Upgrading battery setup

[mdk681]

Currently I am running a 2 battery setup with a 3 position switch (1, 2, 1+2) in my '99 21v. One battery is a group 27 and one is a group 29; they are both a couple years old so I plan on replacing both this spring. I was going to stick with a marine cranking group 27 for starting purposes/while underway. We do a lot of partying at the island close by, so I need to beef up my stereo bank for while parked.

My main question is, if I replace my current group 29 and buy a second, would running these 2 batteries in paralell give me a significant gain in play time while parked? I keep my boat on a lift at the house so I would also buy a 3 bank charger to use while on the lift. Any help would be appreciated. Thanks!

[chpthril]

Although there is typically not a huge price difference between a group-24 and a group-27, a group-24 cranking is more then plenty to serve as the primary starting battery.

A pair of group-29 deep-cycles would give you 200+ Ah. Theres a ton a variables in trying to calculate a stereo's current draw, so its a guestimate at best. Those 2 batteries should give you quite a bit of play time, basically double what you have now, if everything else stays the same.

Since the 2 stereo bank batteries will be wired in parallel as one, a 2 bank charger will work as well.

[mdk681]

Although there is typically not a huge price difference between a group-24 and a group-27, a group-24 cranking is more then plenty to serve as the primary starting battery.

A pair of group-29 deep-cycles would give you 200+ Ah. Theres a ton a variables in trying to calculate a stereo's current draw, so its a guestimate at best. Those 2 batteries should give you quite a bit of play time, basically double what you have now, if everything else stays the same.

Since the 2 stereo bank batteries will be wired in parallel as one, a 2 bank charger will work as well.

I think I meant to say that I will run one group 24 and two group 27's. I will be using 4 guage for all power wire, do you think that 8 gauge will suffice for gound wire?

Would it be smart to run new power and ground wires to my HU while I am at it? I can recall my head unit shutting off and restarting when parked and playing music for a while with the sub at a decent level. I am guessing it was due to a somewhat drained battery but would heavier gauge wire to the HU do anything to benefit this?

[chpthril]

I think I meant to say that I will run one group 24 and two group 27's

Same theory holds true. The cost diff between a 27 and a 29 is minimal. as an example, an interstate 27 is $107 and a 29 is $121. I would go with a pair of 29's for only $28 difference and they have the same footprint and can use the same box or tray as a 27.

I will be using 4 guage for all power wire, do you think that 8 gauge will suffice for gound wire?

8ga is too small for any battery bank related connections. 4ga would be a minimum ga., but there may be some cable runs that need to be 1/0.

Since you already have a dual-battery bank setup w/switch, and assuming its wired with adequate cable size, 4ga would be adequate to use to wire the 2nd house battery in parallel with the original house battery bank.

All ground cables need to be the same gauge as their B+ counterparts, never smaller. In theory, DC flows - to +. Both cables carry a load equally, so if one is smaller then the other, and too small for the expected load, it becomes the week link in the system.

For the head-unit, its it important they the head-units GND and B+ share the same battery source as the amps and all other audio gear. So, depending on how you reconfigured the starting/charging cabling when you installed the switch and house battery, you may need to relocate the head-units GND and B+ off the boats harness and take them to where the amps are terminated. Which should be the "C" post of the switch if you are only running a switch and no ACR.

[mdk681]

Currently there are just 2 main heavy (I think 1/0) gauge wires coming from the motor. With this new battery configuration, do you see the need for any 1/0 runs? Correct me if I am wrong, but I should connect the - from the motor to a - of any of the batteries. I should link all - posts together on all 3 batteries as well. The + from cranking battery to switch post 1, and daisy chain the 2 stereo batteries + to position 2 on the switch. As of now the plan is to run all 4ga...

[chpthril]

MDK,

I would like to see at least 1/0 connecting the main cranking battery NEG to the house battery bank NEG.

Next, 1/0 running from the cranking battery POS to the switch and from the house battery bank POS to the switch. Now, for adding in the second house battery, 4ga to connect the #2 house battery + to house battery #1 + and same for the # house battery - to the #1 house battery -. Since you may already be purchasing some 1/0, its perfectly fine to use the 1/0 where I have stated that 4ga is sufficient.

Hope this help. If we need to, we can create a schematic or may be dig one up thats already been posted. Im a visual kinda guy, so sometimes its easier for me to see it then try to put it to text.

[mdk681]

MDK,

I would like to see at least 1/0 connecting the main cranking battery NEG to the house battery bank NEG.

Next, 1/0 running from the cranking battery POS to the switch and from the house battery bank POS to the switch. Now, for adding in the second house battery, 4ga to connect the #2 house battery + to house battery #1 + and same for the # house battery - to the #1 house battery -. Since you may already be purchasing some 1/0, its perfectly fine to use the 1/0 where I have stated that 4ga is sufficient.

Hope this help. If we need to, we can create a schematic or may be dig one up thats already been posted. Im a visual kinda guy, so sometimes its easier for me to see it then try to put it to text.

