Community Forums

tom chelbana · 08-21-2019, 08:50 PM

Found out that in ND,SD, and WY there are very few diesel fuel stations with DEF at the pump. Heading south from Minot ND from FMCA rally found ourselves running low on DEP with 15 gallon tank. What we found out is that there is about 4.5 gallons of DEF left in the tank when the yellow warning light comes on. Had a little concern since we just don't ever let it go down that far. If we have a half a tank of DEF we just always top it off at the pump. Know now that one could still travel over a 100 plus miles after the light comes on which we just shouldn't have to get to the point of having the light on.
Had some good discussions in Minot at FMCA with a number of irv2 members. Always great to meet in person fellow irv2 members,
Newmar Man

Dutch Star Don · 08-21-2019, 09:23 PM

Good info.

For us, when on local trips, I don't worry about it, but when on longer trips, like our current one, I carry at least one jug. I've owned a DEF DP since 2014.....last week was only the second time I fueled where they had DEF at the pump and I was at 89%.

tom chelbana · 08-21-2019, 09:42 PM

We pick up a 2 1/2 DEF container to keep after this experience. We all need to remember that 1 year would be the most to store DEF.
Newmar Man

Granite17 · 08-21-2019, 10:19 PM

I always keep at least two of the 2 1/2 gal containers and rotate them.
I figure I only use about 1 gal every
160 miles, so 2 1/2 gal. container is lasting 400 miles.

Stuart W · 08-21-2019, 10:58 PM

Quote:

Originally Posted by tom chelbana

Found out that in ND,SD, and WY there are very few diesel fuel stations with DEF at the pump. Heading south from Minot ND from FMCA rally found ourselves running low on DEP with 15 gallon tank. What we found out is that there is about 4.5 gallons of DEF left in the tank when the yellow warning light comes on. Had a little concern since we just don't ever let it go down that far. If we have a half a tank of DEF we just always top it off at the pump. Know now that one could still travel over a 100 plus miles after the light comes on which we just shouldn't have to get to the point of having the light on.

Had some good discussions in Minot at FMCA with a number of irv2 members. Always great to meet in person fellow irv2 members,

Newmar Man

It’s actually way more then 100 miles
In fact it’s much closer to a 1,000 miles
Example;
1000 miles @ 6.5 MPG=153 gallons used

153 gallons x3% = 4.59 gallons of DEF

153 gallons x4%=6.12 gallons of DEF

153 gallons x5%=7.65 gallons of DEF
3 to 5% is average normal consumption ratio

Stuart W · 08-21-2019, 11:18 PM

So 750 miles driven @ 6.5 MPG =116 gallons used
116 gallons of diesel @ a 4% ration of DEF to fuel = 4.64 gallons of DEF.

550 miles driven @ 6.5 MPG= 85 gallons used
85gallons of Diesel @ a 5% ratio of DEF to fuel =4.25 gallons of DEF

Stuart W · 08-21-2019, 11:28 PM

At a worst case scenario of 5% Fuel to DEF ratio and cutting the remaining DEF in 1/2 because you don’t want to run out of DEF it’s 225 miles leaving 225 miles reserve in the DEF tank

CaptainGizmo · 08-22-2019, 01:16 AM

It's after midnight, so my head is soggy with all these numbers which is why I'm glad I have a Cheat-Sheet with SIMPLY math that I can do, in the dark...in my sleep...which I'm very near. ZZzzzZZ

Simple...

Cummins says DEF burns up to 5% (20:1)

Therefore, DEF goes 20 times further than 1 gallon of fuel.

and, for 4% or 3%...
4 into 100 = 25 times
3 into 100 = 33 times

Makes midnight math REAL easy guys!

Good night.

richpatty · 08-22-2019, 05:19 AM

I calculate it more like you do for fuel...in MPG. I don’t think I drive nearly as much as many on here do, but I looked back on my DEF fill ups and have been averaging around 300 MPG for DEF. It seems easier to calculate it that way instead of figuring it out based on diesel usage.

Either way, I still don’t like to get it too low...

superman11 · 08-22-2019, 05:42 AM

One of the many topics that we discussed at Camp Freightliner was DEF. Mike Cody suggested purchasing from the pump and to make it more convenient - to buy a reusable 5 gallon HDPE container and an electric battery pump. Rotate the DEF in from the container and refill at the pump.

I just purchased those items - and plan to utilize on our next trip. It also makes fill-ups more convenient - as I can do both without having to pull forward for the DEF.

tnedator · 08-22-2019, 07:23 AM

Since I work full time and my trips are generally short (330 mile round trip to Branson for instance or 500 mile round trip to dealer), long weekend or week long trips to a fairly close destination, I've been keeping my DEF probably at about 1/3 of a tank, give or take, and filling with 2.5 gallon jugs.

I typically fuel up when I get home, and it's a fairly high volume Exxon truck stop, but no DEF at pump, so I've been buying DEF from there, and keeping two 2.5 gallon jugs in the coach and then I rotate.

As I typically fill up at 1/2 a tank, or 50 gallons, it seems like I'm adding DEF about every other 50 gallon fill up. If I recall, my def gauge is normally going between 1 to 2 bars and I can't remember what they told me that was supposed to correspond to, but looking at the tank, I think I'm normally around 1/3 of a tank, give or take.

In my case, since I don't drive a lot and DEF has a shelf life, I've been avoiding filling it up and topping it off when I get fuel, but instead treating 1/3 to 3/8 of a tank as my "full" DEF point.

If I were to go on a long trip, then of course I would fill it up completely.

CaptainGizmo · 08-22-2019, 09:36 AM

Quote:

Originally Posted by richpatty

I calculate it more like you do for fuel...in MPG. I don’t think I drive nearly as much as many on here do, but I looked back on my DEF fill ups and have been averaging around 300 MPG for DEF. It seems easier to calculate it that way instead of figuring it out based on diesel usage.

Either way, I still don’t like to get it too low...

Agree! It makes it a piece of cake for me. I simply multiply my average MPG by 20 (for a 5% rate), and then I can divide that into my expected Trip’s mileage to tell me how much DEF I’ll need.

tnedator · 08-22-2019, 10:08 AM

Also, I'm going to guess the amount of DEF left is highly dependent on tank size. In my Ventana, I believe my DEF tank is 10 gallons, so I'm sure it's much less that 4.5 gallons when the yellow light comes on.

Just checked my Spartan manual, and it says 10%, so if accurate, that would be 1 gallon left in a Ventana.

Also, I think I've been putting Def in when I get to one green light, which would be roughly 2.5 gallons left. Two green lights is 50% or 5 gallons.

Now that I've looked at the manual, I see that it's 25% per light, so with the Ventana 10 gallon tank its: 2.5, 5, 7.5 and 10 gallons for each of the four lights.

CaptainGizmo · 08-22-2019, 10:44 AM

Quote:

Originally Posted by tnedator

Also, I'm going to guess...

Absolutely right! Why do you think the name for lights on a dash have been named “IDIOT LIGHTS” forever? They give you ZERO SPECIFICS and are only to draw your attention to the problem. It’s up to us to know the specs of our rigs.

Just as any “relative” (1/4 tank) rather than absolute gauge, warning lights drive me crazy until I KNOW how much, what level, what temp, what PSI, etc.