Trimetric Owner Warning
I already posted this but I guess it went out into the ether!
If you have a Trimetric and you stay connected to shore power almost all the time, don't bother reading further. If you have a solar charger that works every day you can skip this too. However, if you spend long periods without a charger connected you need to read this.
Now, first and foremost, I love my Trimetric and wouldn't have an RV without one. It is the only way to keep track of your battery usage and tell you when to charge that really works (there are other brands as well.) However, if you don't charge for long periods it can be misleading. A Trimetric alone is like using a checkbook and never balancing it. Sure you keep track of how much you put in and how much you take out, but never check the ABSOLUTE amount.
That is what a Trimetric does and it does it very well. However, it really doesn't know what the absolute charge level is. It calculates what you put in and what you take out and give you the net charge. However, it doesn't know about self discharge,required overcharge or other issues like that. Modern converters really don't hit the bank with enough voltage to really get you to a solid 100% since they are worried about overcharging and electrolyte loss.
Bottom line is keep an eye on your resting voltage from the Trimetric. Right now my unit says that I am at 90% but the voltage is 12.3 (after a long rest) and...the hydrometer confirms that I am closer to 50% than I care to be.
For people who operate in this mode, the only solution is an SC-2030 charge controller and 150 or 300 watts of solar. It will hit the batteries hard and keep them at 100%. That is where I am going.