Interesting read on battery SOC measurement.

[markopolo]

That leads into what Booster just posted. We want the charged criteria set high enough to be meaningful but, at the same time, easy enough to attain (based on your own equipment's capability) so the counter gets reset often enough to give a relatively accurate SOC.

(edit: typed this while Booster was posting ........ )

[booster]

Originally Posted by markopolo

That's probably because you had not yet reached the "Charged" criteria to automatically reset the SOC counter. It just adds and subtracts amps in and out but amps in are reduced by the setting in P10 - Assumed efficiency factor. P10 is 94% by default on the TM-2025 but can be set between 60% and 100%.

Mine has shown exactly 100% for over a month (plugged in continuously) because it reaches the charged criteria daily (PD charger 15 min boost to 14.4V every 21 hours) and resets the counter.

That is pretty interesting that it is sitting still at 100%, although our solar controller monitor is doing the same thing. Normally, they don't reset to 100% until the voltage hits a certain point on the discharge side. I think most use 12.8v so it is below float and surface charge voltage. It would be interesting to see if yours is actually resetting, or not, or if the batteries are just full you are seeing no amps to them ever. Our solar is monitor is showing zero ah to the battery over 2 weeks, and the magnum shows about .1ah per day. I doubt either are particularly accurate at those tiny readings. We don't get the boost every day, either. Have you noticed any amps going in when it goes up to boost?

[markopolo]

You're right again re: the reset trigger (as per manual). I just assumed the reset occurred when charged status was attained.

Page 9, User manual:

When the battery is full and the “amp hours from full” value is 0 then the Battery% full will be 100.

I have to try to catch the boost event & give an update.

There are some minor loads but they'd be supplied by the converter.

[GeorgeB]

In the 3 months of use I noticed that if I don't plug it on shore power it sometimes takes forever to reach the 100% value and often never reaches the "charged" blinking light status.

It might also be because of my Trimetric settings but I think it is more related to how the solar charger and alternator power are charging the batteries. Even if I get very close to 100%, the solar charger never outputs enough amps long enough to complete the full charge status. It slows down the charging process and doesn't have the extra 6 hours that the shore power charging uses to complete the charge.

Even if I read everywhere that separate uncoordinated charging sources are the norm in the design of RV electrical system I still believe an integrated precise charging that controls all the sources and loads would be the ideal set-up. I'm sure Elon Musk would offer a way to control the whole system of an RV electrical system if he was interested in developing a "TeslaFalia", but R&D budget in the RV world are rare.

I doesn't really bother me if the readings on my Trimetric aren't as precise for the full charge status because the real important use of a battery meter is evaluating how low your SOC is. The controllers (solar, shore) are there to prevent an overcharge, and I guess the alternator simply reduces it's output when the connected batteries are fully charged. Is it really the case?

More sophisticated -and expensive integrated energy management system
e-core energy management system by Dometic
Dometic E-Core Energy Management System - Power - Dometic ECore Power Management - Conrad Anderson UK





.

[markopolo]

You probably have 2 compressor fridges. It would be harder to get to fully charged status if not plugged in.

Maybe, after winter storage, make a note of what voltages you see when the engine is running and let us know what they are.

[booster]

Two out of the 3 charging sources can do totally accurate automatic charging without being integrated or interfering with each other, and that would be the shore charger and the solar. Both can be had with the charging run off a battery shunt and programmable to do return amp charging. Because they look only at the battery current, loads and such don't matter, nor do power from other sources. They read amps just like the Trimetric does, and full charge the same way also.

The engine alternator, AFAIK, has no good way currently to automatically end charge based on amps, unless you do it yourself with a relay of monitor like Victron which has full battery output to run the relay. The good news is that the alternator power will not affect the solar of shore charger accuracy. We have set our alternator up with a manually controlled return amp charging control, which is just an inductive ammeter at the batteries and a switch control charge relay. When it hits the return amps we want while driving, I just shut it off. Not a big deal to watch because it only is needed when driving, so almost as good as automatic. If you have a standalone engine generator, you can't do it like we, though, as you can't shut off the batteries or the generator will lose it voltage reference. Using the stock alternator setup eliminates that issue as the engine battery stays in the circuit.

Tow compressor frigs will probably use 60ah per day in most cases, so you would need 200 watts of solar and perfect sun to just balance that out. Tough to get full with that much down and load on solar.

It is pretty hard to get enough time for the solar to do a complete charge in one day from even a moderate discharge, do to the hold time required to top off the last bit of charge, so would normally be a bit short at the top and need to get totally full once in a while. We can do that by driving until almost full and letting the solar finish, driving alone which is only slightly less accurate, or by using shore power.

