Battery monitor use and settings

[booster]

Some recent contacts with another member concerning settings for their Trimetric battery monitor has made me wonder how others are handling the settings.

The Trimetric, and probably most other monitors, determines if the batteries are full by making sure they reach a minimum amp setting at a set voltage. The amp setting is determined by the batteries used and is a % of capacity, normally, and between .5 and 3% of the 20 hour capacity. The voltage you set for the voltage threshold is usually a .1-.2 volts under the temp corrected absorption setting for you charger. If the batteries see absorption voltage and the amps get below the amps setting, the Trimetric lights the fully charged indicator and considers the batteries full. The display will show over or under 100% at this time, in most cases, do to charge efficiency, but the amp hour counter will be accurate. Having 5-10% more amps returned than was used is normal, so the AH counter will be in the plus direction by that much. When you shut off the charger, and start to discharge off the batteries, the Trimetric resets to 100% SOC and zero amps in/out. This is the reset calibration that is necessary for accuracy going forward. Without it, the SOC and AH in/out readings would get progressively less accurate with every charge and discharge cycle.

The potential problem is that if the charger is not of a type that can consistently get the batteries to full charge, you will never get a reset unless you do it manually. If you do reset manually, and you don't have full batteries, you will set 100% SOC on batteries that are not there, so also be inaccurate.

We have discussed how folks do this with the PD chargers, and Marko has been able to get his working very well with the semi-manual setup. The PD chargers are good because you can reinitiate a charge cycle to get the batteries full so the Trimetric will reset and calibrate.

I would think there are many folks that never touch the Trimetric or reset it, as they aren't into the manual running of things. Nothing wrong with that, but if the charger isn't getting them fully charged regularly, they will be getting very poor readings of the actual SOC of their batteries, I think.

The newer generation of chargers we have seen lately, that do the transition from absorption to float based on amps as a % of charger capacity, are almost certain to leave most batteries undercharged or overcharged, unless they are the exact right right size for the charger and no loads are on, so those would be a minor improvement because you at least know when they will stop charging and could set the Trimetric amps setting higher to allow for it. Of course, it would reset to 100% when you were not at 100% full at that point.

Perhaps with the chargers that stop early, the Trimetric should be programmed to check the float voltage and amps(?) as the batteries will get "mostly" full after a long float?

I guess the question is--what is everyone seeing for resets with their monitors? Do you ever look at the amps on the Trimetric to see how much the batteries are taking? Do you ever look at the AH in/out on the Trimetric or always use the SOC display? Have you ever had an issue with the SOC not being what you expected, like running out of power early, or seeming to have more left than you thought you would? Has anyone used alternate settings in their monitor to make it work better with their charging system?

There is also the possibility that the resets are only happening after longer drives that could get the batteries all the way full. Has anyone noticed that happening?

[avanti]

I have to admit that I am not anal on this topic. But, what I prefer to believe is that my modest solar charger and the fact that I park outside conspire to obviate this issue. I have no evidence to the contrary. If I am wrong, I don't want to hear about it.

IMO, this is the main reason to have some solar.

[markopolo]

My settings are (TM-2025):

P1: 14.3V
P2: 1A
P3: 390Ah

Those settings require both 14.3V or more and 1A or less flowing through the circuit to meet the "Charged" criteria and therefore auto reset.

It's been a while since I used the van to camp though so I'll try to remember to update this to note if I reach that target if off-grid for a few days.

I wonder if the Balmar SmartGauge is the same as the SmartGauge - SmartGauge Electronics - SmartGauge battery monitor - previously discussed here. Actually, it's probably better to spin that off to a different topic so Trimetric users can ignore it if not interested.

[booster]

I think a thread on the Smartgauge may be a good idea. I have gotten several questions about them in the last year. I don't know if the Balmar is the same or not, but that would be interesting to find out. The Smartgauge is not a normal battery monitor in that is does not measure current, as its only connection is a small wire to the positive terminal. It only gives a % SOC regardless of battery capacity (a benefit or detriment depending on how you look at it) based on internal algorithms, which must be based on voltage rate of change readings that are integrated over time to predict SOC loss. It would be very interesting to see if anyone has tried one, and compared to a regular shunt based monitor.

[gregmchugh]

I believe it is the same device. Started a new thread on the Smartguage...

