Balmar SG200 SOC Meter

[Codger2]

I have a 2021 Duffy 22' Cuddy and I just had a Balmar SG200 gauge installed. The Duffy presently has a E..⇡..F gauge but it doesn't tell you anything more than that. The SG200 tells me SOC, SOH (state of health--comparing the energy it had when the batts were brand new), volts, amps in & out, time to go in hours and minutes. You name it, I have owned Victron, Maretron, etc. over the years but this Balmar is the best I've ever experienced. The photos below shows what the gauge indicates when you scroll through the data with quick clicks on the button. The SG200 is a learning gauge and requires no re-calibrating after initial set up which is "dirt simple." Those indications were viewed with shore power connected and everything else turn off. As the boat runs, all those values change instantly as the battery slowly discharges.

 

[socalrider]

Glad you like it! I've had nothing but trouble with mine. As soon as my solar kicks in in the morning and reverses current flow, I get a "Low SOH" fault code, and my SOH goes to 0%. I also get faults every time the engine starts (high discharge current), and every time my alternators exceed 80A of current (high charging current).

I put in a service ticket with Balmar and they told me I needed to update the firmware, which required spending another $55 on a bluetooth module. The firmware update did nothing & they haven't returned my last service call. Basically it's a voltmeter and an ammeter at this point.

 

[catalinajack]

Did you initialize the learning aspect of the gauge by discharging your bank down to 40% depth of discharge six or seven times?

Glad you like it! I've had nothing but trouble with mine. As soon as my solar kicks in in the morning and reverses current flow, I get a "Low SOH" fault code, and my SOH goes to 0%. I also get faults every time the engine starts (high discharge current), and every time my alternators exceed 80A of current (high charging current).

I put in a service ticket with Balmar and they told me I needed to update the firmware, which required spending another $55 on a bluetooth module. The firmware update did nothing & they haven't returned my last service call. Basically it's a voltmeter and an ammeter at this point.

 

[Codger2]

As soon as my solar kicks in in the morning and reverses current flow, I get a "Low SOH" fault code, and my SOH goes to 0%. I also get faults every time the engine starts (high discharge current), and every time my alternators exceed 80A of current (high charging current). .

I wish I could comment on your problems but 3 things you have that I don't are: solar, engines & alternators. My boat is all electric and all the SG 200 has to deal with is a 440 battery bank & AGM batteries.

 

[socalrider]

Did you initialize the learning aspect of the gauge by discharging your bank down to 40% depth of discharge six or seven times?

Is that a thing or are you joking? Can't remember that from the manual & they never suggested it. This is a 660ah bank; doing that would take me several weeks of messing around. I never take the pack down that far under normal operation - we cruised with it for 2 weeks last month and I got the same fault every morning. Still get it once a day while the boat's on her mooring.

I wish I could comment on your problems but 3 things you have that I don't are: solar, engines & alternators. My boat is all electric and all the SG 200 has to deal with is a 440 battery bank & AGM batteries.

I'm jealous! You should put some solar on that big beautiful bimini! You'd never need to plug it in... probably need to get a new battery monitor though

 

[catalinajack]

No, it was certainly not a joke. I encourage you to read RodCollins article (with video) on his marinehowto.com website on the testing and installation of the SG200. You may find it quite enlightening.

https://marinehowto.com/balmar-sg200-self-learning-battery-monitor/

The unit requires deep cycling in order to self-calibrate. It appears that you do not deep cycle your batteries. I have a 932ah bank. I got the SG200 calibrated and working flawlessly by not plugging into shorepower overnight six times. I cycled down to 40% depth of discharge and recharged to 100% which took about five hours. Until you do as Rod Collins advises, you cannot know that the unit does not work. I agree that Balmar's instructions are lacking in this regard. I can only guess that Balmar thinks boaters deplete their batteries to 50% DOD on a regular basis. I do. In fact 40% is my limit.

Is that a thing or are you joking? Can't remember that from the manual & they never suggested it. This is a 660ah bank; doing that would take me several weeks of messing around. I never take the pack down that far under normal operation - we cruised with it for 2 weeks last month and I got the same fault every morning. Still get it once a day while the boat's on her mooring.



