Setting your Trace Auto Gen Start Parameters

[cubeman]

David don't be to hard on those other guys running those sites . True they figure a way to make a few dollars but in the end they add to the overall knowledgebase out there . Also we guys are the" A "personality in the room and we all know where that ends up on most subjects . Maybe one day I will think I know more than others and create my own Office Furniture Site , O wait I did that already ,lol fastcubes.com

But I will add I have know you and Chuck for some time, and I respect your willingness to give to all who come to visit . Thank you and keep giving the gift that keeps giving

[davidbrady]

Al, that's a good message for them too. I'm happy with more forums - the more the merrier. I personally think everyone should run their own server. No more centralized FB's selling your personal data; instead, a network of personally owned servers w/o advertising.

[davidbrady]

Al, remember that your Trace inverter has no non-volatile memory, so if you're inverters ever reset or lose power you'll have to go in and manually restore your configuration parameters. An important parameter to remember to restore is "Set Gen Amps" in menu 11, "AC Inputs". This setting tells the inverter how many amps to let the genny provide before the inverter helps to offset loads using battery power. The default is 30, which of course is way too low. For your bus it should be set to 60. This may be why you ran your batteries down the other day.

[cubeman]

I did take your advise and she is now at 60 . Was at 50 so 60 is much better. Also plan to allow the Inverters to take over control of generator management . Been on Inverter since 10am and plan to stay there till the Inverter turns the genny on . These batteries are new and I want them to go through a proper charge and discharge without me interfering . That means stove , Micro everything .

[cubeman]

Well yesterday while dry camping I decided to test out our batteries. They lasted 20 hours 18 min before the generator started on it's own . This is much more than I ever expected and you could say we are very Happy with the results . The weather was a low of 28 and a high of 37 or so . So the heaters have been running . We have a old Amana and elect cooking stove .


This is not how we would normally exercise the genny but I thought they could use a good long drain on them to stretch there abilities and life span .

So here is the question . If we do not dry camp much but are plugged in most of the time or driving which charges the batteries all the time , do we shorten there Life Span ?

[davidbrady]

AGM lifespan is inversely related to the number of discharge cycles. Fewer cycles, longer lifespan, so pole to pole camping is very easy on batteries. The other thing that messes them up is deep discharge to like 0% state of charge. I try not to go below 50% depth of discharge. Also, discharging them and then putting them on a shelf in a discharged state messes them up.

If you're boondocking, then you need to be careful to fully top-up your battery bank to over 100% of it's capacity during each charging cycle; otherwise, the batteries will "walk down" over time and fail. Over 100% is indicated by an absorption charge amperage of less than .5% of the battery bank capacity.

My coach has 8 4D's, of course wired in a 24V bank, which provides a 840Ah capacity. Lifeline says my charging current should be at least 0.2C which for me is about 170A. Our inverters control charging current based on AC amperage, so divide 170 by 4 to get 42A of AC charging current. We divide by 4 because of losses in the Trace chargers. Now, we have two inverter/chargers, so divide by 2 again to get your "Set Max Charge Amps AC" in menu 10 "Battery Charging". This tells me to set my inverter charging amps to 21A AC on each inverter.

If I do this, then I need the following amount of time to charge my 50% depleted battery bank back to 100%. (Remember my DC charging current is around 170A):

840 * 50/100 / 170 + Absorption Time = 2.5 hrs + 3 hrs = 5.5 hours

For boondocking, where I'm going to be doing this for day after day, there's a couple of things to pay attention to:

(1) I can shorten my charging time by increasing my Trace charger output. When my generator is running I want to use it to it's maximum, so I'll reach in and I'll increase the "Set Max Charge Amps AC" to 30. This will bring the Bulk (constant current) phase of the charge cycle down from 2.5 hours to: 840 * 50/100 / 240 = 1.75 hours, adding in 3 hours of Absorption time brings my charge time down from 5.5 hrs to 4.75 hrs.

(2) I need to make sure I'm spending enough time in Absorption. Remember what I said earlier about the batteries "walking-down" as the days wear on if I'm not topping then up to over 100%. (Lifeline says 102% to 110%). The only measure we have of this is the "Inverter/Charger Amps AC" in the Meters menu (Menu 4). Inverter/Charger amps can be (+) or (-). (+) means the inverter is charging, and (-) means the inverter is powering loads. To make it more confusing the inverter can be powering loads even though the red "Bulk" led is on indicating charging. Then, I also get into the case where one inverter is in Bulk and the other is in Float. So, to read this meter both inverters should be in Bulk and both should be showing a (+) value. In any case, Lifeline says the Absorption time is complete when the charging current reduces to 0.5% of the battery bank capacity.

In my case, with my 840Ah battery bank, this would be 4.2A DC. Dividing by 4 gives me about 1A AC, and dividing by 2 again for the two inverters gives me( around 0.5A per inverter of charging amperage at 120VAC. (In reality, one inverter is bound to dominate so you'll like read a larger value on one inverter and closer to zero on the other). So you can see the Absorption time is difficult to determine based on charger 120VAC Amps, but if you have an amperage anywhere above 0.5A AC then it's not complete and you need more time in Absorption.

For a DOD of over 50% Lifeline recommends an Absorption time of 4 hours. For a DOD of between 30 to 50% Lifeline recommends 3 hours, but the real time required is how long it takes to reduce Absorption amperage to less than 0.5% of the battery capacity. This parameter can be fine tuned - see "Set Absorption Time" in Menu 10, "Battery Charging".

