I have a 3s LiPo battery pack which I have built myself from single cells & works fine.They now need to be charged.
I also have a LiPo charger which has several points to be explained. There is a socket for IN 12v, no probs. There are on the other side 2 sockets, one for 2 cells & one for 3. Each socket has 3 or 4 pins marked cell 1 2 3 & Com, which I assume is the common negative return. I haven't a clue how to wire up. With Ni batteries there are two wires each on the batt & charger & you connect them up & there you go, but all these pins fox me. HELP please & someone kindly tell this idiot what to do. Thanks in anticipation Chris

here is a brief explanation

lipos are more sensitive to over charge so you want as much voltage monitoring as you can. most lipo batteries have a second smaller plug (in addition to the main power wires) that has leads to every voltage level (cell) in the battery. this 2nd plug is called a balance plug and allows the charger or a seperate balancer to monitor the voltage of the individual cells and make sure they are all even and not over the maximum safe voltage of 4.2v per cell.

for a 2s pack you would have your negative (ground) pin, followed by your first positive pin that is connected to the positive end of the first cell. then you have the 3rd lead/pin that is at the end of the second cell. the balancer would read the voltage between ground and the first positive pin to check voltage on cell 1. then between the first positive pin and the second positive pin to measure cell 2. this is because the 1st positive pin is ground relative to the second cell.

for higher S batteries (3s, 4s, 5s, etc) there is simply another positive pin added to the balance plug for each additional cell.

some chargers will actually charge through the balance plug but this should only be for 1amp or less of charge current.

so i am guessing you need to take apart your battery and add this extra plug. lots of manufacturers offer them seperately and there are a few different standards. make sure to get one that works with your equipment.

im too lazy right now to find links to websites with more info, but if you need more help just ask.

Life would be a lot simplier to get a modern type charger that is a balancing type charger in lipo mode. A good inexpensive one is available for ~$60. If your charger did not come with detailed instructions, its more dangerous than useful.

You need to add balance connection to your homemade lipo. You can get the connection here -

http://www.rcdude.com/servlet/the-Co...les/Categories


There are 4 different types in use to day, the JST-XH is most common. You'll find wiring diagrams for the balance wiring here - 3S is on page 3

http://www.allerc.com/Pictures/LBA10...Manual-ENG.pdf


It is important in using your lipo that you know what the individual cell voltages are so you can avoind overcharging and over discharging it. Either condition can lead to damage and is potentially unsafe.

from the 3 and 4 pin sockets, it seems like it is a balancing charger. some specific names of what you have will help in making sure you have the right stuff.

Thanks guys. I have a Mystery cx450-50-01 charger got on ebay from HK. Any more advice? I run an 0 gauge oudoor railway & think I now have a few experiments to do. Already blown a capacitor!!!!!!
I think, changing the subject, that a guy living in Hereford UK as I do, can speak to guys living in Texas is absolutely amazing. Isn't modern technology wonderful. It certainly takes your mind off the bloody general election going on over here. It is all you get on tele! Heigh Ho!

This one?

http://www.alibaba.com/product-gs/23...showimage.html


If this is the charger you have, those connections on the side are standard balance port connectors for the JST-XH type balance connector. If the lipo you have has JST-XH balance connector, it will plug into the side of the charger into the appropriate cell count balance port. So what you need to do is wire a balancing harness on your homemade lipo.

You need a 3S JST-XH harness - I can't locate it explicitly, but in this link, the parts needed are listed and you can find them then on the Digi-Key site.

http://www.gpsy.com/ev/2009/01/balan...-on-li-po.html



As far as how to attach them, this will show you how the cells should be wired to the balance connector - look on page 3 -

http://www.allerc.com/Pictures/LBA10...Manual-ENG.pdf


This will give you a direct balance connection to the charger that doesn't need an adapter like you would need if you used any of the other 3 types of balance connectors (Thunderpower, PolyQuest/Hyperion or Kokam types).