
MovieMaker

Any Engineers out there besides Fred? He can't post right now.
I saw a drawing that Josh made, I think. It sounded pretty interesting.
I will be running two 12vdc and two 6vdc batteries. It was said that I could use 6vdc for one EZB and 6vdc for the second EZB. Then use them in Serial as a 12volt setup to charge all of the batteries at once. Is this possible? Josh, have you put that in operation and does it work. Or, is the paper a theory. I mean, it sounds like a good idea to me. But, other people on the net has said they will short out. So, what should we do? I am just trying to find out.
It seems like it would work for me.
Thanks,
Mel
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If you connected them as both parallel and series you would short the batteries out, consider this schematic
(Probably not the best schematic ever but it was rushed) battery 2 is shorted to ground, therefore the voltage at any load is 0v and the spectacular explosion coming from the batteries would be quite the sight.
You would need to create a switching circuit to change the circuit from parallel to series.
With switch 1 open and switches 2 & 3 closed you have a parallel arrangement
With switch 1 closed and switches 2 & 3 open you have a series arrangement
Which still wouldn't work. EZ-B 1 gets 6v but EZ-B 2 gets nothing since the positive of the battery is shorted to the common ground.
And wouldn't Battery 2 still be shorting to ground (as in EZ-B 1/Battery 1's ground)?
Another way to test this solution is to place a voltmeter at the connection points of each battery. You will measure 6 volts on each battery but will see 12 volts when measuring from Bat 1 (-) to Bat 2 (+).
The first is that you want to charge the batteries while they are in series. In this configuration you will by its nature create a cell imbalance between the two batteries. Each ez-b board will drain its respective battery at a different rate from the other one. Depending on cell type most manufacturers have warnings about the effects of charging systems and imbalanced cell batteries. This should be a concern.
The other problem has to do with the grounding and control of the 12v components. Only the ez-b that shares the ground with the 12v devices should be used to control the 12v devices. The other ez-b with the floating ground should only control 6v devices which share its ground connection or devices powered by the ez-b with the floating ground.
Lots of chances for releasing blue smoke and potential for shorting out a 6v battery.
This would not be my first choice for a setup.
Is there any reason why the EZ-Bs would need 6v to them rather than the full 12V? As in, connect the batteries in series and power each EZ-B from the +ve of Battery 1 and -ve of Battery 2?
What do you think?
Anyone else can jump in when they are ready.
I usually have a common ground because of noise generated in the system. I am scratching my head on this one. The schematic seems ok, but then it doesn't.
Still confused. I may just hook all the stuff up individually.
*confused*
If you use the sketch you posted most recently you will have problems, the 6v batteries are in both parallel and series arrangements which causes the bottom of the 2 6V batteries to short +ve to -ve which is not good. Removing the link will solve this but will cause the charging circuit not to function on the 6v batteries.
You need to either remove the link which makes the short or remove the links which put the 2 6v batteries in parallel and use them in series to make 12v.
Option 3 can be simplified by drawing it like this;
It sorta looks like that ground is floating.
Thank You for all of your time spent on this.
Follow the circuit lines on the first schematic for option 3
The ground coming from Load2 joins the ground from Load1.
The Vcc for Load2 comes from the same point that the Vcc for Load1.
Bat1 and Bat2 are in series which creates a 12v battery, this arrangement is then put in parallel with the other 12v batteries since the +ve side of Bat1 connects to the same point as the +ve side of Bat3 and Bat 4. And the -ve or ground of Bat2 connects to the ground or -ve of bat3 and bat4.
Load 1 and Load 2 are both supplied with 12v.
It does make using 6V batteries pretty redundant unless you are planning to reuse some you already have. If you are buying everything to make this setup then you would be better off just using 12v batteries and putting them all in parallel.