I am new to R/C planes. well, sort of. Im new to stuff over 3 channels and Lipos. I know enough to not go and mess with stuff without consulting pro's. I have the E flite Apprentice 15E, can I upgrade to a bigger battery to increase my flight time? Or will that require a new ESC or any other stuff? I just want to fly longer w/out stopping. I was also wondering if they make low battery audible warnings? Im paranoid about draining the battery too far and want all the warning Ican get. I dont like walking for forever to get my plane cause Ihad to land right at the los of power. And one last question- has anyone made use of the 5th channel? I was curious what modders are up to with this one.

you can use any size batttery as long as it has the same number of cells, you dont need a esc or anything

That's not necessarily true.

The number of cells makes not one bit of difference as long as the combination does not exceed the voltage rating of the ESC.

Assuming that the original poster is using LiPo cells, well, the generally accepted setup for smaller planes is 2S or 3S (two series or three series) for 7.8 or 11.1 (nominal) volts. But, the number of cells in series/series parallel/parallel makes no difference as I said, as long as the voltage rating of the ESC is not exceeded.

With that said, increasing the size of the battery pack has some drawbacks, primary one is weight.

When figuring out the total weight for the watts/pound factor, adding a new, larger battery pack means more weight, so the weight factor, watts per pound has to be reconsidered. That's 16 ounces per pound, or 28.35 grams per ounce.

50 watts per pound for an easy flyer
75 watts per pound for a sport flyer
100+ watts per pound for a high performance

Watts = voltage X current

So, before changing over to a larger battery, make sure your ESC is rated for a three cell pack, and then consider how the added weight will effect the performance of the plane. And, of course, re-set the Center of Gravity.

As far as an audible indicator of low battery, well, you won't really need one becasue you can "feel" the performance draining off as the battery drains. Once you reach a certain point, it will begin to get really sluggish.. time to land and re-charge or change battery packs.

CGr.

To increase your flight time you need to increase your mAh rating. If you bought the RTF version of the Apprentice, it comes with a 3s 11.1V 3200mAh battery so any 3s 11.1V battery with a higher mAh battery will lengthen your flight time but as CG Retired stated you will have to consider the fact that increasing even the mAh of a battery will increse the weight of the battery and thus will affect the total weight of your plane and possibly your CG (center of gravity). Also, as CG Retired stated above, if you are wanting to upgrade to a 4s 14.8V battery you need to make sure your ESC and motor can handle the added voltage.

Brett

Your best bet is to get a decent charger and 2-3 extra batteries....search,.... batteries at the big hobby places are high dollar....try headsuprc...or hobbycity....hobbyking, might take a bit to get here from Hong Kong, but the savings are worth it....Rog

Debay,

I have had the Apprentice for a year now. Get a good charger and two extra batteries and your good to go. You can get the Acuccel 6 (it will charge all typs of batts) for about $25.00 at Hobbycity and 3s 11.1v 3300mah 20-30C for around $40.00 each I have two 3300mah batts. and I can get well over 10 to 12 mins of flight with power to spare. Depending on how you fly will make the diff. on how long you fly. The system you have wil not just stop instantly when your power is low. Your esc will detect when the power is getting low and give you a warning by pulsing the motor. If you notice the pulsing its time to land, but you DO have time. I have seen a fellow at our field fly his Apperentice with a 5000mah batt., but he didn't seem to fly much longer than me. I have flown my plane for 14 mins and still had power left. If you have three batts you can always have one charging while flying.

That plane will not even NOTICE a difference going to 4000mAh LiPo packs of the same voltage.

At worst ONE click of trim may be needed to offset the weight.

Well, my battery is a3200mAh 3S 11.1V 15C Li-Po. Iknow more mAh means more weight and CG shift. As much power as the motor has Im sure it can handle that little bit of weight. As for the CG shift, Illhave to compensqate I know. What I dont want to do is buy the wrong battery and render the ESC and motor useless. The apprentice doesnt give much info on the motor specs. I did find the replacement parts page and this is what it says- BL15 Outrunner Motor, 840K. And the ESC is a 30A Brushless Pro SB Brushless ESC. With that in mind, can someone go the extra mile and help a noob with a lipo question and maybe show a few links on the rightbattery(s)?

Your fine.