HOW TO: Make your own Lipo Hardcase

[Mr. Constructor]

This time i would try to do some little How-To for making a hard case around any given Lipo Battery in order to have it more securely used in cars.

First of all you have to ripp of the shrink tubing that might be wrapped around the battery, then you have to measure your whole battery in all dimensions.
Please be aware that the conncetions are now accessible and that a caliper is made out of steel - a SHORT CUT is POSSIBLE !

It doesn´t matter if your battery is a PCB or direct solder type. The PCB Type allows the xchange of the cables to 4 and 2mm connectors like seen on the picture below. If the cables are directly soldered to the tabs of the cells (you then will not have a pull out protection either) you should re-reoute the cables in that way that they´re coming out from the side (see also last picture for this). You will then have a small pull out protection added.

[Mr. Constructor]

Within the second step you should draw a very precise and exact drawing of the battery in a form that a full shablone will come out. This is easily done either via a drawing, CAD programm or via Hands and a little time.

Please notice that the below shown pictures has a longer side and a shorter side - compare upper end of the middle on the right side with the left side.
This is used to get a small gap in the housing for having the connectors pocked out. This should be done similar if you do want to use a directly to the taps soldered cable battery. the opening shall be redueced in this case to add a extra pull out safety.

This Part is totally versatile as you will use your own Datas do scetch these cutout helper - therefore nearly every Lipo could be protected with and additional housing.

[Mr. Constructor]

If you´re wiling to re-use the drawing on more than one Lipo battery you will have to scetch a outer line around it on a sheet of lexan or PET-A or even PET.
The thickness has to be around 0,5-0,7mm - that´s enough and will had a lot of safety to the battery.

The scetch will be put on the sheet (i used a scetch made out of 2 parts, you could use as many parts as you like or your sheet´s size gives you room) via some heavy weights that nothing will be moved during the marking.

Then mark around the outer lines with a permanent marker - you could remove the weights after everything has been done.

Then you could check the drawn lines by removing the paper - if everything is fine, then do NOT cut it out that fast.

[Mr. Constructor]

You will first have to cut a few bending lines into it.
Use a sharp knife and only little pressure - in order to only slightly cut it in, not fully through the material.
The Housing should then look like the picture below, the second picture shows how the sheet shall be bend to reach a housing.

Please take you tim and make the bending very exact, otherwise the battery will have play within the housing wich isn´t wanted.
Of course you could use a printed out (even a hand drawing could be copied and then re-printed) scetch to first check out if everything will fit - make a paper sample first if you´re not 100% shure.

[Mr. Constructor]

Before applying shrink tube around the new housing to fuly seal it you should make yourself a polarity reminder. The inner side of the clean sheet is used for marking the Plus and Minus poles onto the inside. The marking was then covered against rubbing with a see-through tape (like tesa or whatever).

You will then be able to see the right polarity even when the cables are removed - this step might not apply if you´re using a direct-soldered-the-cables-to-the-taps-lipo.

After this, have it carefully shrinked in, normally the edges will stay in 90 degrees angles and the battery housing will be firmly close after shrinking.
I used see-through shrinking in order to see any damages at the lipo cells, normal white or black shrink tube could also be used.

The last step is to cut a few openings (one for the small 2mm connector has to be made into the plastic during the above steps) for the cables or connectors. If you´re using 4mm connectors you could solder the wires by 90 degrees at the 4mm banana plugsin order to easily access the battery in almost any car.

Please take a note: The shown 90 degrees cable connection was to thick and stands out too much on the battery - please dremel down the 4mm plugs to reach a very short cable stand out in this area.

Hopefully this small How-To might help you to solve some safety issues with these lipo cells. however these protection cannot withstand any vera hard punishment, but it is WAY better than nothing like shrinktube around the costly battery packs. The weight isn´t that much, only a few gramms, therefore it could be ignored.

The safety could be pushed up as the sheet´s used could become as thick as you want.

Have fun with it !

[Demon-TC3]

an excellent guide - i may have to re-build my Lipo's!


take care,
Demon

[TheSteve]

I like the idea of the cases - you really need to improve the solder connections on the tubes though...ouch, lots of loss in those.

[Mr. Constructor]

Yes, you´re absolutely right.

I did a few changes to the batteries now (the pictures where taken around 1-2 weeks ago) and they do now have an internal resistance of under 20 milliohm per 2S Pack - compared to normal NiMh´s: this is HALF the resistance !!

They´re pretty cool now, even when taking these words for 100%, the cells ran at around 45 degrees celsius even after hard pushes in an 1:8 Truggy.

Of course this "Homemade" Case is only suitable for cells/packs that will not exceed the maximum space used in modern RC Cars - it shall fit the car even if the case adds 1-1,2mm to the total lenght, width and height.

But to be honest in most cases there still is room left, esp. in 2WD Buggys or Stadium Trucks. The only worst thing are the 90 degrees cables, these have to be really short - they cannot poke out more than 2-3mm on the side, the ones shown here are way to long. If you´re searching for very short 4mm plugs, then take a look at the Peak or Team Orion site, the ones used for their own hardcased lipos are extremely short and could be purchased separately.

[Mr. Constructor]

Here are some new pics from these Cases, of course other battery types could also be "converted".

I also show you some comparison Pictures between these Celly and a Team Orion / Peak Racing 3200er Hardcase Lipo. THe other pics show a 4S 4400 mAh special Pack that is used on my 1:8 Conversion Kits (only the newer ones could use these huge Cells).

Here we go:

[Mr. Constructor]

And here´s the rest of the pictures:

[aqwut]

Nice!... I did the same things to my lipo.... but I used that vacuform plastic.. it gets really hard when heated up... another method you could use is just to triple or quadruple shrink wrap ur Lipos.. this worked well for me also...