I'm jealous! You should put some solar on that big beautiful bimini! You'd never need to plug it in... probably need to get a new battery monitor though

 

[Codger2]

Is that a thing or are you joking?

CatalinaJack isn't joking, the manual does say to discharge down to 40% and charge back up to full. You may have to do this as much as 7-10 times so the SG200 can give you a true SOH. I did mine in the slip with shore power off, inverter on,TV, refrigerator, lights, etc. ON. I only had to do it once as my bank is only 4.5 months old. New batts respond with an SOH much quicker.


Note: The installation must be done exactly as the directions say or the gauge will not work! (ie: the shunt must be located no more than 12 inches from the negative post of the bank.) When installed exactly as the directions describe, your gauge should work fine!



BTW, Several years ago an owner did put solar panels on the bimini and took the boat from Newport beach, around the outside of Catalina and back to LA Harbor. (100 miles)

 

[catalinajack]

I took the liberty of copying some info from the marinehowto.com article.

Patience is a Virtue:

TIP:*Once your SG200 is installed & programmed*please be patient. The SG200*requires your bank to be deeply-cycled*quite a few times in order for SoC and SoH to hone in. The deeper these cycles are, the faster the SG200 can learn the bank. Don’t be afraid to take your lead acid bank to 11.7V, if you want to speed up the learning process, just be sure you can recharge to 100% on the next cycle. Shallow cycling will just prolong the time it takes for the SG200 to “learn” bank behavior such as SoH.
Quote:*“Rod, I have had my new SG200 connected for almost four weeks and am still getting three dashes for SoH? We have not been able to leave the dock yet but was hoping to know my banks condition before we do?”

***The SG200 can’t learn SoH while tied to a dock charging 24/7***

The SG200 also cannot determine SoH while not charging and resting. To test this, we connected a lead acid battery to the SG200 and let it sit for two and a half months, with no charging or discharging, other than the SG200’s connection to the battery. At the end of 2.5 months the SG200 was still showing three dashes*—*for SoH. Bottom line? The SG200 is smart enough to know whether you’re cycling or not. The good news is that the SoC prediction, at the end of 2.5 months, was accurate to within 3%, while just sitting there.


Also, it is critical that the connection from the battery to the shunt is very short and there are NO negatives connected to the batteries as opposed to a busbar on the load side.

Is that a thing or are you joking? Can't remember that from the manual & they never suggested it. This is a 660ah bank; doing that would take me several weeks of messing around. I never take the pack down that far under normal operation - we cruised with it for 2 weeks last month and I got the same fault every morning. Still get it once a day while the boat's on her mooring.



I'm jealous! You should put some solar on that big beautiful bimini! You'd never need to plug it in... probably need to get a new battery monitor though

 

[Prospective]

I'm afraid I'm in the problems camp with this device. And I've followed the manual, tech support, posts on other forums, and Rod Collins and still was not able to get reliable readings from mine. My major issue is not the SOH (which doesn't appear accurate) but rather the SOC. It indicates % state of charge that is too high relative to resting voltage. Ie.. it appears to tell me I have more power left than I actually do. There is a thread, dozens of pages long on another forum about the SG200 and I have participated on that as well. Plenty of complaints there too along with satisfied users. I haven't pulled the SG200 out yet. Going to give it another season and see.

 

[catalinajack]

I guess I am one of the lucky ones. But, knowing how different one boat is from another, and knowing how some folks do "things" they believe do not make a difference but do, I wonder if, sometimes, it is user error. I am not suggesting that you have made installation blunders. I am just wondering in general.

Having said that I find your observation that you are not getting reliable readings on State of Charge (SOC). To what measure are you comparing the SG200 SOC reading? How do you know that your other measuring device is accurate? Perhaps it is not and the Balmar is reporting a more accurate measure.

My MRC-50 monitor for my Magnum 2812 measures SOC. It differs from the SG200. I choose to think that the SG200 measure is more accurate especially since the MRC-50 does not correct for State of Health.

