays cool to the touch after extended runs" being what's said...Now the motor on the other hand. )

Even on Losi's own Micro-T Gallery there's a picture of the ESC with a sticker indicating voltage operating range from 4.8v-7.2v!

[LBRC]

Yep no car problems. The only 2s failures I’ve noticed have all been with my battery packs and not the cars. The circuit boards have had no problems at all with many hours now of playing around, the other day when I was testing out the 2s pack as mentioned above

Edit:
The weather cleared so I finally got in some good rough terrain, hilly, off road battery sucking tests. I managed to overheat the 7.4 volt 2s pack fairly easily in the stock car causing it to turn into a slug, however the 3.7v 600mAh 2p pack was amazing, just picture a Micro-T pulling a little road kill action on the Energizer Bunny. In the ball bearing equiped brushless car the same 7.4 volt 2s pack did not overheat under identical conditions. So the success and your enjoyment of a 7.4 volt 2s Li-Ion pack will depend heavily on your car and the driving conditions.

I ran it so hard that I permanently shorted the PTC on one of the 10430 cells running it over and over WOT up a dirt hill intentionally trying to kill either the car or battery pack in order to see what they could take, the car won. I’ve also ran it with a 2s LiPo pack and yep that motor gets hot.

The closest thing to a problem on the car side would be that 7.4 volts is a bit hard on the motor, so I drilled a small com-drop hole in my end-bell and every now and then give it a drop with a small syringe to keep from carbon coating the com, so far it seems to be working. I did rebuild the above car to make sure the drive train was operating smoothly but other than that, the battery compartment mod, and the com hole it was out of the box stock with bushings, not ball bearings, while I was testing it that is.

[Namuna]

Wow, that's impressive! Great job Losi!

Thanks for putting the T through it's paces and letting us know your finding LBRC, that's good stuff!

Any plans on bashing a 3s around??

[LBRC]

Originally Posted by Namuna

...
Any plans on bashing a 3s around??

Nope, first it would likely fry the electronics, second there isn’t enough usable space for a 3s that didn’t use pitifully low capacity cells, and third even if 11.1 volts didn’t do a number of the electronics it certainly would make short work of the motor.

You don’t need more voltage to go faster, quit the opposite in fact. What good is speed without runtime and handling anyway, sure you could tape a bunch of batteries to the top of the car but that would just increase the load and make it top heavy. Since the Micro-T electronics run great with a 3.7 volt 2p pack it makes more since to spend the time on a motor option for that 700mAh 2p possibility, i.e. a few less turns and scrap the big magnets, a balanced BB 130 with a larger pinion, or since the stock McT motor is pretty hot anyway all that might be needed to satisfy most people is a larger pinion combined with high current batteries, for example with the below 195 mAh 4-cell pack installed the stock car is not just quicker but noticeably faster top end wise too which means that with the stock batteries the hot motor is already drawing more current than the 150’s can deliver at WOT. With the large pinion the car has just as much punch/torque as the stock pack does with the small pinion, so you could easily add a few more teeth to the pinion for a faster car with torque and runtimes comparable to using the stock battery pack with normal pinions.

Besides I already have the ability to exceed the chassis speed limitations with this McT all I need to do is up the pinion size and adjust the Mamba’s timing.

And if for some reason i wanted to use a 3s all I'd need to do is swap the Feigao 1208430S with it’s 7.4volt max rating out with something a little more robust.


BTW here are a couple of other fun battery options that also fit in the modified chasses, shown next to the AAA 2p or 2s Li-Ion pack: 4.8 volt 195 mAh 4 cell NiMH, and 6 a volt 150 mAh 5 cell.

Note: None of my experiments with 5-cell packs have been particularly successful, for example the above 195 4-cell is much faster in a stock car than the 150 5-cell, it all boils down to current delivery, upping the voltage does no good if the batteries can’t deliver the current the motor needs.

[Keono]

LBRC where did you get yuour receiver that you have in those pictures?!?!?!?!?!?! PLEASE TELL ME!!!

[LBRC]

The AM 27 on the car is just an old Novak XXL taken out of the bright orange box.

The best possible receiver in my opinion for a Micro-T is a Spektrum 2.4gig SR3500 DSM 3-channel micro, it’s so small you don’t even have to take it out of the box to fit, just file down the tops of the connectors so that they are level with the case once you put them in. The only downfall is the $80 price tag and that you need a compatible Tx module and/or radio.

