Technical Question dc/dc converter 12v max amps?

Lots of threads here on doing this - search on inverter.

The consensus seems to be that a 1 kilowatt inverter is about the maximum safe size.

 

Like ftl said, if you will use the Search function and search for inverter you will find more than enough technical documentation.

 

I don't know the answer to your question. However, to be on the safe side, I always hook an additional 12v car battery in parallel to the 12v battery in the Prius, wherever I'm using an inverter. The extra battery is there for handling peak loads. When I'm not using peak loads, the dc to dc converter would charge both batteries.

 

It has been posted on this forum but like the rest of you I forget the value - 70 Amps?

 

The max amp output is 120 amps. but there is a 100 amp fuse in the line to the aux battery.

 

Is this amps can handle 3900w amplifier and 2 subs pioneer 1400w

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No, since 100A * 12V = 1200W

 

According to the Manual:
Fuse for DC/DC converter is 5A. 12V*5A=60W
The recommended charging rates for the 12V is 4.2 A max.

 

That's not the fuse you're looking for.

There is a 5 amp fuse labeled "DC/DC-S" (names from the 2010 wiring diagram), but that is only protecting the converter's remote-sense lead. A funny thing happened in Gen 3 ... in both Gen 1 and 2, the remote sense lead went all the way back to the battery in the rear and attached to the positive battery post through a separate 5 amp fuse, so it really was sensing the voltage right at the battery. The Gen 3 converter still has a remote sense lead, but they must have decided they didn't really need remote voltage sensing after they added a battery temperature sensor, so the converter's "remote sense" lead now senses ... the bus in the engine compartment fuse box, about six inches away.

The fuse labeled "DC/DC" (which you'd hardly recognize as a fuse, it's part number 90982-08297 and pretty much buried inside the whole front right corner of the engine compartment fuse box) is rated 125 amps.

Bear in mind those 125 amps have to run all the 12 volt stuff in the whole car, on top of whatever accessories you are hoping to add. Also, the DC/DC converter has a "help! ease up!" output, called IDH (it's a blue wire from connector A59 pin 2 in a 2010). The HVAC controller (at least) watches that signal; if the weather is cold, the engine isn't warmed up yet, and the electric heat is on, the HVAC controller will drop it temporarily if the converter asserts IDH.

If you're adding a significant load somewhere, you could consider having it watch IDH also. Alternatively, you might think about just putting a red LED on the IDH signal, somewhere easy to see, and then you can watch it and decide how you want to reduce your load if you see it come on.

-Chap

 

this is what I plan to add with 2 dvc sub pioneer1400w

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ChapmanH said something very interesting. I think. Unfortunately, if it answered the question I am not smart enough to decipher it. Can anyone clarify what the max amperage applied to the 12v battery would be in a gen3 / 2010? Something less than 125A, I presume. Do you reckon it's less than 20A? 5A?

Cheers

 

It seems like you might be looking for this thread.

-Chap

 

Thanks a ton for posting that link, CF! I did search, but never saw that. Short of seeing it in the manual, I'd say that's evidence enough that the max amperage is 60A, maybe 70A. Sounds believable. Unfortunately it does eliminate a lot of Lithium batteries I'd been eyeing as a replacement for the 12v, but maybe not the EarthX with it's max of 60-something. But that's for another post, I suppose.

 

Nominal voltage of the Prius is around 14v on ready. That will change your equation.

 

I think Bob Wilson posted some trial results some years back showing that the voltage will sag a bit as the current is approaching the limits.

-Chap