Trimetric 2025RV initial settings

[Bend]

Oh wise one's in PWM and Trimetric’s: I’d like some advice on initial settings for a Trimetric 2025RV. Most of my camping is boondocking using solar with a 2K gen as backup. I’ve been upgrading my 1998 23 foot Kit TT for the last year to include the solar & converter wiring along with equipment. I now have a new 2025RV to integrate into the system and have only the knowledge from the manuals and (very) few ’net posts. I’m thinking of starting with operating level L1 with P1 @ 14.5v, P2 @ 1 amp, P3 @ 80 amp/hr. Your comments please?

Equipment:

Converter – PM4-45 Boondocker 14.6v, 13.6v, 13.2v

210 watt PWM 12v solar

Controller – 1997, 30 amp, 4 stage set at 15v bulk, temp comp

Batts – 2x group 24 flooded w/80 amp/20 hr, 5 years old, doing fine (were 13.2v before dawn at 10 degrees F from yesterday’s solar charge)

Refrigerator - 1995 Dometic RM2652, operates @ 9.5-22v

P1 @ 14.5v will be tripped by converter in bulk and easily by controller

P2 @ 1 amp will be tripped by converter and controller in float or dark.

P3 @ 80 instead of 160 because wife would not understand 50% does not mean 0%.

[BFL13]

Your setting must work for you-- thanks for posting your "lessons learned."

I still go with no settings of anything except turn off the auto reset. I manually reset, eg, such as mentioned above, where AH go positive late in the day so I get a "new full" to start over from. (IMO this happens from more gassing at high SOC than the Tri's 4% allowance is for that)

I am still mad at the Tri for not having an AH reset to a particular number. Yesterday with the batts about 70% I had them all disconnected from the rig while I was doing some work on the wiring so when I reconnected the Tri was at zero AH. I wanted to put the AH back where it was before I disconnected. Nope.

So now I have to wait until the batts get full (must confirm with hydrometer) so I can reset to zero and get back in the groove. Could be days from now.

At least I didn't enter a whole bunch of complicated settings that also would go down the drain on any disconnection! 🙂

[Bend]

Trimetric settings – lessons learned

I installed my Trimetric 2025RV last fall. At that time, I searched the ‘net to see what others had for their settings and why. I found very little. Therefore, I’ll document what I’ve learned. My focus will be to those that use solar as their primary means to charge their RV 12 volt battery system. This could be for a weekend or for the long term.

Using the 2025RV with only the factory defaults, the Trimetric will show amphours (AH) used and count backup to zero with AH replaced through charging. With solar charging only and no other overnight charging source, the unit may automatically reset to zero when the sun goes down. Upon reset, the unit will report that the battery is fully charged no matter what the +- AH count is. There may be no long term (more than a day) running total of AH used/recharged.

The Installer’s Instructions and User’s Instructions recommended Level 1 settings, a review:

Level L1- Basic level
Set P1 (charged setpoint voltage); 1-2% below absorb charging voltage. Default = 28.6v

Set P2 (charged setpoint amps); 2% of P3. Default = off.

Set P3 (battery system AH capacity); approximate AH of charge (or energy) your battery bank holds when fully charged. Usually expressed at the 20amp/hour discharge rate. Default = 400.

The meter will then be set up to measure volts, amps/watts, battery %full and AH from full. However, with all other settings at their factory default, this too might result in a nightly automatic reset when using only solar recharging. If voltage is above P1 AND amps are below P2 at the same time then there will be an automatic reset while metered AH are still negative. Example: P1=13.5v (13.8 x .98) and P2=4a (200 x .02), the controller is in bulk charging stage, the meter reads -50 AH (75% charged), a cloud passes over obstructing the sun, volts drop but momentarily stay above P1 and amps drop below P2. This will result in an automatic reset. 75% charged (-50 AH) now reports as 100% charged (0 AH down).

Note: An automatic reset can be to your advantage, changing a +AH report to 0 AH used. Meaning, your battery bank is charged more than it was prior to the last count down.

Level L2- Allows all of L1 and the observation of historical data.

Level L3 – Allows all of L1, L2 and additional programing.

For solar charging, P12 and P14 are a very important part of L3.

P12 - Automatic reset; the default is on. This should be turned off if only Level L1 and/or L2 are used (P7 must be in L3 to change on to off then reset to L1/L2). With P12 set to off, all resets must be manual.

P14 – Allows a minimum time to be set where filtered volts have to be greater than P1 AND filtered amps less than P2 throughout before an automatic reset is activated. Default = 0.0 hours. Filtered describes a 4.8 minute moving average.

My setpoints, observations, opinions and reasoning:

When is a battery bank considered fully charged so that a manual reset is done to start the AH tracking?

