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New Removable Battery Tray

Old 03-18-2018, 04:08 PM
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rcflyer4fun
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Default New Removable Battery Tray






Howdy! So there has been twice in my life if felt like my emails were hacked and an idea of mine was stolen.... Both times stopped my heart but then I looked at the product and discovered they were different than mine! My name is Evan Krause some of you know me most of you don't. I met a fair number of you guys last your at the Nats in Blyeville. It was an honor and a pleasure to meet y'all. This was my first Nats I've gone to since like 1997 or something. I've been flying rc planes since the late 80's. I started flying pattern after attending a TOC back in 1992. The TOC motivated me to seek out a contest and find out what is was about and I've been hooked ever since. I took a 10 year break or so to raise a family and got back into flying about 2010. Upon my return to pattern electric was a thing! I was bent on sticking with glow as it was all too common to me. After much persuasion, I reluctantly got my first electric plane and was hooked. It was more about flying less about repairing! Mmmm I liked that idea! As a career choice I chose to get into Refrigeration and HVAC. A big part of what I do there is problem solving. A lot of equipment I work on is new untested technology. Well I'm sure its tested but from time to time I discover things the Engineers left out. I'm not an Engineer just a re-engineerer! I have 2 patents to my credit. So problem solving is something I do. So I began flying electric planes and I noticed there was a problem. The batteries never lasted the 100 flights I was told they usually lasted and I watched several guys frantically pull smoking overheated packs from their plane, burning their fingers in the process. It happened to me once and only once! I had no idea if they were about to burst into flames. I couldn't get the Velcro straps undone fast enough. Not cool. At the end of 2016 I had bought some new packs. I hadn't hardly flown the packs. At the beginning of 2017 they were overheating started to puff up and I said to myself it's time to do something different because what we were doing wasn't working. I bought 3 brand new packs from F3A while at a contest in West Virginia. I took them home and went to work to create an removable battery tray. I already had the mounting rods in place I just had to fashion a plate that was easily removable. My criteria for the new tray were it had to be easily removable. It had to keep the batteries separated. It had to keep the batteries cool. And last but not least had to be light and couldn't fail! I started looking around my shop for a suitable piece of material. Lite ply was out because I was afraid it would fail and not do much to keep the batteries cool. After all I already had a lite ply tray and to me it was synonymous with failed batteries. So aluminum sheet was my choice for the material. I went to the hobby shop and found myself a suitable piece of aluminum and took it back to my work shop to fashion it into a battery tray. After much consideration and a couple of pieces of material later a suitable battery tray was formed. It was really a Eureka moment for me. A dream coming to fruition. The plate was a little bit on the heavy side at about 70 grams. I drilled in some lightning holes and was able to get weight down to 60 grams. Still a little heavy but I was ready to fly it and see it in action. I painted it black to increase heat dissipation and was off to the field to try and make it fail! My method was surely not engineered approved. I strapped up a battery pack with Velcro and was airborne! I did some simple maneuvers at first and of course all was ok. So then came the moment I now had to try some snap rolls. Snap right mmm ok canopy still on! Snap to the left mmmm Canopy still on the plane again! I landed and checked inside the plane. The condition of my tray was all good!! The battery had slid a bit on the rails to the right. I added some slide stops to the rails and flew the new tray all last season. I only had the one tray so I had to pull the tray and change the packs after every flight. Towards the end of the season I made a couple more trays to eliminate this minor problem. Through the course of the 2017 season I put at least 100 flights on the new tray system and came up with some pretty amazing results. So much so I decided to make some improvements to get the weight down and do a production run on them because I think everyone can benefit from this system. What I discovered was I have been really setting up my batteries to fail in the past. Id take two 5 cell packs put a spacer between then tape them together to make a set. Fly them and overheat the crud out of them then whine why did they fail? Our batteries are failing due to the heat my friends. Some of the benefits from using the new tray are. #1 in case of emergency the batteries can be removed in seconds without panic.#2 I feel as though I'm burning less milliamps. I use to land with 20-30% now I'm landing with 35-45% consistently. #3 my CG is dialed in to the gram! By using multiple trays I am able to maintain consistent CG no matter the pack weight. I balance all the packs in the plane at the same time then put marks on each tray for proper position. Any future CG change I make now is done by moving the receiver pack in the plane. #4 Using multiple trays allows me to leave spent batteries on the tray for more rapid cooling after the flight. #5 You can mount the batteries in any position you want even vertically if you wish. They can be placed in the plane upside down or right side up. When placing them upside down the locking clip is easier to see and install. #6 the 3 sets of batteries I flew all last year look brand new! They never seen more than 90 Deg F. They are as hard as new with no puffiness at all. Internal IR are mostly in the 2.5 range but a couple of cells measure 3.2 after 30-40 flights. That's incredible. #7 if your old packs are not to far gone the tray can add new life to them. Those old packs of mine from 2016, I decided to charge them up and fly them one last time on the tray to burn them down to toss out. To my amazement they made it thru the entire pattern! One set did not and they will get tossed. I have a limited number of trays available for anyone that is interested in them. Trays weigh in at 42 grams and are anodized in red. They are $20 per tray or $30 for a kit. A kit consists of 1 tray, 2 locking clips, 2 Carbon Rods, 4 Lite ply donuts, 4 slide stoppers, 4 Velcro Straps. You can email me at [email protected] if your interested. I only take PayPal or postal money orders. I may or may not produce more of these so get them while I have them. I am also interested in finding a distributor for the product as well. Please email me if your interested.

