SFF Lingo Aficionado
- Apr 21, 2019
Thanks for detailed explanation, really good points since the description of the item is not very clear. I found CCCV boards marked as buck/boost, boost-only and buck-only, the one I linked was one of the only CCCV boost with a sensible delivery time. Have I misunderstood the linked item? Wouldn't it provide a constant 12.6V 6A at output?I don't really know how to explain this... I'm not sure if I'm even right or not...
Well anyways here is an attempt:
A current limited voltage supply will not usually supply its max current and max voltage at the same time.
If the load is low (high resistance), it will supply the max voltage and let it draw whatever current it wants as long as its below the set max current.
If the load is high (low resistance) and tries to draw more than the set max current, the voltage regulator will lower its voltage so that the updated current draw will be less than max current.
As an example let's take Vmax=12.6V and Imax=6A.
A 5Ohm load would get 12.6V and draw 2.52A
A 1Ohm load would only get 6V and draw 6A.
If the load got 12.6V instead, it would be draw 12.6A.
However with a step-up converter taking a 12V input, the load will always get at least 12V because a step-up converter can't supply an output voltage lower than its input voltage.
The problem is that in this case we have an unregulated 12V charger for battery voltages <12V, a CC cycle only from 12V-12.6V and a CV cycle finally at 12.6V.
I'm not sure if depending on ocp as a regulator for battery charging at the lower voltages is a good idea.
(On the other hand it might allow for pulse charging )
One minor problem with having a low 12V rail is that fans won't spin at max rpm. (And maybe some harddrives will not like it?)
Tried to set it up with a multimeter before I replied, but it was all over the place... set it to 12.60V without load OK. Then switched the multimeter to current and it was all over the place, from 0 to 4A, jumping around. I used the battery as a load and current was more or less stable at 4A, but couldn't adjust it with the second potentiometer. This one looks the same, it's listed as a charger. Maybe I got a faulty board? Or maybe it's not CCCV - tough to tell. I'll return it and have a look around for a board marked as CCCV charger which I can actually test. May have to be patient with delivery
There's no need for posts like thatSpeaking of stepping... Lemme just steps.. away and let people learn their lesson... Again... In the name of fun..