battery management system (BMS)?

I want to know about bms -how it works -how to install -how to get output we r using 1kw motor and 48v battery voltage circuit diagrams will b highly appreciated some simulation files or circuit diagrams thnx

Question by jerry.sra 


How to create a 10w load that turns on once the voltage has risen to 4.09vdc and above?

I want to top balance lithium-iron batteries however, all the BMS that I have seen are rated at 4.25v with an error of +- 0.05v. Is it possible to use zener diodes, diodes and/or 3.2-3.6v LEDs to create a load that turns on at 4.09v with an error of 0.05v?

Question by briandean2002   |  last reply


Wireless Battery Management System? I'm looking for a device to transmit the voltage of each individual battery?

I'm converting my 68 VW Bug to an EV. I'm using twelve Trojan 1275 12v batteries for a total system voltage of 144 volts. I'm looking for a wireless device that can transmit the voltage of each battery to an onboard laptop. I would of course use 12 of them so I can manage each battery. I'll then write an app to display an integrated volt meter on the laptop. I'm designing the Bug to have plenty of get-up and go but the trade off of course is lower range. I want to be able to monitor my usage to eek out the greatest possible range while monitoring my overall usage. In addition by monitoring each battery I can isolate and identify poorly performing batteries. I saw such a device advertised on the homepage of Instructables a couple of months ago. I wasn't thinking ahead and didn't take sufficient note of what I saw.

Question by kcrichar 


Hybrid electric vehicals, batteries going serial or parallel

Can I wire 7000 lithium ion battery cells (about 75kwh) in parallel, and then use a lightweight bike engine hooked to a DC generator and connected in series to the batteries to boost voltage? Are there any flows in this design concept, for use in a hybrid race vehicle to increase the longevity of the batteries?I am trying to develop a race track car which is hybrid, thus utilizing electric motors immense torque.We build original race cars with common petrol engines but now I’m seriously thinking of developing a next generation race car. I know batteries don’t last long in high drain situations and thus any race car I sell will need a battery replacement after a race season. I’m sure this will be bad for business. Thus this is why I’m thinking of ideas to prolong the battery life by reducing current drainage. That’s why I want to have an engine generator with its sole purpose is just to boost voltage, and about 20,000ah worth of batteries connected in parallel so I reduce current demand per battery cell to well under 1C. Giving a Tesla p100d as an example I would require about 1200 amps and 400 volts to produce 480kw of power. If wire all 7000 battery cells in parallel to produce the same amount of current then each cell will need to provide about 0.18amps that’s very low to sustain longevity of the batteries. The generator is then connected in series to help boost the system voltage to 400vIn extrem simple terms, (the batteries provide the current, and the engine generator provides the voltage)I hope you understand why I’m looking at it this way. I know it might not be the most efficient way, but is it a practical doable way? Thanks

Topic by SamA196   |  last reply


Recommendations for lipo cutoff device

I've been looking for a device similar to a battery alarm for 4s lipos that can cut off the power when any one of the cells drops below a certain voltage instead of just sounding an alarm, i've been told that i can get a bms circuit which should be able to do this and that i should try to find the best one i can but i don't really know exactly what to search for. can someone recommend a small and affordable bms please? i won't be charging through it as i have a separate balance charger, i want it purely as a cut off device for when the batteries are in use...

Topic by ambientvoid   |  last reply


should BM make the ADS out of knex

I have been trying to convince BM to make this for a while now and decided to start a poll to see if I could convince him to build it. Here is the wiki article  HERE Put a yes or no answer below,some reasons of why you said yes/no would also be nice =)

Topic by Johnhall14   |  last reply


12v 18650 battery with bms but no balance. Can we use 3.7v output from it for powering bluetooth module directly?

I am trying to make Boombox Speaker. The amplifier is 12v and the bluetooth module is 3-5v input. I have a single 12v BMS module, ofcourse with 4.2v, 8.4v, 12.6v dividers. Now suppose I power the amplifier with total output, it works fine. But can I take the output of one single divider i.e. 0-4.2v for the bluetooth module sepeartely and keep using the 12v for the amplifier?

