So I go to visit the boat to check on things over the winter. When I notice the House bank to be at 0 amp capacity and 11 volts. Turn the charger on, and the house bank started to charge. It hit 12.8 volts and the ACR kicks on then back off,and the house bank reads 12.3 volts. Start bank at 12.7 v.
My setup- 2 12 volt Agm in parallel at 396amps total capacity, (installed July 2012). AGM starting battery connected to house bank with BlueSeas ACR for charging. Shore power charger connected to both start battery and house bank on separate charging circuits. 150W solar with Victron MPPT correctly rated for solar. Selector switch has bank 2 as House batt, and bank 1 as start batt to distribution panel. Start batt also has a second on off switch to disconnect from starter and selector switch. Alternator directly connected to house bank with on/off switch. Victron batt monitor to monitor both banks, house bank has all info monitored, start batt, just voltage monitored.
So with the charger on, I’m just getting 12.3 volts on the monitor, double checked with volt/amp meter. With selector switch off, I test voltage on this switch- house bank at 12.3v, start bank at 12.7v, and distribution panel at 0 volts (just like it should be). Turn to position 2 (house) and get 12.3v on the panel. Turn to position 1 (start) and get 12.7v. Then turn isolation switch for start batt to off, and get 0v. So it seems the selector and isolation switches are good and not shorting.
Also, the monitor is flashing the state of the house bank as dead. Amps at monitor is 20 with charger on, and load reads 0 amps. put the amp meter clasp on the charger cable, and it reads 12 amps. Also check the analog meter on the charger, it reads about 15 amps. Everything seems to be charging/working as designed, except the house bank is still showing 12.3v after charging for over an hour. I even checked the solar, and getting good voltage. The solar monitor sows it in bulk charging.
So I suspect my house batteries, 1 if not both are bad. Installed July 2012, and its now Jan 2019. I also checked the bilge pump. It seems to be working as designed with the float switch in both auto and on, while the charger is on.
Im going to leave the charger on over night and check it again tomorrow morning, and do some more current checks to the panel, anchor winch, and charger.
Unless Im missing something, is my fault isolation correct, and the batteries are dead? All comments are welcomed from this large knowledge base.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Rob - Your setup sounds very similar to ours (except that our housebank is conventional FLA 6v (GC) cells, and the selector switch setup is a little different), and it does seem that you've isolated the problem to a dead housebank..
I don't know what the lifespan of AGMs is (I have no experience with them). I do know that a number of years ago a combination mishaps and stupidity (on my part - don't ask) resulted in the house bank getting discharged over the winter to the point that one of the batteries froze at some point, which I only discovered once the weather warmed up but the battery wouldn't hold a charge. While I assumed that AGMs don't freeze, I just found this online by googling:
Can AGM batteries freeze and, if so, how do you best prevent this from happening?
All batteries can freeze if cold enough. ... The key to
protecting any battery from freezing is to make sure it stays fully charged throughout winter. If the battery is used sporadically,
and left to discharge during this time, the electrolyte begins to change from acid to water as the voltage declines. The more
water-like the electrolyte becomes, the easier it is to freeze.
So that's one theory.
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Yes, I do believe it’s a dead house bank. Left the house bank on charge overnight, and this morning said 12.8 while charging, and 12.3 when charger is off. The batteries were also very warm. Port battery warmer than stbd. I read agm last about 5 years, 7 when maintained well. So it will be 7 years this July. I also checked current to the anchor windlass, distribution panel and charger. All with the same results. So I wired the bilge to the start battery, disconnected house bank from selector switch, charger, and solar. Also shut down the ACR. Leaving the start battery on trickle charge to keep topped off.
Next decision, I’m thinking of going with 2 Battle Born 12v, 100 ah LifePo4 lithium batteries. I’ve read it can handle a lead acid battery charger. I have. NewMar HDM30. It has 14.0V float voltage, 30 amp charger with 3 banks. I think that is original on my boat (1995), so I might replace. But would the ARS5 regulator be compatible. Also, would I be able to keep my Optima starting battery and Blue Seas ACR? If the regulator is not compatible, will the Balmar MC-614 use the same wiring harness and hook up as the ARS5. I have the 105amp alternator with 3/8in pulley from MainSail. I’m kinda hoping he will post a reply as well.
Ive read these lithium batteries have about double the cycles as the AGM, (1000-2000 vs. 500-1000), and it seems it would give me about the same usable AH as 400 AH on AGM. So in theory, w would get double the life at double the price. And they are the size as a Group 27 battery, and only weigh about 30 lbs instead of 130.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
I know even less about LifePO batteries than AGMs (so why are I pontificating here?), although I am quite impressed thus far with the lithium battery on our Torqeedo outboard, which we can run all the way down to 0 with no apparent harm (and it charges rather quickly from our solar panels).
