lipo trouble

[Romelio]

ok this isnt about semis but i have a crawler that runs lipos ive never used lipo but it doesnt seem too bad. but im having a problem. the truck can only take a 2 cell lipo (7.4v) which i have. but when i run the truck it only runs for about 2-3 mins and shuts down. it seems like a voltage cut out which should be 6v.. but when i connected the battery back up to my charger it displayed that the battery still had plenty of power left in both cells. i dont know whats up. im not sure if there is a way to change the voltage cut off or what.. but its not too fun only being able to run my truck for 2 mins... the kit is the night crawler RTR and the charger is multipro intelligent balance charger. the battery came free with the kit. thanks for your helps!

truck-http://www.horizonhobby.com/Products/Default.aspx?ProdID=LOSB0104
charger-http://www.horizonhobby.com/Products/Default.aspx?ProdID=LOSB9602
battery-http://www.horizonhobby.com/Products/Default.aspx?ProdID=LOSB9830

Brian

[Thorsteenster]

The ESC is the kit one, or what comes with it stock?
Sounds to me like it could be a low voltage detection issue in the ESC, of which being an OE ESC there will be no adjustment as it's only made for a 2S.
So, you may be able to get Losi to replace it with a call to them, or look at replacing it with an aftermarket ESC.

Another thing you can check, I'm not familier with that charger, but on mine I can set the max MAH, which I had done for a RX pack and forgot to set it back for running packs. So even showing fully charged they only lasted a few minutes.

[fhhhstix]

Your batery is to small it was intended for the 18th scale you truck is pulling to much from the batery and it can not keep up the voltage and the voltage cut off is shutting it off. Get a higher c rated batery with bigger wires. I had the same problem last year at indy pulling Joes dozer on my lowboy I was trying to use a flight power 2 cell 1800 with 20 c rating it was just to much of a draw on the batery so I put in my common sence 2 cell with a 30 c rating and it worked fine.

[Thorsteenster]

The scale doesn't really matter, but in looking at the battery, those wires are awefully dinky. If it didn't say for the MiniT I'd swear it was a TX or RX battery.
It is rated at 20C constant and 30C bursts.

I have an older Scorpion 15C 1200ish MAH LiPo I've ran in everything I have, crawlers, scalers, buggies, touring cars, with brushed and brushless power, I've never had runtime issues so I wouldn't suspect that.

But higher C's never hurt, other than price anyway, and a higher MAH would be prolong fun between charges. In either case, I'd definitley replace that battery with one that has some good 12 or 14 gauge wire on it.

I didn't look at the battery before my previous post lol, I just figured he'd be using something appropriate.

[fhhhstix]

Wouldn't scale mater from a 380 szed motor and lighter weight truck to a 540 motor and a hevier truck the bigger truck is going to pull more amps? Somebody straiten me out if I am wrong here.

Thanks
Travis

[Thorsteenster]

I just meant the scale doesn't matter as in the battery doesn't care if it's in a 1/18 or a 1/10 RC, it's still a 20C XXMAH.

The 1/10 will for sure pull more but the ratings on that battery should be plenty capable, the wiring looks pretty suspect though. Looks like BEC/servo gauge wire.

[fhhhstix]

Hay Thor no problem discusing this stuff to find a solution is what this is all about.:cool::)

[CorbettTrailers]

Hay Thor no problem discusing this stuff to find a solution is what this is all about.:cool::)

Exactly. The SC10 Short Course Truck I have has a brushless system and I run a 3200 2S 25C battery. I also have low voltage shut-off on my ESC. If I run it with voltage shut-off, turned off, (for NIMH or NICD batteries) it won't run. I have to run it with the voltage shut-off, Turned ON, Which is made for Lipo batteries. In my opinion, it's going to be your ESC is not programmable for the voltage shut-off option, ON/OFF. My 3200 Lipo will last about 25 minutes in my truck. Not sure if I helped but if you can spare the extra $$ for a Brushless/Brushed ESC with voltage shut-off options, it'd prolly be worth it. I've over charged my Lipo and had it way too low and it's 6 months old and still works perfect.

[Romelio]

The wire harness is the stock ec3 that came on the truck and battery. Like I said the battery came with the kit I'd like a bigger one but I haven't ordered one yet. But i still would think it should run more than 2 to 3 minutes. I don't think they would give you a battery that would only last 2 minutes.

[fhhhstix]

ok this isnt about semis but i have a crawler that runs lipos ive never used lipo but it doesnt seem too bad. but im having a problem. the truck can only take a 2 cell lipo (7.4v) which i have. but when i run the truck it only runs for about 2-3 mins and shuts down. it seems like a voltage cut out which should be 6v.. but when i connected the battery back up to my charger it displayed that the battery still had plenty of power left in both cells. i dont know whats up. im not sure if there is a way to change the voltage cut off or what.. but its not too fun only being able to run my truck for 2 mins... the kit is the night crawler RTR and the charger is multipro intelligent balance charger. the battery came free with the kit. thanks for your helps!

truck-http://www.horizonhobby.com/Products/Default.aspx?ProdID=LOSB0104
charger-http://www.horizonhobby.com/Products/Default.aspx?ProdID=LOSB9602
battery-http://www.horizonhobby.com/Products/Default.aspx?ProdID=LOSB9830

Brian

The batery you have came sealed in the box with the 10th scale night crawler?

