jcr

So I have an older ESC (LRP V7.1). I want to start looking to using Lipo but don't really have the money to buy a new ESC (after buying charger and batteries).

Looks like to use Lipo I would need an ESC that will cut off or warn me about battery voltage being too low. What solutions I have so that I can still use an old ESC with Lipo? I believe Novak makes one and you can also get the Lipo alarm, which one do you guys recommend? Is the old battery voltage the only thing I need to look out for (in terms of using it, not charging)?

Or, what's a inexpensive ESC that has the lipo cut off built in?

Raman

iTrader: (94)

I have used the Novak Lipo cut off, it works pretty good. You wire on end the battery terminal, esc plugs into it and you plug the cut off into receiver.

When you hit low voltage.. You'll notice motor will cut off and on signalling you've reached low voltage.

Entry level esc's with Lipo cut off are around $100... These are brushless... I assume that's what you're looking for. Keep your eyes on the for sale section, I picked up a used novak havoc for $50... the novak lipo cutt off is $20 to $25!

lookieaefanboi

iTrader: (39)

One important thing to remember is that you will kill a pack if it goes below 6 volts. Therefore always put at least half a charge back into your lipos after use as they continue to slowly discharge even when not in use. If you run a pack down to cutoff then dont recharge it can still drop below 6v. Another good practice is to know how long you will get out of a pack and run it a few minutes less. LVC or low voltage cutoff is a safety measure and it not a good idea to run until it kicks in as one day it may not work. Always store your lipos at 50% charge or 7.2v, in a cool environment and dont over discharge. Your lipos will last a long time that way

Duster_360

iTrader: (21)

The novak smart stop will protect teh lipo since it interrupts power at the lvc. With an alarm, you run risk of not noticing the flashing light or hearing the alarm. The alarms are far easier to install and transfer from lipo to lipo easily. The Smart stop is pretty much permanent and also more expensive.

If you're running by yourself, alarm might be an alternative, but if you're in a group or racing, alarm may not be noticed. Smart stop is less risky and would be my recommendation.

Thats the way I went when I started running lipo on my Emaxx - I installed a Smart stop.

Toh WL

iTrader: (6)

I aware there are ppl using LiPo for the Tamiya TEU-101BK Esc for mini cooper. What they did was when the car starts to lose punch. Just stop it & manually collect it. But this you need good judgement cause your excitement does cost you.

jcr

hmm.. thanks for the info.

The Novak Smart Stop still seems to be the better choice. But only problem is that it is not transferable between cars......

anyone used the alarm before in a group racing? Then again a group race normally is a lot shorter than the run time of a Lipo. Actually do you get longer run time with Lipo if you compare it to NiMH with the same capacity?

Duster_360

iTrader: (21)

Yes, lipo will give you 25-30% more run time. If you're racing, I wouldn't depend on an alarm. Your best bet there may be to run some timed practices (making sure they are short enough not to approach low voltage) and then recharge the lipo and calculate a mah/min of run time. That should provide a guideline on what run time should be safe even allowing for an ample safety cushion.

I forgot that I've seen smart stop installed using deans microplugs so it can be unplugged and xfered between cars. It takes a little work to do it, but not impossible. Makes it about as involved as moving a rcvr between cars.

jcr

aren't most races around 5-10min long? Pretty sure LiPo can last that time. Endurance race would be a diferent story.... Lipo can me charged without discharging right?

interesting.. i'll keep the micro deans idea in the bak of my head... does the novak smart stop require an extra channel on the receiver?

Duster_360

iTrader: (21)

Lipo can be 'topped off '- no need to discharge like with NiMh. I don't see where you'd have a prob with those kinds of run times unless you're running a really small capacity lipo.

The Smart stop is plugged inbetween the esc and rx and has its pos and neg attached to the lipo pos and neg (where you'd use the micro plugs), so no, it doesn't use an extra channel on the rcvr.

Team Ash

iTrader: (22)

I had a LRP 7.1 with lipo batteries. I used a Novak smart stop with it and it was great. I would never have used lipo without it (not worth the risk). I used plugs so I could transfer the smart stop between cars. I had very short leads soldered to the + and - power terminals on the esc with mini corrally type plugs on them to plug the smart stop to.

Terry

jcr

but if I go back to using NiMH it means I need to unplug the Smart Stop?

Duster_360

iTrader: (21)

Absolutely! NiMh has far more voltage drop than lipo and you'd be lucky to get a few min running with NiMh before teh smart stop would trigger and it would keep triggering to the point you couldn't get much running.


NiMh is run with no voltage cutoff. Even escs that let you run both tell you to deactivate any lvc when running NiMh.

jcr

hmm.. then the smart stop might be a slight hassle because my transition to Lipo will still be Lipo and NiMH...

Duster_360

iTrader: (21)

If you put the mini-plugs on the batt leads and the smart stop, it should take maybe 30sec to unplug the smart stop and plug the esc back in.

If thats going to be too much of an inconvience, look at one of the alarms and just make sure you place warning light somewhere on the car you always look at. These usually plug into the balance connection on the lipo and are easier to use in that regard. The downside is this puts lipo protection mostly on you to notice and recognize the warning.