Making a non-swappable LiPo swappable - Page 2 - RC Groups
Thread Tools
Jan 03, 2011, 08:30 AM
perpetual noob
_pokey's Avatar
Originally Posted by gbjbasdw
There seems to me to be no good reason why a 5888 helicopter motor should burn out because I'm using a 250mAh batttery
There are two good reasons: increased weight = higher load on the motors 100% of the time, and increased battery capacity = longer duty cycles. both of these things would explain premature motor failure on their own, but together they could really cause a problem. That's why it's so important to consider the weight of the battery, and the heat of the motors.

I think a better idea would be to buy another battery of the same capacity as the first and swap them out after a cooling off period. That would also negate any concerns about the battery protection circuitry.
Sign up now
to remove ads between posts
Jan 03, 2011, 12:02 PM
Registered User
I take your point about extra weight/load. I have no idea how much more a 250mAh battery would weigh over a 180mAh one so I can't really make a value judgement on this.

I'd be pretty happy to have another 3.7V 180mAh battery that I could swap as I do in my HoneyBee when the battery runs out.

I have no idea if it i possible to buy 180mAh batteries with protection circuitry already onboard ( as the original 5888 battery has ). Maybe someone out there can give me an internet link to possible candidates ??
Jan 03, 2011, 12:21 PM
perpetual noob
_pokey's Avatar

Here's one
but if you're going to remotely mount the charging circuitry, you don't need to buy a battery with it.
Jan 03, 2011, 01:51 PM
We can rebuild it!
djdavies83's Avatar
These are the cells I hve bough to do this mod on my S107, I have got a 5888 on it's way so I'm very tempted to do the swapmod with that too.


But they would need a stand alone charger as they have no PCB:

Here is the RcGroupes forum on this cell:
Jan 03, 2011, 02:32 PM
Registered User
fr0d0scious's Avatar
With the swapmod are you guys fitting a battery mount from the Heli's that have one from parts, or some other way?

Jan 04, 2011, 07:07 AM
We can rebuild it!
djdavies83's Avatar
Here's my experiments with the s107 removable upgrade.
S107 removable battery test (0 min 13 sec)

This shows the s107 hacked to take the same cells used in parkzone, E-flight and kyosho craft, the cells are completely "as is" off the self, I have done no mod to the cells! The pcb from the stock cell is in place between the main board and the "swapcell" to allow charging from the Stock charger.

S107 removable battery cell hack version 1 (1 min 2 sec)

This is just an experiment to see If it can be done and it is not perfect, there is plenty of space between the skids to have the cell external, I will do this in the version 2 hack by using some thin copper sheet the make little plates that will be held in place under the forward screws of the skid support, these plates will be soldered to a socket terminal each, i will also add a tiny square of Velcro to the Swapcell and the underside of the heli, this should make changing the swapcell really fast and simple compared to removing the canopy in my first version.

On my S107 mod the swapcell was happy the be laid flat in the stock cell tray, I've got the cells coming and a Eflight charger so I won't need to use the little PCB on my next mod.
Jan 04, 2011, 07:40 AM
Registered User
fr0d0scious's Avatar
Looks good DJ! Ultimately practical. Would be so good to have a multi battery charger lined up and a few heli's able to take advantage of it
Jan 04, 2011, 08:22 AM
We can rebuild it!
djdavies83's Avatar
I had enough money at christmas to buy the MSR I've been after for so long with it's 4 x 1S charger, decided to get a 5888 (still 4ch 2.4Ghz) a 2.4Ghz wireless camera and a load of bits to get alot of my resting helicopters back in the air.

I know the S026 is 210Mah cell but I may try and make these Miniaviation cells fit, that would make.....
  1. S107 (R3 needs rebuild)
  2. S107R5
  3. So26
  4. S026
  5. S026
  6. S026
  7. RED5 Dolphin/HX2
  8. 5888

that would need charging and modding, I bought enough parts to make 4 of the Scot Henion DIY LiPo chargers...

it's well liked by the people who have made it, I think I only paid about £8GBP for all the parts, and even then some parts came in a pack which left me a few spares, so the more I make the cheaper they are I guess.
Jan 07, 2011, 04:59 PM
Upstanding Member
Kurt's Avatar
FYI - I ordered 5x200mAH batteries w/ PCB from this seller on 12/20 for $8 and received them today:

They are very nicely made packs, on the outside at least. Tested 2, both 3.8V.
Weigh is about 6g as stated in the ad, vs about 4.5g for a 150mAH.
These 200mAH are the same width and thickness as the 150s but about 5mm longer.