I’ll consider the battery bank fully charged after a rare equalization, after a daily/weekly overcharge/top charge or after a 2 plus hour haul where the engine alternator charges the bank. This charge will be the new basis for the stay and a manual reset will be done. Note: This will also compensate for general temperatures and aging banks gradually loosing AH capacity.

When is a good time for an automatic reset?

I want the conditions for an automatic reset to be hard to achieve and not often. Generally, only when the late afternoon AH count is positive (charged above the AH capacity of the last reset).

Considering the answers to the 2 above questions -

P1: I don’t want it based on the absorb stage voltage. Potentially, there are still too many AH to be pumped into the bank after absorb. I want it based on the float voltage. Anywhere from 1/2 to 1 volt below what the Trimetric reads as the true float voltage that is getting to your battery bank.

P2: I want the float stage to be active for a good while with amps decreasing gradually as the bank tops off. I like 1 amp.

P3: Go with your best guess as to the capacity of your bank.

P7: L3 of course. I want access to P12 and P14.

P12: I want automatic reset set to on.

P14: Greater than P1 volts, less than P2 amps consistently for P14 time = reset. 1 hour seems reasonable to abate the passing cloud or afternoon thunder storm. YMMV.

All the other available P settings except for P10 have no direct basis on daily charging. P10 is above most people’s (and my) ability to measure and adjust meaningfully. Set them as you may.

BFL13 - I apologize for changing some of my numbers suggested in the past.

Flame away gents. 8>)

[Bend]

Tri is installed but the batt box is not quite as neat as before due to adding the shunt. 8>)

12th-

You may have won a blue ribbon! I do hope P1 AND P2 must be met at the same time for an auto-reset. I'll try to confirm. Its a very subtle "and" in the manuals.

Anyway... I did a test to see if the "AH from full" counter continues after %full reaches zero, it does.

[12thgenusa]

Bend wrote:

12thgenusa wrote:

...
I don't understand the need to turn off the auto reset. Mine has never auto-reset when it shouldn't have, i.e., battery not full.
...

The only way I can find for the Tri NOT to reset when solar power goes to zero A at night is to have P14(Required continuous time to meet V (P1) and A(P2) charge criteria) set to something other than zero. I'm curious what your P14 setting is. Maybe 4-5 hours?

Or, a very high P1.

Yep, I'm still installing. Might be done by Sunday.

No. P14 is set at default 0, P1 is 14.3. P1 and P2 have to occur simultaneously to trigger a reset. End of day amp decline should be accompanied by voltage decline if the batteries are not full. Reset should not happen. If P1 is too low and P2 is too high a reset will occur before full. The numbers you gave in the OP should not cause this to happen.

Just had another thought. If your controller stays locked in Abs as the panel output declines, a reset would occur. My controller reverts to bulk (MPPT) if panel output cannot maintain voltage with .2V of Abs set point voltage. So if I achieve float before the solar day is over a normal reset occurs. If in Abs when the power declines, the controller shifts back to Bulk (voltage < P1) and reset does not occur.

[Bend]

12thgenusa wrote:

...
I don't understand the need to turn off the auto reset. Mine has never auto-reset when it shouldn't have, i.e., battery not full.
...

The only way I can find for the Tri NOT to reset when solar power goes to zero A at night is to have P14(Required continuous time to meet V (P1) and A(P2) charge criteria) set to something other than zero. I'm curious what your P14 setting is. Maybe 4-5 hours?

Or, a very high P1.

Yep, I'm still installing. Might be done by Sunday.

[12thgenusa]

Bend wrote:
I understand the %full goes to zero and stays there. However, my question was whether or not the "AH from full" stops or continues its tally independent of the %full at zero.

With P3 programed to full capacity I would never see 0. Since it's counting amps it might just go on counting. Try it.

[BFL13]

I don't know since I never entered in a capacity so my % full thing is blank.

IMO just tell her (if your capacity is say 400AH), "Don't that go below 200 before doing a recharge." then no more problems with "percentages of what?"

[Bend]

12th or BFL13-

Quote from manual:
"The “battery % full” reading of the TriMetric just puts the “amp hours from full” number in a different form, which depends on the “amp hours “Capacity” number that has been programmed in to the TriMetric in program number P3. When the battery is full and the “amp hours from full” value is 0 then the Battery% full will be 100. When the battery is depleted so that the “amp hours from full” goes to a negative value equal to the “capacity” programmed in P3 then the Battery% full goes to zero."

I understand the %full goes to zero and stays there. However, my question was whether or not the "AH from full" stops or continues its tally independent of the %full at zero. If it does continue, then all is sweet for the knowledgeable user and SOC can be estimated.

Otherwise, I'll need to remind (re-train) DW each trip that 1/2 full is very close to empty. She does deserve more credit than I give her but BTDT.

