Inverter in diesel engine room -- how bad?

[ranger58sb]

I've been studying how/where/when/cost/etc. of a inverter installation. Easiest in this case is to replace an existing charger with an inverter/charger in the same location.

That location is in the engine room, very near but not directly above, the easiest supply battery bank, which is currently (and would continue to be) used for the bow thruster. Nearness to the supply bank addresses manufacturers' distance and fusing recommendations. That location would also simplify AC-side wiring from inverter/charger to the main panel.

Of course the installation manuals say as near the battery bank as possible, but not in an engine room or other hot location. Battery manuals say pretty much the same thing, as do charger manuals. Nor are batteries and chargers supposed to live together in the same location. (All this from a synthesis of Mastervolt, Victron Energy, and ProMariner charger and inverter/charger manuals.)

But then every boat we've ever owned, or even shopped on, has had batteries and chargers in the engine room, direct from the boat manufacturer.

(Our new ride, which is as originally built, currently has 4 battery banks and 3 chargers in our engine room. Not immediately next to the engines, not hugely far away from the genset.)

So, how horrible can it be, placing an inverter/charger in an engine room... along with those other chargers and batteries that aren't supposed to be there either?

Would we says it's:
A) Less optimal than it could be but would work OK
B) Not optimal, but better than nothing
C) really bad
D) dangerous and stupid

Or... maybe we could rate it on a scale of 1-10, with 1 being good enough and 10 being dangerous and stupid...

?????

-Chris

[CharlieJ]

For an idea of how bad, look at the temperature derating curves put out by Victron. Pretty significant.

[BillKny]

A great deal depends on how well ventilated your engine room is. Most are not.

We have one large blower pushing air in, and a second blower sucking air out that run anytime the engine or genset are on. The ambient temperature rarely reaches 35C. Another key factor for us is that the inverter is almost never asked to carry a large load when the engine is running, but that will vary a lot depending on life style of the crew.

It’s not the perfect environment for our inverter and transformer, but it has proven effective. On most boats smaller than 60 feet or so, it is tough to find a “perfect” place for an inverter charger. They are bulky, noisy and hot, so as much as my inverter dislikes sharing space with the engine, I dislike sharing my living space with it!

[ranger58sb]

Originally Posted by CharlieJ

For an idea of how bad, look at the temperature derating curves put out by Victron. Pretty significant.

Thanks, I hadn't found those. Now that I know they exist, it seems to confirm an engine room location isn't optimal but at least not dangerous within the temp ranges we'd be seeing.

Our "underway" load on the inverter wouldn't be huge. In fact, even our "at rest" loads wouldn't be all that huge, even if perhaps with an occasional short burst of microwave.

-Chris

[Junk Viking]

Also note that it's all about the air temperature that the Inverter sees.

A solution is to funnel the fresh cool outside air direct to the inverter, so it performs under optimal conditions no matter what.
Take care that the air is nice and dry to avoid corrosion in your expensive inverter.
One way is to take intake air from inside the boat or similar depending on your sailing area and setup.

[stormalong]

I have had a Heart 2000 inverter in my engine space for the last 25 years without a problem. Seldom if ever driven it harder than a kilowatt. When underway probably less than 200 watts.

The original owner had it in the lazarette where it could get wet. The best alternative was the engine space. Never had a problem with it - pretty good for a 35 year old inverter.

[Cadence]

Electronics of any kind are temp. sensitive. If you can get it out of your engine compartment it would be a plus.

[Stu Jackson]

Chris, could you perhaps turn this question around? In lieu of asking whether it is good or not, could you share with us your options, for example: "Moving it out of the engine room would extend the connecting wire (XYZ) feet."


If the relocation extends the wire between the bank and the I'C such that that heavy wire is within voltage drop limits, or within a workable modest wire size increase, could that also work as an option for you?


Remember, you could run, for example, the 2/0 or larger cable for 90% of the distance and use smaller wires for the very short remaining distances at one end if connection bends or lugs are an issue.


In other words, what would it take to move it compared to the other good ideas presented.

[ranger58sb]

Originally Posted by Stu Jackson

Chris, could you perhaps turn this question around? In lieu of asking whether it is good or not, could you share with us your options, for example: "Moving it out of the engine room would extend the connecting wire (XYZ) feet."

If the relocation extends the wire between the bank and the I'C such that that heavy wire is within voltage drop limits, or within a workable modest wire size increase, could that also work as an option for you?

