Smartgauge w/ 3 batterys

[rosco4271]

Originally Posted by john61ct

Yes, one big bank is best.

A smaller "reserve" deep cycling bank can be used for cranking.

You need a separate SmartGauge per bank you want to monitor SoC.

Again with batteries you need to be careful in making suggestions. if you have a large charging source yes a big bank is generally best but from experience you need to be pushing 50 -80 amps plus initially into a large Battery system and still it takes time to fully charge if your a sailor you might not want to run your motor. Making note a 100 amp alternator with good multi-belt system will only charge around 80 amps and will drop because of engine room and belt heart. I have 2 alternators and 2 batteries. I also have a start battery that is connected by a voltage monitor which stops charging a 13.9 and will only charge again if I start the engine. I have separate solar panels and controllers for each bank. I run my refrigeration and anchor winch on one bank and all house requirements on the other bank. I have a shunt ammeter on each alternator and a voltmeter setup similar to the smartgauge the large banks and a voltmeter on the engine panel for the start battery.
Getting more complicated then that is a pain to manage.

[daletournier]

Originally Posted by rosco4271

Again with batteries you need to be careful in making suggestions. if you have a large charging source yes a big bank is generally best but from experience you need to be pushing 50 -80 amps plus initially into a large Battery system and still it takes time to fully charge if your a sailor you might not want to run your motor. Making note a 100 amp alternator with good multi-belt system will only charge around 80 amps and will drop because of engine room and belt heart. I have 2 alternators and 2 batteries. I also have a start battery that is connected by a voltage monitor which stops charging a 13.9 and will only charge again if I start the engine. I have separate solar panels and controllers for each bank. I run my refrigeration and anchor winch on one bank and all house requirements on the other bank. I have a shunt ammeter on each alternator and a voltmeter setup similar to the smartgauge the large banks and a voltmeter on the engine panel for the start battery.
Getting more complicated then that is a pain to manage.

Your point regarding alternator output is very relevant to me. My 100amp alternator really is a 30amp alternator at the moment due to regulator heat sensor. Working on it with manufacturer at the moment.
Another point mentioned earlier which I think was good is size the solar to the overcast days not the perfect days. A big array isnt over kill if you have a reasonable percentage of overcast days or if your deeply discharging while on passage.

[rosco4271]

I sail in the Pacific and Indian ocean mainly, cloudy days are not a problem but yes oversize your panels if you want, on cloudy days you wont get full charge out of your panels I have seen about 60% and over 12 hours that charges the batteries OK. And I forgot to mention the loss of a cell in one bank if properly wired will open circuit the whole bank and if not wire properly the whole bank may drop voltage and may go unnoticed discharging the whole bank.

[john61ct]

Originally Posted by rosco4271

Again with batteries you need to be careful in making suggestions. if you have a large charging source yes a big bank is generally best.

The question is splitting the bank into two or not, total size being the same.

There is a very clear consensus among the leading professionals not to. Accepted is an isolated smaller reserve or dedicated specialized batts, as few as possible.

[daletournier]

I have three 220amp/hr , divided by the switch into 1x 220 & 1x 440.
If I get a dead short in one cell I can turn the switch from all and separate the system. The chances of it going unnoticed and completely draining the entire bank is slim, if that happened that's when the starter battery or generator come into play.

[rosco4271]

OK Ill go my way, most professionals dont go far from a marina, a couple of weeks out and stuffed batteries from a single is a total disaster, half the batteries failing is very livable given our reliance of Electronic navigation these days

[daletournier]

Originally Posted by rosco4271

OK Ill go my way, most professionals dont go far from a marina, a couple of weeks out and stuffed batteries from a single is a total disaster, half the batteries failing is very livable given our reliance of Electronic navigation these days

Rosco, not arguing with you, your way works for you that's great, I view it differently and I do go along way from home and have done for years. Its these years that have brought me to my current setup.

[ramblinrod]

Originally Posted by tml

Doing my homework before purchasing a Balmar Smartgauge. Read several threads / reviews including Maine Sails excellent test results.
My setup which I assume is not uncommon is house bank #1, house bank #2, and a separate starting battery with its own switch. House bank #1 and #2 can be combined as both on the switch.
The Smartgauge installation guide connects to one bank for which it monitors / measures SOC (state of charge ) and a second bank which monitors voltage only. This makes sense for a two bank setup; one house and one start.
What is recommended for my situation? Monitor SOC continuously for House 1 and only voltage for house 2? In that case you don't know SOC for House 2.
Leaving House 1 and 2 combined as both would I suppose give SOC for the entire bank but that seems unwise for all sorts of reasons.
Advice much appreciated
TML

As many have posted you are wise to leave the 1/2/all/off switch in the all position for max battery life. (Using the switch only for testing/ servicing purposes, or off when leaving the boat.)

One thing not included in the OP is your charging scheme. The Smart Gauge is not accurate while charging. If you have solar and wind charging systems, you are charging 24/7. In these cases an Amp counter monitor may be a better choice.

