Battery monitor

Aug 17, 2013
817
Pearson P30 202 Ottawa/Gatineau
Hey everyone quick question regarding battery monitors, my local chandlery carries the xantrek monitors, but they are way overpriced, are there other alternatives available at a decent price, I have to replace both batteries this spring and would like a way to check them properly.
Thanks in advance
 
Apr 8, 2010
1,949
Ericson Yachts Olson 34 28400 Portland OR
I installed a Smartgauge several years ago to replace a much older Llink 10 that died. Nice not to have a shunt anymore and the wiring that went with it. Simple to wire it.
My blog entry is probably of limited interest, but you might appreciate the legal and safe Blue Seas fusing scheme -- it's a great invention.
 
Last edited:
May 24, 2004
7,131
CC 30 South Florida
"Check them properly"; there are ways of checking the batteries properly that do not require a large outlay of money. A hydrometer, a digital voltmeter, and observation can accomplish a good enough task. These battery monitors do have a place and that is in a vessel heavily equipped with electronics and specialty batteries; if that is your case then budget for the monitor, but if not consider checking them periodically by yourself. Learning to read a voltmeter when at rest, when at charge or at discharge and comparing to previous readings goes a long ways to render useful information. I have looked at monitors and decided that for my wet cell regular batteries and just average electronics the investment in one was not warranted.
 
May 6, 2010
472
1984 Oday 39 79 Milwaukee
One caveat regarding the Balmar SG200 is that it does not work if you have more than one flooded battery in a bank. I have been struggling with mine since I installed it early this year. I waited several months for the bluetooth dongle which was supposed to correct the problem by updating the unit itself. Since the dongle arrived I have spent many additional hours applying updates and performing procedures, but it continues to report rapid discharge and wildly inaccurate SOC when the boat is unattended with no draw on the batteries. SOH is always reported as either 90% or 100%., with no discernible reason. I have at their direction performed a number of equalizations, nearly full discharge/recharge cycles, and applied all of the updates as they come out (at least through a month ago) and still have a monitor that reports only voltage reliably. From what I have read of other's experience, if you have battery types other than flooded, or have only one flooded battery in the bank it works well.

Balmar SmartGuage SG2 is the state of the art right now.

 
  • Like
Likes: S34

TomY

Alden Forum Moderator
Jun 22, 2004
2,759
Alden 38' Challenger yawl Rockport Harbor
After 3 boats, I'm still using the same battery monitor (a simple 30 yr old digital voltage meter).

If your electrical needs are simple; i.e. you don't have refrigeration, you can treat your batteries very simply: Don't let them get thirsty or really dead.

To check state of charge, wait at least a day of rest (no charge-no discharge), for a digital reading.

In the fall, charge them fully, forget they exist, and check the voltage in the spring.

If they've lost more than 10-20% SOC, they're serving notice for replacement.

Good to go:
Starting battery 2017.jpg


We had netting with small kids onboard with our second boat. I couldn't wait until they were old enough to tear it off. :)
 
  • Like
Likes: LloydB

capta

.
Jun 4, 2009
4,772
Pearson 530 Admiralty Bay, Bequia SVG
I use the Blue Sea DC Digital Ammeter - 500 to 500A 8236 instead. It monitors all incoming and outgoing power without the need to adjust the meter as the batteries age. I can even see my starter amperage draw, and it is especially useful when I'm using A/C appliances on the inverter.
 
Apr 8, 2010
1,949
Ericson Yachts Olson 34 28400 Portland OR
One caveat regarding the Balmar SG200 is that it does not work if you have more than one flooded battery in a bank. I have been struggling with mine since I installed it early this year. I waited several months for the bluetooth dongle which was supposed to correct the problem by updating the unit itself. Since the dongle arrived I have spent many additional hours applying updates and performing procedures, but it continues to report rapid discharge and wildly inaccurate SOC when the boat is unattended with no draw on the batteries. SOH is always reported as either 90% or 100%., with no discernible reason. I have at their direction performed a number of equalizations, nearly full discharge/recharge cycles, and applied all of the updates as they come out (at least through a month ago) and still have a monitor that reports only voltage reliably. From what I have read of other's experience, if you have battery types other than flooded, or have only one flooded battery in the bank it works well.
Your Balmar is probably / maybe working within their specs... but do not hesitate to check with Balmar for a possible warranty issue. When I did the install on ours, it initially would not read right. Puzzled, I called them and a guy on the phone walked me thru a voltage check of the battery bank and what should have been the expected digital readout. I also have a multimeter. Our measured house bank is a pair of flooded Trojan GC batteries.

