It's not a wake boat but I know someone here can help. <BR> <BR>I have a boat with 4 batteries; House, Engine 1, Engine 2, and Genset. I end up changing out the wet cell batteries approx every 4 years but I'm not sure if it's worth spending $90 on wetcells or upgrading to AGM's at $265 each. I'm thinking of installing an AGM for the house, as this is the only battery that gets drained, and wet cells for the engine and genset. MY question, can this be done? <BR> <BR>The boat has two isolators and an onboard charger that runs on shore power or the genset. The two engines have alternators but not the genset. There is a parallel switch for the engine starting batteries although I don't know what it parallels with. Each component has it own cut-off switch. Batteries are all group 31 with approx 1100CCA. <BR> <BR>Ironically, the batteries all seem to die within months of each other.

Not recommended to mix wet batts. with AGM/Gel batts. Have you looked at 6 volt batts? <BR> <BR>Sounds like you may be using conventional batteries in applications that require deep cycle?

The engine and genset batteries are only starting batteries so they should not be deep cycle. <BR> <BR>The house definitely should be deep cycle. I just don't know if they can be mixed with my isolator set up. <BR> <BR>I have not considered 6 volt, in series I presume, but what do I gain?

How big of motors are you needing to start? IF they are not really big motors you cna get away with running all deep cycle batteries. <BR> <BR>6 volts will be your best bang for your buck when it comes to $$/amp hours. <BR> <BR>2 6 volts will cost you abou $250-300, and are equivallents to 4.5-5 group 31 deep cycle batts.

Not to throw a wrench into the issue of mixing battery types, but... <BR> <BR><a href="http://www.yandina.com/mixedbattery.htm" target="_blank">http://www.yandina.com/mixedbattery.htm</a> <BR> <BR>I don't know if this is will work for the OP, but I thought it might be relevant. This is the main reason I went with the Yandina, I wanted an AGM for the stereo but the standard L/A for starting. Yandina is the supplier to other commonly used ACRs. <BR> <BR>(Message edited by bremsen on July 07, 2009)

So, my alternators and charging system is not set up for AGM batteries or I could be over-charging any one of the 4 wet cells? Does the regulator not take care of this? <BR> <BR>A combiner allows the proper level of charging and an isolator keeps you from killing all batteries by breaking the link. Would my isolator possibly be doing both functions? Should I look at them again? Maybe I need to hit the switch to turn off the starting starting batteries when the engines and genset are shut down. Would the batteries charge with the charger if the switch is off? Does my house circuit only draw from the house battery and does the isolator prevent drawing current form other batteries? <BR> <BR>Arrrr.....I knew this would happen. where's that picture of that can of worms.

Tim, <BR> <BR>Batteries and charging systems are set up entirely different on a small cruiser. So those methods used in towboats do not apply. <BR> <BR>Keep all batteries in the same family. Make sure you're always plugged in to shore power when in the slip or storage. You probably have a 3-bank converter, i.e. house, starting and generator. But verify this. <BR> <BR>There is no point in expanding your batteries beyond what your existing converter can handle. Your converter may be below capacity. Also, make sure that all banks remain isolated at all times, other than for an emergency bypass. <BR> <BR>David <BR>Earmark Marine

David, <BR> <BR>I do believe it's a 3 bank converter as two of the 4 batteries are in parallel. <BR> <BR>I'm always plugged in at the dock but on the water it's nice to shut the genset off when anchored. That's where the abuse of the house battery takes place and my desire to install something else as a house only battery. <BR> <BR>I'm getting 4 years out of a Deka group 31 costing approx $90 each. When I saw $265 plus for AGM's I tthought one house AGM may make sense but perhaps not. <BR> <BR>The boat is a Tiara so I sure the existing system is designed properly.

Adam, <BR> <BR>I have wondered about doing 2 6 volt batteries for my system and a single 12 volt for starting, but worry about how the alternator will charge them. Although they will technically be all 12 volt, I still worry that they are not precisely the same and I may run into issues. For this reason, I have usually only ran and recommended that the same brand and type of batteries be used for the entire system. <BR> <BR>Note that is what David from earmark said...and he does this a lot. <BR> <BR>Adam, how did you do the starting battery? <BR> <BR>(Message edited by talltigeguy on July 07, 2009)

I have run my last two ski boats ( 2004/2007 SSV) with both 6 volts and 12 vot batts no problem. <BR> <BR>I've been running the same 6 volts for 4 years ( two diff boats) now with no prblems and they still hold a very good charge. <BR> <BR>and yes, David does do this alot.

Tim, <BR> <BR>Here's a few possibilities. You can parallel two batteries on the house bank for longer reserve time (or series two 6-volts). But you've got to have a converter than can handle the additional load of another discharged battery. <BR> <BR>If your stereo is moderate you might get by with the factory converter. By the way, DC lights pull some serious current on larger boats. If your stereo is substantial then you can supply the house bank with a dedicated and larger capacity converter/charger like a Kinetik or Progressive Dynamics. This would ensure that you can recharge quickly and properly condition the batteries. <BR> <BR>David <BR>Earmark Marine

Now knowing what to look for: <BR> <BR>Each engine has an 100 amp Balmar alternator and regulator plus a Balmar isolator. <BR> <BR>The Charger is a Professional Mariner Elite which can be set for Lead Acid 14.6 to 14.8 or Gel batteries 14.2. It's a 3 step charger capable of charging 3 battery banks and will not, unlike my wife, over-charge. The charger can put out full amperage continuously at 13+ VDC on all three outputs. I guess this is why two batteries are connected in parallel since the total is 4 batteries but the ability only charge 3. But I don't know why I would have two isolators in this configuration or 4 shut off switches; engine, engine, genset, house. <BR> <BR>My stereo is a head unit plus single amp played at a level you can talk over but I may also be running a baitwell and navigation equipment. If I have lights on, so is the genset. <BR> <BR>The house and starboard engine are the paralleled set of batteries and this set dies first but will start with the parallel button and port engine running. The port engine and genset each have their own battery. <BR> <BR> <BR>If I seperate the paralleled batteries into house and starboard starting, could I simply add another charger for the house battery so I don't kill two batteries at once?