[papab]

I have a trimetric and a 150ah lifeline. I have truecharge 60 which switches to float way too soon, at 6 amps instead of the required 0.75 amps. I get around this by switching the charger to gel and fooling it into thinking the battery is cold, this gives me 14.3 V which is good if the battery is 77F. The temp sensor is a resistance temperature device, so I added 2 10k pots in series so I can tweak the temperature and indirectly tweak the charge voltage.
The other way to get the trimetric reset to 100% is rebooting the charger, then it goes to full absorption voltage for a couple of minutes which is enough to reset the trimetric. Of course if I'm parked and it's sunny I can set up my 100W folding panel and get whatever voltage I want (when the battery is close to full).
I'm kind of fanatic about monitoring and logging the battery data.
I'm adding a 150W panel & trimetric charger so I shouldn't have to fool around with this as much in the near future.

[briancummings]

1. P1 - 14.2
2. P2 - 08.
3. P3 – 220 (Amp Hour capacity of batteries)
4. P4 - A
5. P5 - OFF
6. P6 – OFF
7. P7 – L3
8. P10 – 97
9. P11 – Sh.H
10. P12 – ON
11. P13 – 10
12. P14 – 00.0
13. P15 – 30.2
14. P16 – 01.
15. P17 – 20
16. P18 – 13.1
17. P19 - FAC

[booster]

Originally Posted by briancummings

1. P1 - 14.2
2. P2 - 08.
3. P3 – 220 (Amp Hour capacity of batteries)
4. P4 - A
5. P5 - OFF
6. P6 – OFF
7. P7 – L3
8. P10 – 97
9. P11 – Sh.H
10. P12 – ON
11. P13 – 10
12. P14 – 00.0
13. P15 – 30.2
14. P16 – 01.
15. P17 – 20
16. P18 – 13.1
17. P19 - FAC

Thanks, Brian. Is P2 on your's in amps or %? 8 seems pretty high either way.

[briancummings]

My rig is capable of producing close to 8 amps so I set it at 8 to allow for it. I have 300 watts of panels. I also have 3-130 AH Batteries controlled by a ProStar 30 and a Trimetric TR2025-RV

[markopolo]

The amp flow in will decrease as the batteries get closer to full.
P2 at 8 amps is low criteria (easy) to reach.

Your settings require 14.2V and 8 amps or less to reach charged criteria.
It's unlikely that the batteries would be near full if for example 7 amps were still coming in.

I set mine to 14.3V and 1 amp or less. That's much greater criteria to reach. I can get there when plugged in but haven't confirmed getting there off-grid yet.

[booster]

Originally Posted by briancummings

My rig is capable of producing close to 8 amps so I set it at 8 to allow for it. I have 300 watts of panels. I also have 3-130 AH Batteries controlled by a ProStar 30 and a Trimetric TR2025-RV

As Marko said, the P2 setting in really only there to tell you when your batteries are full, and to reset the meter to 100%. We don't know what batteries you are running, but at 220ah, they are probably GC2 and maybe Lifeline. The recommendation from Lifeline is .5% of capacity, in amps, to indicate full at absorption voltage. In your case that would be 1.1 amps to the batteries when they were full. At 8 amps you will indicate full long before you really are full.

On edit, I just noticed you have 390ah of batteries, but have the Trimetric set at 220ah. That would indicate a 2.0 amp setting to be full at .5%. Are you using the reduced setting to build in a safety factor?

[briancummings]

I'm going to bump mine up to 4.4 and 1 amp and see what happens, currently I've never gone below 66% capacity while camping, that was 3 weeks with no shore power and I run an ice maker, several phone chargers, a laptop or 2, a TV, LED lights, a microwave occasionally and my furnace when needed.

I just forgot to change the AH setting after adding the third battery, oopsy.

[booster]

Originally Posted by briancummings

I'm going to bump mine up to 4.4 and 1 amp and see what happens, currently I've never gone below 66% capacity while camping, that was 3 weeks with no shore power and I run an ice maker, several phone chargers, a laptop or 2, a TV, LED lights, a microwave occasionally and my furnace when needed.

I just forgot to change the AH setting after adding the third battery, oopsy.