I'm afraid I'm in the problems camp with this device. And I've followed the manual, tech support, posts on other forums, and Rod Collins and still was not able to get reliable readings from mine. My major issue is not the SOH (which doesn't appear accurate) but rather the SOC. It indicates % state of charge that is too high relative to resting voltage. Ie.. it appears to tell me I have more power left than I actually do. There is a thread, dozens of pages long on another forum about the SG200 and I have participated on that as well. Plenty of complaints there too along with satisfied users. I haven't pulled the SG200 out yet. Going to give it another season and see.

 

[Prospective]

I guess I am one of the lucky ones. But, knowing how different one boat is from another, and knowing how some folks do "things" they believe do not make a difference but do, I wonder if, sometimes, it is user error. I am not suggesting that you have made installation blunders. I am just wondering in general.

Having said that I find your observation that you are not getting reliable readings on State of Charge (SOC). To what measure are you comparing the SG200 SOC reading? How do you know that your other measuring device is accurate? Perhaps it is not and the Balmar is reporting a more accurate measure.

My MRC-50 monitor for my Magnum 2812 measures SOC. It differs from the SG200. I choose to think that the SG200 measure is more accurate especially since the MRC-50 does not correct for State of Health.

I think it's more accurate to say I'm one of the unlucky ones. I'm sure there are plenty of happy users like yourself. I was a happy user of the original smartgauge and upgraded for the additional functionality.

As to what's leading me to believe there's an issue... I am using the SG200 it's self. It indicates an SOC after a night on the mooring of let's say 86%. But voltage is down to maybe 12.1V on minimal to no load suggesting a much lower SOC. This voltage is confirmed by a separate blue seas voltmeter in the battery compartment. But I know voltage as an indicator of SOC can be misleading...So I run my single cup coffee maker via my Victron 2000W inverter/charger and it shows a low voltage error. I don't believe it would do this if my 300amp/hr FLA bank was actually at 86%. Perhaps I misinterpreting the data? But I've shared this info with Balmar and they haven't suggested I'm wrong. Just that they just don't know "why". But this has led me to not trust the SOC reading. Further, I have never gotten a SOH reading of less than 100% despite repeated charge/discharge cycles on my 5 year old FLA bank. I find this hard to believe.

You are right to say it could be something unique to my system. I carefully installed the monitor shunt with a heavy duty 4/0 cable within 12" of the negative battery terminal. All charge/load negatives are on the other side serviced by a heavy buss bar.

One thing that may be "different" about my system is I have a Blue Sea ACR charge relay that paralell's my banks together during charging. Balmar has stated to me that they have not totally sorted the interplay of an ACR with the SG200. But feedback has been limited so it remains a bit of a mystery. I may just disconnect the ACR to see if it improves performance. But with the SG200 any change requires lengthy recalibrations so it's a tedious trial and error process.

Not trying to trash the product or the company. And I'd welcome any help on getting it to work as it should. Help from Balmar has been limited. Just my two cents.

 

[socalrider]

Mine seemed to work just fine (except for high current faults when starting) until I upgraded my solar array. It'll show a rational SOC reading in the evening as my batteries are drawn down, but then as soon as the solar pushes the bus voltage up to 13V or so I get the "Low SOC" fault, and SOC shows 0%.

It's installed correctly per the instructions. Just a single house bank so a very simple system to monitor. I can understand needing to cycle the pack to get the SOH calibrated, but this is something different.

Does anyone have one that works with PV?

 

[catalinajack]

Prospective, now you have me wondering. My SOH shows 100% after cycling six times. I would have thought it to be lower given that the batteries are four years old. I just assumed that the unit was still learning. But, as you do, I have two Blue Sea ACRs, one for the thruster, one for the generator starting batteries. I could easily disable both ACRs to see if doing so changes the reported SOH. I hardly ever use the thruster and could easily get along without it. Unfortunately, one of my electric heads is wired to the generator batteries but we have two heads. Also, one of my generators has an alternator that provides charge current to its batteries.

When I get back to the boat next Monday, I am going to disable both ACRs and cycle down to 40% several more times. I will report back in two weeks.

Again,12 VDC is proving to be a black art befuddling many with seemingly endless combinations of equipment and wiring alternatives affecting outcomes.

