Replacing 15kw diesel Gen with Propane - Recommendation & Important Considerations?

muirhouse · November 2015

Anawa, right, thanks. I will still have the two starter batteries and wiring connections left from the diesel, wiring going to connect right through that box.

arby · November 2015

muirhouse said:

The SG? and your 3648's are 36 amps?

Specific Gravity--- I think he means that his 8500 puts in 90amps+ when the battery bank is low and will accept this high of a charge rate.

Anawa · November 2015

SG refers to battery Specific Gravity that measures state of charge. The 3648 is Ouback's 3600 watt (48 volt) inverter that charges the battery when the generator is running.

Paul
in Georgia

DanS26 · November 2015

You are wise to be moving to LP. LP is a bi product of natural gas production. With the massive switch from coal to gas generation, LP bi product will be in massive supply for the foreseeable future.

In the Midwest propane tanks are stacked high as people have moved from propane heat to geothermal. What a mistake.

Forget the 500 gal tanks, get two or three 1000 gal tanks. Fill them with $.89 gal propane.....the cheapest energy on earth outside of wood. Yes that's right $.89/gal vs $5.00/gal two winters ago. Market manipulation just caught up with market correction.

mike95490 · November 2015

> Propane seems to give trouble starting in very cold temperatures.

Well, no, it will start, but as the vapor is drawn off, the propane tank can cool down to the point it gets too cold to vaporize any more gas. The propane and generator companies have charts for how much HP and what size tank is needed for winter temps.

inetdog · November 2015

mike95490 said:

> Propane seems to give trouble starting in very cold temperatures.

Well, no, it will start, but as the vapor is drawn off, the propane tank can cool down to the point it gets too cold to vaporize any more gas. The propane and generator companies have charts for how much HP and what size tank is needed for winter temps.

Or you can run liquid propane from the main tank to the generator site and use an evaporator there that can make use of some of the waste heat from the generator once it is running.
Most if not all bulk propane tanks have an additional outlet connected to a dip tube to supply liquid propane.

arby · November 2015

mike95490 said:

> Propane seems to give trouble starting in very cold temperatures.

Well, no, it will start, but as the vapor is drawn off, the propane tank can cool down to the point it gets too cold to vaporize any more gas. The propane and generator companies have charts for how much HP and what size tank is needed for winter temps.

Interesting, My only experience is my honda EX5500 that I converted to propane and found it to be reluctant to start in cold temperatures. I guess i will have to fiddle more with the adjustment.

mike95490 · November 2015

Don't muck around too much trying to get a conversion working properly, Conversions don't have the cold start enrichment (choke) that factory carbs have. converted rigs are a compromise. A dedicated propane engine has a proper propane carb.

muirhouse · November 2015

Looking at Winco (Honda engine, Kohler, and not Generacs)

arby · November 2015

mike95490 said:

Don't muck around too much trying to get a conversion working properly, Conversions don't have the cold start enrichment (choke) that factory carbs have. converted rigs are a compromise. A dedicated propane engine has a proper propane carb.

I'm not sure you are correct about that.
The few propane carbs that I have seen are just ordinary carbs with the float bowls, jets, etc. removed and a nozzle that feeds propane into the venturi. They use a vacuum sensitive regulator to regulate fuel demand. I installed a regulator that electronically enriches the mixture on cranking. Turns out that it was overkill and floods the motor causing a quick start and then dying.

muirhouse · December 2015

I am going to have to use a portable generator, probably max 6 -6.5kw as this is what is most readily available - to use with my two Xantrex 4048 inverters on a temp basis while I look for the larger size. In the past I have simply plugged in a portable during repairs and I am not sure exactly what is happening electrically when I do that. Is the charge strictly a backfeed? Does it charge the my 48 volt battery bank, or just power the house. Does it go through the inverters?

Blackcherry04 · December 2015

Basics, anything connected to the output of the Inverter has to go through the inverter. The Generator is connected to the Input of the inverter. Once the input power is available and qualified the Inverter makes a transfer to the incoming power ( bypassed ) to the loads. At the same time the transformer reverses and becomes a charger. Systems settings determine the amount of power that is directed to each task.

muirhouse · December 2015

Blackcherry, trying to get a grip on whether I can set the max charge rates on the Xantrex inverters and have it affect the input of this (what is looking to be a Dewalt DXGN14000 (honda engine). As I am being told this will be a manual start, stop, NOT controlled by my inverters. If so, then do ANY of the xantrex's inverter settings protect the batteries (like max charge rate)?

Blackcherry04 · December 2015

Yes, there two settings that effect the amount of power you can use. 1) the ACin is set to your breaker size on the generator. 2) the charge limit is set to a Percentage of the charger size and that limits the amount going to the chargers. It also has power share that will raise and lower the amount of power that the charger will draw from the available power based on the limit set.

In your case you have a Master and slave and they will follow the settings, but remember it's x2 unless you separate them. You need to read the manual to see how to set them.

muirhouse · December 2015

There is a communication cable between these two, I think they are stacked?

Blackcherry04 · December 2015

Yes, there is a communication cable. They are networked on the Xanbus. I have Outback so it's different, but basically the same. on mine I can still make the chargers have different settings, you may not be able to. Really to keep the legs balanced they should be the same unless your system needs a different setting.

Start a new thread and someone can help you with the settings. Your system is special and I had no intention of getting to deep into it. There are some guys that know a lot more than I do for your system.

Vic · December 2015

As noted previously, we use a Stacked pair of the older SW+ 5548 inverters -- these are 11 years old (that is, these are NOT the new Conext SW line).

When Stacked, the inverters communicate via the Series Stacking Cable ... BUT it appears that the ONLY thing communicated, is Synchronization of the AC waveform.

