MaineSail or other SmartGauge SG100 guru question

[KWKloeber]

Are the top and bottom scenarios equivalent? 
i.e., Will the SG100 work correctly in both setups?

[Stu Jackson]

While one could make the point that they are identical because IT'S JUST THE DIFF3ERENT END OF THE SAME WIRE, IIRC the SG instructions mandate connection be to a battery terminal, not remote in any way.

When in doubt, RTFM!   

[mainesail]

Ken,

Confused by your wording..?? Are you asking about the Balmar Smartgauge (square face no shunt model # 44-SG-12/24) or the new Balmar SG-200 (round face with SmartShunt)?

In either case the drawing does not make much sense?

If you are asking about the Smartgauge (44-SG-12/24) then it definitely matters where it is connected to the system. It needs to be connected to the house bank positive terminal and the negative lead to the opposite end of the banks neg terminal.

[KWKloeber]

Rod, apologies, I meant the SG - I called it the SG100 (I suppose they wouldn't know it was a 100 until there was a 200, 'eh?)

For clarity (brevity?) (or confusion?) I showed only the Batt 1 wire from the SG (I realize the negative has to be connected.)

So, given that it's the SG I hear you saying (even tho the top/bottom scenarios are functionally equivalent) that the SG won't read correctly on the bottom configuration.  That begs the question (since you tested and are most familiar with it) WHY-- the SG knows it's reading off a heavy cable, instead of directly from the battery post?

Would the third scenario work correctly, since the SG is directly on the bank posts?

Thank you Rod

[KWKloeber]

When in doubt, RTFM!   

Stu - it's elementary that TFMs/instructions can *sometimes* be abbreviated and (imagine this?) not show EVERY scenario found on a boat.

RTFM (as in how to hook up a multi battery bank)?  You mean TFM manual that's WRONG about where to make the connections?  Is that TFM?

So its also elementary that when you only RTFM and ask no questions, it's possible to end up doing things wrong (again I used "you" euphemistically - I realize you've never opined how to do anything differently than how it's described in TFM.)

BTW, not only is the manual effed up --  so is the Balmer tech** --- who says that the SG can't be used on a system with a selector switch -- yet BOTH Rod and Merlin state that it CAN.  So, again, it's elementary that swallowing only what you read/hear can get you into instead of keeping you out of trouble (again euphemistically "you".)

** The techie who also said that the SG-200 cannot be used on a system w/a selector switch.

[mainesail]

Rod, apologies, I meant the SG Smartgauge- I called it the SG100 (I suppose they wouldn't know it was a 100 until there was a 200, 'eh?)

For clarity (brevity?) (or confusion?) I showed only the Batt 1 wire from the SG Smartgauge  (I realize the negative has to be connected.)

"SG"200 is the new 100% Balmar engineeered and designed product. The original Merlin product "Balmar licensed", is a Smartgauge. The new "SG"200 is not a Smartgauge...

So, given that it's the SG Smartgauge I hear you saying (even tho the top/bottom scenarios are functionally equivalent) that the SG won't read correctly on the bottom configuration.  That begs the question (since you tested and are most familiar with it) WHY-- the SG knows it's reading off a heavy cable, instead of directly from the battery post[/s]?

Because that is how it was designed. I obviously can't disclose the actual inner workings of the Smartgauge, or the new SG200 (we are under an NDA as part of the testing team) but suffice it to say you will NOT get accuracy out of the Smartgauge unless both positive and negative are directly connected to the physical battery terminals. On a parallel bank best accuracy is achieved by connecting the positive at one end and the negative at the other end, just as the bank should be connected, even if you're star-wired..

Would the third scenario work correctly, since the SG is directly on the bank posts?

It's right in our article...

[mainesail]

BTW, not only is the manual effed up --  so is the Balmer tech** --- who says that the SG can't be used on a system with a selector switch -- yet BOTH Rod and Merlin state that it CAN. 

Without knowing the actual question, it is hard to say what went down in that conversation? Other than very early on, I have not known Tom, Tim or Dale to tell anyone it can't be used on a vessel with a 1/2/B provided the Smartgauge is directly connected to the house bank terminals.

** The techie who also said that the SG-200 cannot be used on a system w/a selector switch.

The SG200 is shunt based, for this reason it can only monitor one bank per shunt. The big difference between the SG200 and traditional Ah counters, is that you can add multiple shunts, one for each bank if you prefer.

[KWKloeber]

Rod

Ok, I'm dense and the situation doesn't quite match your very clear diagram (I note that it corrects the install manual schematic faux pas) so I just want to be 100% certain here.

Without getting into the weeds of why they're there - in the below, the buss and additional cable makes no nevermind to the Smart Gauge accuracy?



< https://c34.org/wiki/images/f/f3/SG_Buss.png >

[mainesail]

Rod

Ok, I'm dense and the situation doesn't quite match your very clear diagram (I note that it corrects the install manual schematic faux pas) so I just want to be 100% certain here.

Without getting into the weeds of why they're there - in the below, the buss and additional cable makes no nevermind to the Smart Gauge accuracy?



< https://c34.org/wiki/images/f/f3/SG_Buss.png >

The load/charge bus may may not make a difference, unless that pos side bus wiring creates an imbalance in the bank or that positive side wiring is longer than the neg side. It will be best to keep the parallel bank wiring as short and equal length to the neg, as is possible. Typically, in a star configuration, the pos and neg star legs are identical lengths so each battery contributes more equally under load.

[KWKloeber]

PERFECT, Thanks Rod!!