Battery Redesign

[kitelog]

I am planning on upgrading the batteries on my Mainship 40 Sedan Bridge and am struggling to decide which way to go and am hoping for some advice from people more knowledgeable than me. Here is what I have currently.

1. A ProMariner 40A, 3 bank charger
2. Three batteries
- Starboard Engine Start/House - Group 27 but plan on replacing with Grp 31
- Port Engine Start/House - Group 27 but plan on replacing with Grp 31
- Generator Start Battery - Unknown Size
3. Current setup up allows me to run house off of either Starboard or Port battery. I attached a rough diagram of my current set up.

Obviously my house capacity is horrible. So far I have come up with 2 options:

Option 1 - Redesign the system so that I have a dedicated house battery bank that is isolated from the starting batteries. I am struggling with how to redesign my set up to accommodate the dedicated house bank.

Option 2- Stay with the current design but increase the size of both the starboard and port engine batteries to something like 2 Group 31s (can't fit 4Ds) in parallel to give myself a much improved house capacity of approximately 200ah. This option would be easy to do but it really limits my ability to increase the size of the house bank. In calculating my aH needs I would really like to be double this in order to reduce generator run time but I could live with this.

I have tried to find an expert here in Port Aransas, TX that I can hire to make recommendations and potentially do the work but I have not been successful in finding someone.

I would appreciate any and all thoughts on the best way to go without breaking the bank. Thanks in advance.

 

[ksanders]

If it were me, I'd start over.

I'd go with a dedicated house bank and dedicated start batteries for each engine. For a 40'boat I'd think to start planning at a minimum of 400 amp hours for the house bank.

Tie the battery banks together using ACR's and on/off switches

Get a larger charger or it'll take forever to charge a decent house bank. I'd use a inverter/charger combo unit. A boat your size would benefit from a dedicated inverter and the combo units come with 100 amp or larger chargers.

 

[Crusty Chief]

Concur with KS-

For the house batteries try 4 or 6 golf cart 6 volts, tie in 2 each to get the 12 or 4 for 24 depending on your system.
1 ea 12 volt for each main.
1 ea 12 volt for Gen and Thrusters if you have them.
Upgrade your charger/inverter, maybe use existing charger for 12 volt batteries and a new one for the house.
Recommend getting Nigel Calders, Boatowner's Mechanical and Electrical Manual
Great referance book.
Good luck!

 

[SCOTTEDAVIS]

I re-did my system to make if fool proof and easy.

Main engine 2-grp 27's in parallel direct to starter no other connections.

8-6 volt golf cart lead deep cycle battery's wired series/parallel (4 sets of 2 = 12 volt and 880 amp/h)

1 smart charger and 100 amp alternator with 2 temp sensors, one to alt one to house battery.
Balmar 6-Series Alternator Kit - 100 Amp Single Foot - 12 VDC

Balmar duo-charge from house bank to engine start battery giving 30 amp as needed to charge start battery.
Balmar Digital Duo Charge

All alternator current goes to house battery bank 100amp

All solar power goes to house battery 310 watts.

All boat needs run off house bank (except one bilge pump backup wired into the start battery's, not on float switch but on manual switch) start battery's only for starting.

Starter battery gets up to 30 amp regulated charge profile when ever solar or engine is making power (above 13 volts)

Gen-set has 2 grp. 24 battery's with a 3 way switch separate from other battery's but wired into the 120 volt charger and charged from 12 alt on gen-set.

Sun keeps house and engine topped off when I am away or on the hook, I do not leave on the shore power charger.

No switches to remember, no way to run down starting battery's as they are isolated by Duo-charge that only allows them to be charged not discharged.

No need to remember to change switch positions to charge different battery's and risk destroying alternator by turning the switch off or leave in wrong position and running down the starting battery's.

So easy a cave man can run it, that works for us.

 

[DavidM]

All of the ideas stated above are good, but may be overkill depending on how you use the boat and your desire for redundancy.

A low to middle cost battery/wiring scheme would be:

1. Set up one Group 31 battery to start both engines.

2. Use the other battery location for at least a pair of 6V golf cart batteries for your house. This will give you 220 AH of true deep cycle capacity. If you need more capacity add pairs of golf cart batteries.

3. Wire one engine's alternator output to the house and the other's to the starting battery.

4. Use one of the Promariner's outputs to charge the house, another to charge the starting battery and another to charge the genset. If you find yourself running the genset for long periods just to recharge the house batteries, upgrade to a larger amp output charger.

This scheme uses no ACRs or combiners and is inherently isolated. You don't need to think about it or adjust any switches.

If you ever want more engine alternator ouput then upgrade the alternator that feeds the house to a Balmar or equivalent. But most power boats with gensets don't need this.

This scheme does eliminate the redundancy of separate starting batteries. But given that the above scheme is inherently isolated and that you have a genset with a separate starting battery that can recharge a depleted main engine battery with the Promariner, I think that you are ok.

David

 

[ranger58sb]

1. A ProMariner 40A, 3 bank charger
2. Three batteries
- Starboard Engine Start/House - Group 27 but plan on replacing with Grp 31
- Port Engine Start/House - Group 27 but plan on replacing with Grp 31
- Generator Start Battery - Unknown Size
3. Current setup up allows me to run house off of either Starboard or Port battery. I attached a rough diagram of my current set up.

