Balance Adapter

[helismeagol]

I have purchased a para board (JST-XH/T-plug) for my Thunderpower TP610C but the balance adapter is a few mm too big for the charger. I cannot seem to find the correct para board with a smaller adapter.

[cjcj1949]

There's one shown in this advert.
Thunder Power TP610C 1-6C LiPo 0.25-10ADCChar/Bal

Which board did you buy? There are lots of places selling adapters. You can always solder on the right connector. I'll look up links if you like.

Chris

[helismeagol]

Thanks Chris.

I purchased this board Parallel Charge Board for ThunderPower & T-Plug AC-PCBTT

Could I use the board (came with the thunderpwr) to plug the adapter onto then into the paraboard?

Brendon

[cjcj1949]

So long as your lipos are all plugged directly into the parallel board, including the balance leads, the lead length to the balance output of the charger is not critical as the balance current is quite low, usually only a few hundred milliamps. I don't understand parallel charging, but a lot of people use it and it seems to work. Lipos can go wrong when being charged and you should have a plan of what to do if they do go wrong. Someone did get very badly burned recently when he tried to disconnect a lipo on fire. That wasn't parallel charging by the way. The smoke is very bad as well. When connecting the batteries to the parallel board be careful that you do it in the right order as shown in the instructions. Some people think that batteries should be carefully matched for ESR, Capacity, Temperature and Voltage. Others just get on with it and plug things in.

If the voltages are different on connection, then current will flow from one battery to another. If you plug in the balance leads first, you can burn out the leads on the balance board. This is easy to repair for anyone who has worked on pcbs. The current does drop quite quickly and there are no reports of these short high charging currents shortening the life of lipos.

You can work out the initial current using ohms law. Voltage difference divided by resistance. Maximum voltage difference per cell would be 1.2 volts (4.2 - 3.0). Good 2300mah Lipos are less than 5 milliohms and connectors around 10 miiliohms. That's 1.2*1000/2*(5+10) or 1200/30 = 30 amps in round figures. That's an initial charge of 30/2.3 or around 12C which is high, but only for a short time as a discharging battery volts falls as a charging battery volts rise.

Current sharing is more difficult as different esrs and connectors resistance will cause short term differences, but all batteries will end up at the same voltage and will be charged according to their capacity.

Longer battery leads made of thinner wire ( not that much thinner) introducing a resitance of perhaps 50 milliohms would limit this surge if it thought to be a problem. In line 15 to 30 amp fuses in these adapter leads could be a good idea to prevent accidental shorts causing a problem. The fuses would also reduce the initial surge current. I'm not sure if they should be left in when charging as if they do blow when charging they could make a bad situation worse as the current through the remaining batteries would then increase possibly causing another fuse to blow and leading to cascade failures or higher tha anticipated charge currents. If you charge 5 batteries at 1C, then worse case one battery will end up at 5C which is ok for most lipos.

Chris

[helismeagol]

paraboard.jpg So what you are saying is that I can plug B into A with no problems at all?

[cjcj1949]

Yes. If the plug fits there should be no problem. The charge won't start unless it sees the right number of cells. Assuming you're balance charging.

Chris