Diodes. Which to use? How to add them?

[Jess Haas SOC]

I am thinking of adding some diodes to my sled. I am thinking that the slight decrease in voltage would actually be helpful with certain cameras, and that it will allow me to mix the lithium ion batteries I plan on buying with the trimpacks that I currently have.

 

If they will fit I am thinking of adding the diodes inside of the AB mount. Is this a suitable place for them and what diodes should I use? They are mounted to an aluminum plate so I figure that this will function as a heat sync if necessary.

 

My sled currently has 2 AB battery mounts that can be run in series, parallel, or power the camera and accessories separately. I am thinking of adding a 3rd and maybe even a 4th battery mount which could be hooked up in various ways. Will the diodes allow me to safely mix battery types and how should they be used together?

 

I have seen some people say that they use 2 Lithium ion batteries with a single Nicad to allow them to draw more current when running at 24v. Is putting a single Nicad in parallel with one of the lithium ions enough? Since the lithium ions are run in series wouldn't I need a nicad in parallel with each of the lithium ions?

 

What about running a lithium ion battery in series with a trimpack for 24v? Is it a bad idea? I know that the diode should allow me to run them in parallel for 12v. Is it a bad idea to do that without the diode?

 

Will the diodes waste much power? If they shorten the battery life much then they might not be worthwhile.

 

Thanks,

Jess

[RobVanGelder]

Hi Jess, though I cannot answer all your questions, as I do not have experience with the mixtures you mention, here some info in the diodes:

diodes are only used for blocking them from charging/discharging on each other.

so they are connected in such a way that the current only can get out. One good reason to mount them in the plates and not in the batteries them self

When batteries are in parallel, they are needed, when batteries are in series, they just lower the output voltage slightly, depending on the type 0.3 to 0,5 volt per diode.

Find diodes with a minimum of 8 to 10 amp forward current, higher if possible, most diodes in this range can handle short overloads up to 20-30 amps or more.