I will eventually put the SR3500 at the bottom of the photo in the brushless McT but for now I want to use the same radio for both cars as I play around with different battery and motor options.

[Stompers Rule!]

Originally Posted by LBRC

The closest thing to a problem on the car side would be that 7.4 volts is a bit hard on the motor, so I drilled a small com-drop hole in my end-bell and every now and then give it a drop with a small syringe to keep from carbon coating the com, so far it seems to be working.

Hi. I'm thinking about buying one of these Micro-T's and putting a Li-Ion battery in it. But first, I have a few questions:

1. Would a couple of these 3.7v batts fit in there?
2. How does a 3.7v 2P pack work since the ESC requires 4.8v?
3. Is there a 3.7v 2P pack on batteryspace?
4. Which one of these PCB's should I use? They limit the current draw from 5v up to 9v and I don't know which would be best for a 7.2v 2c pack. What about for a 3.7v 2p pack?
5. Will you post a pic of the comm drop hole you drilled so I know where to drill mine?
6. Lastly, how often do you add drops?

Thanks for all your help!

[LBRC]

Originally Posted by Stompers Rule!

Hi. I'm thinking about buying one of these Micro-T's and putting a Li-Ion battery in it. But first, I have a few questions:

I do recommend getting a Micro-T, they are great fun and a must have for any Micro/Mini enthusiast. However I also recommend holding off on a 7.4volt lithium setup until you are absolutely sure you want one. Since I don’t know how familiar you are with lithium batteries in RC cars; I do not recommend them for anyone who is unfamiliar with them, their safe handling, and additionally their limitations.

Would a couple of these 3.7v batts fit in there?

Fit? Yes. Work? NO. The el-cheapo 170mAh LiPo you are referring to has a 2C (2 times the rated Capacity) maximum discharge rate that’s 0.34 amps max while the Micro-T motor easily draws over 2 amps. Even when used in parallel (2p) for a 3.7volt pack you are still well over 1 amp short in the way of performance and especially safety. Anything less than 210mAh with a 10C discharge is a waste of time and even then it’s not enough for a good 2s 7.4 volt pack. Basically for a 7.4 volt LiPo if it isn’t at least a 250mAh 10C forget it.

How does a 3.7v 2P pack work since the ESC requires 4.8v?

Simple, the ESC doesn’t require 4.8 volts. It works great at 3.7 volts especially with a lithium battery where that 3.7 is a nominal value the cells are charged to 4.2 volts and drain down to less than the nominal 3.7 as they discharge.

Is there a 3.7v 2P pack on batteryspace?

Don’t know I’ve never looked for one, but my guess would be no.

Which one of these PCB's should I use? They limit the current draw from 5v up to 9v and I don't know which would be best for a 7.2v 2c pack. What about for a 3.7v 2p pack?

And you plan on putting this where? Generally we don’t use this type of circuit for micro RC car applications primarily for size but also because of their internal resistance. They are use and required for cameras and such that use low end chargers. Functionally they disable the pack if the voltage drops below safe limits when discharging or above safe limits when charging, often permanently, and should not be confused with hobby type lithium battery low voltage protection circuits which temporarily turn off the pack before it is discharged below preset limits. For safety hobby grade chargers like the Duratrax Ice or ElectroFly/Great Planes Triton have better circuits installed in the charger itself instead of the pack that do much the same thing. How do you know when your car needs charging? Simple, when it slows down. With a good hobby type lithium charger the only thing you need to do/worrey about/remember to do is to turn off the car and/or unplug the pack and charge it when you are done driving.

Will you post a pic of the comm drop hole you drilled so I know where to drill mine?

http://lbspd.com/v-web/gallery/albums/album149/Hole.jpg

Lastly, how often do you add drops?

As needed, that depends on your car, motor, and driving.

[Stompers Rule!]

Originally Posted by LBRC

The el-cheapo 170mAh LiPo you are referring to has a 2C (2 times the rated Capacity) maximum discharge rate that’s 0.34 amps max while the Micro-T motor easily draws over 2 amps. Even when used in parallel (2p) for a 3.7volt pack you are still well over 1 amp short in the way of performance and especially safety. Anything less than 210mAh with a 10C discharge is a waste of time and even then it’s not enough for a good 2s 7.4 volt pack. Basically for a 7.4 volt LiPo if it isn’t at least a 250mAh 10C forget it.