Question by SalilG2 


How to build a 5Kwh Power Wall using Headway 38120 LifePo4 Batteries

Frequent power cut during the summer and hours of no power issue during the monsoon makes our lives miserable. It's a common picture in rural areas where the overhead power line connection is prevalent. This led me to think about an alternative power back up that would be way better than the conventional LA or SLA battery solutions. With the constant advancement in the technology, new dimensions are being unfolded to us and I believe, the powerful Headway 38120 batteries are going to reign in the market for quite sometime. I need help from the experts to build a 5kwa Power Wall using Headway 38130 LifePo4 cells and an Inverter too. The parameters are: Output Voltage: 230v, Max Load: >500wh (I'm looking for 10hrs bkp= 5kwh), I'm clueless about how many cells I might need and how many of them will be in series and in parallel connection. Do I need a custom built charger for these LifePo4 cells and BMS too? Please help me up.

Topic by akik007   |  last reply


What powersupply or charger should I use?

It is for a battery pack for a cordless drill made of good sony high drain cells from "died" makita packs. It is for another drill then makita. I found this bms: http://www.ebay.com/itm/Protection-Balance-Module-PCM-BMS-21A-for-5S-18-5V-Li-ion-Li-Po-battery-5S21W005-/321790566576? Should I use an Imax charger, or a regular notebook charger, about 19-21 volts? http://www.ebay.nl/itm/iMAX-B6-Digital-RC-Lipo-NiMH-battery-Balance-Charger-AC-Power-Adapter-PD1205-/291180722863?var=&hash;=item43cbb93aaf

Question by rnijland   |  last reply


My drawings

Just some of my drawings from new to old

Topic by kwintisolo12234   |  last reply



How to convert a google sketchup project into a bmp or other image format?

I tried to convert the final project from googlesketchup but nothing.I was wondering if there is a programm which does this work

Question by arv_christos   |  last reply


Need Help in Building DIY LiFePo4 battery pack

Hello all, my wishes to everyoneam very new to this Electrical, Batteries and DIY, with the help of google i can gained little knowledge with that i could able to gather products to build my own electric scooter (1500W 60V HUb Motor and 60-72V regenerative controller with Daly LiFePO4 60V 45A Comm BMSactually am planning to Build 60V 36Ah LiFePO4 Battery Pack Using 19S6PBattery : LiFePO4 32650 3.2V 6Ah BMS : Daly LiFePO4 60V 45A Comm BMS Controller : 60-72V 1500W 35A am confused when times comes to assemble the battery pack, pls help and guide me with appropriate diagram or chart for 19S6P pack, help me how to connect batteries in series and parallel along with BMS so that i can build my first battery pack with out no mistakes Do i have use capacitors while connecting batteries, if so provide me the type already bought the battery tab spot welder from my friend for reference i have attached pictures of the products i mentioned and bought already please don't mind if i asked too much help/suggestions, want to make my own DIY battery pack by learning ad gather information about battery pack and build one one in perfect way Thanks in Advance

Topic by tejeyes 


Charge AND balance 4 Lipo packs? Series Parallel solution help.

I have x4 identical Turnigy Graphene Professional 5200mAh 3S2P 15C LiPo Packs w/XT60 - and I need 22.2v out of them for a portable boombox project.   I have x2 12S 30A BMS's to balance / charge on board and a 600w 48v 12.5 A power supply. By wiring up the battery packs in series then parallel to get the 22.2v output - if I then connected the BMS (either by directly wiring to each cell or using the pack balance plugs) would it would cause a short circuit through the balance wires?    The ideal solution would be a wall plug power supply that plugs into the (sealed) boombox and charges all of the batteries through the BMS's. Is there any way of achieving this through parallel charging (not a fan) or could I switch easily between the two wiring set ups?   I'm trying to avoid buying a £200 Lipo charger and connect the batteries directly or keep disassembling the boombox every time it needs charging. Thanks

Question by MechaMatt   |  last reply


How should i name my knex ballmachine? Answered

I need a name for my ballmachine. And i hope you can help. Picture http://desmond.imageshack.us/Himg215/scaled.php?server=215&filename;=bild0022pl.jpg&res;=medium

Question by sathothy   |  last reply


can some one post a ball machine called kriss kross?

