2018 R31CB Luxury Battery Questions

[Bobby P.]

Getting ready for a Keys and Bahamas trip, so I really want to bring myself up to speed on my batteries.

Just curious about layout first, then size and dedication of batteries...

Port side has:
4 Group 31 (I assume) AGM house batteries, with a charge lead from the inverter and supplies the bilge pump forward of the engine constant juice.

Starboard side has:

1 Group 31 (I assume) AGM battery dedicated to the starter, with a charge lead from the inverter. It supplies th bilge pump aft of the engine with constant juice and supplies the propane cutoff relay with constant juice.

1 Group 31 (I assume) AGM battery dedicated to the thrusters and generator.

Do I have this right?

A few questions...
Why is the propane sensor drawing off of the starter battery?
Why is a deep cycle group 31 batter used for the starting battery?

BTW, I purchased and installed a new starter battery that had the same exact numbers as the others (UB121100). None of my current batteries have the "L" after the numbers and neither did this one. After installing it, I realized that it is a group 30 (https://www.solar-electric.com/upg-univ ... ttery.html), not a group 31. It has the exact same numbers as all of my other batteries. Does this mean that all of my batteries are really group 30 (that came with the boat) and not group 31s?

I have since pulled that batter out and installed an Optima 8050-160 D31T YellowTop Dual Purpose Battery. Is there any drawback (other than price) to using this for the starter? Can the all the terminals fit on the terminal post? Not being a deep cycle, does it matter that it has the constant draw from the propane sensor?

Looking forward to hearing from those who know.

Thanks much,
Bobby

 

[Ralf H]

Hi Bobby,

Yes, the layout should be as you described. To add: on the starboard side, the engine battery is inboard, and the thruster is outboard. The starter battery is also considered the 24/7 battery and has all the critical items on it that should not be routed through a main switch, such as the CO sensor and bilge pumps, etc. That's why you have the propane sensor on that battery.

I tried to follow the link however it says that the page is not available. So not sure what that is. If it is indeed a Group 30 battery, it would only be a slight decrease in physical size, as the group designation is only for physical size and does not have any performance rating. The batteries we provide should be Group 31.

The Optima battery should work perfectly fine for the starter. I don't think you would have any issues with it powering the propane sensor, etc. as long as you do not do any long-term storage without shore power connected. If you do that on the hard, you would simply pull the drain plug, etc. and pull all the fuses from the 24/7 panel that has the propane sensor, bilge pumps, etc.

Hope this helps

 

[Bobby P.]

Awesome, Ralph. Thank you very much!

The new Optima arrives tomorrow, so I will move forward with confidence.

Thanks again,

Bobby

 

[CAPTCRUNCH]

I just finished shopping for replacements for the batteries that came from the factory on my 2013 R27 and came away with two certainties: 1) my wallet is lighter, and 2) the original Universal Battery UB121100 sealed lead acid AGM's are Group 30H 12 volt 110 Ah (SKU #D5751), which are available from Northern Arizona Wind & Sun. I also learned that the only Group 31 AGM battery made by Universal has 100 Ah capacity and the familiar post and stud dual terminal "marine" arrangement instead of the L3 blades on my originals. Finally, tech support at Universal explained to me that the letter after the "UB121100" has been used to designate the production line that made the battery (mine was a "V" instead of the more common "L".) The new ones are due to arrive in a couple of days, and I'll share any surprises I find.

 

[Bobby P.]

CAPTN,

This is what I thought I learned, as well.

Why do so many people think the UB121100, which came on my boat, are a group 31s?

Bobby

 

[bill46]

on our 31CB I replaced all our original UB121100 30s with AGM 31 size from Sams Club. Made by west Penn fine american battery for $180.00
only gotcha is threaded studs did not want to crank engine, so used post adaptors on engine battery, house and thrusters fine with studs.

 

[iggy]

Has anyone looked at Batteries+ for their AGM batteries? Their warranty seams better than most.

 

[Bobby P.]

Just installed the Optima 8050-160 D31T YellowTop Dual Purpose Battery.

It was tight, but I could get all of the terminals on each of the two top studs. I had to move one ground to the neighboring thruster batter (they both share the ground, anyway), giving each of the grounds 3 cables.

Question about the thruster/genset battery... Does this battery receive any charge from the solar panel? How about when running the D4?

I now have an "extra" group 30 (seems that we've figure out all of my batteries are group 30s). I am thinking about putting it in parallel with the genset/thruster battery and moving the propane solenoid to this battery bank. I don't like the idea of a constant draw off of the starter battery. Or should I add it to the house batter bank and move the propane solenoid there? Thoughts?

Thanks,
Bobby

 

[Wee Venture]

Good to know that you were able to get all the cable lugs back on the terminals. I remember now that was how ours was done too, with one ground cable being moved over to the thruster battery.

Regarding charging, 10% of the solar and 100% of the alternator go to the engine battery. But which battery they go to is usually irrelevant because the ACRs will connect all the batteries once they see the charging voltage and all will get charging current.

We have moved the propane solenoid over to the house bank. I don’t see any reason for it to be on the engine battery. It is not a safety issue because the solenoid is normally closed and all that would happen if the house bank is completely depleted is the propane will shut off and you won’t be able to use your stove. If my house bank is so completely depleted that the solenoid won’t work, cooking is the least of my problems. And that is when I most want to rely on my engine battery to get us started.

Our single thruster battery has always done the job. We only use the thrusters when the engine is running and tend to use them sparingly so that helps too. If I had an extra battery, I would want it in the house bank. The only thing is, if you already have a port side list from the weight of the four batteries on that side, another battery on that side would only add to that. Also we don’t have the built-in genset so that may influence your decision.

John