[markopolo]

Just took a look at my display:
dSC: 0.73 (days since charged)
dSE: 33.0 (days since equalized)
Amps in slowly fluctuate between 0.00 and 0.01 (even saw -0.01)
% Full: 100
Voltage: 13.2V

I found other info in the manual that indicates the reset occurs when charge criteria is met:

page 5, installation instructions TM2025:

What’s the purpose of these numbers?
The numbers P1 and P2 tell the meter when your batteries have been charged: that is, when the battery 1 voltage goes ABOVE P1, and the charging amps go BELOW P2. Then the meter will reset the “% Full” to 100%, the “amps hours” to 00.0 and your “Days since charged” to zero. P3 calibrates the “Battery% full” display according to your battery size.

[GeorgeB]

Originally Posted by markopolo

You probably have 2 compressor fridges. It would be harder to get to fully charged status if not plugged in.
Maybe, after winter storage, make a note of what voltages you see when the engine is running and let us know what they are.

On average with our 400W solar array it often takes a maximum of 5 hours of summer sunlight to get to 98-99% from a 60% SOC but very rarely to a 100% status. And you're right it doesn't stay fully charged for a long time. As soon as one of the two fridges kicks in it changes to a charging (from solar) or discharging status.

To answer booster question:

Originally Posted by booster

...
Perhaps if George knows the charger make and model we can check it out and see how it will work. ...

as mentioned before our Solar charger is the TriStar solar controller I believe it is a TS-40 will check in my photos

Our shore converter/charger is the Tripp Lite RV1512UL



Thanks everyone for all your help!


.

[avanti]

Originally Posted by booster

If you have a standalone engine generator, you can't do it like we, though, as you can't shut off the batteries or the generator will lose it voltage reference.

You can't do it that way, but (at least if you have the Balmar external regulator), it can easily be done. The regulator has an external enable input that is easily manipulated. I have it connected to the Sprinter's "engine running" signal and also my master shutoff switch so that if somebody shuts off the master switch while the engine is running, the alternator will shut down.

[GeorgeB]

Originally Posted by markopolo

Maybe, after winter storage, make a note of what voltages you see when the engine is running and let us know what they are.

Markopolo, I generally get 13.4 to 13.8 volts when the engine is running, except when the solar quicks in. When there's a very bright sun and the battery is below 80%. it gets up to 14.2 volts when driving ( at highway speed)

[booster]

Originally Posted by markopolo

Just took a look at my display:
dSC: 0.73 (days since charged)
dSE: 33.0 (days since equalized)
Amps in slowly fluctuate between 0.00 and 0.01 (even saw -0.01)
% Full: 100
Voltage: 13.2V

I found other info in the manual that indicates the reset occurs when charge criteria is met:

page 5, installation instructions TM2025:

Bogart seems to have a lot of conflicting statements on this. This is out of the 2025 manual they have online and is the way they had told me it worked way back when we got it.

"1.First the battery must be initially charged fully. When the charger is charging the battery, the TriMetric senses
that the battery is charged when two conditions are met: (1) battery voltage must exceed the “Charged setpoint
voltage” (which you set by Program P1.) and (2) the charge current (amps) must decline to below the “Charged
setpoint amps” (which you set by Program P2). It is also (optionally) possible to set a third condition: that the
page 9
above conditions must be sustained for a minimum time which you set by Program P14. Note that filtered
versions of “Battery voltage” and “battery amps” are used, described in step 5, below.
2. When the above occurs the TriMetric then declares the battery “charged” by flashing the “charging” light, .and,
resets the “Days since charged” to 0.
3.When the charging is finished, and the batteries start to discharge again then the “Amp hours from full” is reset to
0.00, and Battery%Full is reset to 100%. (This assumes that the “auto reset” is on, which is always the case in
Level L1 or L2. It may be turned off if desired in Level L3)"

[booster]

I think both of George's chargers are straight timers, and I couldn't find any absorption times for either, although the Tristar can be hooked to a laptop and should be able adjust the time. The solar probably needs all the time it can get with the frigs, and such.

When we had a Tripp-lite RV750 it had a very short absorption time and always left the batteries at about 90% or less. Tripp-lite doesn't have anything on charging profile in the manuals anymore, so really hard to tell.

I am surprised that his driving voltage is so low, I would expect over 14.2v or so. At his voltages, the recharge will probably be quite slow.

[markopolo]

George - If the fridge or fridges are off and you see 13.4 to 13.8 volts then that is low as Booster pointed out. Do you know if your RV uses an isolator or does it use a separator to keep the house and chassis batteries apart?

The photo you posted here: http://www.classbforum.com/forums/f5...html#post38167
looks to show DIP switch A1 in the up position indicating a GEL cell type battery.

If it was my van I'd make sure that DIP switch is in the Wet Cell position even with AGM batteries. If you phone Tripp Lite they'll probably tell you to set it to GEL for AGM's but I doubt you'll be speaking to an engineer. GEL is a particular type of sealed battery that requires lower charging voltage. AGM's are not GEL.

From an older Tripp Lite owners manual I have: (includes RV1512)

Common Specifications for All Models
Wet** / Gel
14.4 V** / 14.2 V
Float Volts DC (wet/gel): 13.3 V / 13.6 V
**Factory setting.

