Now don't go blowing your corks and calling me names but I am looking for a thread, maybe a sticky, that explains lipo in terms a dummy can understand and how I can apply them. I use only NMh stick packs now but have just acquired a lipo powered crawler and am interested in maybe using lipos on my Emaxx.

what u trying to find out??? also u should get some lipos for ur emaxx, once u use them ull never go back

Well just some general descriptions and what everything means. How to apply the numbers to a need, charging data, cautions....that kind of stuff. Yes I'd like to get some for my emaxx but I want to be sure of what to get so I don't ruin my setup.... e revo stock motors esc radio 16.8 volt

some general stuff http://maxamps.com/lipo-care.php

max amps also has a disc they can send u for free explaining how to use lipos.
there really aint much to them just buy a good charger with a built in balancer. also make sure u have a voltage cut off cuz if ur cells go below like 3v they r usally no good. they r great though more run time less weight seems like u get more power out of them, all around goodness

I found this excerpt on Horizonhobbies website.

Lithium Polymer (LiPo) cells are the newest and most revolutionary cells to come to market. LiPo cells typically maintain a more consistent average voltage over the discharge curve when compared to NiCd or NiMH cells. Add to that the higher nominal voltage of a single LiPo cell (3.7V versus 1.2V for a typically NiCd or NiMH cell), making it possible to have an equivelant or even higher total nominal voltage in a much smaller package. LiPo cells also typically offer very high capacity for their weight, delivering upwards of twice the capacity for sometime ½ the weight of comparable performance NiMH cells and packs. That’s right, with LiPos you can often achieve higher voltage and power output, with more capacity, in a lighter weight package.

With all of these benefits, why aren’t LiPo packs more widely used? With so much energy packed into such a small space, there are some important safety measures to take when dealing with LiPo cells. A LiPo cell needs to be carefully monitored during charging as overcharging a LiPo cell (to beyond 4.2v), or the charging of a physically damaged or overdischarged cell (discharged to below 3.0v under load) can be a potential fire hazard.


Many LiPo batteries come with safe charging circuitry integrated into it. This circuitry prevents over charging, over discharging, and in some instances helps to balance the pack out. If your pack has a “Charge” lead on it, always charge through that connector.


While some battery chargers can charge either NiCd/NiMH or LiPo cells, chargers that do all three major chemical types are starting to surface. The Dynamite Vision Peak Ultra can charge your LiPo packs along with NiMH and NiCd batteries as well.

If you are going to go the LiPo route, use a charger that can correctly charge them (using a constant current, constant voltage method of charging as LiPo cells can not be “Peak Charged”), such as the Vision Peak Ultra (DYN4053) or the E-flite Celectra 1-3 Cell charger (EFLC3005). Not only must care be taken when charging LiPo cells, but when discharging them as well. You should never over-discharge a LiPo pack to below 3.0v per cell under load, and you must use an ESC programmed to provide the proper low voltage cutoff for your pack (for example, a 9v cut off for a 3 series LiPo pack). Also, you should never dead short a LiPo pack, even if only for an instant, as the large amount of energy stored in the small package can catch fire quite quickly as a result. While these seem like major deterrents to using a LiPo battery, these usage guidelines are quickly becoming well known as they are typically well outlined in the instruction manuals included with most LiPo packs, ESCs and LiPo chargers. However with all of their performance benefits, there is little doubt that lithium polymer battery packs are currently the future of battery technology for electric powered models.

Thank you for the link and explanations. They are very helpful!

Latest and greatest? Funny...didn't Horizon buy the rights to A123's?

Are voltage cutoffs actually needed on each battery? If I was to use two lipos in my Emaxx would I need two cutoffs or is there antother way to insure the voltage doesn't drop below 3v/cell? Sorry for all the questions

Gary, the voltage cutoff I think is built into the EVX2, but I dont think it it built into the original EVX. ( i mean, it MAY be, but I dont think so)

as far as needing 2 of them, I would have to let a emaxx professional answer that one.

I dont have voltage cutoff on any of my rc junk, becuase Im usually tired of doing laps by the time the lipo pack starts to poop out. I frequently check for tempature of the ESC and motor as a guide.

I only had one bad expierence with the lipo, and it was all due to user error. ( i hit it with 3amps on the NiMH setting. almost had a fire, but caught it before it burst.
Other than that, I love the performance gain. Lipo to RC is like steroids in baseball maybe.. except lipo is gaining legal-ness in most places now.

Pete

Some Lipos(not sure if all) come with a fire retardant hard case to lessen or contain the effect of a damaged cell. And as long as the cells are balanced and not overcharged, you should never have a problem. Most ESCs can be programed to use a Lipo cutoff. A good maintained LiPo should last you well over 4-5 years. Which is the reason I switched to LiPos.

I have the older Emaxx and know there is no voltage cutoff - mine will let you run until it just slowly grinds to a halt. The newer Emaxx, 3905 says it is not lipo compatible and states "The EVX-2 is not equipped with low voltage detection" on page 12, lower corner in a warning so its no different than the older one as far as having a cutoff.

Hope nobody read my dumb*ss idea - def wouldn't work. Still don't know how to wire an lvc for an emaxx to use lipo. May have to settle for one batt - I know one batt does more than other (supplies rx and servos) cause I always have one (same one) thats takes more on charge - maybe put lvc on this one and setup with 6.2-6.4v as safety margin? I'm not cool with risking over $200 in lipos on a maybe though, guess thats why I'm charging my NiMHs.

Just buy a cutoff, they are fairly cheap and plug into the esc. I have used them and the alarms before on helicopters when I cheaped out on ESC's that had no or poor cutoffs.

Check here, great shop, ship fast and good pricing: http://www.helidirect.com/index.php?cPath=384


-Perry

Well at least that one has good instructions, even pics. I have another brand and its not obvious how to wire it. This is what I don't understand - Emaxx uses two batts, each connected separately to the esc. There's not a single batt connection to the esc. The esc internally connects them in series.

There has to be a way to protect both batts using just one lvc, thats what I'm trying to find out. Either lipo is just run without lvc on a stock emaxx or everybody switches to bl and handles it that way with their bl esc.

Thanks