This was a big help, thanks. I am going to order a couple 25' spools of 1/0 this week. Do you have any reccomendations on ring terminals for 1/0? I have been looking around online and have found some crimp style on eBay for a decent price.

I need to track down a 2 bank onboard charger as well. Do you have a certain brand that you like to use? I plan on going with a group 24 for the cranking battery, and a pair of group 27's for the stereo bank. From what I can recall, my exisiting 24 and 27 barely cleared height wise when putting them into the trays on my 21v. I figured I would just go the safe route and stick with the existing heights for my new setup.

[chpthril]

This was a big help, thanks. I am going to order a couple 25' spools of 1/0 this week. Do you have any reccomendations on ring terminals for 1/0? I have been looking around online and have found some crimp style on eBay for a decent price

Since I make all my battery/amp cables custom in house, I buy my lugs in bulk. I use heavy-duty tinned copper battery lugs. I solder the cable into the lug, then use double walled heat-shrink to bridge the gap between the cable insulation and terminal body.

This what they look like

I need to track down a 2 bank onboard charger as well. Do you have a certain brand that you like to use? I plan on going with a group 24 for the cranking battery, and a pair of group 27's for the stereo bank. From what I can recall, my exisiting 24 and 27 barely cleared height wise when putting them into the trays on my 21v. I figured I would just go the safe route and stick with the existing heights for my new setup

I would recommend a 2-bank in the range of 20A output or a 3 bank.
Promariner Pro Sport 20 + Gen-2
Promariner ProTournament 200
Schumacher Ship-n-Shore 3-bank.

[mdk681]

Great, thanks a lot for the suggestions, just what I was looking for. I am going to track down all of my parts online and hopefully save a few bucks. Thanks again!

[ST.TIGE]

you might want to order as much from chp as possible.save yourself the time,headaches,extra parts and alot of money also.i searched and tried to save but in the end,i should of just bought it all from him in the first place.i learned the hard way,just trying to help you out with my !

[mdk681]

MDK,

I would like to see at least 1/0 connecting the main cranking battery NEG to the house battery bank NEG.

Next, 1/0 running from the cranking battery POS to the switch and from the house battery bank POS to the switch. Now, for adding in the second house battery, 4ga to connect the #2 house battery + to house battery #1 + and same for the # house battery - to the #1 house battery -. Since you may already be purchasing some 1/0, its perfectly fine to use the 1/0 where I have stated that 4ga is sufficient.

Hope this help. If we need to, we can create a schematic or may be dig one up thats already been posted. Im a visual kinda guy, so sometimes its easier for me to see it then try to put it to text.

Well I went ahead and ordered 2 spools of 1/0 gauge wire to re-do my battery setup. Now it comes down to the batteries. I have decided to go with one group 24 cranking for everyday use, and two group 27's wired together for a stereo bank when parked.

I have seen all kinds of batteries out there from the cheap Menards Exide brand, to Die Hard at Sears, Napa brand, and Interstate at MN Inboard (my local and gear shop). I am steering towards Interstate at this point due to their reputation, but what I would like to know is if they are worth the extra money. I figure battery replacement is only every 4 years or so, so spending a bit more this round on Interstate wouldn't be that big of a deal.

I plan on getting a 2 or 3 bank charger that I will plug in whenever the boat is home on the lift. Any thoughts on battery selection/brand would be greatly appreciated!

[chpthril]

theres only a handful of battery manufacturers out there making 75% of all the batteries. the brand is not as specific as choosing the right size for your needs and proper maintenance. The group-29 is almost identical in footprint to the group-27, but will offer more Ah for just a little more of an investment.

You cant beat the cost p/Ah of a good wet cell lead acid, but a quality AGM will handle deeper and more frequent cycles with better recovery, but it comes with a price.

[mdk681]

I am looking at purchasing the Promariner Pro Sport 20 + Gen-2 as you recommended a while back. My only question is, with the 3 battery setup I plan on running, is it ok to run a 3 bank charger even if two of the (stereo bank) batteries are wired in parallel? Or should I just go for a 2 bank with this particular setup?

[chpthril]

When 2 batteries are wired together, they become one. So in theory, you only need a 2-bank because you only have 2 batteries.

[uttige2002]

Greetings - I picked up this older thread and wanted to ask a couple questions.

I've recently purchased a new for me '95 2002 FSLM and have a couple battery related questions - and as it relates to the stereo. First off - it has a single battery, and the stereo is wired such that it turns on both when the key switch is at the accessory position and on postition. Totally expected.

The question becomes: When I add a second battery with either a Perko or Blue Sea switch and ACR - do I want to keep the stereo wired off the key switch - or do I want to add a bus underneath, wire all the stereo components to that (I want to add a sub, etc), eliminating the key switch and then run the stereo off the house battery and keep the other battery isolated as a starting battery.

What are the advantages/disadvantages - I can see that by eliminating the key switch I get:

1. The stereo stays on when going from having the engine on to off. It takes a few seconds for the sirius to kick back in when going from "on" to "acc".


I've been out a couple times so far - but I'm excited about getting down to Lake Powell in June for a week.

Thanks for your help - this has been a great resource so far.