[BFL13]

The AH count resets to zero when the Tri thinks batts are full unless you kill that. The Tri instructions explain if you are on solar you will want to. I did see the AH reset when amps went neg as it got too dark for solar to keep amps pos. Drove me nuts until I read that part in the instructions. (when all else fails, read the instructions)

The Trimetric does not use Peukert but it still comes fairly close within reasonable RV draws. We had a thread about that a while ago ISTR. I ran a test and Peukert capacity wasn't as bad as the tables show. Those are for taking the batt down to 10.5v, but we don't do that, so the batts have a chance to bounce back after a heavy draw and do ok on the next draw, so capacity doesn't get too far out of whack.

[12thgenusa]

Bend wrote:

12thgenusa wrote:
... the Trimetric will no longer be able to provide information as to the actual depth of discharge.

There is the AMP HOURS FROM 'FULL' tally that can be compared to your real battery capacity. Is it independent of P3?

No. It's the same thing as %full in a different form.

Quote from manual:
"The “battery % full” reading of the TriMetric just puts the “amp hours from full” number in a different form, which depends on the “amp hours “Capacity” number that has been programmed in to the TriMetric in program number P3. When the battery is full and the “amp hours from full” value is 0 then the Battery% full will be 100. When the battery is depleted so that the “amp hours from full” goes to a negative value equal to the “capacity” programmed in P3 then the Battery% full goes to zero."

BFL,
I don't understand the need to turn off the auto reset. Mine has never auto-reset when it shouldn't have, i.e., battery not full.

You are correct about temperature and capacity. However, a possibly greater impact on capacity is discharge rate. A "known" battery capacity of 400 Ah is only good at one temperature and discharge rate, usually 20-hr rate. But who always discharges at 20A (assuming the 400 Ah bank)? I don't. Most of the time for me is it much less. However, there are short bursts where it can be 132A (MW), 82A (Coffee pot or Toaster),75A (vacuum), etc. The Trimetric counts these all the same—an amp is an amp, which it is. However, the actual capacity is changing with each change in discharge rate. But the Trimetric just goes on using whatever value has been set for P3. The amazing thing is, at least for my usage, it is remarkably accurate. Much better than a SWAG. Maybe my usage time-averages out close to a 20hr rate.

[BFL13]

I think the whole "full" thing is bogus, because your battery capacity changes so much with temperature. So I never did set the "three things" I just use it as is except I turned off that auto reset of AH.

I get amps, voltage, or accumulated AH plus or minus at the push of a button. I start out with full batteries as measured by SG and reset the AH. Then I just let it run. Accumulated AH go down then back up when doing a recharge. When they get back to where they started, I figure the batts are close to full. When doing a 50-90 I can tell when close to 90 if I am 46AH down on my 458AH bank so I stop the generator. then AH start back down again with loads while camping some more.

Sometimes the AH on the way up with solar goes "over" into positive readings in the late afternoon, so when it stops going up I reset to zero and that is my new top.

I have a pretty good idea what the capacity of the batteries is, so I just look at the accumulated AH figure and do a little math to get approx. SOC. eg, if I figure my 458AH (at 80F) is really now 400AH when it is cold out, and I am down 100AH, then I figure the batts are down to 75% SOC.

The trick is to compare your 'resting' voltage with that calculation to see if they are both saying the same thing. Early morning , before you start running loads and before the solar starts jacking up the voltage, observe your "morning voltage" ( being as close as you can get to "resting voltage" while camping) If that were 12.4 and you are down 100AH on an estimated 400AH bank it all more or less matches.

If you get a mis-match you know something has gone funny and you need to do some checking.

[Bend]

12thgenusa wrote:
... the Trimetric will no longer be able to provide information as to the actual depth of discharge.

There is the AMP HOURS FROM 'FULL' tally that can be compared to your real battery capacity. Is it independent of P3?

[12thgenusa]

I'm not convinced that setting the capacity at 50% is really to your advantage. You will always be doing mental calculations to know the "real" % full. If you ever do go below actual 50% SOC, which there is absolutely nothing wrong with doing on occasion, the Trimetric will no longer be able to provide information as to the actual depth of discharge.

But it (P3) is easy enough to change and experiment with.

[Bend]

BFL13 wrote:
You need to turn off the auto reset of AH count (see manual on programming that) for when you have solar. If not, when you go from pos AH to neg AH in the evening you lose your AH count when it resets as AH goes negative.

You’re right! Since solar will go to zero at night, P2 is useless.

Might as well simplify - leave P1 and P2 at factory settings; 28.6v (unobtainable at the batt’s with a 12v system) and off. Therefore, generally do a manual reset of Batt% at the beginning of a trip when the batt’s are saturated and anytime the % is over 100.