Well i found a cool look bm ok ki (ki bad!) and i would like to know if some one could post it

Question by knexsuperbuilderfreak   |  last reply


Battery options for a reverse para-scope.

Hey everyone!so I'm building a para-scope for the dock at our cottage, except it will be used to peer down into the water and watch the fish. Just need a battery solution other then a 12V sealed lead acid battery that I already have. (hopefully light weight)1X waterproof camera tested @12 V (maybe 9v? test soon but does not work at 5v)1x lcd screen tested @ 5-12Vplus some pvc piping and other bits and bobs.....I have some spare lipos that I can connect in series but a bms would require 12.6v (Less voltage drop?) Ideas?BMS link ==> https://leeselectronic.com/en/product/16178.html?...9V battery will not last long enoughAny other ideas that will not cost an arm and a leg?

Question by Wired_Mist   |  last reply


The 12345 series of knex ball machines

Hi guys! Im gonna make 5 mini ball machines!! i will make them and you will decide on the winner They will be mini!! so dont go off thinking they're gonna be like shadowman's awesome bm's I'll make\post the first one today or tommorow -megametal8

Topic by MegaMetal8   |  last reply


Something to build?

Hey knexers ANYTHING KNEX  APART FROM CARS But not too many pieces This includes machines, BM, guns, contraptions I don't really see the point in knex cars, you just push them along Only tell me if its like a REALLY cool car Please spread! Thanks mm8

Question by MegaMetal8   |  last reply


Failed MTAR

Hey guys. Well, after seeing BM's latest Bullpup (L85A2), I thought I'd try my hand (again) a a new Bullpup. I intended to build an MTAR from Black Ops 2, but as you can see by my title, I failed / was unhappy with what I had. If you'd like to, go ahead and finish it. -The Red Book of Westmarch

Topic by The Red Book of Westmarch   |  last reply


How to charge a Powerpack of 18650 li-ion cells 4s3p 14.8V?

I plan to make a portable audio system with 4 speakers and a subwoofer which are driven by a 12v TDA2030A 2.1 Amplifier. Everything is already packed in a small enclosure (approx. 30x15x30cm) and works fine so far. At the moment the amp gets it's signal from a 3.5mm audio jack and the power is provided via a 12v 1.5Ah wall wart. That's what I have for now. But that's not really portable right? So to complete my project I want to add 2 more things - a bluetooth receiver powered with 5v and of course I need to get this thing of the mains. That's where my questions actually starts. I've read tons of forum posts, instructions and watched a lot of videos about making a 12v battery pack but I'm confused with all that information. From what I've read 18650 Lithium-Ion batteries have an excellent power density and would suit my system best (small enclosure and portable). But of course I'm open for new ideas anytime. I planed to make the power pack out of 4s3p 18650's from an old laptop battery (don't have the exact data of them yet). So the pack would provide about 8Ah at 14.8V nominal. With a step down converter to 12v it't could power the amp and for the bluetooth I would use a car usb adapter to get the 5v needed. So far so good, but regarding the power pack I have a few questions. 1. Would a 3s4p (11.1V) arrangement be good enough to power the 12v amp since the 11.1V are in average right? 2. The biggest question I have is - How to charge that thing? As I want to have it as portable as possible, to be able to charge it anywhere from a normal power socket would be ideal. I know there are dedicated chargers for lithium batteries but they are quite expansive and not really handy to carry around. Is there any other solution to handle that? 3. BMS, PCB - I'm confused. From what I've read, to charge multiple cells they have to be in balance right? An over-charging and over-discharging can lead to fire/explosions and to prevent that a BMS is essential right? But first - how do i connect that BMS? Only to each of the parallel strings or to every single cell? Second, is it possible to use that BMS to charge the pack? Maybe also in balance? 4. For the case that the 18650 from the laptop battery are undercharged, where is limit to withdraw them and to charge them to balance with a TP4065 at 1A? That's it for now. Sorry for the long text and thank you for reading through it. I read so much on the net but didn't find the right answer for me.

