Looking for the most accurate, highly recommended battery monitor

[Dr Gil]

I searched through all the posts for a battery monitor. I see some mentioned but not the criteria I'm looking for. Sorry if I missed a post that I need.

I'm looking for the most accurate, highly recommended battery monitor for my auxiliary battery. Cost is a distance 3rd concern. Don't care about Bluetooth. In fact, it's better for me if I could just glance at a monitor mounted in the cab and know immediately what my auxiliary battery status is at.

What your favorites?

 

[dwh]

In no particular order of preference...SmartGuage (algorithmic, no shunt), Xantrex, Victron (both shunt based).

 

[trecash6850]

I like my Blue Sea.

Sent from my E6810 using Tapatalk

 

[jacrider]

Xantrex LinkPro works well on our sailboat with two battery banks.

 

[1leglance]

I just got this one as part of my solar setup and love the bluetooth and history for watching things over time.
https://www.amazon.com/Victron-BMV-...tron+battery+monitor&psc=1&smid=AERMGYAT5R869

 

[Dr Gil]

Why would a shunt be necessary or an added feature benefit?

 

[dreadlocks]

I really like my Victron, works very well.. a shunt lets you monitor current consumption and can more accurately calculate SOC.

 

[jonyjoe101]

tk15 coulomb meter is my favorite, I use it on my 110ah lifepo4, but you can use on any battery. You program the battery ah and then it counts amps going in/out of battery. The screen is lighted, it blinks while charging and is solid when discharging. The screen tells you percentage, available amps, current amps being charged/discharged, even tells you eta before battery is 0 percent at current rate use.
The one I bought 50 amp version was 23 dollars, they have a 350 amp version for around 50 dollars.
The accuracy is good enough for me, I checked it against a dc wattmeter.

In this picture it is shown next to a dc wattmeter, readings are almost the same.

 

[john61ct]

None are very accurate for SoC.

SmartGauge is the best in that regard, but does not have a shunt, does not count AH.

Victron BMV-712 is IMO the best out of the AH counters, but like all such, needs owner to calibrate and adjust to keep its guesstimating pretty close.

Go to http://marinehowto.com, ctrl-F for

battery monitor

and read those three articles closely.

 

[john61ct]

For maximum benefit of Victron gear, get the Color Control GX as well.

Not necessary but. . .

 

[Dr Gil]

Great information from everyone, Thanks.

What would you say is the lowest voltage you can safely drop to before recharging the battery and damage it? This is for a deep cycle battery. That is what I want the battery monitor to tell me.

 

[Dr Gil]

You can google plenty of state of charge graphs. Make your decisions from there. Virtually all graphs display slightly different values.
On average lead acid gives best lifespan to dollar ratio when not discharged below 50% what is right about 12.0V

Yikes. So I've metered my battery at 10.9 volts in the past, and in the 11's several times... Is that battery trashed? Which is why I need an accurate battery monitor.

 

[dreadlocks]

If your goal is to prevent damaging the battery consider a Low Voltage Disconnect, I also have a Victron Battery Protect that does that job nicely.. mine is set to disconnect @ 12v automatically, you plug your charger in between it and the battery and it'll reconnect when you have a charge back on it.

I always screwed my batteries up when I was away, go on a few day backpacking trip and dead flat.. or hell even a day cruise down some trails come back and realize I left the fan on full blast for a full day and the battery is in low 11s

The alarm on the Victron BMV-712 is pretty good, having heard some claxons going off from other people's low battery alarms from great distances over and over all night I didnt want any of that.. its a soft buzzer that wont wake a hard sleeper, but you will hear it if you wake up.. and when you silence it it stays silent and dont keep going off every few mins all night long.. I have mine setup to alarm before it disconnects the load, so like 12.2v the buzzer is alarming and 12v its dropped all loads and isolated battery from em.

 

[Dr Gil]

If your goal is to prevent damaging the battery consider a Low Voltage Disconnect, I also have a Victron Battery Protect that does that job nicely.. mine is set to disconnect @ 12v automatically, you plug your charger in between it and the battery and it'll reconnect when you have a charge back on it.

I always screwed my batteries up when I was away, go on a few day backpacking trip and dead flat.. or hell even a day cruise down some trails come back and realize I left the fan on full blast for a full day and the battery is in low 11s

The alarm on the Victron BMV-712 is pretty good, having heard some claxons going off from other people's low battery alarms from great distances over and over all night I didnt want any of that.. its a soft buzzer that wont wake a hard sleeper, but you will hear it if you wake up.. and when you silence it it stays silent and dont keep going off every few mins all night long.. I have mine setup to alarm before it disconnects the load, so like 12.2v the buzzer is alarming and 12v its dropped all loads and isolated battery from em.

That is exactly what I want a battery monitor for. I don't care about how many hours are left, or how many amps I've used. Just want to protect my auxiliary battery from getting damaged. Thanks.

 

[jonyjoe101]

Yikes. So I've metered my battery at 10.9 volts in the past, and in the 11's several times... Is that battery trashed?


I trashed mine after going under 11 volts 3 times, it was a 102ah agm. After that it still charged up and showed it was fully charged but its capacity was maybe 25 ah. It would go from 12.7 down to 11 volts very quickly. 12.1 volts is the lowest you ever want to take a lead acid. Once you go under 12 volts, thats not good. Only the golfcart type heavy lead acid battery can handle that abuse.