Remember, you could run, for example, the 2/0 or larger cable for 90% of the distance and use smaller wires for the very short remaining distances at one end if connection bends or lugs are an issue.

In other words, what would it take to move it compared to the other good ideas presented.

A useful approach, thanks.

The non-engine-room location I've found that's nearest to the proposed battery bank looks to be about 15-17' of DC wire run, and then with an AC wire run of maybe 10' or so.

These are guesses, anticipating a bit of up here, around there, down inside, back up, over... etc.... since there's not much in a straight line.

Comparing: the in-engine-room location would be about a 3' unobstructed (straight) DC wire run and probably in the neighborhood of 8' AC wire without much of a roundabout route involved.

There are some other locations that could be suitable for the inverter/charger plus a whole additional battery bank, instead of using what is now the thruster bank, but the AC wire run from those locations starts getting tortuous.

That approach of course also brings with it the cost of a whole new bank of batteries. much higher than the cost of dual-purposing an existing bank. In the dual-purpose scenario, I reckon I can consider the cost of the thruster bank as one I've already got to deal with when replacement becomes necessary anyway. Bulking it up a little, probably when that eventual replacement happens, wouldn't be such a big bite for an inverter bank.

-Chris

[stormalong]

I just noticed that the OP has a 58 foot boat so when he says engine room I think walk in engine room. That probably runs much cooler and is better ventilated than the engine space on my 44 ft sailboat.

Since he is already running battery chargers off of a generator and has large batteries in there I think he would be OK with an inverter.

[boat driver]

the conversation fails to suggest type of boat, invertor size, and temps involved.
Batteries gas, so that is a reason to have them separate in a well vented area - chargers/invertors get hot, particularly when charging, so that is an ignition source.
the rest is simply elementary to where is a suitable location.

you mentioned batteries- be sure to understand the invertor and battery combination or you will eat the batteries up.

[boatpoker]

Originally Posted by boat driver

the conversation fails to suggest type of boat, invertor size, and temps involved.
Batteries gas, so that is a reason to have them separate in a well vented area - chargers/invertors get hot, particularly when charging, so that is an ignition source.
the rest is simply elementary to where is a suitable location.

you mentioned batteries- be sure to understand the invertor and battery combination or you will eat the batteries up.

Battery chargers and inverters may share the same space or even be immediately adjacent to batteries. ABYC requires that they not be mounted over batteries. Adjacent is acceptable as the hydrogen (explosive & corrosive) gassed off from batteries is the lightest known element and rises at 20/sec. Ventilation above the batteries is important for this reason.

[boat driver]

Originally Posted by boatpoker

Battery chargers and inverters may share the same space or even be immediately adjacent to batteries. ABYC requires that they not be mounted over batteries. Adjacent is acceptable as the hydrogen (explosive & corrosive) gassed off from batteries is the lightest known element and rises at 20/sec. Ventilation above the batteries is important for this reason.

not sure if you supporting logic or quoting regulation? issue is understanding the reason for the manufacture explanations and liability vs an individual hardship by lacking room.

[ranger58sb]

Originally Posted by ranger42c

The non-engine-room location I've found that's nearest to the proposed battery bank looks to be about 15-17' of DC wire run, and then with an AC wire run of maybe 10' or so.

I should have added this first "nearest" non-engine-room location would also maybe be suitable for a new/separate battery bank... which would greatly improve the distance required for the DC wiring... but due to space limitations and weight/balance concerns, I'm pretty sure they'd have to be LiFePO4.

That wouldn't be horrible, but I'd not mind saving the cost of a whole new and relatively expensive battery bank. (Conceptually compared to half of the cost of adding capacity to an existing bank of less expensive technology that can be dual-purposed.)

-Chris

[ranger58sb]

Originally Posted by boat driver

the conversation fails to suggest type of boat, invertor size, and temps involved.

you mentioned batteries- be sure to understand the invertor and battery combination or you will eat the batteries up.

58' Sedan Bridge power boat (see profile/avatar). The builder positioned three chargers and four battery banks in the engine room.

Probably 24VDC 3000W 70-ish amp 120VAC inverter/charter, coupled to (eventually) a 24VDC 428Ah battery bank that also powers the bow thruster. Inverter to supply 120V fridge, freezer, small galley appliances, TV/Stereo, and outlets for charging laptops and phones and so forth. At anchor, genset to be probably running 2x/day, for 1-2? hours each, coinciding with cooking and heating water.

Don't know temps.

Yes, of course.

-Chris