Electronics info needed

[Jeepguy91]

I just picked up a Losi Night crawler the other night for my son. This is my first time having a Lipo battery. Was wondering if someone could give me some pointers on stuff about lipo batteries? I know they are more expensive than the normal nimh batteries so don't want to mess this one up. I also got an Onyx charger with the truck as well. Is this a good charger to use for this battery? How long does a charged battery normally last? Anything i should look out for so i don't ruin this one?

Thanks,
Ben

[Trubble]

Originally Posted by Jeepguy91

I know they are more expensive than the normal nimh batteries so don't want to mess this one up.

Three years ago they were, and the 'name brands' might still be, but......
Duratrax 5000mAh 6-cell NiMh..... $34.99
G-force 5000mAh 2S LiPo..... $18.99
even if you put in an external BEC and stepped up to a 3S,
G-force 5000mAh 3S LiPo..... $26.99
Still leaves room in the budget to buy one of THESE.

That aside, still don't want to see you bugger up a decent battery needlessly.

Originally Posted by Jeepguy91

I also got an Onyx charger with the truck as well. Is this a good charger to use for this battery?

Which Model Onyx?
I've got a 230, with an external charge-through balancer, and I love it. Works great for my smaller crawler batteries, but if I were to start buying bigger packs for the go-fasts, I'd want more amps.

Originally Posted by Jeepguy91

How long does a charged battery normally last?

No experience with worm-drive axles/gear trains, somebody else will have to take this one. Or poke around in the Losi forum and see if it's in there.

Originally Posted by Jeepguy91

Anything i should look out for so i don't ruin this one?

--Make sure your charger has a LiPo profile, and use it.
--DO NOT run your LiPo down too low, set the LVC in your speed control or get an external alarm.
--DO NOT leave anything plugged into the battery when it's not being used. Don't leave balancers or LVAs plugged in during storage.
--I advocate frequent balancing. Being that I charge through my balance taps, it's automatic for me. Some like to quick-charge and run 'em. Let your conscience be your guide.
--I also use charging sacks, and this is the first house I've ever lived in that has had a (working) fire extinguisher in it. Even when I was teaching myself to do stuff I'm not going to tell you about, still never needed either one. Got 'em if I ever do, though.
--Don't leave your battery unattended while charging.

Those basic tips should put you on the path to LiPo happiness.




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[Jeepguy91]

Wow. Guess i need to get to reading up on everything thats new in rc. Things sure have changed since i got my first electric truck some 14 or so years ago. What do these abbreviations mean, BEC, LVC.

[envious8420]

bec is the battery eliminator circuit- means the esc also powers the rest of the electronics system, without the need for a separate battery for the servo/rx.

lvc is the low voltage cutoff- keeps you from over discharging the lipo battery. over discharging will puff and ruin a lipo and also create a possible fire hazard. which can be pretty severe/ violent. usually not even enough time to allow you to remove the battery from your r/c before your r/c burns/melts to the ground.

search youtube for lipo fire. always charge and store your battery in a fire safe lipo sack or another safe method. I like to store all of mine in a military ammo can. better safe than sorry. also never puncture a lipo cell the reaction between the lithium oxygen and the foil the lipo is cased in cause the same reaction.

[k7zpj]

Here is link to a site with really good information on Lipo Batteries.
Understanding RC LiPo Batteries

It takes a while to read it but you will understand how to safely charge, use and store lipos. You will also have an understanding about the truths and myths about lipos and lipo fires.

[Johnnysplits]

+ 1 ^

[Olle P]

I'd recommend a smaller and lighter battery than the 5Ah options provided by Trubble.
~1800 mAh per half hour of runtime is my estimate. You don't want to have very long continous runs anyway, since the motor and/or worm drives need some cooling down in between.

A physically smaller and lighter battery will lower the centre of gravity, and can also be relocated to some better location than on top of the chassis. I've built a battery plate that's mounted on the upper front links on my Losi.

While you're at it, do check my advice on friction reduction for the Losis.

You will also find tons of other helpful advice in the LNC/LCC section.
(LNC = Losi Night Crawler, LCC = Losi Comp Crawler)

[Trubble]

Originally Posted by Olle P

I'd recommend a smaller and lighter battery than the 5Ah options provided by Trubble.

Agreed. I just threw those out there as a price comparison since the 5000 seems to be one of the more popular NiMhs.

That said, I run the 3s, 1300mAh LiPos in my crawlers and that's good for somewhere around 45ish minutes or so. And it's easily enough carried on top of the front axle.






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[supermoturd]

Holy crap! And all this time I've stored fully charged 1S lipos for my micro heli on a bookshelf!

Here's my question. If I only go crawling once a month, how do I safely (safe for me as well as the battery) store a lipo battery? What if I don't go crawling for 2 months or longer?

[Johnnysplits]

Originally Posted by supermoturd

Holy crap! And all this time I've stored fully charged 1S lipos for my micro heli on a bookshelf!

Here's my question. If I only go crawling once a month, how do I safely (safe for me as well as the battery) store a lipo battery? What if I don't go crawling for 2 months or longer?

Store at 50% of capacity. Your charger should have a storage charge function.

[supermoturd]

I read that on the Heli site. Also said to store in the refrigerator near and just above freezing. But do I need to remove and charge periodically? If so, how often? Or does it depend on the battery, which requires me to check the charge periodically to determine when recharge is needed?

[k7zpj]

Originally Posted by supermoturd

I read that on the Heli site. Also said to store in the refrigerator near and just above freezing. But do I need to remove and charge periodically? If so, how often? Or does it depend on the battery, which requires me to check the charge periodically to determine when recharge is needed?

I check my batteries every two months if being stored for an extended period of time. I check the battery by connecting it up to the charger and doing a lipo store charge.

[Olle P]

Checking every two months is more than necessary for LiPo, but NiMH should be topped up at least once every three months.
LiPo is okay if checked every six months, and stored in room temperature (with 15 degrees C being about optimum).

Learn more at Battery University.