Question by Johnny-Pi   |  last reply


Best non-lithium battery technology

Hi Instructables community! I am looking for any insight / suggestions regarding what battery technology (non-lithium) that offers the best specific energy (MJ/Kg), preferably rechargeable and reliable. My research led me to looking to consider rechargeable alkaline batteries, given data on wikipedia (the BEST source ;)  ) but are these even manufactured? I cannot find any place to buy them. BACKGROUND: I am in need of this for the design for the solar car team at UVa, as the BMS (Battery Managment System) mandates a backup battery that is separate and any lithium technology is not allowed.

Question by -max-   |  last reply


Knex BMSG

Here is my Knex tube fed, shell ejecting BM shotgun. It was fed off tube feeding shell bullets, which were three grey spacers taped together with a white rod on the inside. It fired white rods only 30FT with two bands. It held 5 shell loaded rounds which ejected where a real shotgun would. The way you'd eject the empty shell would be to press the button in pictures 7 & 8, it would automatically load in another shell waiting to be fired. Ram rod powered. Built for engineering creativity, not looks! It was a fantastic little gun. There are no more pictures, the gun is no longer together.

Topic by DELETED_Blue Mullet 2   |  last reply


BMSS-62v2.5 - ???

I have decided to make a forum topic for the BMSS-62 so that I can keep updating you guys on new versions of the gun. Right now there is v2.5, v2.8, and v2.9. Here are the pictures.Historyv1.0: I made a good breech-mag barrel combo with no trigger.v2.0 Used the breech-mag combo and added body with trigger.v2.2 added stock.v2.5 Added handle and reinforced mag the barrel.v2.8 Added bendys to make the gun look better. It is now able to hold dsman1's sidearm on the side.v2.9 Fixed the handle guard and made the handle comfier.

Topic by jollex   |  last reply


Solar LED strip using lgabc21865

I have 2 solar panels that were used to charge shed lights (2 x AA batteries from each panel). And some lgabc21865 lap top batteries. I'm curious what would be needed to run some 12v led strip lights instead of the poor lights that were originally there using the LG batteries. Or if the idea is even worth the trouble. I'm very new to electronics in this capacity of setting up batteries with BMS. But I feel like it would be a good starting point to learning and useful at the same time. I have seen many tutorials on setting up battery packs with the batteries, but nothing for charging with solar or outputting 12v. Everything seems to run 5v using the TP4056 and micro USB. Any advice or information would be super helpful.

Question by NathanA52   |  last reply


Question: I made a power pack of 18650s with protection board. Is voltage drop normal?

I made a power pack using 18650 batteries from an old laptop. All batteries tested individually are good. 4 batteries in 2S format. I used a cheap 2S 3Amp rated protection board I got on Ebay from China. I correctly connected all the terminals and properly soldered, B+/B- to the +/- of the final ends of battery and BM to the middle.The voltage measured directly at the battery terminals (at B+/B-) is 8.4 volts but at P+/P- (the input/output terminals of the board) it measures 7.5. Which means this board will not produce more than 7.5 volt usable voltage even when the batteries are fully charged to 8.4. Is that expected and normal? or is there a problem with the board.Thanks for help.

Question by ju1234   |  last reply


Cellular NiMH battery pack; can they be charged directly ?

I have some perfectly good Nokia battery packs from useless 5165 phones (Model "bms-2s"). They are 3.6 - 3.7V NiMH and have 4 flat copper contacts which 'make' with the phones by sliding on. The Phones have matching 'teeth' and happily 'smart' charge either these or the newer LI batteries. (Clear pic here: http://www.jpldisplays.com.au/catalog/images/CPB-BLS2N.jpg ) I want to know if it is OK to simply connect the matching output from the charger across the +/- terminals (the 2 outer ones AFAIK...) and charge them directly ? These work great to power LEDs and I already made a 5165 LED torch, but it was a pain to do and I'd rather just use the batteries naked. Thanks for any info !

Question by vtsnaab   |  last reply


using a lipo charger to charge a SLA? Answered

Hey everyone ! I'm planning to use a lipo charger from my Ebike to charge some scooter SLA batteries. I'm more of a li-po guy and haven't tried charging 3 SLA's in series before. Original lipo was a 10s 8.8Ah 36V (nominal, maxed out at 42V) and had an on board BMS that took a stright 42V input from the charger. the charger for it will deviver 42V @ 2amp and will let current flow until it hits 42V then automatically shuts off. The scooter batteries are 3X 12V 20ah  (six cell I assume?) by all-means, I should be able to wire the three batteries in series, (3 x 14.5V = 43.5V) then my charger should be a direct replacement right? Still need to manually balance them occasionally but for daily use on a 2amp charge should be ok eh?

