Finally made the jump to LiPo

[soniccj5]

This topic has been very informational. I picked up an iMax B6 charger recently, which has a built-in balancer. Is this balancer good enough, or would I need to bother purchasing a separate balancer? Any B6 owners have any tips on usage?

I was also pleasantly surprised to find it has a discharge function--not many of the under $50 chargers I looked into had the ability to discharge.

I have the SkyRC Imax B6, is that what you bought?

[Coelacanth]

I bought it from a different seller on eBay, probably the same thing:

http://cgi.ebay.ca/ws/eBayISAPI.dll?ViewItem&item=290555485625&ssPageName=STRK:MEWNX:IT

[soniccj5]

I bought it from a different seller on eBay, probably the same thing

You got a different manufacturer, but if the internals are the same, it is a great charger. It also has a nice LiPo storage feature.



Tried charger at 10amps for the first time this weekend. My battery says it can be charged at 15amps, but my charger only does a max of 10amps. Noticed the connector gets warm, so it is time to upgrade to bullets on the charger.

ED

[Coelacanth]

Here's one on the SkyRC site, it looks exactly like the one I have. If I'm not mistaken, SkyRC is only the reseller; the manufacturer is iMax.

http://www.skyrc.com/index.php?route=product/product&path=20&product_id=9

[soniccj5]

So they must have the same internals

I have the Imax b6 Ultimate.

http://www.skyrc.com/index.php?route=product/product&path=20&product_id=3

[flipwils11]

OK, got my balancer plug. Tried the battery out for the first time last night. Wow, it is so good. As others had said, the punch and power was always immediate. What I thought was pretty quick with a 13.5T motor and a 4500nimh was now a rocket.

The 8.5T motor and 4500nimh was a rocket probably doing 30mph down my street in my B3. I can't wait to try the 5000mah lipo and 8.5T!

[Rootdown4594]

i got my batteries in today. i haven't really gotten a chance to run them. they're a very tight fit in my b3 and very much lighter than my old nihm/nicd packs.

[Greebo]

Just on the subject of punch, its all about current delivery and voltage drop.
When switching my Team Car to LiPo, I put my Eagletree datalogger into the car and ran a few of my NiMH packs through it, then did the same with the LiPo. One look at the graphs from the Eagletree tell the whole story (I don't have the graphs handy any more but I could generate some new ones if there was interest).

Basically with the NiMH, when you punch the throttle, the current draw is about 30Amps and the pack voltage drops to around 6V, recovering as the car accelerates and the motor current drops.
With the LiPo, the current draw was higher AND the voltage stayed constant at around 7.8V (remember a fully charged 7.4V LiPo is actually 8.4V). Simple maths for power (current * voltage) says the LiPo is delivering a lot more power thus the punch we all notice.

The other thing this shows is that if you do fit a LiPo cutoff, make sure its disabled if you ever decide to put a NiMH pack back in otherwise it'll cut-off VERY early

[flipwils11]

Thanks for the comments on the voltage with nimh vs lipo. Again, just echoing what's been said in this thread, my son and I went out last night for some bashing and I put my lipo (only have 1, but ordered 3 more from hobbyking) in his 2wd stock Slash and the thing really hauled. By comparison I put my old standby 4500 mah lipo in my 13.5T brushless B3 and it wasn't bad, but it had no balls. Then later after my son went to bed I snuck back out in the dark with my B3 again and put the lipo back in and it was just so unbelievably different.

The question I keep asking myself is, why the hell didn't I do this sooner?

[Coelacanth]

The question I keep asking myself is, why the hell didn't I do this sooner?

Probably the same reason we all don't go 2.4GHz, brushless, updated ESCs with LiPo cutoffs, LiPo batteries & corresponding LiPo-capable chargers all at once...cost! I'm not quite there yet, and the only thing holding me back is the cost to make the transition. One LiPo battery may be cheap, but all the other stuff that's needed sure adds up.

