Can coach batteries be monitored by a MPPT solar controller not connected to panels?

[michael trumbull]

We plan to get a complete solar system in 1-2 years but can’t afford the entire system now. We ruined our 2 golf cart 6Volt batteries by relying on the factory idiot light battery monitor and cigarette lighter voltage meter.
We need to buy new coach batteries and would like to find a better way to monitor the volts, amps and state of charge without purchasing a $300.00 Trimetric battery monitor that we were told we won’t need when we buy the complete system. Does anyone know if a MPPT solar controller can be used to monitor volts, amps, and state of charge of coach batteries without being connected to solar panels? Thanks in advance.

[GoneSouth10]

We're in a similar situation (looking to install a robust solar system down the road), and I just purchased new coach batteries. Looking to prolong the life of the new batteries (4 X Duracell 6 V 235Ah), I bit the bullet and bought the Victron BMV-712 battery monitor as the first component in the future solar system. I couldn't be happier. Installation was very easy and the Bluetooth functionality and Android app (iPhone also available) is very slick! Gives me way more information than I probably need right now, but will be perfect for the eventual solar system.
Note: you'll need a short length of battery cable to install the shunt on the negative side of your battery setup (match the gauge of your current negative/ground side) and two mounting screws - the unit doesn't provide either as your particular mounting needs will be different. I just left the monitor unit in the basement for now as everything you need to see/monitor is on the phone app.
It's worth it!!

[babock]

A solar controller can not monitor anything other than voltage. Voltage alone is not a good way to monitor batteries.

Like GoneSouth did, buy a monitor that measures current through a shunt like the Victron BMV-712.

[FFred]

"We need to buy new coach batteries and would like to find a better way to monitor the volts, amps and state of charge without purchasing a $300.00 Trimetric battery monitor that we were told we won’t need when we buy the complete system."

The basic Trimetric SOC system is 1/2 that price , as a SOC meter is the only way to know what the batts are doing. It is a wise investment, if you plan to boon dock a lot.

There is no need to have the solar charging installed in the SOC meter.

Remember solar has a hard price , you can not park in the shade , and expect it to work.

[camaraderie]

A real battery monitor as GS10 & Babcock says is necessary even when you finally do get the entire system installed.
Any of the Victron 700 series lineup is are good choices depending on your needs and start around $150 and are VERY easy to install. BMV 700 gives you house bank monitoring, BMV702 adds engine battery readout...BMV712 gives you smart phone access. Trimetric also makes good moitors but at higher prices.
I note also the Balmar Smart gauge which to me is the best of all,,, IF... you are going to often not fully recharge your battery.. runs between $250-$300. Full description over on marinehowto.com but good victron comparison here,,,
https://shop.pkys.com/Smart-vs-BMV
Note that the Balmar does not work for lithium.
Based on your comments about price...I think you will be happy with a Victron...and ALWAYS fill em up full!

[boondocking]

Here is an inexpensive battery monitor that works great.

[michael trumbull]

Thank you all for your responses. A goo battery monitor definitely seems the way to go. Thank you also for the information on installation from Gone South 10 and the comparison on the different Victron monitors from Cam.

[babock]

Originally Posted by michael trumbull

Thank you all for your responses. A goo battery monitor definitely seems the way to go. Thank you also for the information on installation from Gone South 10 and the comparison on the different Victron monitors from Cam.

And make sure it is a monitor that measures current through a shunt of some type. Voltage only monitors are pretty much worthless.

[TowPro]

I use Bogart engineering system. It even has a add on solar charger that is controlled by the trimetric. And it counts amp hours to determine battery charge, not volts.

[fmc]

I use one of these for my coach. I purchased it from ebay. There are many different types to choose from. Very easy install and works great.

[ScottBrownstein]

Really interesting SOC monitor that sells for less than $120. Uses Bluetooth to your smartphone. If you need more than 75 amps you will need an external shunt which retails for less than $10.00. Thornwave is probably the new solution since you needn't pay for a display and can mount it in the battery compartment without running wires to the accommodation.

Nice solution. I have a Trimetric which I am very happy with but if I had to do it over again I might go this way instead.

https://www.thornwave.com/collection...dc-power-meter

[babock]

The good thing with the Victron is that it integrates with the Victron solar controller wirelessly and gives you remote voltage sensing..

[ScottBrownstein]

Originally Posted by babock

The good thing with the Victron is that it integrates with the Victron solar controller wirelessly and gives you remote voltage sensing..

Trimeteric also has a companion solar charger that uses it for remote voltage sensing.That is why I installed it. This is especially useful for solar charging since there is plenty of voltage available to hit solid charge targets with no problem. rr

[babock]

But no Bluetooth right?

Mppt solar controller??

Originally Posted by ScottBrownstein

Trimeteric also has a companion solar charger that uses it for remote voltage sensing.That is why I installed it. This is especially useful for solar charging since there is plenty of voltage available to hit solid charge targets with no problem. rr

[ScottBrownstein]

Originally Posted by babock

But no Bluetooth right?

Mppt solar controller??

Nope, it is a PWM controller which is probably best for 300 watts or so. They do have a new WiFi interface dongle that's extra (no price yet.) However, the TM2030 has a serial interface that I use with a Raspberry Pi server in my coach which supports my SmartPhone monitoring app in the RV and anywhere over the web. Very useful for me but not really that applicable to the "average joe."

