Quark + Lipo + rookie error = low voltage failure

[2old4rc]

How'd I miss this? All my research on which lipo and charger to get, and I never knew I needed anything other than a good batt & charger . So apparently I need a low voltage alarm/cutoff when running lipo, huh? Bummer.

I put a brand-spanking new lipo into my truck, ran it for only 20 min or so, and then forgot to unplug it. A week later I went to charge it back up, and got an error message on my also-brand-new Hyperion charger. Clueless, I read up on the "low voltage" message, and vhola, I've just learned something new.

Solution? It seems I might be able to program this into my Quark ESC, if I find and dust off the ol' directions. What should I set it to, 3.0 volts???

[Charlie-III]

Minimum 3.2 volts/cell....minimum....

I usually use 3.4 volts/cell, it's a little safer.

[SMR 510RR]

Yea I agree with Charlie on this one. I like from 3.2v or above, since the ESC only sees total pack voltage and the cells may get a little unbalanced this allows for enough wiggle room to make sure you dont go below the safe voltage.

Also if you have not already put that pack in a salt water solution (search google for lipo disposal) to discharge it to make sure that it is safe.

[fred0000]

rookie move, live and learn.

never leave lipos plugged in when not in use (in fact dont leave any battery plugged into an ESC when not in use). dispose of the lipo properly and dont do it again is the best I can say, lipo cutoff set anywhere from 3.0-3.4v is fine.

lipo cutoff is not in affect when the truck is sitting there for a week with a battery plugged in.
also the power switch only shuts off the internal BEC, the ESC is still being fully powered, just no power being sent to the reciever so yes of course it will drain your battery.

(most RCer's hate switches and remove them, I suggest you do the same, its a perfect reminder to unplug the battery)

[2old4rc]

Thanks guys, I appreciate the guidance. One more question.... for anyone who knows Quark ESCs:

The directions have 3 lipo cutoff settings (lipo high, lipo normal, and manual). Which should I choose? The manual option only allows for a cutoff as high as 3.0 V per cell, which is lower than your recommended 3.2-3.4. Would the standard lipo high/lipo normal be safe enough bets to cut off the lipo prior to going below a reasonable low-V threshold?

Never though playing with an RC car would cause so many electricity theory flashbacks from Physics class.

[SuperRoo]

Lipo High or Normal are set more for battery quality. High offers more power than Normal, Normal is current limited. Both use 3.0v for cutoff.

If setting to manual then the highest voltage cutoff should be applied, so use one of the above.

My rule for all things rc these days is to use the battery connector as the on off switch and just leave the on/off switch on all the time.

[2old4rc]

Thanks SuperRoo! So is a 3.0V cutoff safe enough, or should I buy a separate cutoff that I can set to 3.2/3.4V?

[ZippoMan]

Is the lipo actually dead? Did it balloon up on you or anything? I have heard guys jump the life back into them by using NIMH setting for a few minutes to get enough juice back in the battery. I do not recommend it but I have heard others doing it and saving their lipos.

how to shock a lipo battery with out a fancy charger?

[Charlie-III]

Originally Posted by 2old4rc

Thanks SuperRoo! So is a 3.0V cutoff safe enough, or should I buy a separate cutoff that I can set to 3.2/3.4V?

As I stated before, 3.2VPC is considered "low", I use 3.4VPC to be "safer".

Originally Posted by ZippoMan

Is the lipo actually dead? Did it balloon up on you or anything? I have heard guys jump the life back into them by using NIMH setting for a few minutes to get enough juice back in the battery. I do not recommend it but I have heard others doing it and saving their lipos.

how to shock a lipo battery with out a fancy charger?

Yes, I've "zinged" packs back up in NiMH/NiCD mode so they would charge in LiPO mode. Not a great idea....definitely not to be done WITHOUT you nearby "just in case".