Here is my problem; I am using a behmor roaster with no extension cords.
Typical roasts run to 15 Mins with a 300 Gram load FC at about 10 Mins
Wish to get first crack to about 9 Mins or less.
Line voltage is 118 with no load when elements cut in I am down to 113 volts per a Kill-a-Watt
Is this voltage a problem since I feel my roasts are too long?
If so will a variac solve the problem?
Can you suggest a few models that would work
thanks in advance

Funny, I used one until a few months ago but can't remember the minimum recommended dose (sounds like a vitamin). I think it was something like 150g, but am not sure. No doubt someone will be along to fill in my blank, directly. Anyway... lower doses take less time. That's the first thing to try, but be aware you can only take it so far.

If you've got quite a few roasts under your Behmor's belt, a deep cleaning can shorten roasting times as well. There are directions on the Behmor site.

A Variac, or similar device, is mostly valuable to develop consistency within the framework of changeable power availability at your site. A Variac doesn't make or store its own power. Consequently, there are limits to what it can do in terms of shortening roast times.

Try roasting a 200g charge and see if that doesn't get you there.

Without commenting too much on strategies, goals and methods, you may better approach your desired profiles with a roaster which allows a higher drop temp than a Behmor. Great value for the money, but it can only do what it can do. Again with the limits. Always with the limits.

Good luck,
BDL

I would review this CoffeeGeek post on Behmor and Voltage, I feel that the roaster dropping to 113 V is going to be a problem for you in your quest to get to first crack in nine minutes or less.

Things to try are a different outlet that is either closer to your sub-panel or higher rated (see if you have a 120 V outlet for your washer/dryer you can use), or roasting in the morning or evening if you see the voltage droop during the day. I've never used a Variac with the Behmor, I do understand that it can boost the voltage to help compensate for a voltage drop, but it might be better to try and find a better outlet or roasting time. Also make sure that your not running your microwave / air conditioner / electric meat smoker at the same time. I tried doing a coffee roast in the garage (off my washer/dryer outlet) while I was smoking meat in the back but quickly realized it would be a disaster.

300 grams should be fine. That's about what I roast with normally, though for some Ethiopia coffees I'll go down to 250 grams to try and maximize the berry.

Did another roast of Sumatrian at 200 gram load (1/2# P2 A) voltage was a bit better at 115 (as you point out a different time of day)
hit F/C at 8 mins and EOR at 13. Roast looks good about a full city; had a couple of 2nd cracks