Last edited by rcflyer4fun; 03-18-2018 at 04:23 PM. Reason: Forgot to add weight of production tray
Old 03-19-2018, 05:55 PM
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OK.... well here are the "Cliff Notes" and bullet points from my last post!!!

I created a new removable battery tray system that works better than I ever expected! So much so I made improvements to my prototype and had a small production run made. I have a limited number for sale if your interested. Kits are $30 each. Tray with 2 locking pins are $20 each. I may or may not produce more in the future. So get some while you can. Send inquiry's to [email protected]. I take Paypal or Postal money order... Shipping is free in the US. I will ship overseas but buyer pays for shipping and their import taxes.

EB Power Tray
  1. Tray removable in seconds in case of emergency! No need to undo Velcro straps to pull out smoldering batteries. Pull the locking pin and tray comes out. Safety is ALWAYS first! But that's not all....
  2. Durable Anodized Aluminum keeps the batteries cool when in use. Buy multiple trays and keep the batteries on the tray after each flight for rapid cooling. Your batteries will love it I promise! Weight of the tray is 42 grams.
  3. Batteries last longer maybe forever....other lithium batteries used in cars and solar systems are rated to last 10,000 cycles running down to 0% without damage. I'm guessing our batteries are not much different when treated right. Heat is a battery killer!
  4. You get more flight time out of a pack. I use to land with 20-30% left in the packs. Now I land with 35-45% left consistently. Heat build-up in the packs is lost milliamps burnt up internally. Since the power tray is constantly wicking away the heat you are left with more milliamps!
  5. The internal structure of your plane is now accessible for inspection.
  6. The batteries can be mounted in any position even vertically if you wish. If you load the batteries upside down it makes it easier to insert the locking pin.
  7. CG is repeatable flight after flight. This one should be further up the list!!!
  8. Add a little Bling Bling to the inside of your plane to match what's on the outside.
A Power Tray Kit consists of
  1. 1 Tray
  2. 2 Locking Pins
  3. 2 Carbon Rods
  4. 4 Lite Ply Mounting Donuts
  5. 4 Velcro Straps
  6. 4 Slide stoppers
A Tray by itself comes with
  1. 1 Tray
  2. 2 Locking Pins

    Battery Tray Kit


    Battery Tray comes with 2 locking pins


    Battery Trays ready for action!
Old 03-22-2018, 05:18 PM
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rcflyer4fun
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Default battery post flight temps



1st Battery temp preflight temp


1st Battery post flight temp while on bench


1st Battery post flight temp


2nd Battery preflight temp


2nd Battery Post flight temp


2nd Battery Post flight temp


3rd Battery Preflight temp


3rd Battery post flight temp


3rd Battery post flight Temp
I was working close to home today and got home earlier than usual. It was a very nice day today so I deceided to head to the flying field and get you guys some post flight battery temps data. The ambient temp today was 50 deg. and maybe 3-5 mph winds. I flew the new Masters pattern. I flew it big and felt I flew it faster than I would like. My timer is set for 7 minutes and went off as I was entering the last maneuver on all 3 flights. Each pack was at 31% when I landed.

I have 2 sets of tray mounting rods set up in the plane because I have a couple lighter packs that needed to be moved up more.

I have also removed my battery labels because they are insulators that can trap heat inside the batteries. The batteries in these photos feel as hard now as they were when new and have an easy 30-50 flights a piece on them. I flew a lot last year but didn't log the flights. This year I am logging my flights and I already have 23 flights.
Old 03-23-2018, 10:12 AM
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Hi,
It is great that there is a tray like Yours available. Perhaps it is little on the heavy side but in light planes it should be OK. 40 gram would be to heavy in my already heave plane.
It seems not te be much possiblility to move batteri forward-back on the tray? That might be some disadvatage at least during initial trimming process when one is trying to find optimal center of gravito for the plane. Although it seems to be an advantage with metal tray for the cooling but I was thinking of the risk for short circuit by accidents during handling of tray and batteries? Murphys law... Your comment of that?
The fastening of the tray - is it not risk for "rattle" at the carbon tubes where it rest on these tubes? Is the locking pin absolutely bullet proof and impossible to come loose by accident during flight? Have any other users used Your tray yet and given any comments/feedback?