Question by Wired_Mist   |  last reply


K'NEX SL8

Hey guys! Well, a couple days before BM and I posted our BM59 PARA, JonnyBGood asked me to build a SL8. At first I had a mind to turn him down, as SW already had an amazing one, but, in the end, I took him up on his offer, and this SL8 is my first installment. I am not quite finished with it yet, and it could use a bit more work, but over all, it is almost finished. I don't have much time to write about this gun now, so here is the features list: Features: Nice and sturdy Carry handle Great pin pull Looks boss with scope Great range: 50 - 60 ft. Nice stock Looks just like a SL8 (IMO) Well, that is all for now. Tell me how I could improve it before I post it. -The Red Book of Westmarch

Topic by The Red Book of Westmarch   |  last reply


Can I charge and use 18650's simultaneously or better charged first, block from solar, then use with the power inverter?

Hi all, I have been into DIY Solar / Wind for a while. Everything been working great until I planned to replace my lead acid batteries for the 3.6V LG HG2 3000mAh 18650's. With the lead acid I could power my house anytime during day (using solar panels) or night off-grid with ease. So, I bought a lot of 200 18650's and spot welded them in 4S50P. Balanced them, and all that good stuff (time consuming, and a learning experience). Installed a BMS on it too, have a 30 Amp charge controller for 4x100W solar panels which I reserved for this project. Now, I have been searching for a while if these 18650's can be used anytime (connected to solar panels and with the power inverter feeding the house at the same time) ... with no success.

Question by LuisE47   |  last reply


How to build battery pack 9.6v from 18650 batteries?

I would like to create a good battery pack for my dead hilti drill. Originel nc-cd 9.6v battery. I have some panasonic cgr18650cg batterys here.  But when 3 in series, the voltage is higher. Maybe the drill can work with a higher voltage but I dont know. Will it work, would like to create first a 3S pack and maybe later a 3S2P  I need a PCB and thinking something like this one : http://www.ebay.nl/itm/12-6V-8A-w-Balance-Li-ion-Lithium-18650-Battery-BMS-PCB-Charger-Protection-Board-/321853922824?hash=item4aeffd1e08 Or this one? http://www.ebay.nl/itm/3-Cells-Li-ion-Battery-18650-14450-Input-Ouput-Protection-Board-PCB-12-6V-8A-/321804037521?hash=item4aed03ed91 And how to charge a pack, can I use a common 12v laptop adapter or other adapters or specia li-ion charger? I dont think the original ni-cd charger can be used with pcb's above?

Question by rnijland   |  last reply


Series Parallel 4S2P Li-Ion Battery Pack

Hey guys,I'm busy making a boombox*, my first version had an old small car battery inside which obviously weighed a tonne!Looking to make the switch to Li-Ion.I have already purchased for the battery pack:8 x Samsung 30Q Li-Ion batteries (3000mAh - 3.7V)BMS board I found online (CF-4S30A-A)2 x 4S 18650 Battery Holders.I'm unsure how to go about setting up the batteries and balance cables etc. Need the 4S2P configuration for the Voltage.I want to expand this in the future by increasing to maybe 3P or 4P (depending on how much space I'll need in my boombox).I have watched multiple YouTube videos but sick of watching 15 minutes of somebody soldering. I understand the safety aspects of Li-Ion.*I know this project could have been done with Raspberry Pi or Arduino but the rest of the guys who will use this would not be familiar with hence why I went with a Car Stereo.If anybody has any criticism, I welcome it but make it constructive!(I know I'll get a roasting for the terrible MS Word wiring diagram I made)

