Using small transformer-coupled battery chargers, each cell in a lithium battery pack can transfer energy to all the other cells to prevent overvoltage.
By Julian
Youtuber, shed dweller, solar charge controller aficionado
Good morning all…
Youtuber, shed dweller, solar charge controller aficionado
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Why not use a isolated boost converter to take the cell voltage up to pack voltage
Run it at 3 volts and step up the output with an additional "standard mains" transformer from 3~ volts AC to whatever you need. Then rectify it
How did you get the batteries to stick to each other?
pst… go with a fet based active bridge rectifier if you can find one with a low enough voltage (I know of one that goes down to 9v by linear tech)…if you can break your addiction to china and ebay you will find you may even get samples of these non shit components for free, then reengage your adiction and get the ssop or qfn to dip converters from ebay. Linear also has a two part system (two systems but one is less capable/older) that does one chip per cell that connects to a 1:1 transformer and all other components are intigrated. this chip sends voltage current and temp back to their stack ccontroller via spi(i think) which does all the fet switching. Im trying to figure out what its min config is…just need to clarify with sales rep. it says the switcher chip does something like 12 cells and can transfer up to 6 or cells to any other series connected pack of up to 6. Thats a bigger pack than I want so im trying to confirm if I can go with something like 2x 3s groups. I know it also has a slower mode where it can switch them all two one transformer (only one active primary at ta time)with multiple primaries but its best to have a bunch of transformers. I got something like 5 free from coil craft by requesting a sample… i fucked up a little bit though cause i started with their old chip then after request for those realized the new chip existed and takes diff ones. im not paid by linear nor was I asked to write this im just a dude in the middle of my first "Big" project with multiple ics and the linear sales rep I was assigned has gone above and beyond to understand my design and see if it can be improved. He then got me a bunch of samples very quickly. idk if they ship to uk for free but checkem out.
Ultra fire battery needs to charged 230v ac. after get som Real brand 18650
Julian any update on this good idea?
what a genius idea, patend it before turnigy starts doing this;-)
Brilliant idea and would like to see you succeed in this breakthrough plan. I am in need to 3 LiPo cell balancing and I wont consider the energy wasted (or conserved as heat to the environment) during the balancing process.
ahhhhhhhhhh my brain hurts…..
This may be too simple but why not run zener diodes with series fuses in parallel with each cell to prevent any cell from overcharging in the first place. If a cell reaches it's predetermined charge (zener) voltage then the zener clamps the charge voltage at that level forcing the lazy other cells in series to accept more of the charge voltage instead of the fully charged cell going over voltage.
You could take a more powerful version of the DC-AC converter (let's say 30W which could be built in "ZVS/Mazzilli Driver" topology) or even an "electronic transformer" (those cheap SMPS used for halogen lights nowadays) and place several secondary output windings on the transformer depending on how many cells you want to charge. These should have 5-8V. Then you add a bridge rectifier to each output winding and connect a TP4056-based charger to each rectifier. Et voila, you should have intelligent charging via balance port for each cell…I think I'm gonna give that a try. The problem withe the cheap halogen transformers is that you need a load of about 20W in order to get them oscillate properly. Should be possible to get that solved though.
Perhaps you should hack that Duracell battery charger you have, which you threatened to pitch anyway, the one with the fancy series-parallel switches on the board, to charge 4 caps in parallel from the donor battery, then switch to output the caps in series to the entire bank. I can not envision anything more efficient, and you already have the parts.
Please do not leave our robot brethren out of work.