In my case, I have solar but no wind. I just read the house bank voltage at sunset. If it is 12.7, all is well. If it is 12.2 in the am before sun is on the panels, all is well. If the forecast is for good sun, it will read 12.7 at sunset. If partly cloudy, I charge by alternator for a half hour in the am. If overcast, run alternator for an hour.

Closer monitoring may increase battery life 5%. In my case that would save me C$3.14 annually. Payback for the SMART GAUGE = 150 years. (I'm fine with reading battery voltage in Vdc instead of %.)

[Exile]

Originally Posted by ramblinrod

As many have posted you are wise to leave the 1/2/all/off switch in the all position for max battery life. (Using the switch only for testing/ servicing purposes, or off when leaving the boat.)

One thing not included in the OP is your charging scheme. The Smart Gauge is not accurate while charging. If you have solar and wind charging systems, you are charging 24/7. In these cases an Amp counter monitor may be a better choice.

In my case, I have solar but no wind. I just read the house bank voltage at sunset. If it is 12.7, all is well. If it is 12.2 in the am before sun is on the panels, all is well. If the forecast is for good sun, it will read 12.7 at sunset. If partly cloudy, I charge by alternator for a half hour in the am. If overcast, run alternator for an hour.

Closer monitoring may increase battery life 5%. In my case that would save me C$3.14 annually. Payback for the SMART GAUGE = 150 years. (I'm fine with reading battery voltage in Vdc instead of %.)

Good point about the SG not being accurate when charging, esp. for those who use solar & wind. I assume this also means that a SG's display of 100% while the batts. are still undergoing charging is equally unreliable, and the only way to really determine if your batts. are topped off is via the amp counter.

Not sure about other batt. chargers, but mine has a display showing voltage as well as amps going into the battery. So when it goes into float mode it shows minimal amps going in (depending on any loads I may have going) that is consistent with the 0.5C that my battery manual says = topped off (about 2.5A with my 510ah bank). Not sure how reliable this is so I confirm with a separate amp counter.

Rod -- when you say your voltage meter reads 12.2v first thing in the morn and therefore all is well, I assume that means 12.2v is worse case in the event you have any loads going which might pull the meter reading down. In other words, "all is well" because the actual voltage is higher. I ask because my battery specs show 12.2v as 50% but I know that reading can be a bit deceiving depending on loads.

If I've got this right then I also question what a SG offers over a combo of a voltage meter and an amp counter.

[sailcrazy]

FWIW....a marine electrician and expert, whom I have used and followed in the past, recently advised me that a Smart Gauge would NOT be a good replacement for the 2 Link 20 Batt Monitors I now use. He sells, and installs both, but strongly recommended that for us, with both wind and solar(24 hr chargeing) as well as running our genset (and batt chrgr) 1-2 times per day, to use the Victron monitor (amp counter). That advice just confirms the previous 2 posts....with solar or windgen-the Smart Gauge is not the best choice.

[Bleemus]

According to SG manual they are within 10% of actual state of charge while charging. Its not like they turn off.

[Exile]

Originally Posted by Bleemus

According to SG manual they are within 10% of actual state of charge while charging. Its not like they turn off.

True, but there can be a big difference btwn. 90 & 100% when you're trying to get the most durability out of LA batts. The SG may be more helpful in not going below 50%, but that can apparently also be accomplished with voltage meters, albeit with a bit more margin of error (maybe).

[john61ct]

Even with the SG lower accuracy, it is overall **more** accurate than AH counters.

And much more so, once charging is done.

If this is critical for you, you could briefly interrupt charging.

Or the ideal would be to use both, which many with expensive banks indeed do.

But it takes knowledge, the right tools and regular attention to keep the AH counters accurate, not least regular 20-hour load tests to determine true AH capacity as that walks down over time.

The most useful parameter is ensuring saying well above 50%.

Ideally, stopping charging is done by looking at tail current amps declining.

[Exile]

Originally Posted by john61ct

Even with the SG lower accuracy, it is overall **more** accurate than AH counters.

And much more so, once charging is done.

If this is critical for you, you could briefly interrupt charging.

Or the ideal would be to use both, which many with expensive banks indeed do.

But it takes knowledge, the right tools and regular attention to keep the AH counters accurate, not least regular 20-hour load tests to determine true AH capacity as that walks down over time.

The most useful parameter is ensuring saying well above 50%.

Ideally, stopping charging is done by looking at tail current amps declining.

I only use my Victron amp counter for amps in & out. Too many variables & too much fussing to always be testing & then resetting to try & determine total AH capacity. Once in awhile an informal load test seems enough to give me an idea about battery health.

My understanding is that the SG won't give you that either. If it reads 100%, for e.g., then that only means you're at 100% of your battery bank's remaining capacity in its current condition, right?

[john61ct]

Well the other way to say it is the SG gives an accurate **actual** % SoC based on current reality, not what the owner guesstimates AH capacity may be at the moment.

I've heard of owners with both actually using the SG to try and determine AH capacity by cross-referencing the two, but myself I'd just bite the bullet and do the proper 20-hour load test.