It appears that the Series Stacked inverters (stacked to yield 240 VAC) are completely independent, as to Qualification parameters, Mac AC input currents, Charger voltage & time settings, and, unfortunately, there is also NO sync of when and how much current each charger takes from the genset, when a voltage-regulating charge stage is reached. This lack of input current sync can upset Inverter gensets, as the load on the gensset is often ALL on only one leg of the 240 V genset output.

Even when Series Stacked, the system is quite happy running on a 120 VAC genset (connected to only one SW inverter). Using just one inverter/charger in this 120 V genset configuration does NOT create a "Stacking Error" in the system.

Believe that muirhouse is also using Series Stacking on this SW/SW+ set of inverters.

Just trying to be clear about the almost complete independence of each inverter/charger, at least when Series-Stacked.

FWIW, based on experiences here with SW+es. Vic

muirhouse · December 2015

Vic, you are right. So, given that (which I did not know - I thought the Master/Slave lingo meant that the Master dictated and the plus followed, given that itself, it has no generator control settings. Even though I make sure the settings are exactly the same on both. So the best situation is to avoid the inverter generators, yes?

Blackcherry04 · December 2015

I see what your saying now, I know very little about these old Inverters, there is no remote control, just a cable to connect the sync and everything else in independent of each other. That would be a shot in the dark. I assume you can still adjust everything on their display. The older ones may not have used the percentage and the new 4048's do.

muirhouse · December 2015

But, with my old diesel, I have gotten sync errors. Also I am now confused by the "In your case you have a Master and slave and they will follow the settings, but remember it's x2 unless you separate them." Blackcherry can you clarify.

Blackcherry04 · December 2015

On the newer versions they are set up like I explained ( master & slave ), but what Vic said these do not operate like that, they are independent of each other but for the sync.

muirhouse · December 2015

Ok, now I have a 7-8500kw Westinghouse Generator with thick cables but no appropriate male plug to go into my outlet that goes straight to the inverters. Call in to my electrician, and losing power as I write this. This is my backup generator now until the larger propane is delivered and installed. Backfeeding into inverters is not the question. Anyone done this? I have done it once with a little Honda, but the plug was a borrowed one (so was the generator) and I am not sure what we used. All kinds of Danger Will Robinson warnings out there on backfeeding, but most are for on grid and 0 inverters setups.

Vic · December 2015

Hi muir,

Generally, portable gensets will have several outlets on the control panel. If one looks closely, there are almost always a number for the outlet molded into the front body of the outlet ... L14 - XX and similar.

These larger outlets would usually be a Twist-Lock (r) type outlet. You would normally look for the Mate to that receptacle -- so the receptacle would have an ' R ' at the end of its part number, and would want to find that same numbered plug, but with a ' P ' at its end.

Here is a link to some examples of some Plugs:

https://www.platt.com/platt-electric-supply/Nema-Twist-Lock-Switches-and-Receptacles/Nema-Twistlock-Plugs/search.aspx?SectionID=8&GroupID=103&xVoltsAC=240&CatID=998

The circuit breaker on the gensset that protects that outlet would normally tell you a lot about that receptacle's current rating.

Good Luck, Vic

muirhouse · December 2015

So, I have the male, that goes into the generator, problem is, it is female on the other end, and needs to be a male. Then we have male to male, and all those warnings! Not sure if my wiring setup gets around all that, give that it goes into the inverters, is grounded, etc.
That's my concern. Still waiting on my electrician! And trying to learn more while I do. Thanks Vic.

BB. · December 2015

Not sure I understand:

Backfeeding into inverters is not the question. Anyone done this? I have done it once with a little Honda, but the plug was a borrowed one (so was the generator) and I am not sure what we used.

If the AC inverter has an AC INPUT connection (120/240/whatever)--Assuming you make the appropriate voltage connection (i.e., 120 VAC, 120/240 split phase+neutral, etc.) and the right size circuit breaker and wiring--You should be OK.

If, you are planning on connecting to the AC output of an Off Grid Inverter (or even hybrid inverter)--Usually that is a fast path to letting the magic smoke out of much of your equipment.

Exactly, what AC inverter are you using right now?

-Bill

vtmaps · December 2015

muirhouse said:

So, I have the male, that goes into the generator, problem is, it is female on the other end, and needs to be a male. Then we have male to male

Are you trying to make a male-male cord? Those are also known as suicide cords. I'm a bit confused about exactly what it is you want to connect... but even if the connection is OK electrically (and I'm not sure it is), a suicide cord is not the way to do it.

--vtMaps

muirhouse · December 2015

I have two xantrex SW4048sa, They have been controlling the start stop of my 15kw diesel when the batteries reach a certain level that I set in the inverter controls. There is an AC in good reading which when it does the right handshake with the generator (usually dictated by the right hertz frequency being present) begins to cycle appropriately in charging the batteries and float the house. I haven't had to do this in a long time, so I am spoiled and a bit jittery, as the solar has been doing so much of the work and the diesel worked up until March, when I got by with no back up generator needed.

muirhouse · December 2015

vtMaps: yes, this is why I am asking, warnings all around. But before I knew that, when the diesel was being repaired, that is what we did. The Honda generator came with a cord, plugged one into the generator, the other into the plug wiring in the generator shed, just a normal outlet but wired into the inverter, and off we went powering the house. Now that I have my own backup generator my new Westinghouse, and don't have my own cord, just the huge ones with the horizontal Nema plugs, I am trying to figure out what to do about a cord! And still waiting on my electrician.

Replacing 15kw diesel Gen with Propane - Recommendation & Important Considerations?

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Replacing 15kw diesel Gen with Propane - Recommendation &amp; Important Considerations?

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Replacing 15kw diesel Gen with Propane - Recommendation & Important Considerations?