Question by alexmallaburn 


Red's Reliable (R3) Mods and Review

Whatup. So I built Red's Reliable (R3). It was pretty ownage, but there were a few things that popped out at me as annoying, but easily fixed/modded: -Flimsy trigger guard and short trigger -The mag wasn't preloadable -Looked a little long (imo) -Asymmetric at 6 layers -Pin was hard to grasp and could wobble once pulled -Back sights were flimsy -Pieces would break where the pin hit the gun Now, these are all the negative things, but in the original gun, the positives outweigh them. Here are all the things I love about this gun: -Looks AMAZING -Fires green rod/grey connector ammo, my second favorite type -Shoots 35-45 feet (for me), so pretty powerful at close-mid range -Really good pin pull distance -Sturdy -Almost never jams -Reliable mech (heh heh) -Did I mention it looks amazing? So I decided to mod the gun and fix all the things that annoyed me. Here's what my mods have done: +Mag is now preloadable (Has a ceiling) +Trigger guard is sturdy, and trigger is longer +Shorter front barrel (which increases range because of less barrel to bounce off of) +Symmetric, and has metallic 6th and 7th layers (Sorry for jacking your style BM but it looks better that way) +Pin is now much easier to grasp, and doesn't move left or right when pulled +Back sights are now very sturdy +Where the pin hits the gun is now reinforced so that no pieces are damaged when the gun fires So that's kinda an overview/review of the gun. Before the mods, it was like a 7/10. After, I would rate it at an 8.5/10. Props to Red for making such a great gun. More Mods/Review - Johnhall14's Tactical Shotgun v2

Topic by FlyingFish10   |  last reply


Big battery bank project. Circuit related questions?

Hello everyone! I have a project in my mind and I would love some guidance and some ideas if possible. I already have a lot of 18650 batteries in an “acceptable” state (1800-2100mAh each) and I am planning to make a large battery bank, for use in camping mostly (smartphone charging, led bulbs, electrical air pumps 12v, etc) I did read a lot of articles in here about battery banks, but i didn't find something as complex as my idea. I have already made a 12v battery pack with 12x18650, 3 rows in parallel, of 4 in series in each row. My goal was to operate a 12v air pump for inflatable mattresses. It worked like a charm! (Also created with instructions from here! Thanks for that!) But since my “DIY disease” does not leave me in piece… I want to build a large enough pack that can support the following: 1) 12v car plug 2) 5v/1A + 5v/2.1A USB plugs 3) charge circuit for the battery pack, so I will no longer have to remove the batteries to charge them separately 4) switches in each plug 5) led voltmeter also with switch ?) at some point I would like to add a circuit to charge it with a solar charger or a mini wind turbine that i will create at some point with my 3D printer, but for now let stay with the basic stuff! For the case i will use a modified screw organizer case, with those classic 18650 black holders from ebay. (photo below) The case will fit almost 8 to 10 holders (4x18650), so we are talking for 32 to 40 batteries... My main concern is the circuit design. I have done a few simple things in the past, but this is a bit more complicated and that is why I want your guidance/ideas. How to safely connect all those things together or maybe suggest a different plan/design, cable thickness, etc... Links gathered so far: I am thinking about 4S in a row. Is that too much? Or should i consider 3S? 3S Li-ion Charger PCB with BMS For charger... something like this maybe? 12.6V 5A Charger optional... maybe i could fit sothing like that, for laptop charging? 150W DC-DC Boost Converter for 5v 1/2.1Amp charger i m looking at this. 5A Charger Step down Module for usb/12v plugs/voltmeter i am considering this option. Thanks in advance for your time!

Question by the_phantom_boy   |  last reply


Questions on building a lithium battery pack with pcb?