He immediately issued an RA, and I did so. The replacement worked perfectly when installed. Several years later it still does.
One caveat - when I left it disconnected for over a month while the battery bank was out as part of the new engine install, it took several days to "re learn" it's information. As Maine Sail, points out their measurement algorithms are "mil spec" proprietary, and he accepts the mystery of it since it works. (!)

Like all solid state gear, sometimes you get one that is DOA or exhibits out-of-spec behavior soon after use. It's just the nature of automated production of microscopic bits and connections.... :(
 

S34

.
Jan 3, 2016
17
Self built Stewart 34 Auckland
One caveat regarding the Balmar SG200 is that it does not work if you have more than one flooded battery in a bank. I have been struggling with mine since I installed it early this year. I waited several months for the bluetooth dongle which was supposed to correct the problem by updating the unit itself. Since the dongle arrived I have spent many additional hours applying updates and performing procedures, but it continues to report rapid discharge and wildly inaccurate SOC when the boat is unattended with no draw on the batteries. SOH is always reported as either 90% or 100%., with no discernible reason. I have at their direction performed a number of equalizations, nearly full discharge/recharge cycles, and applied all of the updates as they come out (at least through a month ago) and still have a monitor that reports only voltage reliably. From what I have read of other's experience, if you have battery types other than flooded, or have only one flooded battery in the bank it works well.
I have had mine (SG200) in for nearly a year and it does EXACTLY what you described.
4x US 6v batteries ( series to 12v then parallel to double capacity)
On rest self discharge it drops from 100% to <70% in days, then slowly gets more accurate.
Volts and amps are ok.
Haven't done much heavy cycling which is the reason they said its inaccurate.
Who knows, but I certainly wouldn't recommend for this application.
Maybe gibbo's previous version would have been better for this app?
Too much work to take out, cutting cables to remove deutsch connectors and main negative.

I Would like to try the victron 712. Maybe it would even fit in the hole. ;-)
 
Last edited:
Feb 2, 2010
373
Island Packet 37 Hull #2 Harpswell Me
I have a Link 2000 that has failed. looking for a suggestion for replacement, it also needs to handle my inverter / charger .
 
May 6, 2010
472
1984 Oday 39 79 Milwaukee
I have had mine (SG200) in for nearly a year and it does EXACTLY what you described.
4x US 6v batteries ( series to 12v then parallel to double capacity)
On rest self discharge it drops from 100% to <70% in days, then slowly gets more accurate.
Volts and amps are ok.
Haven't done much heavy cycling which is the reason they said its inaccurate.
Who knows, but I certainly wouldn't recommend for this application.
Maybe gibbo's previous version would have been better for this app?
Too much work to take out, cutting cables to remove deutsch connectors and main negative.

I Would like to try the victron 712. Maybe it would even fit in the hole. ;-)
I have now done three cycles of discharge to around 20% or less on the monitor, 11.4 - 11.6 volts, then recharged. No change in the behavior of the monitor yet. I'm now over a year in with this monitor, and can't begin to count the hours I have spent trying to make it work correctly.
 

S34

.
Jan 3, 2016
17
Self built Stewart 34 Auckland
Thanks for that; So I won't wait in vain hope its going to work when
I start deeper cycling.
SOC & SOH are not accurate for our application. Better off ignoring them.
Rested voltage versus SOC much more accurate.
Guess my radar was off when I read the hype on the SG200.
Balmar were good I must say.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
SoH is no where near an instant reading and this unit cannot learn SoH while tied to a dock. It requires multiple deep-cycles, ideally followed by full recharges, to begin to hone in on SoH. The deeper you go the faster it will learn.

If you have a unit where the software has not been updated this is the best place to start. The "at rest" SoC walk-down is hopefully going to be in the next software update. This is something that none of the field testers even considered as we were testing for "cruising" type behavior not for boats that sit unattended with the batteries naturally self discharging.