The batery you have listed is for the 18th scale vehicles and is not suitable for the 10th scale truck.

Here is a link to the truck and the batery recomended and it is not the one you say you have.

http://www.horizonhobby.com/Products/Default.aspx?ProdID=LOSB0104#quickAccessories

Check it out and get back with us.

[Espeefan]

That is rediculous! The wires are way to small to even support 20 amps continous. 10 gauge wire is rated for 30 amps, 12 will handle 20. But that wire is no bigger then what you'd find on a servo. I would not be surprised if that isn't seriously limiting the current capacity. Like Thor said, it looks like a receiver pack. No way would I expect that to run a 1/10 scale crawler. Even if that pack had a 30 or 40 amp rating, those little wires will absolutely kill the potential.

[Thorsteenster]

I don't even see how he connects it with that BEC looking connector!
:D

[CustomRCmodels]

That battery listed is for sure to small for that Night-Crawler,
Even thought it’s probably just a 55 turn 540 motor , it still draws more when the small 280 size motors from a 1/18 scale vehicle for which these type battery’s are intended.
Probably already just from the steering servo ?
But check your instructions , since I would expect it still should give you a longer run-time as just 2-3 minutes , as long your are easy on the throttle-finger !
There should be something in there how to program the Lipo shut-off .

Because of ( usually ) larger size vehicles , like 1/10 scale , use 540 type motors and full-size steering servos ( a high torque steering servo can pull easily 1- 2 amps alone , and even more if it has to work hard or being blocked in movement ! )
Compared to smaller stuff , like 1/18 or 1/16 scale vehicles with 280/380 type motors and mini or micro-servos , yes , I would say as a rough judgment you can go by scale to figure out needed battery size

Don’t just go by the C-rating !
That only means that battery can dump up to x-amount of the rated capacity !
So if you have a 1000 mA/h 20C battery and compare that to a 2000 mA/h with just 15C battery , that 2000mA/h 15C battery gives you more punch !

I don’t believe this 20C rating on that small 1650mA/h battery anyway !
These small 18 or 20 gauge wires sure as **** don’t take no 33 amp abuse !
That would probably cause a nuclear meltdown on the battery as well on the wires and connectors.

For the other guys “fighting” the Lipo-shut-off problem in general ,
If you just run regular NICD’s or NIMH’s , there is no need to disable the LIPO-shut-off , as long your NICD or NIMH is still in good condition , means under load not to much of a voltage drop .
If your vehicle shut’s off to soon with the LIPO-shut-off enable , with the use of a NICD or NIMH , that means that your NICD or NIMH battery has seen better days .
LIPO shut-off’s usually work in the 6 volt range ,
Means voltage drops below 6 volt , shut-down .
A good battery , no matter if LIPO , NICD or NIMH will maintain , even under heavy load ( high current draw ) a voltage above 6.5 volts .
If it drops below , that means your battery is worn down .

As for the guys with the Tamiya MFU’s in there trucks ,
A LIPO shut-off is not necessarily needed here , since the MFU shuts down anyways when the voltage get’s to low ( even thought not indented as a LIPO-shut-off , but it’s handy side effect of the MFU’s )
The same applies to the Tamiya tank- MFU’s .

As for deep-discharge of a LIPO , yes , as long the LIPO is new , it will probably survive it , but you may run in trouble with some chargers .
Some chargers will NOT recharge a deep discharged LIPO !

And be very careful with these LIPO’s !
They are an extreme fire-hazarded !
There is nothing else more dangerous in the battery-world as a LIPO !
Get a LIPO-charging bag !
LIPO’s do NOT get hot during charging , so they can be charged inside a closed bag / container !
I have not seen one yet going up in flames , but supposedly it is a much bigger mess as if you blow up a NICD or NIMH.

Either it’s at my place or in our TankMuseum , LIPO-charging bags are mandatory if you use LIPO’s !

Much cheaper way for good batteries are Lithium-Ion battery’s .
I use them in my trucks with low RPM motors and gear-reductions .
They do not give you the high C-rating , but they are cheap and available in high capacities .
The ones I use come as a 3.6 volt D-cell size cell with 4000mA/h , I use 2 of them ,
Which even can be installed in the tanks on a truck , like in a short-wheel-base day-cab in which you may don’t have the room for regular size battery’s .

[Espeefan]

I've always feared the LiPo packs myself, even though they are pretty safe. Something about the need to store them in a fireproof container or sack, and charge them in one as well freaks me out. Chances are it will rarely burst and start a fire, if you treat them well, and LiPo packs can be found everywhere in your house already. Cameras, cell phones, your electric shaver, ect. But I have been looking at the LiFe cells, which are supposed to be as safe as NiMh cells, have a longer life with more charge cycles, and they also can handle some serious discharge currents. Even better then LiPo packs, plus you can recharge them faster. The only downside is they are really pricey!