I have to build a pack to run my portable N64.  I have some experience building with NiMh and NiCad, but I havent built a li-ion yet. Ive done my research but would like some feedback before I start building. Parts 18650's - 3.7V  3600mAh ea 7.4V PCM for 18650 Li-Ion/ LiPo 7.4V Li-ion/LiPo charger at 1.2 Ah Plan Either to build a 2S2P pack or a 2S4P pack.  Currently the N64, 7" TFT LCD, Controller, and Audio amp w/ 2x 8Ohm speakers is consuming just over 1A from what i can tell.  its running off of a perfboard w/ regulator and rail, thats hooked up to a universal transformer that is set to 7.5V  1A.  Everything works but when I turn the volume up it cuts off and then powers back on.  I dont know any other way to find out the over all power consumption.  I cant just look up all the specs because the LCD is from china and i dont have any specs. Anyway, back to my plan.  obviousely I want as much run time as i can get out of it with out compromising weight and space.  all componants of the portable can run off of 7.4V or lower, to include the lcd even though its rated at 12V. it can run as loas 6.5V. I have been debating between the 2S2P which should yeild 7.4V 7.2 Ah, and give me a runtime, some where in the ball park of 4 hours. or a 2S4P which should yield 7.4V 14.4 Ah. It would only be slightly more space and provide approximately 8 Hours+ Thats if I am even calculating everything right Ok, Regardless of whether i run a 2S2P or 2S4P the connections to the Protection Circuit will be the same, Right? Pos --> B+ Neg --> B- + to - ( Between Series connection) --> B1 or BM I understand that Li-Ion are safer when it comes to balancing then LiPo, but is this right?  having 2 parallel cells or 4 parallel cells connected with the only balance connection between the series.  I just want it to be safe. Next  is the charging.  I bought a cheap smart charger for 7.4V 1.2A output.  Will it matter whether i build the 2S2P or 2S4P, or will it work for both.  I know it will obviousely take twice as much time to charge with the bigger pack, but is their a max number of individual cells that a PCB can handle, or does it only matter the overall voltage? I also Included in my diagrahm a setup for a DPDT switch to change between pack powered, wall powered and battery charging.  I want it to have an "ON" and "OFF" setting. while off, pack is disconnected and if wall charger is plugged in, it will charge the pack.  while in the "ON" position, pack will power the device, but if wall charger is plugged in, then it will run off that. Can I even use a wall charger for the Li-Ion pack to power the device, or will it not work.??

Question by supramp 


Bolt Action Rotary Magazine Gun (updated with internals)

Alright, it's been a while, forgive me. I work in spurts of an hour or two every few nights. It's not quite finished, but it's at a point I'm comfortable showing. I'm also working with BM, so hopefully he can make some improvements on it before it's posted. This gun is the combination of two different goals I've had. First off, I always wanted to make a bolt action. I came up with the idea for the modern bolt action long ago but was beaten to the punch. So since then, as others have made their own bolt actions, I still struggled to make one up to my own standards. I wanted something sleek and compact with a removable magazine. Second, I went off on a little tangent while building, which then turned into its own project: a rotary magazine. While it's been done before, I don't know if it was ever successfully used in a gun. It's more about the novelty than the practicality, but what it does do is give you more storage in a compact design and act as a decent foregrip. I wanted to make it a decently usable. At first I thought of making just some cruddy gun to show off the concept as a usable magazine, but then I decided I may as well go the full nine yards and make it perform well. So this is what I ended up with. I don't have a real name for it yet, but I've considered calling it the Barackuda, a portmanteau of Barack (Obama) and barracuda because...well why not. I wanted to keep it as compact as possible, so I used a barrel similar to my Oodassault 3 series and a stock connection similar to my PDR. The stock is a bit long compared to the body of the gun, so it may look awkward, but I wanted to give at least enough room to aim the gun without sticking the pin into your eye. The blue connectors in the stock stop the bolt right after the trigger engages. The bolt is somewhat typical. I like how it sits flush with the back of the gun rather than looking like an extension on the back of it. The handle isn't amazing, just a variation of my tried and true handle I've come to like. The trigger also isn't amazing, and in hindsight, I want to block a bit further back still, but it works for the limited space I've got. The magazine on the other hand is magical. Go look at my last topic for details on its operation. This version is for yellow rods. I've added a rotary lock and band. When the middle rod is pushed toward the trigger (like in the pic), it's locked. It can securely contain 10 usable yellow rods while locked, though it can load up to 12, the top 2 can fall out. You insert it into the gun by pressing the top two red rods at an angle into gaps in the grey connectors at the front, then rotate the magazine, slightly pushing in, until you get the white rod in the gaps of the yellow connector. Finally, you push in the middle red rod by the trigger all the way forward to unlock the magazine. Edit (9/10/2015): Made my adjustments and now I'm mostly satisfied with the weapon. Here's the video.

Topic by TheDunkis   |  last reply