Also, we find many folks are tweaking the settings other than battery type and the banks "rated" Ah capacity. Set battery type, set rated Ah capacity, and let it go. This is where you will find the fastest SoH & SoC learning.

We have sold many hundreds of these and the vast majority of customers are very, very happy. We've even had a chance to test a few that were installed last spring on customers boats. At decommissioning we noted SoH and SoC then physically tested the batteries. All the field units were at or better than 3.6% accuracy after a full seasons use. On my own LFP bank the accuracy was in the 1% range...

Balmar is committed to continual improvements of the SG200 as they are necessary. If you compare this to a typical Ah counter, that has not seen a base software change since the early 90's.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
SOC & SOH are not accurate for our application.
IIRC your current application is batteries sitting & not being actively cycled.

A "learning" battery monitor, that is designed to learn the behavior of cycled banks, and get smarter and smarter the more cycles it sees, will not learn the banks behavior with no use. The SoC walk down (for resting batteries) is being addressed, but SoH will not be accurate until the bank starts being cycled.

We have had customers still have three dashes for SoH after three months charging at the dock. This is 100% normal. The monitor is designed to learn banks based on the cycling behavior. Once you start using the boat it will learn.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
One caveat regarding the Balmar SG200 is that it does not work if you have more than one flooded battery in a bank.
There is not an accurate or correct statement. We have plenty of multiple battery flooded DC banks out there with testing results that show incredible accuracy.


Since the dongle arrived I have spent many additional hours applying updates and performing procedures, but it continues to report rapid discharge and wildly inaccurate SOC when the boat is unattended with no draw on the batteries.
There is an update coming soon to fix this.


From what I have read of other's experience, if you have battery types other than flooded, or have only one flooded battery in the bank it works well.
Again, this is not the case. Is it possible to get a photo of the bank wiring and shunt installation?
 

S34

.
Jan 3, 2016
17
Self built Stewart 34 Auckland
Thanks for the update Rod.
Our sailing, owing to work, is confined to day sails, with the odd overnighter and couple of four or five dayers
per year. Our main draw from these is autopilot.
But I am working towards several month cruisers in the near future.

Looking at average use in my marina, I think my use is pretty par.
One thing I don't recall is the "best used for cruising type power cycling" in the marketing.

My settings are per manual except for taper which is 2%. ( bottom end of recommended)
Looking forward to the sw update that fixes the inaccuracy of SOC on slow self discharge.
Also, thanks for the offer via Tom. I guess he informed you.
 
Last edited:
Feb 2, 2006
464
Hunter Legend 35 Kingston
I've posted here about my SG200 previously. I now have the BT dongle and latest updates (as of a couple months ago). I didn't have the latest updates/dongle during our trip last summer.

We spent 140 continuous days on the boat last summer. About 30 of which were at anchor and a handful of those for a couple of days. Most of the rest of the time was at docks with shore power. There was a good amount of motoring too. Certainly 5-10 days of drawing the batteries down to about 60%, but not much deeper than that. Point being is that we didn't draw the batteries down very far or very often.

I have had the SoH spend most of it's time at 90%, with occasional periods at 100%. SoC reading seem'd reasonable. The batteries were new at the beginning of the trip.

Seems like the SoH has not really honed in on it's actual value (or the battery manufacturer overrates their capacity).

Just echoing S34's comments that our extended cruise may not have provided the type of cycling needed to let the SG200 fully learn the batteries.

I may do a few forced deep cycles in the next weeks to see if it reports any variation to the 90% SoH.

Chris
 
Last edited:
Apr 8, 2010
1,949
Ericson Yachts Olson 34 28400 Portland OR
Regarding the battery maker's advertised capacity....
We are on the second same-model of Trojan GC (T-145+), and I recall that the advertised number of AH does vary. It might depend on who is running their marketing dept during any given year. :)
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Regarding the battery maker's advertised capacity....
We are on the second same-model of Trojan GC (T-145+), and I recall that the advertised number of AH does vary. It might depend on who is running their marketing dept during any given year. :)
The T145 has been 260Ah rated (20 hour rating) for as long as I can remember.

T-105 is 225Ah
T-125 is 240Ah
T-145 is 260Ah