Max Charge MC-618 Voltage Regulator

[TPG]

RE: Max Charge MC-618 Voltage Regulator

Wondering if anyone can give feedback from using this on their vessel, good, bad or otherwise. I'm using this to protect my alternators while charging LiFePO4 house bank.

If I read the specs right on this thing, it has an allowable 15A max of field current - but not sure what the output current is. (I understand that field current and output current are related but that's about it.)

That being said, why would you ever need large output alternators if you're adding this item midstream?

[jordanbigel]

The Balmar 618 appears to be a great product, although I have not used it - I have used the MC-612 and now I have an MC-614 which has worked great for me using LifePo4.

The field current is an input signal to the alternator which is used to tell the alternator how much output to produce, in layman's terms (I am not an electrician, I could not explain exactly HOW the field current controls alternator output).

I am sure someone else here can explain how this works exactly, but the key point is that the regulators max field current (15amps?) does not mean that an attached alternator cannot produce its fully rated output, whatever that is.

I can't answer the last question, I don't understand it. A large frame alternator can put out a lot more power than a small frame alternator, that I can tell you for sure. So if your bank is large enough to be able to utilize (for example) 100+ amps charging (for a 12v system) then you want a large frame alternator. A small frame alternator in a LifePo system has to be de-rated significantly to prevent overheating. My large frame alternator is capable of putting out about 180amps, but I have it de-rated (using the belt manager feature of the Balmar regulator) so that it only puts out about 120amps - this should help improve longevity of the alternator by preventing it from running too hot.

[fxykty]

Originally Posted by TPG

RE: Max Charge MC-618 Voltage Regulator

Wondering if anyone can give feedback from using this on their vessel, good, bad or otherwise. I'm using this to protect my alternators while charging LiFePO4 house bank.

If I read the specs right on this thing, it has an allowable 15A max of field current - but not sure what the output current is. (I understand that field current and output current are related but that's about it.)

That being said, why would you ever need large output alternators if you're adding this item midstream?

Output current can be whatever your battery wants and the alternator can provide - there is no maximum according to Balmar. Field current is related to output current, but it’s not a limiter.

The point of this (and other similar ones) external regulator is to 1) protect the alternator and 2) manage the charge voltage and current to better match your battery type.

[rbk]

Originally Posted by jordanbigel

The field current is an input signal to the alternator which is used to tell the alternator how much output to produce, in layman's terms (I am not an electrician, I could not explain exactly HOW the field current controls alternator output).

Electromagnetism. Field current is power to the magnets in your alternator, increase the power to them they will have a stronger electromagnetic field and in turn will produce greater output.

*This assumes that it is common knowledge that passing copper through a magnetic field will excite the electrons and produce current.

[nuku34]

"Field current is related to output current, but it’s not a limiter."
I beg to differ on this statement. Output is directly related to, and limited by, the amount of field current. An unregulated alternator by itself doesn't care or know what the state of charge is on the battery its connected to. If there is enough field current, it will happily put 100A into a fully charged battery and eventually blow the battery apart.

The whole point of a "regulator" either internal of external, is to sense the level of charge in the battery and control the field current to produce an appropriate output which avoids over (or under) charging the battery.

[wingssail]

Originally Posted by TPG

RE: Max Charge MC-618 Voltage Regulator

Wondering if anyone can give feedback from using this on their vessel, good, bad or otherwise. I'm using this to protect my alternators while charging LiFePO4 house bank.

If I read the specs right on this thing, it has an allowable 15A max of field current - but not sure what the output current is. (I understand that field current and output current are related but that's about it.)

That being said, why would you ever need large output alternators if you're adding this item midstream?

An Alternator works by spinning an electromagnet (the rotor) inside the coils of the stator. The spinning electromagnet causes current to flow in the stator and out of the alternator through the diodes.

The field current is the DC electricity supplied by the regulator (in your case the MC-618) to energize the electromagnet. Without the field current there is no electromagnet, and no electricity is produced. From a small amount of field current (1 amp) to the large amount (15 amps) the field strength of the electromagnet in the rotor increases.

HOWEVER, Your engine supplies the spinning power. It is the powerful spinning of the rotor by your engine that actually generates the output amps and when the engine spins a strong electromagnet (15 amps of field current) you get a lot of output.

The MC-618 regulator adjusts the field current according to the settings and measurements of the output voltage, temperature, etc. It can protect your batteries by not allowing the voltage to exceed the settings.

[goboatingnow]

Originally Posted by nuku34

"Field current is related to output current, but it’s not a limiter."
I beg to differ on this statement. Output is directly related to, and limited by, the amount of field current. An unregulated alternator by itself doesn't care or know what the state of charge is on the battery its connected to. If there is enough field current, it will happily put 100A into a fully charged battery and eventually blow the battery apart.

The whole point of a "regulator" either internal of external, is to sense the level of charge in the battery and control the field current to produce an appropriate output which avoids over (or under) charging the battery.

Regulators know nothing about batteries(Usually)

Stock alternators vary the field current to generate a output current and attempt maintain a stable alternator output voltage irrespective of current , upto the max available current capability of the alternator

The typical current gain for a standard alternator is around 25 so 2A of field current could produce 50 A of output current depending on speed of rotation.

The regulator will allow greater field current upto full field limits , in order to output enough current to attempt to hold the set point voltage. If the load resistance is too low. The output will go to full current but the setpoint voltage will not be reached for a given rotation speed , this is a form of Constant Current output.

As the current drops the output voltage will rise and if it meets the setpoint the fiejd currebt will be restricted until the voltage holds stable at the setpoint