I'm using Deans micro plugs to connect the battery in my Wessex conversion, which adds a bit less than 1g more. If anyone knows of smaller plugs please let me know!
Don't mind the extra weight on the Wessex conversion, it'll still be under 35g and need the CoG moved forward.
Last edited by Kurt; Jan 07, 2011 at 05:06 PM.
Jan 11, 2011, 10:06 AM
We can rebuild it!
djdavies83's Avatar
Adding a removable higher quality cell
Before cutting away wires or parts it's always a good idea to take photos of where the wires are, it saves a big head ache if things done work first time.


Take the overcharge cutoff pcb from the stock LiPo and solder a Micro JST XH connecter to the Lipo terminals, the same type of connecter found on the heli that is used for charging.

Now cut the plug off the charger cable, keep a good three inches on the plug part of the cable, it could come in handy for another mod. If you have some heat shrink tubing you shoud slide between one and two inches over the remaining wire of the charger, you don't want to have to unsolder it all to put it on if you forget!
The wires need to be soldered to the output (to the heli PCB) terminals Red to POS and White to NEG, if in doubt or you have different colour wires check the polarity with a volt meter.

With this mod can safely charge any cell that is capable of receiving the Mah provided by the charger, in this case I can charge a 180Mah Miniaviation in about half hour, the 350Mah S026 charger is just under the 2C max charge rating for this cell.

You will also need to solder a connecter to the LiPo terminals on the heli PCB.

With the overcharge cutoff PCB now part of the charger, (where it would be found in hobby grade chargers like the E-Flite MCX charger) you can charge one cell while flying the other, what to do with the other half of the Micro JST XH cable? Add it to your stock cell, here's a stock S107 cell as an example.
Last edited by djdavies83; Jan 11, 2011 at 02:17 PM.
Jan 17, 2011, 06:15 PM
We can rebuild it!
djdavies83's Avatar
Hey guys, just started a new thread, please view comment and vote.

Sorry for the shameless plug.
Sep 26, 2011, 07:37 AM
We can rebuild it!
djdavies83's Avatar
Ok time for a little bump, as this thread is for generic swappable upgrades rather than a specific model, here is my latest mod in progress over in the S107 Battery upgrade thread I've been working on something you may like....

It still need s abit of polishing but I may go into production on this, if anyone would like to beta test a prototype just PM me and we can work it out.
Sep 26, 2011, 08:21 AM

Questions more important than function here:

What is the suggested street on this invention? Do you realize how many of these you will have to sell, to replace even a minimum wage job? Have you targeted manufacturers at all?
Last edited by killbucket; Sep 26, 2011 at 07:15 PM.
Sep 26, 2011, 08:50 AM
We can rebuild it!
djdavies83's Avatar
Originally Posted by killbucket
What is the suggested street on this invention? Do you realize how many of these you will have to sell, to replace even a minimum wage job? Have you targeted manufacturers at all?
At present it's mainly just for me and others here who are tired of having to manage a LiPo in each heli, I have local access to a 3D printer very cheaply priced I know I could never live off this one item, I do hope to have somekind of Rc hobby related company in the future, this item (which still need s alittle work before I see about a manufacturer) would be one of quite a few small items such as TTTT parts and RTF craft and these toygrade thing we love to throw about.

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Non RC Lipo idocdave01 Dock Talk 7 Oct 09, 2010 09:04 PM
Discussion making a 3.7v lipo Jetskeeter Batteries and Chargers 9 Oct 02, 2010 09:03 PM
making battery swappable for extended run? victory7 Vendor Talk 1 Dec 19, 2004 05:11 PM
Any instructiontions out there on making non rotating can/cdrom motors? mrneutron Power Systems 2 Apr 23, 2004 06:28 AM