[CorbettTrailers]

Holy cow. I just saw your pics. If your running brand new equipment, I'm really not sure. My only guess is your battery isn't powerful enough. I'n not too familiar with Crawlers.

[Thorsteenster]

I've always feared the LiPo packs myself, even though they are pretty safe. Something about the need to store them in a fireproof container or sack, and charge them in one as well freaks me out. Chances are it will rarely burst and start a fire, if you treat them well, and LiPo packs can be found everywhere in your house already. Cameras, cell phones, your electric shaver, ect. But I have been looking at the LiFe cells, which are supposed to be as safe as NiMh cells, have a longer life with more charge cycles, and they also can handle some serious discharge currents. Even better then LiPo packs, plus you can recharge them faster. The only downside is they are really pricey!

Same here on the LiPo's. After getting back into RC a few years back LiPo's were pretty much just coming into the scene. I tried it and wow, it really is some battery. I had Scorpion batteries and charger, I still have a battery and the charger.
I've since gone to A123 LiFe batteries, they are much less hassle, no worries about over discharging, LiPo fires etc etc. Although each cell is only rated at 3.3v nominal vs LiPo 3.6v.
As far as safety goes, this are a much better battery type, I would recomend them to anyone looking to go to lithium type batteries or tired of LiPo's.
The LiFe's are getting more popular with Max Amps now offering LiFe packes in flat cells. Mine are round cells and a little bigger than a sub C cell. I got mine from a DeWalt battery pack from Ebay for under $100. I want to say it had 10 cells but don't remember exactly. Nice thing is they are easy to solder because they have tabs spot welded on for soldering, so no worries of damaging the cells.
Any who, sorry to get off topic.

Yeah, now that Willy mentions it I remember reading somewhere the MAH rating needs to be high enough, easily figured out with some magical formula I have no comrehension of.....
lol
That's interesting on the LiIons, I'll have to see if my charger handles them and check them out. It would be nice to have a cheaper alternative for RC's not needing high C rated batteries.

[ihbuilder]

I run Li-ions in my few trucks , they are actually the milwaukee m12 . you pop the black handle piece off and you can slide it in a 2"dia tank . I get about 2hrs running time ,(have to clock it some time ) . what I like about them ,is they are duel purpose ,for play and for building and last a long time .

[Espeefan]

One other thing I wanted to point out is if one compares a typical 6.6 volt, two cell LiFe pack to a standard 7.2 volt, six cell NiMh pack, the LiFe pack looks a little weak. What is important to remember though is that we run our packs under a load. Sometimes a severe load, and under a load like that, nonimal voltage ratings drop off a lot with NiMh packs. Not so much with a LiFe pack, or LiPo pack. Your 7.2 volt NiMh pack might be capable of maintaining a 6 volt or less rating underload, especially as it reaches the point where it has given up half it's capacity already. At it's very near discharged state, a good NiMh pack might only be providing 5.4 volts or less. A LiFe cell will maintain it's 6.6 volt rating right up to the end of it's capacity. So even if you are worried about the LiFe pack looking like it has less voltage, it's more capable of maintaining that voltage, even under load. It really doesn't give any performance away to a NiMh pack like you could think. Don't just look at the nominal voltage ratings, in other words. :D

Now let's switch subjects. The forumla for figuring out a LiPo pack's max continous current rating is to multiply the pack capacity by the C rating.

Pack capacity is the mili-amp rating. The C rating is the discharge capacity, or how fast you can discharge the pack. To figure out the maximum continous discharge rating you have to multiply the C rating by the battery capacity. Example - a 2200 mili-amp pack that has a C rating of 10C.

Convert the 2200 mili-amp rating to full amps. One mili amp is .001, so we multiply 2200 by .001 to get 2.2 amps. Simple, right? Now take 2.2 amps and multiply that by the C rating, which is 10. That would be 22 amps, and this is the continous discharge rating for your pack.

Hope this will help. :D

[ddc333]

There was a really informative thread about lipo's on the garden forum any chance any one still has some of that info ??

[tc1cat]

That thread was written by Paul- Tamiya Cowboy. Hopefully he still has all of the info.

[Thorsteenster]

I remember a really good thread on RCC a couple years back about MAH and C ratings but can't find it now.
Really though, Espeefan pretty much summarizes it with his post above.

[doodlebug]

I run Li-ions in my few trucks , they are actually the milwaukee m12 . you pop the black handle piece off and you can slide it in a 2"dia tank . I get about 2hrs running time ,(have to clock it some time ) . what I like about them ,is they are duel purpose ,for play and for building and last a long time .

Hey Steve, are the M-12 batteries working out for the rc stuff? Still happy?
I did have one new battery that was bad, warranty replaced it. I have the greasegun, borescope, and a compact driver.
Thank's, Neil#2 aka doodlebug.