/Bo
Old 03-23-2018, 01:49 PM
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Default Battery tray weights ready to fly old vs new setup



My old factory supplied battery tray all up weight 1305.892 grams


My new battery tray all up weight 1301.265 grams


Locking pin first position requires some minor force to disengage. Pin in this photo is pulled all the way back and now requires force to disengage.


Locking pin in the second postion. Again requires minor force to engage and disengage. This is the preferred locking position of the pin.
Originally Posted by bem View Post
Hi,
It is great that there is a tray like Yours available. Perhaps it is little on the heavy side but in light planes it should be OK. 40 gram would be to heavy in my already heave plane.
It seems not te be much possiblility to move batteri forward-back on the tray? That might be some disadvatage at least during initial trimming process when one is trying to find optimal center of gravito for the plane. Although it seems to be an advantage with metal tray for the cooling but I was thinking of the risk for short circuit by accidents during handling of tray and batteries? Murphys law... Your comment of that?
The fastening of the tray - is it not risk for "rattle" at the carbon tubes where it rest on these tubes? Is the locking pin absolutely bullet proof and impossible to come loose by accident during flight? Have any other users used Your tray yet and given any comments/feedback?

/Bo
Hi Bo

You have asked some very good questions! Thanks for asking. The weight issue sounds heavy but really may not be as heavy as it sounds ready to fly. I weighed my old factory supplied set up that I pulled out on my Allure. The old set up used lots of Velcro. It had 2 long straps to go around the batteries. I also had a long piece down the entire length of the tray and 1 piece of Velcro on the bottom of the batteries to keep them from shifting. I also had 4 spacers between the batteries and had the 2 packs taped together the weight of which is not factored in to these numbers. The carbon rods are the same for both setups.

My old tray with battery ready to fly weight was 1305.892 grams.
My new aluminum tray set up is 1301.265 grams.

So in my situation I'm actually saving 4.627 grams. So basically an even up trade off. I have gotten rid of all my Velcro and have secured the batteries to my trays with Kevlar cord. I was told that's crazy!! lol. I haven't broken a cord yet. It's a calculated risk. This saved about 11 grams of weight. The Kevlar cord I'm using is rated to 58 Kilograms times 4 loops. The edge of the tray not as sharp as you may think.

There is actually about 50mm of reasonable adjustment to the batteries on the tray. Of course Ideally you would not to end up with the batteries in the center of the tray. The tray is very strong. I statically weight load tested it to 24 kilos without damage to tray. That exceeded my 20 g load expectation.

So Murphy and I have an understanding. I won't bother him if he don't bother me! The short circuit thing has crossed my mind a few times. Ideally one would use a dean type connector that has some sort of protection. I am using 4mm bullets and these are inherently as dangerous without an aluminum tray as with an aluminum tray. For my situation the benefits out weigh the risks.

The locking pin can not in any way accidentally come out. there is a small force required to get it engage and disengage. See the attached photos. The carbon rods are a very good fit. The locking pin side can see very minor movement. This can be eliminated with 1mm foam stick on dots from Seacraft. If you look close you can see them in the photos I have posted in previous posts. They are not necessary though.
Old 04-29-2018, 06:15 PM
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So I have about 70 flights on the Power Tray this season flying the new Masters pattern. The Masters pattern is super power hungry and required me to change my engine setup slightly. I never flown with an esc break active. I always flew with an idle setting. This year though the down line's especially on the vertical 8 were very fast. I set up my esc break and the down lines are much improved now. This break though eats up about 10% or 15% of my battery power over the course of a flight. Instead of landing with 30-40% left in my packs I have been coming back with 15-20% left. With all that being said I am wondering how my packs will hold up using the Power Tray. This year will be a true test of it's performance! I will keep y'all posted as the year progresses. I am proud to announce that The Power Tray's will soon be available thru Mike at F3A Unlimited!
Old 05-12-2018, 10:03 AM
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I picked up 3 new sets of batteries from F3a Unlimited the other day. These are Mikes new lighter 5s-5200 packs. I was happy with last years packs from F3a. The fact that these batteries are about 50 grams lighter overall is a bonus. It basically justifies the weight of my battery trays. Time to put the connectors on and strap on some trays!
Old 05-12-2018, 02:09 PM
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I got my new packs ready to go. Got them all on the battery trays. I am also using some sample cooling plates that just came in. With the addition of these cooling plates I will be able to remove heat from 2 sides of the batteries. The overall weight of the battery tray cooling plate and Velcro is 62g. This gives me the same amount of mass I used in my first prototype tray which worked well.

So so overall the old battery weighed 1299.90 grams on the tray ready to fly

The new batteries rtf weigh 1247.83. This includes both plates and Velcro.

Weight savings is a whopping 51.07 rtf!

Im really impressed with these batteries and will hopefully be flying them tomorrow.

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