LBRC, thanks for all the great info. I'm left wondering where to find 10440's that have a decent discharge current. The ones at batteryspace are 0.7a (2c) max for discharging current, even though they're 300mah. I'm thinking maybe they're hard to find or something. I know people are running the Watt-Age Battery Pack for the Micro Flyer/Rookie Lipo and having success, but I can't find the specs and it's $20 per set of 2 cells, which seems kinda pricey to me; do you know the specs and are they worth it?

Maybe I should just go with NIMH since the stock charger will charge them. Any ideas where to find cheap 1/3AAA batts and/or packs? BatterySpace doesn't seem to stock them and hasn't replied to my request concerning them. I'm bumm'd 'cuz I need to order some other things off BS and would have liked to have saved some $$$ on shipping.

[LBRC]

Funny how just a week ago “BS” had their 10440’s listed as 350 mAh and now they are 300. Interesting my receipt from the test cells I purchased clearly states 350mAh too but a close look at the cells shows that the capacity has been scratched off, hate that. They are also clearly surplus cells since if you look close you can still see the original 2005 manufacturers label even though an attempt has been make to wash it off too. Oh well what can you say they are after all from “BS” dot com, but hey they are what they are and I have never expected more from a discount battery reseller no matter what they try to imply on their webpage, and if a tad expensive their shipping and delivery is still good. Maybe they ran out of the supposed 350’s.

The 10440’s I received from BS, 350 or not, are working ok as a 2s but as I said the pack heats up and the car slows down, due to an internal safety device called a PTC that lithium ion cells have. It’s not a bad option, since with the mod this thread is/was about, I can swap out battery packs in seconds, especially with Velcro holding the body on. Unlike LiPo cells the discharge rates for lithium ion cells are not going to vary significantly.

Back to the point, the Micro-Flyer uses a 150mAh LiPo. So far the best LiPo option in my opinion for a stock chassis is a 250 10C pack made by E-Tec I believe, that can fit with work and a little chassis modification, search the net for Viperdout’s car.

As far as NiMH packs go Cheapbatterypacks.com sells Kan 160’s that fit but as yet they don’t have Micro-T connectors, OnlyBatteryPacks.com sells a Gold Peak 160 pack that comes with a Micro-T connector. The problem with both of these options is that they are only 10mAh more than the stock packs which hardly seems worth the effort, and it’s looking like the stock 150’s deliver a good deal of current for their size, so they might not even be much of an improvement at all. One thing you have to be careful about with an unmodified chassis is the 1/3 AAA designation, it is only a ball park reference so some 1/3 AAA’s like the 195 cells I use are too long to fit in an unmodified chassis, although they are well worth modifying a chassis for.

[Stompers Rule!]

Originally Posted by LBRC

The 10440’s I received from BS, 350 or not, are working ok as a 2s but as I said the pack heats up and the car slows down, due to an internal safety device called a PTC that lithium ion cells have.

What kind of run times do you get with these? How long does it take to charge them? What about using them in parallel as 3.7v 600mah?

Originally Posted by LBRC

Back to the point, the Micro-Flyer uses a 150mAh LiPo. So far the best LiPo option in my opinion for a stock chassis is a 250 10C pack made by E-Tec I believe, that can fit with work and a little chassis modification, search the net for Viperdout’s car.

I couldn't find these using Google; sorry. Besides, I'd like to order from HorizonHobby.com, BatterySpace.com, or HobbyPeople.net since I have other things to buy from them anyway and want to save on shipping, so no worries.

Originally Posted by LBRC

As far as NiMH packs go Cheapbatterypacks.com sells Kan 160’s that fit but as yet they don’t have Micro-T connectors, OnlyBatteryPacks.com sells a Gold Peak 160 pack that comes with a Micro-T connector. The problem with both of these options is that they are only 10mAh more than the stock packs which hardly seems worth the effort, and it’s looking like the stock 150’s deliver a good deal of current for their size, so they might not even be much of an improvement at all. One thing you have to be careful about with an unmodified chassis is the 1/3 AAA designation, it is only a ball park reference so some 1/3 AAA’s like the 195 cells I use are too long to fit in an unmodified chassis, although they are well worth modifying a chassis for.

Couldn't find these either, unfortunately. I'm thinking about making a lexan chassis eventually but that's pretty far down the line; I need to buy a Micro-T first!

Thanks again for all your help; don't know what I'd do without ya except spend hours Googling for answers that might not even be out there or that I might never even find.