[dangermouse]

Probably the same reason we all don't go 2.4GHz, brushless, updated ESCs with LiPo cutoffs, LiPo batteries & corresponding LiPo-capable chargers all at once...cost! I'm not quite there yet, and the only thing holding me back is the cost to make the transition. One LiPo battery may be cheap, but all the other stuff that's needed sure adds up.

Not really, it depends on your application. If you aren't into competitive racing you don't have to spend a fortune.

My Lunchbox gets up to 45 minute runtimes, and is pretty mental with a cheap setup:

Ezrun 35a esc, $25
Ezrun 9T 4300kv motor, $30
Programming card, $6
Turnigy 2cell 20c 5000mah Hardcase lipos, $20 each
Flysky 2 channel 2.4Ghz radio, $30
HobbyKing ECO6-10 200W 10A 6S Bal/Dis/Cyc Charger, $35

You could easily spend more than all of that on just a "brand name" brushless esc.

[flipwils11]

Yep, I'd have to agree. I've spent far more on shelfer vintage builds.

I got a Duratrax onyx lipo charger (about $50 via Tower's scratch and dent section), $20 for the balancer, $20 for the lipo sack, and then I bought used gear off rctech.net ($120 for 2 LRP Sphere Competition ESC's in very good shape with all boxes and manuals and $90 for two Speed Passion V3 brushless motors).

I didn't have to get two ESC's obviously and two motors so that would take the cost down a lot. Then of course the $20-25 Hobbyking lipos in the 5000-5300 mah range.

My Futaba 3pm-x 2.4ghz radio is more than many need, but I got it used on this site from bearickster for $90. I like that it is programmable for multiple models so I only need one radio and can put a receiver in each car.

[losiXXXman]

Probably the same reason we all don't go 2.4GHz, brushless, updated ESCs with LiPo cutoffs, LiPo batteries & corresponding LiPo-capable chargers all at once...cost! I'm not quite there yet, and the only thing holding me back is the cost to make the transition. One LiPo battery may be cheap, but all the other stuff that's needed sure adds up.

Not really, it depends on your application. If you aren't into competitive racing you don't have to spend a fortune.

My Lunchbox gets up to 45 minute runtimes, and is pretty mental with a cheap setup:

Ezrun 35a esc, $25
Ezrun 9T 4300kv motor, $30
Programming card, $6
Turnigy 2cell 20c 5000mah Hardcase lipos, $20 each
Flysky 2 channel 2.4Ghz radio, $30
HobbyKing ECO6-10 200W 10A 6S Bal/Dis/Cyc Charger, $35

You could easily spend more than all of that on just a "brand name" brushless esc.

I've enjoyed reading this thread, now I;m boomarking it for when I have some $$. I have one of the reedy xp brushless setups, but I want to go Lipo too. THe outlay I was thinking would be well over $100 for only 2 packs and a charger. Looks like I could do it for $75 with this !!

[losiXXXman]

So, i've got my first lipo and I'm experiencing some issues. I think the battery is seriously out of balance, so I'm trying to balance charge it... how long might a slow balance take at 1s on a 5000 battery thats fully discharged? I've heard that a lot of guys don't balance, as it takes a lot longer, and so my first couple cycles on the battery, I didn't balance. I'm clueless on this whole Lipo thing, so thanks for any advice...

[CamplinP]

Time depends on many factors such as how much current your charger will put out. Most batteries now a days can take a 2c charge without issues if the charger can do it. The higher the battery rating, the charge requirements also go up. To charge a 6000mah at 2c takes more than most entry level chargers can do especially if it is run off ac power. If the cells are way out of balance it can take quite a while to equal them out as the balancers use very low current. A balance charge does not take any longer unless you have a pack out of balance. I balance every time. You can destroy a battery quickly if it is way out of balance as the cutoff on the esc only sees total voltage. If one cell is severely low it may run well below 3 volts before the esc commands a cutoff.