Lipo Battery Testing and Balancing

[skellyo]

We've got a couple of these here at work:
http://www.nhresearch.com/Products/4...onic-load.html

I've run tests on some of our power systems to 10kW peaks with 2 of these paralleled (up to 36kW capable with 6 in parallel). For any real high power testing, a consumer oriented load just isn't going to get you there IMO. For instance, if you want to run a steady state load of 30A and then peak it to 150A for 10mS, this will do it with ease.

[sikeston34m]

Originally Posted by skellyo

We've got a couple of these here at work:
http://www.nhresearch.com/Products/4...onic-load.html

I've run tests on some of our power systems to 10kW peaks with 2 of these paralleled (up to 36kW capable with 6 in parallel). For any real high power testing, a consumer oriented load just isn't going to get you there IMO. For instance, if you want to run a steady state load of 30A and then peak it to 150A for 10mS, this will do it with ease.

That looks like a great piece of equipment. I wonder how much they are?

I'm trying to keep costs to a minimum on this project. If only I had sponsership. LOL

As for a "consumer oriented" load, I've been thinking about using the coils of a space heater. Possibly even 2 or 3 of them in parallel. Rewire the heater(s) to run their fans normally with house current. Then send the coil power leads out to be powered by DC.

As long as the setup can handle it, all that has to be done is measure the amperage level at the battery leads.

It is true that the watts of discharge is what has to be considered when sizing something like this. A space heater can go up to 1500 watts under regular household use. This would be comparable to 4S under a 100 amp load. If a 200 amp load was desired, then a 2 parallel setup would be required.

For 6S testing, a 2 parallel setup would be required for testing with 100 amp load. 25.2 volts x 100 amps = 2520 watts of power.

I haven't checked the resistence values or anything yet, but I'm hoping this will work.

[skellyo]

Originally Posted by sikeston34m

That looks like a great piece of equipment. I wonder how much they are?

I'm trying to keep costs to a minimum on this project. If only I had sponsership. LOL

I can't remember exactly how much they were when we bought them. It's been several years. I do believe though that they are over $5kea.

[sikeston34m]

Still looking for a decent High Amperage Load for Testing. I have just about decided the entire space heater idea is a bad one. There's no way those wires will support the Amperage. So I'm still looking.

In the meantime, I got the balancer in and it does GREAT. It can be used along side ANY charger. So it can balance during charging. Or it can stand alone like the Blinkie.

This one is better though. I love the software.

With this, multiple cells and packs can be balanced to each other. In other words, pick a voltage. Let's say 4.15 volts. Then discharge each cell in a pair of 5S packs to 4.15 volts. Now the pair is ready to be ran in series with each other as a perfectly balanced 10S pack.

Are these cells in balance good enough? 5mv spread.

[lincpimp]

Looks interesting, but it is not a charge thru desing, correct? So it will not interrupt the charge should one cell go over 4.2... Unless it is hooked into the matching xtrema charger...

I like the on screen info, should work for your uses!

[sikeston34m]

Originally Posted by lincpimp

Looks interesting, but it is not a charge thru desing, correct? So it will not interrupt the charge should one cell go over 4.2... Unless it is hooked into the matching xtrema charger...

I like the on screen info, should work for your uses!

It is not a charge though design, but.........

With the MRC Superbrain 989, set the charging amperage to .5

This is right at the amperage the balancer discharges at. The charger is trying to charge all the cells, while the balancer is knocking the tops off the cells that have more voltage.

This method takes awhile but is effective.

[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?