Hello,
Can someone point me in the direction for the best DC/DC board to convert 13.8V from a LiPo battery to a steady 12V output.
Obviously, the 13.8V will vary as it is coming from a battery, but a steady 12V output is what is needed.
I have tried the XL6009 DC-DC board but it is a step up board and doesn't have the range to meet 12V.
Any help much appreciated.
What load? 10mA or 10A?...
What battery, your voltage suggests 4s but maybe you mean 12.6V/3s and it would be a whole different thing.
For 3S you definitely need a step up/down since battery will go <12V. For 4S no, but then the solution has to handle 16.8V.
Depending on the current draw, you may be better off with a low-dropout regulator (eg. LM1085IT-12) for this as the power loss as a result of the voltage drop will essensially be 13%, but if you are not taking much current then that's the loss you'll get with a typical DC/DC buck converter.
Some loads such as motors and even some equipment like decent routers/modems/switches can actually handle the extra 1.8V too, so if your load can cope with it, then it is a good idea to omit the LDO or DC/DC converter.
The battery is 4S, my apologies on the voltage being wrong. And there will be ~100mA of current.
SD-50A-12 from Meanwell 9-18V input, constant 12V(11-13,2V adjustable) /4A out.
there is also 25W/ 2A version.
ok so we have 12.8 - 16.8V input range and 100mA load. that's 4V drop @ 100mA worst case, so 400mW power dissipation... 0.8V drop is the lowest drop required...
LM1117 costs few cents, 16.8V input would be on the edge but 400mW diussipation not a problem.. 1.2V drop + 12V out will give us 13.2V which is more than the desired 12.8 , but close enough (at least you will not overly discharge the pack).
worst case efficiency with lm1117 would be approx 70% - that's on par with a simple buck converter.
EDIT:
and forgot to mention - nothing gives you more steady voltage than a battery followed by linear regulator.
For 100mA with that drop I would also probably just use a linear regulator, the dissipation will be fairly low. A buck regulator would work too, there are some small inexpensive parts but even a lowly 7812 will do the job just fine. All it needs is a capacitor across the input and output.
For a 4 cell LiPo it probably doesn't even need to have a super low dropout, you should never drain one of those packs below about 3.4V per cell anyway so that leaves around 1.2V of overhead. Of course having a lower dropout never hurts and does give you some wiggle room if you accidentally drain the battery too far.