$21.99 Refractometer for Battery, Anti-freeze, and DEF

pigman1 wrote:

otrfun wrote:

pigman1 wrote:
First class. I have one that measures battery specific gravity and antifreeze freeze point but the DEF feature is a worthwhile addition. Thanks.

If your refractometer can measure a battery's specific gravity (and the freeze point of antifreeze), I'm guessing it should be able to measure DEF, too. The refractometer only measures the concentration percentage of soluble solids dissolved in the water. The concentration percentage of usable urea is within the concentration percentage range of battery acid's specific gravity.

According to my refractometer (with a urea scale), a sample of DEF will read approx. 1.31 on the battery specific gravity scale if the urea concentration is 32.5 percent (ideal). Approx. 1.33 if the urea is high at 34 percent, and approx. 1.29 if the urea is low at 31 percent. I believe the urea concentration percentage tolerance for Cummins is +/- 1.5 percent or 31 - 34 percent.

Thanks a ton for that info.

I was going to copy the Amazon blowup picture of the reading glass and use that as an estimating tool for the DEF. I'm curious because I installed an additional DEF 15 gal tank at the very rear of the rig and engine, just under the rear fiberglass cap. We use it when going to Alaska (bulk DEF is hard to impossible to find in Canada and Alaska) and the fill on it is set up so I can fill from the driver side instead of the OEM passenger side fill. The DEF does get quite warm behind the engine, but we've had no problems with it so far in over 40,000 miles. Be nice to know if I'm changing the concentration though.

Thanks again for the post and the follow up.