House batteries for R29

[Nancy & Hugo Shaw]

We have a 2014 R29 and it seems our house batteries are not holding a charge. A battery supplier is suggesting we consider replacing our four G31 house batteries with two 6volt/210Ah deep cycle batteries. Dimensions are 260x180x252 mm for each battery.

I would appreciate comments from anyone. Is this a good idea. These batteries are larger than the existing G31’s - is there room for these larger and taller batteries.

A related question. Are the 100% pure lead G31 AGM batteries worth the extra costs. In Canada these are $400 CDN apiece.

Thanks in advance

Hugo

 

[Dale777]

Hugo,

I think you have three issues:

1. One is size: Will the proposed two G31 six volt batteries fit? I suggest that you open the cockpit hold(s) where the current batteries reside to measure that space to determine fit.

2. Cost: Lots of arguments for and against AGM batteries. I won't give an opinion on that, except to say that given the difficult access for inspection and watering the batteries in my R31, I'm willing to pay the extra cost for AGM.

3. Amp-hours is a more important issue: Presumably, you currently have four 12 volt G31 batteries wired in parallel. Also, presumably, those batteries are 105Ah each. When wired in parallel, that total bank provides 12 volts at 420Ah (i.e. 4 x 105 Ah).

But to use the 2 proposed 6 volt batteries, you need to wire them in series to get 12 volts in which that total bank then provides 12 volts at ONLY 210Ah, only half of what you now have.

Perhaps, to better understand the parallel versus series connection of batteries, take a look at this tutorial link about batteries: https://www.batterystuff.com/kb/article ... orial.html

 

[knotflying]

Dale is spot on. If you go with the golf cart 6 volt batteries you will have less amperage. Go with the same type and size that you had and don't reinvent the wheel. If cost is concern, In lieu of AGM you may want to go with a maintenance free battery if access is difficult to add water to a standard flooded.

 

[captstu]

Dale and Mike are both correct - but I've adopted a slightly different - and I think easier and cheaper - position.

There is no inherent advantage to using 2 6-volt batteries over a similar size 12-volt battery except for weight and ease of maneuvering. I suggest you stick with approximately the Group 31 batteries - they fit, are the best price vs Amp-hours I can find - and require no modification to the boat.

In the states, Walmart competes very heavily for the battery market. G31s run under $90 each with a 1 year warranty and turn over very rapidly in the stores so you get fresh batteries.

Walmart guarantees them for 1 year - I've had 6 without a failure. After 3 years, I just replace them all without considering if they are still working - I think of it as fueling the boat even though there may be 15 gallons left in the tank.

With a 3 hear replacement cycle, I've never had to add water (although I check them monthly) and never had to worry about a dead battery. Power management at the end of 3 years is just about the same as the first day.

And, at less than $300US for my boat, it is not really a significant boat expense.

If you don't have access to a Walmart-type place, maybe a boat trip to the states is in order? /Stu

 

[trailertrawlerkismet]

Hugo….would Canadian Tire be a good source for your batteries. Like Walmart Canadian Tire is all across Canada therefore warranty or replacement down the road would be somewhat seamless. I echo Mike, Dale and Stu.

Jim F

 

[Jim and Jackie]

In our 2010 R 29 just installed all AGM batteries 2 group 31 for the engine & thruster and 4 220 ah 6V in parallel and series. Fit wan't a problem. Agree it's personal preference on either AGM or lead acid batteries. We sold our 38' sailboat last year and house bank was all Lifeline 6 V AGMs. They had been on the boat for 6 years and still holding maximum charge. Found that they held a higher voltage longer than our lead acid 2V Rolls batteries.

Jim Demerest
2010 R29 Chessie

 

[Irish Mist]

My understanding is the reason for going with the 6 volt batteries is the plates are thicker and survive more charging cycles.

As to watering the batteries. I have seen some electric boats here in Victoria and they have a watering system. All the caps on all the batteries ( there are a lot ) are connected with a watering tube that terminates in a central location. The caps have floats inside. You connect a hand pump ( looks like the bulb on an outboard motor gas line ) and every now and then ( they check weekly ) you take a container of distilled water, connect the hose and pump the bulb until all the batteries are topped off. ( pumping bulb gets firm ) all the batteries are now watered in a couple min. This hose could be located remotely away from the batteries allowing easy access.
There are lots of watering systems on the Google ..
I am on the fence trying to decide if I will replace all with AGM's.. (Original's still seem to be doing everything fine on my 2011 but they are going on 7 years old ) Or going with the wet cells and a water system ( much cheaper then the AGM's ).
I am not at all interested in going with 6 volt as I feel this will in my opinion just complicate things.
I am leaning towards the AGM's as they have done a great job so far.

 

[Chimo]

Hugo….would Canadian Tire be a good source for your batteries. Like Walmart Canadian Tire is all across Canada therefore warranty or replacement down the road would be somewhat seamless. I echo Mike, Dale and Stu.

Jim F

Canadian Tire has gr 31 Nautilus AGM on sale for $305 CDN (~240 USD) . There’s a $20 core charge but that should be refundable. Got to add 12% tax of course.

 

[Scottfree]

I just don't see the value in AGM's. I have always had wet cell batteries with good luck. I have a regular high cranking amp engine battery and the rest deep cycle wet batteries. I will be going to 6 volt golf cart batteries for house batteries after we are done the Great Loop. Four 6 volt, two sets wired in series (to make 12 volts) and those two sets wired in parallel. Reasonable price and good serviceability.

I think buying the cheapest battery with the best warranty is the way to go. Canadian Tire, Walmart and Costco are my go to places.

Save your money for beer and use your cheap batteries to chill it. The beer doesn't know the difference!

Good Luck, Leon