In short, when the generator is running and when it's pretty much dedicated to charging my AGM's, I increase my charging amperage to 30, and I make sure I don't walk-down the battery bank as the boondocking days wear on by staying in Absorption long enough. Stay in the Absorption period for long enough to bring the battery bank back to 102 to 110%! Not doing this is probably the number one reason folks don't get years out of their AGMs.

[cubeman]

By George I got it

Believe it or not I'm starting to get this ! I did think absorption was very important to the life of the batteries and feel good about how we are charging them now . After this charge I will resume how we have been using them and pay attention to the float time .

One question I do have remains . Is it ok that 1 inverter goes to float, while the other has remained at bulk ? Is this a setting issue ? Again thank you for the class

[davidbrady]

(02-22-2019 12:05)cubeman Wrote:  One question I do have remains . Is it ok that 1 inverter goes to float, while the other has remained at bulk ? Is this a setting issue ? Again thank you for the class

It's more of a nuisance. The Trace recommended way to use two inverters is to either series connect them or parallel connect them using the front panel SWI port. This way one inverter becomes a Master and the other a Slave and charging algorithm transitions are made synchronously. Well, the parallel mechanism never worked very well and it works even less well if the inverters are running different software, and the serial mechanism requires running the inverters as a 240VAC single phase centertapped source which then requires a big hefty transformer for balancing across the two 180 deg 'phases' which doesn't work very well in a coach that has few, or in my case any 240VAC loads. I'll be forever trying to balance the system.

So, the third alternative is what we have - two inverters working two separate legs but drawing from and charging the same battery bank. It's a nuisance because there's no Master inverter; i.e., they're peers. As such they have a limited view of the world. The inverter in Bulk wants to hold the battery voltage at 28.6 while the inverter in Float wants to bring the voltage down to 26.6. Luckily it can only go on for whatever time period is remaining in the Bulk inverter's Absorption timer, which in most cases will be short, but during that time period one inverter is charging and pushing current into the battery bank while the other is inverting pulling power out of the battery bank. It's a less than optimal situation. Remember the Float inverter can only bring the battery voltage down if there are loads to power. Many times there aren't any or are very few so it doesn't succeed in affecting the battery voltage. Also recall that each inverter will spend it's specified Absorption timer duration in Absorption. So the only way one inverter can end early is if it started early. This again gets back to the two inverters acting independently. The one that ended first saw an acceptable Bulk voltage level before the other. No big deal really. It just goes to show how each inverter is using it's own measurements to gauge battery voltage, current, and time. Is it bad for the batteries. I don't think so as long as we are conservative with our Absorption timer settings; i.e., err on the conservative side by adding in more time.

Like I said earlier, I think we tend to under charge more than over charge by not spending enough time in Absorption. When I'm driving and the 50DN is trying to keep my batteries at 28.8 and the inverters are in Float and they're trying to bring it down to 26.6 and the generator is running and I have heavy loads like 4 Cruisairs running, before I pull out I increase my Absorption time to like 8 hours. This keeps the inverters from fighting the 50DN and it keeps the genny powering all my loads instead of the inverters picking up some of it.

BTW, another way to minimize the Bulk/Float conundrum, at least when running the genny, is to fine tune your Absorption timers. Let's call the inverter that controls your generator Inverter_2 and the other Inverter_1. Reach into your "Battery Charging" menu for each inverter and set Inverter_2's Absorption timer to say 3 hours. Now go into Inverter_1's "Battery Charging" menu and set it's timer to 3 hours 30 minutes. This way Inverter_2 will expire it's timer first and it will then shutdown the generator. Shutting down the generator will push Inverter_1 out of Absorption. This works well for the generator but not so well on shore power. On shore power I simply reach in and work my magic with the timers to extinguish the Bulk charging LED.

Not the perfect answer. Maybe someday, in my infinite time, I'll find some way via software to make one inverter the Master and the other the Slave and this problem will be solved. Till then, happy motoring!

I think you're now seeing the power of these inverters and why they were wired in as the brains of your entire electrical system. They far eclipse anything that Wanderlodge ever used, and even to this day there's really nothing on the market that matches their configurability and their grunt or ability to start and power huge current sinking loads, ACs motors, etc.

[cubeman]

Just when I thought I was getting a Gold Star in Class ok , I will study harder Mr Brady

[cubeman]

There has been a lot said about this phenomenon at the end of the charge cycle of using twin Trace SW4024 inverters, and most is true, however, anyone with this inverter setup needs to remember the "big picture":
This is only allowed to happen for a short time period that one inverter is in Absorption charge while the other is in Float. The absorption time limit is only 3 hours. This is really not a problem, and has been installed in coaches that get battery life of up to 10years, depending on number of cycles. As for the "fighting" between the inverters, is not detrimental in reality, as this series of inverters have the highest reliability rate of ANY INVERTER I have seen on the market now or in the past. They are installed on literally a thousand or more coaches (this number made up mostly between the huge fleets of Vantare's and Marathons, plus Angola's and Parliament's and the last version of Country Coach and Legendary).
I just want to reassure owners of these inverters not to "sweat it" when it comes to the exact workings of their inverters. As long as they have the battery temperature sensor feedback, they will not damage your AGM batteries.
Thanks,

Ben Cummings
Parliament Motor Coach
ben@parliamentcoach.com
888-571-5755, ext 230
813-830-8619 (Cell)