I think it's more accurate to say I'm one of the unlucky ones. I'm sure there are plenty of happy users like yourself. I was a happy user of the original smartgauge and upgraded for the additional functionality.

As to what's leading me to believe there's an issue... I am using the SG200 it's self. It indicates an SOC after a night on the mooring of let's say 86%. But voltage is down to maybe 12.1V on minimal to no load suggesting a much lower SOC. This voltage is confirmed by a separate blue seas voltmeter in the battery compartment. But I know voltage as an indicator of SOC can be misleading...So I run my single cup coffee maker via my Victron 2000W inverter/charger and it shows a low voltage error. I don't believe it would do this if my 300amp/hr FLA bank was actually at 86%. Perhaps I misinterpreting the data? But I've shared this info with Balmar and they haven't suggested I'm wrong. Just that they just don't know "why". But this has led me to not trust the SOC reading. Further, I have never gotten a SOH reading of less than 100% despite repeated charge/discharge cycles on my 5 year old FLA bank. I find this hard to believe.

You are right to say it could be something unique to my system. I carefully installed the monitor shunt with a heavy duty 4/0 cable within 12" of the negative battery terminal. All charge/load negatives are on the other side serviced by a heavy buss bar.

One thing that may be "different" about my system is I have a Blue Sea ACR charge relay that paralell's my banks together during charging. Balmar has stated to me that they have not totally sorted the interplay of an ACR with the SG200. But feedback has been limited so it remains a bit of a mystery. I may just disconnect the ACR to see if it improves performance. But with the SG200 any change requires lengthy recalibrations so it's a tedious trial and error process.

Not trying to trash the product or the company. And I'd welcome any help on getting it to work as it should. Help from Balmar has been limited. Just my two cents.

 

[Rossland]

Although this is slightly off topic, and only partially answered OP's question, calculating battery state of health (SOH) is easy.

Assuming you have a reasonably accurate voltmeter and battery monitor that calculates state of charge(SOC)
1. Look on your battery manufactures web site or owners manual and copy the state of charge vs voltage chart.
2. Discharge your batteries slowly, stopping periodically and testing voltage.
3. Adjust the battery monitor battery capacity input to match the SOC at that voltage.
4. The resulting capacity figure vs the manufacturers claimed capacity will give you a good idea of battery SOH.

A few things to keep in mind:
- Some batteries do not meet mfg's rating even when new.
- Batteries loose capacity as they age.
- Batteries produce less power the faster they discharge. Most are rated at what is called "a 20 hour rate".Therefore don't discharge too fast or your calculations will not be accurate.
- Batteries show a lower voltage as they are being discharged, therefore before checking voltage, stop all discharge, and "rest" the batteries for 20 to 30 min.
- Do this test over the discharge range that you usually use. Testing every 10% discharge from 100% to 60% will probably be appropriate for most.
- It is not necessary to do this test every day. Probably a couple of times a season is sufficient.
- SOH is the figure you need to decide when it is time for new batteries.

 

[4arch]

I bought one of these plus the bluetooth module earlier this spring and haven't installed it. Between reading this thread and others about this device, I'm questioning whether I ever want to. I initially thought it might be more user friendly than my existing Victron BMV-600S, but it seems I'd just be trading the devil I know for the devil I don't. I'm considering selling it and waiting to see how the technology continues to evolve. If anyone wants an uninstalled open box unit, feel free to make me an offer.

 

[catalinajack]

I had a long conversation this morning with Rod Collins of the marinehowto.com website about ACRs, DC-DC chargers, alternators, and the Balmar SG200. He was very generous with his time. As for the SG200 he emphasized that, for the SOH function, patience is the key. He said it takes many iterations of deep discharge before the unit will learn. I told him I had done six discharges down to 40% depth of discharge but I was still showing 100% SOH. He said it will take many more iterations but it will eventually learn. It will not self-calibrate plugged into shore power or when the bank is not deeply discharged, at least to 50%. He also said having ACRs feeding auxiliary batteries has absolutely no affect on the learning. So, folks, it appears we need to be more patient with this device before passing judgment.

Rod also educated me on a few other things electrical.

