Fast battery change in pit stop... need ideas. - RC-Monster Forums

tom255 · **Fast battery change in pit stop... need ideas. -** 02.15.2009, 06:28 PM

Ok guys
I have made Battery Box for my XT8 but its pretty similar as everyone has. Just box with straps. Main issue that now we have new rules and separate 1/8 class for e-buggyes and truggyies. Problem that mains are 20 or 30 min. Last time was 20min.
I have 4S 5000mah battery option right now which is optimal for weight and time. But my setup lasts 15min (15min 40sec before 3.1V LVC kicks).
Have two ways bigger battery or fast battery change.
Big battery for me not OK because of weight and it anyway will not last for 30min with 8000mah battery.
Battery cange took about ~40sec with removing clips and etc then tried without clips and with some training I archived ~25sec, but in rush its pain if strap slips out etc Too much mess.
I thought maybe design box that can be changed without removing a body and disconecting a connector what is simple and fast takes time maximum 10 seconds
I have CNC and can do new chassis from Al and boxes from derlin so any idea is welcome.
First tought is changing from the side, second thought was from the bottom.
Locking mechanism must be a simple. Your inputs are welcome
Thanks and sorry for my bad English

Mozzy · 02.15.2009, 08:48 PM

Sorry I can't offer any advice on this other than, I know some of the major manufacturers are already on the case in developing a quickchange battrery tray.

Perhaps your option is to reduce the kv of your motor to draw less power & gear it up to get a longer runtime on 5S. If you're not already.

I run a Neu 1700kv on 5S 5000 in my CRT & get 25min runtimes. What's your setup?

suicideneil · 02.15.2009, 08:56 PM

Hmm, I have seen a quick-change battery setup on here before- long time ago though, so the thread is nodoubt burried.

A hinged battery holder strap/plate with a simple locking mechanism at the other end would be good for a quick change over- if you can incorporate the battery plug(s) into the strap then all you would have to do is close the hinge to connect up the plug; Im thinking bullets would be good or those ec5/ ec8 connectors from losi maybe.

Spiffy drawing can be supplied if needed

This would need the shell to be removed to do the change over though, but a sideways removal version would work too- lots of custom work envolved either way.

tom255 · 02.16.2009, 04:57 AM

custom work not issue for me. EC5 connectors are 5mm in diam and similar to 4mm? Issue with 5.5mm bullets and 6mm bullets that they are not last long they tend get sloppy with time. 4mm banana stile connectors are OK but dunno how they hold up 120A of current. To use deans its still the option.
I dont want to remove the shell its waist of time, better slip battery from side from spec ial shell cutout from side.

Mozzy my setup is: CC2200KV combo with Polyquest and Zippy-h 4S 5Ah batteries. Car geared to ~40mph.
New eficent motor and new batteries are new expenses for me besides rules are for 4S batts and I just bought two 4S 5Ah PQ batts. And still if you plan hold weight under control you need reduce batt capacity then your gain in time not so huge, only from efficency maybe 10%
I will try to draw something maybe post
Truggy weight is right now 4460g and I want to shave 100-200 grams more

Mozzy · 02.16.2009, 05:30 AM

Quote:

Originally Posted by tom255

custom work not issue for me. EC5 connectors are 5mm in diam and similar to 4mm? Issue with 5.5mm bullets and 6mm bullets that they are not last long they tend get sloppy with time. 4mm banana stile connectors are OK but dunno how they hold up 120A of current. To use deans its still the option.
I dont want to remove the shell its waist of time, better slip battery from side from spec ial shell cutout from side.

Mozzy my setup is: CC2200KV combo with Polyquest and Zippy-h 4S 5Ah batteries. Car geared to ~40mph.
New eficent motor and new batteries are new expenses for me besides rules are for 4S batts and I just bought two 4S 5Ah PQ batts. And still if you plan hold weight under control you need reduce batt capacity then your gain in time not so huge, only from efficency maybe 10%
I will try to draw something maybe post
Truggy weight is right now 4460g and I want to shave 100-200 grams more

4.46kg?

What truggy are you using?

My CRT is 5kgs both with Neu etc (listed in my sig) & I've been testing the 80mm Medusa with 2 x 2s Intellect 4600 hardcase packs to make 4S which still weighs 5kgs.

Do tell how you got this weight. Would you mind posting a few pics of your machine & how you've cut the weight?

I can't wait for this nano technology in batt's to be released to the general public.

Cheers Mozz.

starscream · 02.16.2009, 05:43 AM

Instead of using clips, use velcro on the body and mud guards to hold on the body. Use a tight batt tray with only one velcro strap.

This is the best way to acheive a quick batt change without major engineering work.

If 1/8th scale electric grows as big as I hope it does, we'll be running 10-12 minute mains not 30.

tom255 · 02.16.2009, 05:54 AM

Actualy I didnt do nothing special.
My truggy is Xray XT8, no mech brakes or so. Battery box weight is 70grams, motor mount is similat to mikes one, but mine. Use MTR Proline tires
I will post some pics.

