Johnnyrocco123

Can anyone give me run down on Lipo batteries??? When to charge them, do you keep them half charged when storing, balancing? The pros and cons to using them vs. nmh??? Any feedback would be appreciated. I am very interested if they can increase fly time and achieve better performance. Thanks

Fliprob17

They are lighter than an equivalent NiMh and hold there charge much much better. In fact they do not really lose their charge at all while resting. You can charge a LiPo 3-4 days before you fly and have it ready, it does not lose any voltage, as long as it is in good condition that is.

Example and charging, etc.:

Say you have a 2100mah 11.1 volt 3 cell LiPo. Each cell when fully charged = 4.2 volts, so the pack will hit 12.6 volts when fully charged. There are some different opinions on what exact voltage to let the pack get to before charging again. I like to have a full pack everytime out so that silly low-voltage cutoff does not wreck my plane So if, in this case, my pack is below 12.3-12.4 volts, I will top it off to 12.6.

For storage of more than say 5 days, you should keep the cells around 3.7 volts each. So on the above example pack, 11.1 volts. It is not good to keep it stored at full charge.

Balancing, again differing opinions here, but I would say that it is a must. There is a great little charger called the Cellpro 4S, charges and balances at the same time, and it is only $55. Otherwise, I use the AstroFlight Blinky balancer and the AstroFlight 109 Charger, works great.

Johnnyrocco123

Thanks for the help, I appreciate it. Im new to these type of batteries and all of the info I have read on them is scaring the hell out of me. Im not sure I want them in my house.

BTW how do you like the Yak 54 3D?? I was thinking about getting the Yak 54 EP

Fliprob17

The LiPo's are not as bad as the stories. I keep mine in a metal cash box that has a lock and is fireproof. You can get one at target for $20.

The Yak 54 3D is ok for a flat out foamie. I just really like the balsa/ply planes a whole lot more.

tester423

HI -- I am not trying to butt in but I have been looking around for this info.

When you charge theese li-pos do you guys just keep cheap volt meter handy to check them with. I assume the charger lets you know the pack is finished. Then you check the voltage with the meter and if not at the above mentioned 12.6 V do you hook it back up and try to charge it again till you get the desired voltage? I am also fuzzy about the min. voltage. Say I fly my plane till the motor stops and then dead stick it in. Do I check the volts again and see how low it is? Once the battery has been run is it necessary to allow it cool off before recharging?

Ok about what to charge them off of. Lots of people are buying a 12 volt power supply. Does the car battery not work well enough? Or do they just use a power supply because they are charging in the house? Sorry for the elementary questions but I am new to electric power.

Thanks
Richard

Fliprob17

The charger will shut down when the resting voltage of the pack balances out at 12.6 volts (on the example of a 3 cell LiPo). If the charger stops and says the battery is done, but when you check it, the pack is not at the full charge voltage. Something may be wrong with the pack, the cells could be out of balance preventing it from charging correctly, etc..... I use the E-Flite PowerMeter, it can just connect to the battery and give you a voltage reading, or it can connect inline and give you amp draw, voltage, watts, etc. of the system while the motor is running.

I usually check the voltage after every flight whether the low voltage cut-off chimes in or not. Just to keep a close eye on the pack.

Generally the LiPo's will not get warm/hot to the touch, unless you are over taxing it. If it does, you need a higher C rated battery.

In my opinion, a car battery is more of a field option for charging. The power supply is a more steady/clean supply to the charger for home charging. I only use the power supply.

Flypaper 2

You won't crash your plane if the ESC shuts the batt. off at low voltage. Pull the throttle down to stop then put it back up to half throttle and you have enough power to come around and land. Cellpro charger is a plug and play charger . it decides at what rate to charge the batt. at, depending on it's condition. A readout tells you how much you have taken out of the batt., How many volts of each cell, Voltage at end of charge, Charge rate at any time while charging. Does it all. Good tool out at the field is a jumpstarter to charge the batts. Get one with no less than 17 AH. Mine has an inverter so I can plug in the hotglue gun for repairs.

tester423

I was wondering about a automotive jump box. Probably would be better than the 12volt little thingy in my nitro flight box. I was actually wondering if I could turn on the battery charger (car battery and it is a big charger) and use it for a 12 volt power supply. How many times can you charge a battery from a jump box? eventually that battery in the jump box is going to go dead.

Flypaper 2

12 volt charger is not good to use. To much ripple to it. I mostly run 1320 lipos and it will last all day. That's why you need to get one with the biggest batt. After three yrs of hard use I finally had to replace the batt and I put in a 20 AH batt of the same physical size

tester423

what about charging off of an extra car battery? I don't see why not it is nothing more than a big jump box. I could use it for nothing but charging li-pos. we have some smaller batterys like for a civic. You wouldn't beleive how many people have a perfectly good battery replaced. Most of these car batterys are like 500+ cranking amps. You had mentioned 25A. Do you think that would be ok? -- If you can't already tell I work on cars so I am trying to use what I have already.

Flypaper 2

Sure, they would work great, especially the ones with the built in handles. Garden tractor batts. would work fine too. The only plus, but not necessary, is that the jumpstarters are gell cell batts that can be laid on their side, upside down and won't hurt them. As you know, you don't do that with a wetcell. Sometimes I'll throw a mower batt. in the van if I know I'll be pushing the Jumper to hard like running two chargers at once and a number of guys are using the hot glue gun steady.

tester423

got another q -- when told not to let the battery get below 3 volts per cell -- Is that a total of 3 volts or total of 9 volts on a 3cell li-po?? when checked at the discharge connector

Flypaper 2

That would be 9 volts on a 3 cell batt. BUT that's under load. As soon as you take the load off it usually bounces back up to over 10 volts. Not good to let it go down to 3 volts no load.

packyj

Most are using power supplies at home because the effort to remember to charge a lead acid battery every time you use it can leave you with a flightless perfect day. Do a google search for computer power supply conversion for rc power supply. A lot of times you can get sufficient power supplies from local computer repair places for little to nothing. If you are confident in your electrical skills it is an easy conversion and you won't put as many cycles through your field battery.