1. My two Balmar 100 amp alternators are insufficient for charging my 920 Ah battery bank. The alternators are being overworked, get too hot, and if a temp sensor is used as one should be, the regulator will derate its output down to 50%.Then, when the alternator cools down enough it will put out more until it gets hot again. This repetitious cycling is NOT good for the alternators. His recommendation for the Balmar regulator is to derate to Level 3 or 4 to,prevent this cycling and mitigate heat damage to the alternators. Rod recommended the Balmar XT-170 for a two engine system as a good upgrade.
2. Thruster batteries should be AGMs. He recommended two Group 31s, either Odyssey or Northstar.
3. I should combine my two separate four golf car FLA banks into one. It is now configured with a Blue Sea on-off-1-2 battery switch. It is as simple as taking the feed off the #2 position on the switch and adding it on top of the #1 position. That will mean I do not need two smart shunts for the SG200 but it also means I have to start the learning process all over again. Oh well. It also means that I now have an extra shunt if anyone is interested.
4. A shunt to monitor the thruster bank is a waste according to Rod. He explained that, although the current draw can be as high as 400 amps, the total time the thruster is being used is so short that the batteries will never be depleted more than a few per cent and is recharged fairly quickly.
5. Presently, I have a single Group 31 sealed lead acid battery for my thruster. Rod strongly recommended replacing it with two Group 31 AGMs and feeding them with a DC-DC 30-amp charger rather than through an ACR. Charging the generator starting batteries through my existing ACR is just fine. He also said my two Group 27 generator starting batteries are overkill. One Group 31 is more than adequate. He also had no issue with the fact that I start my mains with the house bank.

 

[socalrider]

Thanks for that - very helpful! Makes me feel good about my super-simple single FLA (6 GC batt) house bank that I use for starting and everything else.

So, folks, it appears we need to be more patient with this device before passing judgment.

I'd buy that if the issues were just with the SOH algorithm. That's the true innovation of the SG200, and it's meant to track long-term battery health, so taking a long time to calibrate isn't an issue per se (though if you're like me and never discharge to 40% I'm not sure if it will ever properly calibrate).

I can deal with the nuisance current faults, stupidly factory set & non-modifiable.

The real issue is the SOC algorithm, which shows me a fault every time the solar kicks in (and re-sets the SOH and SOC both to 0%). This renders the device useless, and Balmar can't seem to resolve it. They finally responded to my latest reminder e-mail by offering to send me a free Bluetooth module. Nice gesture, but I already bought it & the updates didn't fix my issue (as I had told them in the preceding email). Now more silence.

 

[Jeff F]

"He also had no issue with the fact that I start my mains with the house bank"

I continue to wonder about the effect this has on the SG200. I'm pretty sure their shunt is rated at 350 amps, but am not sure what that means in practice. If it can't accurately measure a larger starting burst then the cycle-based learning goes out the window...

 

[socalrider]

"He also had no issue with the fact that I start my mains with the house bank"

I continue to wonder about the effect this has on the SG200. I'm pretty sure their shunt is rated at 350 amps, but am not sure what that means in practice. If it can't accurately measure a larger starting burst then the cycle-based learning goes out the window...

That's a good thought - starting my FL120s does fault it out sometimes, as the starter current is right around 300a, but doesn't impact SOC or SOC readings. The actual amp-hours that could be "missed" would be de minimus (lots of amps, but very few hours!), so it shouldn't really impact things much. More A-h would be "missed" due to resistance losses in wiring, for example.

 

[Jeff F]

The real issue is the SOC algorithm, which shows me a fault every time the solar kicks in (and re-sets the SOH and SOC both to 0%).

Did you connect the solar controller to the house side of the shunt?

 

[socalrider]

Did you connect the solar controller to the house side of the shunt?

Yes, everything's wired properly. Have all my batteries going to a dedicated pre-shunt negative bus, then the shunt connecting that to my main negative bus to which everything is connected.

 

[catalinajack]

Perhaps not properly letting the unit self-learn by depleting to 40% ten or twelve times is the source of all your troubles. I'm not sure what the big deal is about doing that anyway. DOD to 40% 10 - 12 times will not affect your battery life in any measurable way.