Since you mentioned Mainesail, he has a long article on his site on the subject, at https://marinehowto.com/lifepo4-batteries-on-boats/ with a lot of details and consideration, but which early on has this: "Warning - I do not believe LiFePO4 is ready for mass DIY prime time builds. Read with caution and especially focus on the things that you don’t want to hear rather than only what you want to hear."
However, without getting into the technical issues about charging and regulating (beyond my pay grade! -- although the Battle Born manual says"the ideal voltage is between 14.2v-14.6v", and the battery has a built in Battery Management System, like our Torqeedo, so it looks relatively stupid proof), I'm wondering whether the long life (and light weight) is an adequate trade off for the expense of the LiFePO4. The Battle Born looks promising, but according to the webside it looks close to $1000. So even if you go with just 2 of them -- under the assumption that you will have effective use of their full 200 Ah by discharging them fully (unlike your current 400Ah of AGMs, which if you go safe and only draw down 50% gives you the effectively the same 200Ah) -- you're looking at almost 2 grand.
By comparison, our house bank currently uses a pair of US125 XC2 6V batteries, which are rated at 242 Ah, and they can be found for around $200 each (or even less), so 4 of these would give you 484 Ah @ 12vs for about $800. Even assuming you get twice the life from LifePOs over FLAs, still significantly cheaper with the 6Vs, and if one dies during that time your replacement costs aren't so bad. (BTW, we've never found our 242 Ah house bank to be insufficient while cruising, even running the fridge full time since we added solar).
Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY
Yes, I too read MainSails article, and was impressed, and a bit concerned about LPO. I’ve thought about 6v as well. Actually been thinking about them when time to replace. I’m going to contact Battle Born company and get more info on the batteries, and my current configuration. I’ll post what I find.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Our boat has two Lead Acid 4D batteries (12V each) for the house bank and a regular Lead Acid automotive starter battery. A combinor ties all together, depending on voltages and charging conditions. All the batteries show 12.5+ volts after sitting idle since October. The starter battery is 8+ years old and the House Bank batteries are both 3 years old. I think we can get another 2 years from the house batteries. We mostly daysail with maybe 10-15 overnights per year. We don't run the refrigerator (use ice instead unless at the dock) and most of the boat's lights are LED. The house batteries are not deep cycle and came from Tractor Supply at just over $160 Each. They are designated as "4DLT" and measure about 1 " less in height than the old 4D's we pulled out, and weigh about 80 lbs compared to the 100lb original 4D's .That 20 pound weight savings is nice. My point is, for medium-light duty sailing, you don't have to break the bank to purchase the batteries.
Paul & Wendy Keyser
"First Light"
Rye NH
2005 C36 MKII #2257
Wing, M35B
I agree. We decided not to go LPO for batteries. Instead get the 4d we have already, and update the charger. The plan is to have all charging circuits ready for Lithium at the next battery change, if we still own the boat. By then, hoping the price drops, and there is a larger market and knowledge base for LiFePO4.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
"So with the charger on, I’m just getting 12.3 volts on the monitor,"
With a 20A charger on heavily depleted house bank it is going to take a loooong time to reach absorption voltage. Also, some current will be going to the start battery so you really have less than 20A going to house.. If your bank was at 11V and you flipped on the charger and the batteries quickly attained 14.6V then the bank is done for. If they take a long time to increase in voltage during bulk charging this is a sign the batteries are still accepting current like they should.
-Maine Sail
https://www.marinehowto.com/
Main Sail,
I left the batteries on charge overnight, about 20 hours. When I returned, the voltage still read 12.8 v on charge. Turned charger off, and it reads 12.3 still. The house bank was very warm, and on the monitor, it also said there are 0 amps / percentage of charge on the victron monitor. The capacity indicator was flashing with 0%. This was the same the day before.
What at is your impression?
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA
Isolate the batteries from one another and let them sit for 24+ hours and then read the voltage of each battery. The one with the lowest voltage will be your culprit. It could be a failed battery.
-Maine Sail
https://www.marinehowto.com/
Yes, that has been done. There is a faulty battery. Got replacements on order. Also ordered another charger.
Robert Trinkle
Troubador, 1995 C36 MKII #1433, SR/WK
Universal M35A
Kinsale Harbor Marina
Kinsale, VA