With 390ah of batteries, you may not get all the way to 1 amp while charging at absorption voltage, and if you do it will take very long time. You may want to try 2 or 3 amps first to see if it makes it there.

For P1, you would normally want to set it at about .2 volts lower than your charger runs in absorption (hopefully temperature compensated), so if the charger is set at 14.4v, you would use 14.2v, etc.

I think the main thing is to get the amps set so you a good indication of fully charged, but also so to make sure you get the 100% full charge reset activated so you keep your accuracy.

[papab]

These are my settings (150ah lifeline AGM)
P1 14.3
P2 0.9
P3 150
P10 96
P14 0.5

When camped & charging with the 100W panel I was having false indications of 'charged' when P14 was set to the default. I think what was happening was that it was getting close, the voltage was adequate and the amps were fairly low (<2), the fridge would come on (~4.5 amps), the panel couldn't keep up so the amps dropped as well as the volts. Evidently the filtered volts stayed above the 14.3 & the amps met the 0.9 briefly and it showed charged. By setting P14 to 0.5 (hrs), it fixed this issue. P14 is an additional time that the volts and amps criteria must be met.
I just installed a 160W rooftop panel and a SC-2030 so I suspect I'll be tweaking the parameters a bit.

[booster]

Originally Posted by papab

These are my settings (150ah lifeline AGM)
P1 14.3
P2 0.9
P3 150
P10 96
P14 0.5

When camped & charging with the 100W panel I was having false indications of 'charged' when P14 was set to the default. I think what was happening was that it was getting close, the voltage was adequate and the amps were fairly low (<2), the fridge would come on (~4.5 amps), the panel couldn't keep up so the amps dropped as well as the volts. Evidently the filtered volts stayed above the 14.3 & the amps met the 0.9 briefly and it showed charged. By setting P14 to 0.5 (hrs), it fixed this issue. P14 is an additional time that the volts and amps criteria must be met.
I just installed a 160W rooftop panel and a SC-2030 so I suspect I'll be tweaking the parameters a bit.

That was a very good catch on your part, and got rid of the false tripping of the full indicator.

We have had similar issue, but not with a battery monitor. It was with our Blue Sky solar controller. It will be interesting to see if your Trimetric controller does similar of if the greater adjustability you likely have will help. What we got was on days that we either drove a while or didn't have much to make up with the solar, the solar would run in absorption under good sun and then go to float and continue to run the loads. If the sun got weaker due to clouds, and/or if the loads increased (like you, frig comes on and off), the solar wouldn't keep up with the loads, and the voltage would drop. With the Blue Sky, it would go back and do a reabsorb cycle, as soon as the voltage went under the float setting for a minute. If good sun came back or loads dropped enough, that is no big deal and it would quickly go back to float, but if the sun and loads hold it down somewhat, above float, but under absorption, the voltage would hold at higher the float forever because it never got to full absorption to trigger a float transition. I called Blue Sky, and it appears their head tech guy figured this out also, as in newer models, they will be turning on the rebulk only if the voltage drops under 12.8v, so they are sure the batteries are being run down, not at the float setting. The current units do the transition as soon as it drops below the set float voltage. We have changed our float voltage to 12.8v to see how that does. It was pretty irritating to see over 14.5 volts for hours at a time, when I knew the batteries were full. This was for our wet cells that had absorb at 14.7 volts, so now less bad with AGM at 14.3v. The wet cell water use would go up a lot under those conditions, and it took a while to figure out why.

[markopolo]

That was a good catch & something to be aware of if the charging source is unable to supply enough current (temporarily).

The default voltage filtering is 2.4 minutes on a TM-2030 and 4.8 minutes on a TM-2025.

I'm curious to know if upping the voltage criteria to 14.4V would reduce the chance of a premature "charged" indicator.

[booster]

Originally Posted by markopolo

I'm curious to know if upping the voltage criteria to 14.4V would reduce the chance of a premature "charged" indicator.

That is a very good question. I tend to think that it probably wouldn't stop much of it, as when our solar drops out put and can't keep up, the voltage drops more than .2 volts. It is more likely to go right down to near battery voltage. It would be interesting to watch for sure, though.

You do have to be careful of the voltage setpoint if you have a temperature compensating charger. We had the monitor not reset in very hot weather due to the charger reducing the voltage enough to go under the monitor voltage setpoint while in absorption.