Obviously my house capacity is horrible. So far I have come up with 2 options:

Given it's a Mainship, which was a sister company to our brand...

Doesn't each start/house battery run only about half of the house? With additional load on one of them being bridge electrics (nav lights, horn, etc.)? And with the additional load on the other being for bridge "accessories" (electronics)?

If so, you can increase your house capabilities by simply adding batteries to each bank. For example, increase each from a single G27 to two or three G31s (200 or 300 Ah each bank).

Or if space is available increase one or both banks to 4x 6V golf cart batteries (440 Ah each bank). That would require some additional attention to minimum cranking amps, but it's likely doable, especially since you've likely got a parallel switch just in case.

-Chris

 

[dhmeissner]

So you can get ideas from Bluesea.

https://www.bluesea.com/products/8690/Dual_Battery_Bank_Management_Panel

In my current project to simplyfy things I'm going with one of these. If you open the links you can get a good idea of wiring options.

 

[kitelog]

Thanks for all the great suggestions. Every post so far has been very helpful. I realized after reading Ranger42C's post that I really don't fully understand what is running off of each bank currently so my next step is to map that out.

Thanks again. Will post when I finalize the design.

 

[FF]

Belt and suspenders (as sailors do ) is always best.

You should be able to KILL the house and still be able to start any engine or the noisemaker.

The system should be set up so nothing in terms of operator knowledge is required for operation and charging.

And STUPID should not cost the system.

You may have to replace rotary switches with ones that will disconnect the alts field , should someone accidentally move one to OFF during operation.

 

[kitelog]

Yesterday I checked my current configuration and it is different than ranger42c's boat. With mine there is a switch on the panel where I can switch the house load to either the port or starboard battery but the entire house load switches.

The new design will isolate the house bank from the start, and to FF's point, it will be simple to operate and hard to screw up. I have to keep it simple to protect me from myself!

 

[FF]

"I have to keep it simple to protect me from myself!"

Thats what the RV folks think , and require a seamless setup that requires ZERO knowledge or actions.

Their solution a key "ignition" switch with an ACC position and an $18.00 solenoid.

Been working for over 50 years , no boat bucks involved.

 

[Wxx3]

All of the ideas stated above are good, but may be overkill depending on how you use the boat and your desire for redundancy.

A low to middle cost battery/wiring scheme would be:

1. Set up one Group 31 battery to start both engines.

2. Use the other battery location for at least a pair of 6V golf cart batteries for your house. This will give you 220 AH of true deep cycle capacity. If you need more capacity add pairs of golf cart batteries.

3. Wire one engine's alternator output to the house and the other's to the starting battery.

4. Use one of the Promariner's outputs to charge the house, another to charge the starting battery and another to charge the genset. If you find yourself running the genset for long periods just to recharge the house batteries, upgrade to a larger amp output charger.

This scheme uses no ACRs or combiners and is inherently isolated. You don't need to think about it or adjust any switches.

If you ever want more engine alternator ouput then upgrade the alternator that feeds the house to a Balmar or equivalent. But most power boats with gensets don't need this.

This scheme does eliminate the redundancy of separate starting batteries. But given that the above scheme is inherently isolated and that you have a genset with a separate starting battery that can recharge a depleted main engine battery with the Promariner, I think that you are ok.

David

I like this more simple idea also.

And to keep things simple, your backup in case of dead engine battery are.....
... jumper cables

 

[kitelog]

Richard, I reached the same conclusion that the configuration David outlined was the best fit for my needs.

The only difference I am thinking of is instead of needed to use jumper cables to combine, I would connect the House bank to the Start bank with an On/Off Switch. This would normally be set to Off but if I need to combine I turn it to On. This saves me from having to get out the jumpers and pull the top off the battery box if I need to combine. The only risk I see is if I were to forget to switch back to Off after starting the engines. Anyone think this is bad idea?

 

[FlyWright]

Richard, I reached the same conclusion that the configuration David outlined was the best fit for my needs.

The only difference I am thinking of is instead of needed to use jumper cables to combine, I would connect the House bank to the Start bank with an On/Off Switch. This would normally be set to Off but if I need to combine I turn it to On. This saves me from having to get out the jumpers and pull the top off the battery box if I need to combine. The only risk I see is if I were to forget to switch back to Off after starting the engines. Anyone think this is bad idea?

That's a good plan, kitelog. That's how we set up our boat and have been very pleased. Never have had to use the switch, but it's there when we need it. I think it's a good idea to place those switches outside the engine room so they are immediately available in the event of an electrical fire or runaway starter.

 

[ranger58sb]

Yesterday I checked my current configuration and it is different than ranger42c's boat. With mine there is a switch on the panel where I can switch the house load to either the port or starboard battery but the entire house load switches.

Interesting. Useful to know it's different, given our owners club also sometimes hears questions about sister brands. This would be a '90s era Mainship, yes? During their non-trawler years?

-Chris

 

[kitelog]

Its a 1997.