Also, a guy on the Sportmobile forum took the trouble to escalate the question beyond 1st level support by opening a ticket and got a written response. Link: Tripplite Dip Switches - Sportsmobile Forum

Check the link - I'll quote a bit here:

Thank you for your recent inquiry.
Our inverter chargers use a 3 stage charger. The dip switch for GEL and WET sets the float and absorption voltage as follows.

*Absorption/Acceptance
*14.4 VDC WET
*14.1 VDC GEL
*
*Float
*13.5 VDC WET
*13.6 VDC GEL

The wet cell settings (either from the manual or the email) more closely matches the requirements of modern AGM batteries.

-----------------------

Also, I messed up reporting the amps in at 0.00 and 0.01 - that display was for amp hours from full. Amps in or out are at 00.0.

[gregmchugh]

GeorgeB, Is there a temperature compensation probe installed on your Tripp-Lite?

[GeorgeB]

Originally Posted by markopolo

George - If the fridge or fridges are off and you see 13.4 to 13.8 volts then that is low as Booster pointed out. Do you know if your RV uses an isolator or does it use a separator to keep the house and chassis batteries apart?

The 13.4 to 13.8 volts I get when driving is with the two fridges on, but of course working intermittently.

There's an upfitter's power connection circuit with a relay that connects the van and house batteries when the engine is running. I suspect a weak link between the alternator/van battery and the house batteries because the 50 amp fuse that protects it blew once when I was using the microwave and started the engine. The house batteries were low so I figured it would help to run the motor. To prevent this problem to happen again the upfitter considered using a 70 amp fuse but never implemented it in it's built. It only happened once so I didn't pursue the investigation.

Maybe the cable that runs between the systems is not big enough (never checked what size). I was told that the van 220A alternator could get prematurely damaged from having a cable that's too big because it could draw too much amperage. An alternator doesn't regulate it's output and it could get harmed if the house batteries demand is too big when the van's battery is also charging.


And thanks a lot for the info about the GEL settings on my converter/charger. I will also check the settings on the TriStar solar controller.

Really impressed with all your help!


The 50 amp fuse to the house batteries




The diagram of the circuit with a relay that connects the van battery and the house batteries.

[GeorgeB]

Originally Posted by gregmchugh

GeorgeB, Is there a temperature compensation probe installed on your Tripp-Lite?

Yes, there's a probe for the Tripp-Lite. But no probe for the Morningstar Tri Star solar controller.

[booster]

Interesting that the upfitter mentioned the 220 amp alternator could be damaged from too much output to the coach. I have always believed that could be an issue as stock OEM alternators weren't designed for that kind of of service (unless they are police or ambulance optioned) and often don't have as sophisticated output reduction regulators or heavy duty parts like the designated high output aftermarket stuff. That said, the low voltage you see could also be because the alternator has turned itself down to protect itself.

50 amp breaker would normally indicate a #6 wire in most cases, and 80 amps would be a #4. The microwave probably pulls about 85 at 14 volts. To get less voltage drop a bigger cable would be nice. With our 250 amp alternator we have a 3/0 cable, and some even go to 4/0 with the 270 amps alternator, but those alternators are made to handle the output.

[GeorgeB]

Originally Posted by booster

Interesting that the upfitter mentioned the 220 amp alternator could be damaged from too much output to the coach. I have always believed that could be an issue as stock OEM alternators weren't designed for that kind of of service (unless they are police or ambulance optioned) and often don't have as sophisticated output reduction regulators or heavy duty parts like the designated high output aftermarket stuff. That said, the low voltage you see could also be because the alternator has turned itself down to protect itself.
...

Do OEM alternators have regulators that lower their outputs?

The dual alternator solution is very tempting!
(http://www.classbforum.com/forums/f5...nced-3330.html)

I would love to have a second alternator dedicated to the house batteries like avanti installed on it's Sprinter. Don't know if ProMaster dual alternators Roadtrek are installing are reliable?

or changing the 220 amp I have with the 270 amp you recommended
https://www.dcpowerinc.com/fit/Chrys...formance_sheet

Our 2014 van is still under warranty for another 3 year so all the mods have to be done or approved by the upfitter. I will wait until I start replacing the falling components. The AGM batteries might be the first ones to go, replaced by Lithiums with a new Converter/charger. We are enjoying our dry camping with the actual system so it's not an urgent project. Fine tuning the actual system is on my list for next spring and the info you gave me is greatly appreciated.

[gregmchugh]

The idea that the alternator could be damaged by using too large a cable does not make any sense. Larger cables cannot result in increased loads on the alternator.

[GeorgeB]

But gregmchugh why do some of the upfits have bigger cable like the #4s that are installed in ARVs? Isn't it to increase the amperage to the house batteries? How come that increase doesn't translates to a load increase on the alternator?

Are you implying that standard OEM alternators have a bigger capacity than the combined load of the van and house systems when both demands are high?

I am a real newbie in that field so please correct me if I'm wrong.