The LiPo's I am using

[TheSteve]

I have tried two different LiPo packs in my Micro-T

The first is a 2S 160mah pack that easily fits in the stock battery compartment. It warms up a little with both the stock motor and a brushless motor. I believe the cells are rated at 7C which is a little low for the stock motor but not too bad with the Feigao 5250kv brushless.
This pack was purchased assembled at a local hobbyshop.


The second is a 2S 250mah pack that will fit in the stock battery compartment as well, it is a little tight though. I found it fit in a little better by shaving down the plastic around the edges of the metal posts that the battery latch screws use. The plastic really isn't required so it makes no difference removing it.
This cells are rated at 10C continuous and 20C pulse and are made by Fullriver. I have a discharge graph of these cells at 4 amps and they hold voltage just fine and still provide the full 250mah of rated capacity. At a 1 amp discharge rate to 6 volts I drained 270mah out of a brand new pack.
These cells were purchased from a website in the UK and I assembled them myself, careful assembly is required to ensure they will fit in the stock battery compartment.
Anyone thinking of buying these cells please only do so if you are familiar with Lithium Polymer cells. The tabs on cells this small are very delicate and you are putting the cells in a very small space!
This pack shows very little signs of heating with the stock brushed motor or my Feigao brushless, they can take the current drain with no problems or voltage sag. In fact battery life is so good with my Feigao brushless I haven't yet fully drained them, I get tired of driving before it happens and I am pushing the truck as hard as I possibly can. My rear tires are nearly bald.

Summary:

Stock pack - 4.8 volts @ 150mah, total power: 0.72 watts, weight: 18 grams, size: 32.3x20.8x11.3mm

160Mah LiPo - 7.4 volts @ 160mah, total power: 1.184 watts, weight: 10 grams, size: 35x20.1x9.02mm

250mah LiPo - 7.4 volts @ 250mah, total power: 1.85 watts, weight: 14 grams, size:34.3x21.1x11.37mm

The clear winner is the last pack, weighs less then the stock nimh pack, still fits in the stock battery compartment with careful assembly and has a whopping 2.5 times the original batteries total power.

For those interested the 250mah cells can be purchased for $7.25 USD each here: http://www.ekmpowershop2.com/ekmps/shops/indoorflyer/index.asp

Here are two pictures. First is the 160mah pack, 250mah pack and stock nimh pack. Second picture is the 250mah pack installed in my truck.

[m18_racer]

very nice,. there is a new thread where u can post reviews. u can post this there as well. way to go Steve, udaman!

[alfred]

Maybe this will clear everything up with the battery pack for the M T..........im going to also put a copy of this in the review section and make this a sticky.....the one in the review section will be closed though so the members will have to post here.

Get it got it done.......:p :D

[mugmug]

>>>> Qusetion for the lipo people<<<<


when running these lipos in the micro T how do you know when to stop before ruining the battery by dropping the voltage too low??? I know the esc does not have a cut off for that.

[TheSteve]

In my case its easy, I am using a Mamba25 which has LiPo cutoff.

Without a proper LVC I'd use a timer or stop running as soon as you notice a lack of power.

[m18_racer]

get a LIPOSHIELD it has a soft cutoff at 3.0 volts/cell and costs around 20 dollars.

[Lostinturn3]

can you run the 250mah lipo w/ the stock esc/motor?

[mugmug]

Do you know who carries/makes the liposheild? It's kinda hard to find.

yet another piece of electronics we have to squeeze on that chasis. i think for me the final solution will be a different body with more vertical space as I'm not a fan of decasing any of the electronics. for now i ordered a womp womp 1/32 scale vw bug body which apparently fits with mild creative trimming. Hope that will have more space.

http://www.shopatron.com/product/product_id=PAR00875C/137.0.6083.11028.0.0.0

By the way I heard it through the grape vine that one of the mini z aftermarket outfits will be coming out with a body that will cover the wheels all together for a sedan look. i hope they go for a Rally type feel.

(i think we need to create a micro-t body tread too)

[alfred]

Nice lid....do you know what color scheme you plan on going with.......:D As for the thread we will have to see about it.....right now its not at the top of the list.

[m18_racer]

Do you know who carries/makes the liposheild? It's kinda hard to find.

yet another piece of electronics we have to squeeze on that chasis. i think for me the final solution will be a different body with more vertical space as I'm not a fan of decasing any of the electronics. for now i ordered a womp womp 1/32 scale vw bug body which apparently fits with mild creative trimming. Hope that will have more space.

http://www.shopatron.com/product/product_id=PAR00875C/137.0.6083.11028.0.0.0

By the way I heard it through the grape vine that one of the mini z aftermarket outfits will be coming out with a body that will cover the wheels all together for a sedan look. i hope they go for a Rally type feel.

(i think we need to create a micro-t body tread too)

i think novak either makes it and if not i know they do make one.. and i know that helihobby has lipo shields... ill post some links in a sec..

[m18_racer]

here you go:

http://www.dimensionengineering.com/LipoShield.htm

http://teamnovak.com/products/lipo_cutoff_module/index.html

[mugmug]

m18_Racer
Hey thanks for the links. The Dimension brand would be the way to go which i hadn't seen before. it seems to be as tiny as can be. I knew about novak's lipo cut-off but I also knew it was way too big for the micro t.

[mugmug]

TheSteve,

I'd really would like to buy one of those 250 mah lipos you put together.Payment can be through paypal.

[TheSteve]

Not really planning on selling them at this time. I only bought 4 cells so I could make 2 packs.

[Ckoz5.0]

hell, I'd buy one from you, too. I ruined my first pack somehow. My mamba 25 cutoff was set correctly, but I left the battery connected and the mamba power switch off, yet the batt discharged to 2.3 volts. Now my charger faults out and will not attempt to charge it.

I cant find another built pack anywhere.

Are there any step by step instructions out there to build your own pack?

[TheSteve]

The Mamba draws power even if the power switch is off(this is why they shouldn't include a power switch at all)
Anytime you have a LiPo powered vehicle you need to disconnect power when you're done using it, on/off switch or not. Its the only way to ensure you won't overdischarge the cells and for safety(we're using tiny LiPo's here, but imagine the larger ones in 10th scale etc)

I changed my second 2S pack to a 2P pack for a friend. He is now running the stock electronics with a 500mah pack and loves it. To say the runtime has improved is an understatement .

I also slapped the larger Fiegao 5800kv motor in my Micro-T last night and drove it today, what a blast! Still got killer runtime and its even faster then the 5250 smaller motor. I am also running 300mah Fullriver cells now, you do need to mod the stock chassis for them though as they are thicker.
Now I would like to change to 3S packs.

As for building the packs, well you really should have some building experience because of how tight the space is in the Micro-T with the 250mah cells. I also highly recommend using Kapton(polymide) tape to insulate everything - its the reddish brown tape you see on lots of LiPo's. Its very strong and is burnproof.
When soldering use a small iron with low heat, pre-tin all wires with solder so they stick instantly, pre-tin the tabs on the LiPo's as well, this will keep the heat needed to solder on the tabs itself as low as possible and prevent cell seal damage. Also bend the tabs as little as possible, if you go back and forth they will snap off.
Then finish the pack off with some thin shrink wrap.