Balmar Smart Gauge and my AGMs.

weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Boat originally had 3 identical lead acid batteries (2 house, 1 start). I replaced them over last winter with 3 exide AGMs and reconfigured the smart gauge for AGM mode but I allowed it to 'learn' the capacity of the banks rather than just charge them full and set the gauge to 100%.

After a whole season of use, I find that the most the gauge is reading is about 90% on the house bank. The bank is connected to a 50W solar panel and controller which after a day or two in the sun switches to float mode, so I know the batteries are topped off. With the old batteries, the smart gauge always read 100% when I came back to the boat after it had couple of days in the sun.

Is the issue with the gauge or with one or both of the house batteries? What is the best way to solve this?
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
Boat originally had 3 identical lead acid batteries (2 house, 1 start). I replaced them over last winter with 3 exide AGMs and reconfigured the smart gauge for AGM mode but I allowed it to 'learn' the capacity of the banks rather than just charge them full and set the gauge to 100%.

After a whole season of use, I find that the most the gauge is reading is about 90% on the house bank. The bank is connected to a 50W solar panel and controller which after a day or two in the sun switches to float mode, so I know the batteries are topped off. With the old batteries, the smart gauge always read 100% when I came back to the boat after it had couple of days in the sun.

Is the issue with the gauge or with one or both of the house batteries? What is the best way to solve this?
#1 We need a lot more information on your charging system including the controller brand/model, absorption voltage and the duration the controller stays at absorption voltage before dropping to float. How are they being charged beyond the PV system?

#2 A controller dropping to float means nothing other than it decided to drop to float. It absolutely positively does not mean the battery was at 100% SOC when that occurred.If the float voltage is low enough and the battery as dropped to float prematurely then it is possible the bank may not get to 100% SOC. Exide allows for a 13.6V to 13.8V temp compensated float. If you are not towards the 13.8V charging further will slow to a crawl..

#3 A 50W panel is pretty small and if the vessel has any parasitic loads that can play a large role in the batteries never truly reaching 100% SOC.

#4 The max recommended charge voltage for the Exide Edge AGM battery is 14.4V temp compensated. Exide expects 14.4V to be held constant until current drops to less that 1% of Ah capacity @14.4V.

#5 The Exide Edge AGM is not a deep cycle battery. It is a dual-purpose AGM and these don't hold up well to PSOC cyclic use or deep-cycling use. The bank may already be suffering from the effects of sulfation.

#6 If you did not perform a "factory reset" on the Smartgauge, when you switched batteries, it may be giving erroneous data. It is important to perform a factory reset when changing batteries not just to reprogram battery type.
 

weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
#1 We need a lot more information on your charging system including the controller brand/model, absorption voltage and the duration the controller stays at absorption voltage before dropping to float. How are they being charged beyond the PV system?

Genasun GV-5 controller attached to a 50W panel bungied to the bow when moored and about 5-10 minutes of low idling while I sail away from my mooring. I basically sail on and off my mooring and rarely motor. A few times a month I'll speed around the bay at WOT just to exercise the 3ym20.

#2 A controller dropping to float means nothing other than it decided to drop to float. It absolutely positively does not mean the battery was at 100% SOC when that occurred.

#3 A 50W panel is pretty small and if the vessel has any parasitic loads that can play a large role in the batteries never truly reaching 100% SOC.
No parasitic loads to my knowledge. Batteries are turned off... even bilge pump is factory wired AFTER the battery switches.

#4 The max recommended charge voltage for the Exide Edge AGM battery is 14.4V temp compensated. Exide expects 14.4V to be held constant until current drops to less that 1% of Ah capacity @14.4V.

#5 The Exide Edge AGM is not a deep cycle battery. It is a dual-purpose AGM and these don't hold up well to PSOC cyclic use or deep-cycling use. The bank may already be suffering from the effects of sulfation.
Understood. These batteries were a drop in replacement from the OEM factory batteries which were an odd size.... kinda like a group 24 not as tall. I didn't have any choice in batteries without having to significantly rebuild the battery compartments. My sailing is almost all day sailing anyway with the the only real drains being the autopilot, two B&G MFDs and the stereo. Not using fridge or any industrial sized margarita blenders.

#6 If you did not perform a "factory reset" on the Smartgauge, when you switched batteries, it may be giving erroneous data. It is important to perform a factory reset when changing batteries not just to reprogram battery type.
The batteries were installed in the spring. In the fall, I removed all the fuses to the smart gauge (and solar controller) as well as made sure the switches are off.
Direct connections to this bank are 1. cable to house panel 2. smart gauge 3. solar charge controller 4. Factory installed Cristec A/C charger (not used at mooring of course) 5. Alternator (via factory installed isolator)
 
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weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Regarding your #2:
I re-read the genasun manual. If I'm correct, it goes to float after only 2 hours of charging? For some reason, I thought it kicked into float mode when the current draw reached a certain percentage of the maximum output.
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
The GV-5 is factory set at 14.2V (my one complaint about Genasun controllers "factory set") and 13.8V absorption. You can send it back for reprogramming to 14.4V and see if they can bump absorption a bit longer.

A factory re-set is not simply removing the fuses.
 

weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
I didn't know it had to be reset. I will try that.
Thank you.
 
Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
FWIW, I think these batteries should be charged as follows:
14.1V-14.4V absorption
13.6V-13.8V float
based on the file below:
Yes and you'll absolutely want to be at the upper end of of both float and absorption for PSOC use as as I mentioned 14.4V and 13.8V.... 14.2V is inadequate, with a 2 hour absorb, to get them to 100% and not fend off the effects of sulfation.

In a car with a dumb regulator that pumps out an absorption voltage continuously, and the bank is not cycled, then 14.1V can work. On a boat it will lead to a very short battery life.
 

weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
Short of sending the controller back, is their anything else I can do prevent this undercharging? Replace with another controller perhaps?
Am I not much better off by skipping the solar entirely and just running the engine for 10-15 while sailing back to the mooring?
 
Oct 2, 2008
3,807
Pearson/ 530 Strafford, NH
Would that be the same for old gel batteries? Ours have had an issue lately and I think they're on a decline.