Xantrex Freedom Marine 20

[clayzone]

I have a Freedom Marine 20 that needs to be replaced. The boat has a transformer between the generator and the inverter/charger. It needs to be replaced also but I can't figure out why it is even there. I don't see any requirement for one in the inverter/charger manual. Do I need one? Also while I am at it, should I consider something other than another Freedom Marine 20? I have a chance to buy a nice used one. Thanks.

[Stu Jackson]

Have you considered that the generator provides AC power to the charger side of your I/C when shorepower is not available?

[clayzone]

Originally Posted by Stu Jackson

Have you considered that the generator provides AC power to the charger side of your I/C when shorepower is not available?

Yes but that still doesn't explain why there was a transformer in between. The generator puts out 110 volts.

[AndyEss]

The transformer is for AC isolation between your generator and the inverter. The generator feeds AC power to the battery charger side of the inverter.
Not sure why this was done, unless shore power is connected at the generator and uses the same AC wiring to feed your 110 Vac system. Then it makes electrical sense to have the isolation transformer where it is.

[Stu Jackson]

Originally Posted by AndyEss

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Not sure why this was done, unless shore power is connected at the generator and uses the same AC wiring to feed your 110 Vac system. Then it makes electrical sense to have the isolation transformer where it is.

Andy, that could very well be. In this case, wouldn't he then still be using the ATS inside the I/C if there is one (usually is) to avoid shorepower or generator working at the same time as the I? Then he'd also need a transfer switch between the shorepower and the generator to avoid having them both on at the same time, would he not?

[77Californian]

I'm wondering if, by any chance, we can see a picture of the transformer?

A few ideas. None of them would seem super common:

1) The transformer could be there as a noise filter to prevent noise from the charger from making its way onto the AC power. Chargers tend to be switching power supplies and, especially when really dumping current into heavily drained batteries, can put a lot of noise onto the AC source line. This could, conceivably, be a concern for sensitive electronics running off of the same AC power source. This might be especially true when running off of the generator as opposed to shore power, because the smaller system might be more susceptible to the influence.

2) It could be, as has been suggested, unusual wiring where the boat's isolation transformer was installed after, rather than before, the selector switch. (This seems odd)

3) Maybe, instead of a transformer, it could possibly be a shore power transfer relay (automatic transfer switch) of some kind, that automatically switches to the generator if shore power is lost and the generator is supplying power? (This seems odd, though, since even though relays can sort of look like transformers sometimes, these two uses would likely be vastly different in dimensions, weight, etc).

Overall, it seems odd to me -- I'm just guessing wildly.

[AndyEss]

I'm not sure if he would need a transfer switch. That does assume the generator comes on automatically due to some triggering situation i.e. Low battery voltage.
If the generator is manually started - don't start if connected to shore power.
I'm not sure if having both shore power connected while the generator is running, will really matter (current draw will only happen if there is a load) except if shore power has appreciable grounding issues.
Also, come to think of it, the generator will then power up the shore power system and potentially cause unsafe conditions for other boats, marina personnel working on what they might have thought to have been a de-enegized shore system.
Yep, you are right, if in fact the shore power is fed upstream of the isolation transformer, there should be a transfer switch, auto preferably.

[smac999]

Originally Posted by AndyEss

I'm not sure if he would need a transfer switch. That does assume the generator comes on automatically due to some triggering situation i.e. Low battery voltage.
If the generator is manually started - don't start if connected to shore power.
I'm not sure if having both shore power connected while the generator is running, will really matter (current draw will only happen if there is a load)

this is highly illegal and dangerous as f*ck. you could kill people. you certainly need a transfer switch.

[Mattm]

I had a freedom sw which had a 100 amp charger. It would sample the power and then immediately punch 100 amps into the batteries and the generator would lag and cause the charger to stop charging re sample and then kick back in over and over again. This may have been the solution for this problem I had.
Also
Is it possible it's a 230volt generator and 120 volt system or 230 volt system and 120 volt generator the voltage could be getting stepped up or down

[77Californian]

As I think about my earlier post...

I think I typed that up without thinking it through fully. I don't think an isolation transformer would do much to filter out the noise that can make its way back to an AC line from a switching power supply. It would probably just get coupled across the transformer like any other AC noise.

So, I guess it is still possible that someone would a transformer there for noise isolation, but I doubt it works very well for the type of noise that a charger would produce.

[AndyEss]

Originally Posted by smac999

this is highly illegal and dangerous as f*ck. you could kill people. you certainly need a transfer switch.

Why would you have "edited" my post that way, and leave off my last sentence which clearly reads that a transfer switch is necessary.

Don't selectively edit another poster to make it seem they are saying something they aren't.

[77Californian]

Mattm,

That is a really good thought. Take a look at that photos he uploaded. It looks like that could be a 2:1 transformer.

[clayzone]

[QUOTE=Is it possible it's a 230volt generator and 120 volt system or 230 volt system and 120 volt generator the voltage could be getting stepped up or down[/QUOTE]

One would assume that is why the transformer was needed but my generator is in fact 110v. Yes, I know that for sure. Needed or not it looks like the previous owner was convinced it was needed. So maybe the "why" is simply because the proprietor could sell it.

[guyrj33]

Originally Posted by clayzone

One would assume that is why the transformer was needed but my generator is in fact 110v. Yes, I know that for sure. Needed or not it looks like the previous owner was convinced it was needed. So maybe the "why" is simply because the proprietor could sell it.

Perhaps the PO hooked up shore power first and wanted an isolation transformer, then installed the generator and it was convenient to route the connection to the transformer.

[waterman46]

Originally Posted by guyrj33

Perhaps the PO hooked up shore power first and wanted an isolation transformer, then installed the generator and it was convenient to route the connection to the transformer.

Convenient yes, but then this transformer would not be in the shorepower circuit. Almost always there will be a GENERATOR/SHORE selection switch in the main AC panel. So any component connected directly to generator is isolated from the shorepower input circuit, thus not useful as shorepower isolator.

Sounds like a case of mistaken installation. But OP would be well served by tracing out and diagramming relevant wiring. If needing to work with any connections such as doing continuity checks with multimeter, be careful to disconnect shorepower and turn off main battery switch so invertor can't start accidentally.