[TowPro]

Originally Posted by babock

But no Bluetooth right?

Mppt solar controller??

I don't feel the need for this data on my phone, having had the Bogart in 2 different RV's over 5 years I just find I use a couple screens. current and % charge. If your computer tech enough you can get output from the 2030 that you could record I think.

as far as MPPT vs PMW, click here and go down to C1.
As you read this, think about your application. Mine is hot everywhere I go. no cold camping for this crew.

[ScottBrownstein]

Originally Posted by TowPro

I don't feel the need for this data on my phone, having had the Bogart in 2 different RV's over 5 years I just find I use a couple screens. current and % charge. If your computer tech enough you can get output from the 2030 that you could record I think.

as far as MPPT vs PMW, click here and go down to C1.
As you read this, think about your application. Mine is hot everywhere I go. no cold camping for this crew.

I agree. I think that one user interface is all that you really need, not a panel AND a SmartPhone. Frankly, that is why I think the Thornwave is the coming thing. Smaller than the standard SOC gauge, fully potted for wet environments and a display on a SmartPhone. Saves routing all the cables into the coach and finding a wall to cut a hole in...forever.

However, "screens" is something kinda foreign to a Trimetric. I too use current, voltage and SOC. My smartphone app shows me plots of those variables vs time say during a boondocking generator charge cycle. A little geeky but well that is the way I go.

[babock]

It doesn't matter how many watts you have to make mppt better than pwm. MPPT is 30% more efficient no matter how many watts you run.

Don't know where this idea that mppt is only beneficial at a certain point!

The Bogart monitor is just out of date. No reason to buy one when there is so much better ones out there.

BTW, no need to even mount the Victron monitor unless you want to. It can just sit with it's wires all bundled together next to the current shunt if you don't want to drill a hole.

I paid $185 shipped with no tax for my Victron BMV-712. If I bought the thornwave on Amazon, it would be almost $20 more by the time I bought a 500A shunt. No brainer to go the Victron route.

Originally Posted by ScottBrownstein

Nope, it is a PWM controller which is probably best for 300 watts or so. They do have a new WiFi interface dongle that's extra (no price yet.) However, the TM2030 has a serial interface that I use with a Raspberry Pi server in my coach which supports my SmartPhone monitoring app in the RV and anywhere over the web. Very useful for me but not really that applicable to the "average joe."

[TowPro]

Originally Posted by babock

I paid $185 shipped with no tax for my Victron BMV-712. If I bought the thornwave on Amazon, it would be almost $20 more by the time I bought a 500A shunt. No brainer to go the Victron route.

I researched the 712, and I think I am seeing I can select Monitor chassis battery voltage OR monitor battery temp but not both. (I want both)


and how many MPPT chargers are there that use coulomb counting to know when batteries are fully charged?. Since the Bogart solar controller charging is controlled by the 2030 it knows how much to charge the batteries.


Example: on my motorhome the Battery Isolation Module can "latch" when the chassis battery goes below 12.6 volts (70% charged) and the Solar is over 13.3. when this event takes place you will be charging BOTH your Coach and chassis battery. Since the Bogart is counting Ah put back into the House batteries, and the solar is hooked to the Load side of the Shunt, the output from the solar will become divided with some going to chassis battery and some going to House battery. Because the Bogart is counting Ah across the shunt to control the Solar charger, the charging will still fully complete (if you have enough sun light) until your House batteries are fully charged.


But I have not purchased my new equipment yet. Can you show any MPPT controllers that will mount on wall (hopefully filling the hole left when I remove my GoPower controller and be flush mount, with wires on back side of controller?
I am pretty sure i can fill this GoPower controller hole with the Bogart 2030-a (same as Rv gut size of double gang box)

[babock]

You can measure both. You have to measure voltage since that is how power is supplied. For temp, you buy the sensor

Hopefully, the Bogart is NOT using the monitor to determine when the battery is charged by amps produced. That is a very poor way to do it and really doubt that is it's method.

Originally Posted by TowPro

I researched the 712, and I think I am seeing I can select Monitor chassis battery voltage OR monitor battery temp but not both. (I want both)


and how many MPPT chargers are there that use coulomb counting to know when batteries are fully charged?. Since the Bogart solar controller charging is controlled by the 2030 it knows how much to charge the batteries.


Example: on my motorhome the Battery Isolation Module can "latch" when the chassis battery goes below 12.6 volts (70% charged) and the Solar is over 13.3. when this event takes place you will be charging BOTH your Coach and chassis battery. Since the Bogart is counting Ah put back into the House batteries, and the solar is hooked to the Load side of the Shunt, the output from the solar will become divided with some going to chassis battery and some going to House battery. Because the Bogart is counting Ah across the shunt to control the Solar charger, the charging will still fully complete (if you have enough sun light) until your House batteries are fully charged.


But I have not purchased my new equipment yet. Can you show any MPPT controllers that will mount on wall (hopefully filling the hole left when I remove my GoPower controller and be flush mount, with wires on back side of controller?
I am pretty sure i can fill this GoPower controller hole with the Bogart 2030-a (same as Rv gut size of double gang box)