Lipo Battery Testing and Balancing

[sikeston34m]

I was just sitting here and it hit me!

The DC load that will be used is Electrolysis. I already have one made with a Stainless Steel plate configuration of 4S2P.

I built it with the intention of installing it on my Blazer to improve the fuel Mileage. Did my homework on varying the amp draw by using a ratio of Sodium Hydroxide and Water.

The amp draw and Gas output is quite low without adding something to increase the conductivity of the water. PWM is normally used in conjunction with this to limit the amp draw.

SO..........with an increase in the concentration of Sodium Hydroxide AND the use of an ESC to turn it up and down, shazam!..........DC load capable of big amp draws.

Big Amps thrown at a Hydrogen unit will normally boil the water in time. Since rarely, 30 minutes at a time will be exceeded with testing, this should do.

The product of Electrolysis is Hydrogen and Oxygen. It breaks down water into it's elements by breaking the covalent bond of the atoms.

Hydroxy gas is VERY explosive. I'll just vent it to the outside.

Ok, now that we have established a good working DC load, we need a good heavy duty amp meter. Something that will accurately measure up to ummmmmmm............let's say 200 amps.

I wonder if I can find one of those digital types that work with a shunt?

[johnrobholmes]

Nice idea for the load! How big of a tub do you plan to use?

Have you decided on some standards for the testing? Temp, voltage, and capacity requirements for 1c vs stated capacity maybe?

[sikeston34m]

Originally Posted by johnrobholmes

Nice idea for the load! How big of a tub do you plan to use?

Have you decided on some standards for the testing? Temp, voltage, and capacity requirements for 1c vs stated capacity maybe?

Thanks John. I kinda like the idea myself. A tub? huh? LOL

The Hydrogen Generator that I built resides inside a 18" long stick of 4" pvc. It works best vertically. Gas rises to the top and exits through a screw in fitting to a secondary bubbler. This also "lifts" water along with it into the secondary bubbler.

Water from the secondary bubbler travels back down into the bottom of the Hydrogen Generator chamber through another tube.

In other words, as water is lifted out the top with the gas, water is replaced into the bottom. It circulates and the Hydrogen/Oxygen of course rises to the top of the bubbler. The bubbler is useful in extracting water vapor from the gas, and also helps prevent flashback to the generator in case something goes wrong.

There is some question in my mind about just how many amps this setup can maintain. I know raising the concentration of sodium hydroxide will inherently raise amp draw, BUT..........once you have so many bubbles forming on the plates it becomes a limiting factor. The bubbles begin to insulate the plates because they can't get off there quick enough. LOL

I'll have to put this to the test. Thinking back, I remember directly hooking a 4S lipo to it, and it was getting a rubber insulated 14Ga. wire REALLY hot. It would have melted the wire if I would have left it hooked up. Of course, silicone wire doesn't do this.

I would like your input concerning standards of testing. To be fair to each brand, conditions have to be controlled.

One thing that I DON'T aggree with:

In all the testing methods that I've observed, they always hook the test equipment directly to the tabs on a single cell. That's NOT where we hook our stuff.

We hook our ESC's directly to the power connector on the pack. This makes our setups work with the resistence in the wiring. Most packs "only" come with 12Ga. wire on them. At 100+ amp load, resistence in 12Ga. wire becomes a factor.

If a PACK is rated with a certain C rating, shouldn't that PACK deliver that C rating? I think so.

One thing about standards I believe, it should be the PACK tested at the connector that determines C rating.

Any thoughts or suggestions?