Duracell 8D versus Trojan T-105 for HOUSE batteries...

[mikelutestanski]

Hello,    Just watered the t105s this am.  We have 12 T 105s in series parallel.   24 volt system.  3banks of 4 for 675 amps of power feeding a trace 2500 inverter U2624.  The system has been in service 10 years.   I lost one cell last year so I replaced the battery.  I usually don't let the voltage go below 25. Before charging.   
     The systEm requires attention for watering.  If you can't afford to check the batteries weekly when using and monthly when idle, go with a different type battery.
    I forgot twice in 10 years and uncovered a plate so take heed and be prepared for the maintenance chores.    We don't run the Ac units from our system but do run the toaster oven and microwave and lights.. This system has been good to us .
     Regards and happy bussin,   Mike

[zimmysurprise]

Hi Mex-Busnut,

We just recently replaced the 8 each 8D house battery bank in our Eagle at a cost of approximately $3500.  We also have 2 each 8D wet cell batteries for starting and the bus' 12v lighting system. 

There is a HUGE difference in the care and feeding of the two different banks.  The start bank requires regular cleaning and topping off while the house bank is pretty much totally self sufficient.  As Tom says, if you haven't experienced the freedom of using the AGM battery, then... 

It is my opinion that over the long haul, the AGM outshines its wetcell counterpart in every department - including cost. 

Also, I agree that having two seperate battery banks is 'penny wise and pound foolish'.  The house side should never be discharged past 50% in any case, which leaves a more than sufficient amount of cranking amps to fire the engine. 

I'm also considering building a house battery system (24v) and combining with vehicle start system (also 24v). Garhawk- You suggest a huge difference in "feeding of the banks". Would changes need to be made to the vehicle charging system?

[buswarrior]

Re: changes to the vehicle charging system...

AGM type need the regulator settings changed somewhat from lead acid type.

Failure to match charging voltages correctly to battery type will shortly destroy the investment in good batteries.

If an investment in AGM is going to be made, buying a modern multi-stage regulator for your vehicle alternator to support them makes a lot of economic sense, and is a relatively small amount in comparison with the battery purchase.

happy coaching!
buswarrior

[bobofthenorth]

While I'm sure what Ewen just said is true in theory and I would never want anyone to destroy a set of batteries based on what I said, here is one data point:  Shortly after we bought the frenchy-bus we went to Rickreall and I bought a set of 3 x 8D AGMs from Dick Wright.  Those batteries are still in the bus and still going strong.  That was the 1st year for Rickreall - I can't remember exactly when it was but its going on 10 years now.  They are tied directly to the bus alternator whenever the engine is running.  So at least in this one instance, a standard automotive charge profile hasn't done any damage to a set of AGMs.

Moving on though, I have noticed in the marine world that external regulators on the engine alternators are much more common.  I have a Balmar 614 which is a three-stage regulator to drive my twin alternators when we are underway.  I don't know if its any "better" but at least in theory it pulls higher amps out of the alternators than a conventional internal regulator would deliver and it didn't cost much.  It is also able to be configured for different battery types although as I have already confessed, I haven't done that.  In my defence I think it may default to flooded batteries which is what I have on the boat and may explain why I don't know how to configure it for anything else.

[belfert]

I put Trojan Group 31 AGM batteries in for starting batteries two years ago.  I did not adjust the alternator regulator.

[buswarrior]

Lots of good stuff found here, courtesy of Trojan:

http://www.trojanbattery.com/Tech-Support/TechSupport.aspx

From the chart under "charging", the charge voltage called for VRLA/AGM batteries, is slightly lower than flooded lead acid, (13.8-14.4 vs 14. and the float voltage is slightly higher (13.5 vs 13.2).

From the experience shared, it sounds like, in leaving things alone, the combination works.

happy coaching!
buswarrior

[gus]

Ever since I started using smart chargers I've doubted that mass produced chargers can really charge and maintain batts to tenths of volts, especially ganged ones?

[Emcemv]

Dr. Steve

Our 73 MCI has four 12v AGM batteries as the house DC supply. These are charged by a standard 12v alternator on the motor.  They look to be at least 5-6 years old with no problems.