Thanks for that - very helpful! Makes me feel good about my super-simple single FLA (6 GC batt) house bank that I use for starting and everything else.



I'd buy that if the issues were just with the SOH algorithm. That's the true innovation of the SG200, and it's meant to track long-term battery health, so taking a long time to calibrate isn't an issue per se (though if you're like me and never discharge to 40% I'm not sure if it will ever properly calibrate).

I can deal with the nuisance current faults, stupidly factory set & non-modifiable.

The real issue is the SOC algorithm, which shows me a fault every time the solar kicks in (and re-sets the SOH and SOC both to 0%). This renders the device useless, and Balmar can't seem to resolve it. They finally responded to my latest reminder e-mail by offering to send me a free Bluetooth module. Nice gesture, but I already bought it & the updates didn't fix my issue (as I had told them in the preceding email). Now more silence.

 

[catalinajack]

When I had just three iterations of deep discharge I was getting faults. They disappeared after more deep discharges but six of these, according to Rod Collins, is not enough to get the SG200 to report SOH accurately. So, if you are not willing to go through the complete process, your SG200 is not likely to ever work for you. I am not saying that it will definitely work with your configuration but one cannot know that it won't work with no faults without first getting it calibrated.

I went back and read the Balmar installation manual. It is very cryptic in this regard so I do understand why some folks are so skeptical that this product works as advertised or that faults are experienced. Now that I will be combining my two separate banks into one I will have to do a factory reset and start the deep discharge process all over again. We are live aboards so I can do it dockside. I just turn the inverter-charger off so that my subpanel (air conditioning, cooktop) is still powered by shore power while the inverter still provides AC current to the the main panel. I simply monitor the amphours out through my Magnum remote panel and turn the charger back on when the batteries have been discharged enough. It takes about five hours to fully recharge my batteries from 40% DOD. It is going to take over 20 days to cycle them 12 times. We will have some "at anchor" days mixed in in the next few weeks.

Thanks for that - very helpful! Makes me feel good about my super-simple single FLA (6 GC batt) house bank that I use for starting and everything else.



I'd buy that if the issues were just with the SOH algorithm. That's the true innovation of the SG200, and it's meant to track long-term battery health, so taking a long time to calibrate isn't an issue per se (though if you're like me and never discharge to 40% I'm not sure if it will ever properly calibrate).

I can deal with the nuisance current faults, stupidly factory set & non-modifiable.

The real issue is the SOC algorithm, which shows me a fault every time the solar kicks in (and re-sets the SOH and SOC both to 0%). This renders the device useless, and Balmar can't seem to resolve it. They finally responded to my latest reminder e-mail by offering to send me a free Bluetooth module. Nice gesture, but I already bought it & the updates didn't fix my issue (as I had told them in the preceding email). Now more silence.

 

[socalrider]

Perhaps not properly letting the unit self-learn by depleting to 40% ten or twelve times is the source of all your troubles. I'm not sure what the big deal is about doing that anyway. DOD to 40% 10 - 12 times will not affect your battery life in any measurable way.

Thanks again - do you have solar?

My issue is that I'm not a live aboard, so this kind of cycling is a real hassle and will take a very long time. I'd need to shut off my solar & let the refrigerator draw down the house bank over ~5-10 (?) days, then re-connect and let it top back up. The process would take months and I'd be nervous about accidentally drawing the bank down below 40% if I couldn't get out to the boat for a couple of days.

That level of fussiness is not what I signed on for... And, I'm not at all convinced that it would solve my issues, particularly given that Balmar has not suggested it as a remedy.

 

[catalinajack]

I do not have solar. Although I have plenty of real estate to install a larger solar array, our use profile does not justify the expense. We generally stay in one anchorage no more than two nights. The following day's cruise is almost always long enough to fully recharge our batteries.

You do have quite a challenge getting the SG200 fully learned. Balmar should make it very clear in their materials but they do not. Perhaps they just assume that it gets done in the ordinary course of a boaters life on the water.

Thanks again - do you have solar?