George16 · 02.16.2009, 05:57 AM

Quote:

Originally Posted by Mozzy

4.46kg?

What truggy are you using?

My CRT is 5kgs both with Neu etc (listed in my sig) & I've been testing the 80mm Medusa with 2 x 2s Intellect 4600 hardcase packs to make 4S which still weighs 5kgs.

Do tell how you got this weight. Would you mind posting a few pics of your machine & how you've cut the weight?

I can't wait for this nano technology in batt's to be released to the general public.

Cheers Mozz.

My truggy's weight:

Kyosho ST RR:
RTR with 5S 6000mah Polyquest lipos, TeknoRC Neu 1515 1Y, CF MTR on LPR dish wheels.
10.23 lb - 4.65 kgs. Weighed using USPS digital scale.

Jabe · 02.16.2009, 06:05 AM

I think that fastest way would be trought bottom.
Cut piece out of bottom plate, size of battery, then make some guide posts for it to make it move smoothly up and down, then something for quick lock it from bottom.
Then you could have two battery trays, one for each.

tom255 · 02.16.2009, 08:43 AM

In first tought, fixing from bottom was OK, but I am realy worry about chassis flex and weakness. If I use guide posts I need at least two locking mechanisms, And locking from bottom looks risky too for me. Why not use simple way one side of box going behind of chassis (difficult explain) like usualy battery trays in different devices and second side have locking mechanism and maybe one or two guides with integrated locking mechanism. But dont have nice ideas about locking yet.

Now I think inserting battery from side is bit better. My english is bad and difficult to explain but I drawed what I mean.
On the picture Green is the box and red same box but how I mount it. On topyou can see how box fix to the chassis. Box sides slips to the socket.
http://www.hot.ee/tom255/design.JPG

JERRY2KONE · **Best idea. -** 02.16.2009, 09:28 AM

I would think that the best way is to have a cutout area in the sides of the body, with custom trays that allow for side battery insertion. Using some kind of soft liner to compress the battery as you install it(making it snug), and finally having the snap-type locking mechanism double as some kind of snap connector. Say with a slight push or pull it opens up and the battery slides out, and then a new one slides right in. Finishing with a snapping connector plug that holds the battery in place.. I agree that the battery box should be a custom-made derlin or even thin aluminum battery box. It is just a matter of time before it is presented to us from the major manufacturers, but if you could mod something up as a prototype that would be a good start. Good luck and keep us informed of your progress.

rootar · 02.16.2009, 12:15 PM

you could do a solid hinged aluminum strap with a twist lock knob on the other end so you wouldnt have any straps to mess with. a little trick i use is to sew a small button on your strap tip so they wont pull out of the loops, this saves a good 5-10 seconds for m, i have done battery swaps during a race in 22 seconds including taking the body off.

Jabe · 02.16.2009, 07:50 PM

Lets see, things that makes battery swap slower are, opening and closing straps (velcro), disconnecting and connecting plugs, taking off body and putting it back. So you need "6 points" to swap batterys.
So you should get rid of velcro straps and use some locking mechanism, here you save "1 point", you should mount battery connectors, so when you slide battery in or out, you dont have to disconnect or connect, those disconnect and connect "by itself", so now you have saved "3 points".
Combine here machanism that allows you to swap batterys whitout touching body and you have saved "5 points".

Im thinking, battery tray, that slides from back of car (need hole in body), quick release (like in your picture) and mounted connectors, you would need somekind of quide posts where battery tray slides, so it matches those connectors.
Just open quick release and slide battery out, then just slide new battery in and go go. You should be somewhere in 5secs, in battery swap.

tom255 · 02.26.2009, 01:08 PM

OK here some 3d pics what we designed with my friend he is pretty handy with his 3d cam software.
I will do custom chassis which is based on original chassis, posible that I will do chassis from 4mm CF or if I find tought aluminium 7075-T6 or 2014-T6 I wll do from that.
some update will come soon.

BrianG · 02.26.2009, 01:37 PM

Any quick-change solution will not be perfect unless it is designed around a specific battery size. Fine if you are a serious racer, but not for the casual type (like myself).

I have also been thinking of this topic though, merely for convenience, and keep coming back to an idea where the body has a cutout on the side where you can access the battery. Simply eliminating the need to remove/install body clips and the body reduces swap time considerably. Then, a couple clips holding the battery in (kinda like how the Slash/Pede trays work) releases the pack. The plug will still be Deans. I don't know if I would trust any connection solution that is integrated into the tray simply because of the abuse these vehicle endure. I think this would be more of a generic solution. Not as fast as a solution geared towards a specific pack, but certainly more versatile.

As battery technology gets better, capacity vs weight will get better as well, and the need to swap batteries will not be needed. Even if such a mechanism is created, I think it will be obsolete before the design is perfected.