Stupidist Plan yet to save gas -- muzzling the alternator

Induction refers to a wire coil that is charged up with what ever the cell voltage is and holds what ever cell capacity was required to fully charge the wire coil ..... this may be only milli amp hrs, but the rapid switch combined with the voltage differential, it could be anywhere up to 5 amps of current moving in and out through any single induction coil, but on average, it's generally 1 amp or less ....., switching at a high hertz rate, it can move a fare amount of capacity from one cell or a multiple of cells, to the lowest voltage cell, rapidly bring all the cell voltages to within 15 millivolts, then it shuts down and turns on again at approx. 150millivolts ..... but you have to be either logging the cell voltages or be "Jonny on the spot" to see the switch on point, the high cell voltage drops rapidly from the 150millivolts higher than the other cells ..... 3 cells at 3.5v would see the high cell reach 3.65v before the cell equaliser turned on again .....

T1 Terry

 

Is this related to switch mode power supplies?

 

In ECOmodder forum, there were proposals to eliminate 12 V charging load to improve MPG. If the 12 V battery is replaced with a modern battery and solar panels, this could work. Still carry the alternator for backup but run the low voltage system from a modern battery and stored solar energy.

I would implement it with a solenoid belt tensioner to minimize mechanical drag and the problem is solved. Normal practice is to use solar-battery around town and only when driving longer distances, backup with the belt tensioned, alternator.

Sad to say, I don't have an engine driven alternator. My BMW i3-REx has a two-cylinder engine driven generator used only when the battery charge is too low or I'm doing a long cross country. I prefer to use my battery is backup for the 2.3 gal gas tank.

Bob Wilson

 

A simpler mod was to replace the starter 12V with a deep cycle, take the alternator out of the belt loop, and just charge up at home. Some EV conversions did similar, as the deep cycle 12V was cheaper than a DC-DC converter with controls.

 

So essentially a switch-mode DC/DC converter to boost the voltage to a low cell and move charge into it faster.

 

No, not a converter or a booster, just a basically simple method of moving capacity from a high voltage cell to a lower voltage cell. Similar to using capacitors, but a lot more capacity, negates the risk of a capacity exploding due to surge current and doesn't suffer with the storage capacity loss the capacitors suffer over time and heat degradation.

The inductor coil charges to the cell voltage, disconnects and all the coils link together so the voltage equalises across all the coils, then reconnects to the cell, either discharging current till the coil voltage and cell voltage are the same, or receiving current, charging the coil till it is the same voltage as the cell if that is a high voltage cell, then the process repeats

T1 Terry

 

Not really, more like a better choice than capacitor active balancing ..... the still make an audible squeal that some people can hear when they are working hard, but I have zero upper level hearing now, so I can't hear it

T1 Terry

 

It's a little sketchy to talk about an inductor charging to a voltage. A capacitor charges to a voltage. The work you did raising its voltage to that level is stored in it as electric charge. You can get that work back out by letting it discharge.

An inductor 'charges' to a current. The work you did raising its current to that level is stored around it as a magnetic field. You get that work back (whether you want it or not) if you try to interrupt the current. The inductor's voltage then becomes whatever it takes to give you back the work that you put in. (That's why transistor switches used to switch inductive things like relay coils generally have a diode or the like protecting them from the voltage spike they would otherwise suffer upon trying to turn it off.)

That exact property, exploited by high-frequency switching of the inductor—as you mentioned in post #41—is the basic principle of a DC/DC converter right there. I'm not sure how important it is to try to say this application isn't one.

 

The first post in this link, from a solar power forum (the first to pop up in my search) shows two topology choices in the base post of this thread. People familiar with DC/DC converters and switch-mode power supplies should be able to identify with these very quickly:

https://diysolarforum.com/threads/what-bms-uses-inductive-balancing.39149

 

Rather than trying to explain it, tripping over my tongue and getting another put down, hopefully this will explain it Why does an inductor behave as a capacitor at high frequencies? - Electrical Engineering Stack Exchange

T1 Terry

 

Parasitics inherent to non-ideal real-world devices.