My issue is that I'm not a live aboard, so this kind of cycling is a real hassle and will take a very long time. I'd need to shut off my solar & let the refrigerator draw down the house bank over ~5-10 (?) days, then re-connect and let it top back up. The process would take months and I'd be nervous about accidentally drawing the bank down below 40% if I couldn't get out to the boat for a couple of days.

That level of fussiness is not what I signed on for... And, I'm not at all convinced that it would solve my issues, particularly given that Balmar has not suggested it as a remedy.

 

[FlyWright]

I bought one of these plus the bluetooth module earlier this spring and haven't installed it. Between reading this thread and others about this device, I'm questioning whether I ever want to. I initially thought it might be more user friendly than my existing Victron BMV-600S, but it seems I'd just be trading the devil I know for the devil I don't. I'm considering selling it and waiting to see how the technology continues to evolve. If anyone wants an uninstalled open box unit, feel free to make me an offer.

I'll offer you $100 plus shipping to California.

 

[FlyWright]

I had a long conversation this morning with Rod Collins of the marinehowto.com website about ACRs, DC-DC chargers, alternators, and the Balmar SG200. He was very generous with his time. As for the SG200 he emphasized that, for the SOH function, patience is the key. He said it takes many iterations of deep discharge before the unit will learn. I told him I had done six discharges down to 40% depth of discharge but I was still showing 100% SOH. He said it will take many more iterations but it will eventually learn. It will not self-calibrate plugged into shore power or when the bank is not deeply discharged, at least to 50%. He also said having ACRs feeding auxiliary batteries has absolutely no affect on the learning. So, folks, it appears we need to be more patient with this device before passing judgment.

Rod also educated me on a few other things electrical.

1. My two Balmar 100 amp alternators are insufficient for charging my 920 Ah battery bank. The alternators are being overworked, get too hot, and if a temp sensor is used as one should be, the regulator will derate its output down to 50%.Then, when the alternator cools down enough it will put out more until it gets hot again. This repetitious cycling is NOT good for the alternators. His recommendation for the Balmar regulator is to derate to Level 3 or 4 to,prevent this cycling and mitigate heat damage to the alternators. Rod recommended the Balmar XT-170 for a two engine system as a good upgrade.

Great post. Thanks for the info. Rod is a great font of knowledge and as you said, very generous with his time and expertise!!

I had a similar conversation with him after I fried my Balmar 120A alternator two summers ago while shooting the Delta Bridges. Extended hours of idling while shooting photos and cruising during the July 4th festivities pushed the limits of my alternator. As it turned out, my Alt temp sensor was connected to the ground lug which is normal on most Balmar alternator models. But mine was designed to fit into tight spaces and the ground lug was on an offset L-shaped bracket which rendered the temp sensing ineffective so the alternator overheated without proper sensing. He told me how to remedy the temp sensor location by identifying a 10mm threaded hole in the case for use on this alternator and mentioned that some folks use cooling fans to assist in keeping the alternator within temp limits.

I had the alternator rebuilt with Balmar parts, repositioned the temp sensor cable and added a 12V ducted ER fan to blow fresh air directly onto the alternator. Now it all works perfectly, thanks to Rod Collins!!

 

[ssobol]

I also have issues with my SG200. Part of the issue seems to be that the SG200 is not all that happy with smaller battery banks.

My biggest issue is that if I start the engine, I'll get an alarm for low SOC % (indicates very low in the single digits). After running for 15 or 20 minutes, it'll show 100% SOC. Based on the battery size and alternator output, one of those two numbers is wrong.

Sometimes it'll show the low SOC after trailering for an hour to the ramp with the fridge on. Since the engine will start fine with an indicated SOC of under 5%, clearly the SOC is incorrect in that case too.

So I don't really trust the SG200 to give me an accurate SOC. Mostly I use it to see the charging/discharging current (so far I assume these indications are correct). When the charging current gets very low at a reasonable motor RPM, I take it that the battery is charged.

So far the only reason I don't take it out completely is that the display is SOOOO much easier to read than the on the Victron 602 I had in there before.

 

[Boatcrazy]

Following....very interesting!

 

[Codger2]

Following....very interesting!

Me too & I have one!