I noticed recently that while charging a small bank with 2 t-105's (225ah), that the voltage while in absorb was up to 15.3. The setpoint is 14.8. The system is installed on our travel trailer and we are currently parked in southwest Arizona. The two panels (520w) have been getting full sun and with our minimal power usage, we are at 100% soc early in the day.
We have another system, with two Kids, back home and in the last year that we've been using them i've not seen the voltage above setpoint.
Any thoughts on this would be greatly appreciated.
Btw, first time poster and newbie on this forum. I looked and also searched for similar topics, but finding none, started this thread.
Just a thought, do you have a BTS and is it cold where you are at this time?
What are the compensation values you have programmed in? Temp? Charge efficiency, etc?
Hi Westbranch and thanks for the response.
The BTS is in place. The current daytime temps are high 60s-low 70s F.
The temp set in the Kid is 25c and the efficiency is at 85%. The temp setting is from Trojans website and the efficiency setting was given by a product engineer at Trojan.
This may be helpful also. I am using the WBJR with end amps set at 3.5. That number is a work in progress as I try to find exactly where the full mark happens. I believe it is pretty close currently though. The rebulk setting is at default.
I think what Westbranch meant was that if the Battery Temperature sensor is in the battery compartment and the batteries are cold then the battery setpoints will be raised to compensate - according to the temperature offset setting - forget what it is called - but I think the default is 5mv/c degree or something like that . Battery manufacturer will give you the correct number for that setting.
The numbers and settings you referred to above are for setting up the SOC .
Larry
Ok I think I understand. The BTS is in the battery compartment. Night time lows are in the 40's so i
I would guess by 9 am (we see absorb then or even earlier) it might be low to mid 50's. I hadn't realized that the absorb voltage would be raised but it makes sense. Initially I was worried when I saw voltage almost equal to equalize setting. I'm thinking that if that's normal I'll just check the fluid level more often and not worry about it.
Larry was thinking the same as me... :)
Scott, you should do the calculation to see if what you are getting matches pen and paper... in case the adjustment is not in line with the math.. there are some other factors that may be impacting a bit as well...
hth
When I had my first solar system in a camper with a cold battery and dumb charge controller that was not temperature compensated I discovered how you ruin a deep cycle battery !
So yeah - the charging voltage goes up as the battery temperature goes down.
Larry