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Help! Battery Hold Down Alternatives

rockyboy

Skill Collector
Mentor
#1
I'm just going to come right out and say it - when it comes to holding batteries in planes, hook and loop fastners (aka velcro) are the debbil. :mad::devilish:(n)


Put on a few flights in the cold this morning (below freezing with the wind chill). My hands were numb and clumsy and I ripped the whole battery tray out of my balsa Ugly Stick when I was disconnecting the battery. :eek:

20190209_170451-1024x576.jpg

And this isn't my first run in with velcro either - I've tore velcro straps out of planes left and right, had sticky velcro peel off planes at the field, and have generally grown to hate the stuff. :mad:

So instead of gluing the battery tray back in with new velcro straps into my Ugly Stick, I want to come up with some other design to hold the battery in the right place. Design requirements as follows:
  • It should be simple to load and unload a battery.
  • It should not require tools to operate.
  • It should prevent the battery from moving around in flight or on landing.
  • It shouldn't add significant weight to the airplane.
Battery tossed into the nose for scale below. It needs to sit with one end of the battery as close to the firewall as possible for balance.

20190209_170515-1024x576.jpg

I was able to come up with a good solution for my balsa Cuda. I padded the insides and front of the nose with 1" foam insulation that a 3s2200 slides firmly into, with another little block of foam I push in behind the battery to lock it in place once it's loaded. A drawback is no airflow to reduce heat, but I've never had a problem with batteries coming down warm in that plane before or since.

So what do ya'll think? I might try something similar for the Ugly Stick, possibly with some channels cut for airflow, but I'm really hoping other folks on the forums have some other examples or great ideas.

Help!
 
Last edited:

mayan

Well-known member
#3
I don't know if this would work for every model, but works great for me on the Tiny Trainer. I use BBQ skewers to hold the battery from the front and top and I promise you one thing, the battery doesn't move any where. You can see the bottom holes underneath those that belong to the power pod.
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wilmracer

I build things that fly (sometimes)
Mentor
#4
I feel your frustration. I've used removable trays that secure with a thumbscrew but I still used velcro straps to secure the packs to the tray. That being said it was much easier to deal with the velcro while the tray was out of the plane. I suppose you could use a piece of light ply or balsa as the tray and just permanently glue your pack to it and swap them out like cartridges, but that doesn't seem very elegant.

I could see doing a box with a lid secured by a latch, but it would be very battery specific and wouldn't give much wiggle room for different packs to fit snugly. I'm not sure there is going to be a one-size-fits-all solution.
 

PsyBorg

Fly Angry
Mentor
#5
Ummagrip ftw!!!

Not tauting Rotor Riot in a fixed wing thread but imo the RR battery straps are great. They are stretchy and very grippy. Have only ever broke one since I started using them.

Consider the speed and viloence of my crashes at times these should last for ever in a fixed wing.

Add a pad of Tommys ummagrip and that battery will never move
 

rockyboy

Skill Collector
Mentor
#6
I hadn't seen that ummagrip stuff before - looks interesting... still don't want to use a velcro strap on it though. Those are fine for my quads, but not my friend in balsa planes.
 

rockyboy

Skill Collector
Mentor
#7
I feel your frustration. I've used removable trays that secure with a thumbscrew but I still used velcro straps to secure the packs to the tray. That being said it was much easier to deal with the velcro while the tray was out of the plane. I suppose you could use a piece of light ply or balsa as the tray and just permanently glue your pack to it and swap them out like cartridges, but that doesn't seem very elegant.

I could see doing a box with a lid secured by a latch, but it would be very battery specific and wouldn't give much wiggle room for different packs to fit snugly. I'm not sure there is going to be a one-size-fits-all solution.
Sort of leaning in this direction. I only fly this plane with 3s2200's so the one-size limitation isn't a problem.
 

rockyboy

Skill Collector
Mentor
#8
I don't know if this would work for every model, but works great for me on the Tiny Trainer. I use BBQ skewers to hold the battery from the front and top and I promise you one thing, the battery doesn't move any where. You can see the bottom holes underneath those that belong to the power pod.
View attachment 123739
I like that idea for foamies - will do that on my next FT Simple Scout - thanks!
 

Hai-Lee

Old and Bold RC PILOT
Mentor
#10
Well I remove all factory fitted velcro straps and replace then with cheap Velcro cable straps. They are 8 for around $2. As for further description they use single sided velcro, (loops), of about 200mm in length with a piece of hook velcro, (40MM IN LENGTH), Sewn reverse on one end. In the sewn end there is also a non-velcro loop of a plastic material that acts as a handle for undoing the velcro bond.

No more struggling to find the end of the velcro and no more huge area of contact making removal difficult.

See attached pic:

DSCF0021.JPG

Easy to fit and remove battery and plenty of holding strength even in case of impact.

Just what works for me!

Have fun!
 

Arcfyre

Well-known member
#12
You could also use lengths of safety wire instead of Velcro straps. Think of a slightly scaled up version of what holds fresh loaves of bread bags closed. Strong, secure, provides ample cooling and requires no tools once installed.

I don't have a pic as the plane I used this on has long since died, but I hope you can figure out what I'm talking about.