Thunder Tiger Raptor E550FBL Maximum Battery Size?

You might have noticed that I have ordered the new Thunder Tiger E550FBL.  I need to order some batteries  for it, since it calls for 6S 5000mah, and I don’t have any of those. I was checking out my usual battery of choice, Turnigy Blue or Nano-Techs. I like them because they are inexpensive, and other than one that came to me with a dead cell, they have worked well. If you take care of them, they can last a long time.

Not wanting to buy batteries that don’t fit in the heli, I was trying to get an answer to what I thought was a simple question.  What’s the maximum sized battery that will fit in the E550?  Well, it turns out to not be such an easy answer. The best that the manufacturer tells you is that it “Requires one battery — accepts the same size as E700 and E720 machines.” That’s helpful…only if you have a E700 or E720, or know what size battery they can take. That’s not so easy to look up either, it seems.

I looked at the battery that Tower Hobbies recommends with the E550, and they spec a FlightPower LiPo EONX 30 6S 22.2V 5000mAh 30C. I took a look at it’s dimensions, and it is 45mm x 58mm. Okay…so I expect that at least that will fit.  But, when I compare that to the Turnigy batteries, I started to get concerned that they may not fit:

Turnigy 5000mAh 6S 40C Lipo Pack

Height-B(mm) 49
Width-C(mm) 52

Turnigy nano-tech 5000mah 6S 45~90C Lipo Pack

Height-B(mm) 49
Width-C(mm) 50

So basically I am looking about 50mm x 50mm for the Turnigy or Nano-Techs. I am getting nervous that they won’t fit. The only thing I can find that comes close to answering the question is the following post from Spacecopter the Runryder Forum:

My friend in Germany just received his Raptor e550 FBL


He told me that the maximum Battery-size diameters are :


In metric :


Maximum 44 mm wide maximum 60 mm high and maximum 22.5 cm long


At the front of the battery compartment (next to the carbon posts) are


two plastic-pieces that are reducing the possible battery size from


51 mm to 44 mm (width ))
So what you are looking for is 44 mm X 60 mm or smaller .


Well, that gives me a place to start, but I still wanted an authoritative answer.   I ended up calling Great Plains Heli Tech Support, and spoke to a really nice guy who actually went and got a heli and a ruler to help me figure it out.  First, that was impressive as all get out! : )  He said he didn’t have a E550FBL because they just got them in stock, but he could go grab an E550S and measure it. He said that the E550S and the E550FBL use exactly the same frame.  That was another great data point.

So here are the measurements he gave me:

Front of ESC to tabs on the front of the battery tray:  6″ (152.4mm)

Section of battery tray in front of the front tabs: 1 1/2″ (38.1mm)

Height of the battery tray to upper part of the frame: 2 1/2″ (67.5mm)

Width of the battery tray: 2″ (50.8mm)

Available width between the two front tabs on the tray:  “no more than 44mm”

Here’s a couple pics to help orientate your thinking.  Those two tabs on the front of the tray appear to provide structural rigidity to the frame sides to prevent frame flex above the battery tray.   I expect some people will (or have) modded this tray to remove or reduce the impact of those tabs.  I would expect that you may want to find another way to provide support, but I’m not going to speculate how at this point.



In the end, we talked a lot about this, and I just won’t know for sure until I can either get the batteries in place myself, or get some reliable information from someone who has. Because the battery has a significant impact on the CG of the heli, it’s possible that it will be far enough back on the tray that the tabs will be a non-issue.  The rest of the battery tray can easily hold a 50mm x 60mm battery (which is consistent with spacecopter’s information above). So it really is going to boil down to where the battery needs to be as to whether it has to be where the tabs are and whether it is limited to 44mm or not.

In addition to the main battery, there are other ways to tinker with CG.  Lets say I buy a big battery and put it all the way up to the tabs…but need more forward CG.  I could relocate the ESC farther forward on the side. I could put a receiver pack up front. I could even add weight to the canopy (which people are known to do).

Still, at this point I don’t know. I need to buy batteries, but haven’t quite resolved what to do. I could always just go find a battery that I know will fit. The problem with that is they are often more than I want to spend. I was hoping for a $60-$75 battery. Is that just too unrealistic?

If anyone has any tips or battery advice, please let me know. I will update this article with any new information I get. I would really like someone to tell me if the Turnigy/Nano-Techs fit okay or not. Anyone?  Anyone?  Bueller?  Bueller? : )


Looking at Nick Maxwell’s video again, you can see where they have the battery.  It’s pushed up to, not not at those posts. I can only assume that the CG will be fine with it there, making that 44mm restriction a non issue. I’m about to stop stressing and just buy some batteries. : )

Screenshot 2014-02-26 06.41.41

EDIT AGAIN:  Okay, gang! I’m living on the edge!  I went ahead and ordered a couple of Turnigy nano-tech 5000mah 6S 35~70C Lipo Packs. They are 49mm x 50mm.  That’s about the typical size of a 5000mah 6S battery, so I think the best thing I can do is just buy them, see if they fit, and report back to you.  I have to remember that I consider this a budget 550 purchase. It’s the best bang for the buck setup I have seen. Folks like me that are looking for the most economical way to get into a quality 550 sized heli are likely to look for batteries that also fit that budget model. These Nano-Techs were $85 each, and that’s reasonable. I just can’t see spending $200 on a single battery. BTW…if you use my buddy code, you can get these batteries for $79!



I’ll let you know for sure if they fit!