new battery configuration

Ahoy Mates!

Spring is breaking on the East Coast and attention is turning to the DEBORAH.* ('81 35' CHB Trawler).* I'm seeking opinions from the group.* I want to reconfigure my battery bank(s).* I had 2-12V batteries that served both as starters/house set.*

I'd like to dedicate a 12V starter and then have a pair of 6V's to use as a house set.*The starter is for a single 120 Lehman diesel.* *My house needs are relatively light.* I*do weekend-overnights and run the cabin lights, radio-cd player, laptops, cellphone chargers.* Cuerrently no ac or electric fridge.

In addition to battery size/power*recommendations, I'd like to ask what moves over to the starter vs. the house set.* I'm thinking the ignition, gauges, starter motor, all move over to the starter battery.

I have a Charles battery charger on board as well.* How would I wire this in?

Thanks,

Tom Smith

tomtomterrific wrote:

*

Ahoy Mates!

Spring is breaking on the East Coast and attention is turning to the DEBORAH.* ('81 35' CHB Trawler).* I'm seeking opinions from the group.* I want to reconfigure my battery bank(s).* I had 2-12V batteries that served both as starters/house set.*

I'd like to dedicate a 12V starter and then have a pair of 6V's to use as a house set.*The starter is for a single 120 Lehman diesel.* *My house needs are relatively light.* I*do weekend-overnights and run the cabin lights, radio-cd player, laptops, cellphone chargers.* Cuerrently no ac or electric fridge.

In addition to battery size/power*recommendations, I'd like to ask what moves over to the starter vs. the house set.* I'm thinking the ignition, gauges, starter motor, all move over to the starter battery.

I have a Charles battery charger on board as well.* How would I wire this in?

Thanks,

Tom Smith

Click to expand...

You certinly need to wire a seperate battery for your start battery.

If you do not have one.**A battery switch is in order.

I use 3 battery switches.

1. *is wired to the start battery.
2. *to the house bank*
3. *switch to parallel the two banks if I need x-tra power to start.

The 1. *2.**Both is to much to remember.**

3 switches I dont have to wory if someone switches the banks and I drain my start battery listening to tunes on the hook*

I would wire everything to the key that doesn need to be on when the motor is not running.

As to your charger. I run a battery combiner to permit charging of both banks when hooked to shore power.

The charger is* hooked to the start battery and then through the combiner *to the house bank.

When the engine is running the alternator takes the place of the charger.


It's a start.

SD




-- Edited by skipperdude on Friday 18th of March 2011 09:27:11 AM

-- Edited by skipperdude on Friday 18th of March 2011 09:32:58 AM

Tom,I'd consider more house battery.

charles wrote:

Tom,
Definitely get BOAT OWNERS MECHANICAL AND ELECTIRCAL MANUAL by Calder. This book will ans all of your questions.*

Click to expand...

But don't expect an enjoyable read. It's like a textbook and much written in tech-over-your-head langauge. Look up what you want to know and put it away.

A single 31 as start should do fine , with 2 or 4 6V golf carts as the house.

I would put the emergency bus on the house , bilge pump , gas sniffer and CO2 alarm, with fuses.

I would get an alternator with an EXTERNAL regulator and switch to a 3 or 4 stage unit as sailors use.

Only an off switch for the house set , the engine would be hooked to the house with a $17-$20 RV solenoid odd the ACC position on the start switch.

Seamless , hop on start , run , anchor out start return, all the battery management is automatic , no effort or thinking.

If you contemplate days of anchored bliss an E - meter is required.

Thanks Guys,

Great suggestions and options on how to go.* I like the simplicity in FF's last post...

<q>Only an off switch for the house set , the engine would be hooked to the house with a $17-$20 RV solenoid odd the ACC position on the start switch.

Seamless , hop on start , run , anchor out start return, all the battery management is automatic , no effort or thinking.</q>

Let me rewind and repeat to see if I have it right:

1 - I'd have an ignition switch with OFF/ACC/START postions
2 - STARTER would be wired to the START position
3 - A solenoid that*turns "on"*the HOUSE*circuit would be wired to the ACC position

FF, you mention and an "off switch" for the house set, can you clarify that?

Also, what are the merits for either 6V vs. 12V for the house set?* Better to go with:
*
- (2) GC2 6V, each with 240AH (20 hr rate), or
- (2) 30H 12V, each with 130AH (20 hr rate)

Thanks!

Tom

" you mention and an "off switch" for the house set, can you clarify that?"

The rotary switch would only be to secure the house batts , turn them OFF from any boat loads.

This would stop dead discharge from a tiny load left on like a compass light , or?

While "off" the emergency bus would still be on, the bilge pump etc , those could be secured by removing a fuse.

"A solenoid that turns "on" the HOUSE circuit would be wired to the ACC position"


When the engine is operating the ACC terminal connects the house set to the alternator and start batt to charge them.

Weather the house bank "ON" supplying the boat is not important , tho underway it is expected they would be.

Not in use , once a month the key would be left in ACC , to charge the house set from the shore power charger.

IF the boat is operated once a month this is not needed.

Tom,
I redisgned my bank for my MT-36 single Lehman 120 and 4KV Kohler genset two years ago and it has worked flawlessly since. This is my set up.

Single group 24 low maintenance auto start battery for the engine and genny. This battery is charged off the battery charger only.

8-6V cart batteries in continuously power vented (computer fan) in a box under port stateroom. These batteries are charged from the alt and battery charger.

My alt is old style no smart regulator. Charger is smart charger 3 bank type. I wanted to design a system that would not involve buying anything new other then batteries. The tiny little group 24 starts the engine on the first crank every time. It uses a tiny fraction of the bat capacity to do so. When ever we are underway or genny running or tied to shore the smart charger is humming along off the inverter/shore/genny and as such the battery is topped of immediately and the smart charger takes care of it.

The house bank is out of the hot engine room and stays nice and cool. The dumb alt or the smart charger charges the bank depending on the engine running or not. Because of the size of the bank the fact that the alt is without a smart regulator is minimized. The next upgrade I would make would be an external regulator for the alt.

Thanks FF,

"...the engine would be hooked to the house with a $17-$20 RV solenoid odd the ACC position on the start switch."

So where would the solenoid come into the picture?

Also, any thoughts on the merits of 2 6V vs. 2 12V batty's for the house set?* My needs are low; just cabin lights and the occassional accessory.* i.e. no electric fridge, microwave,*or ac.

Thanks!

Tom

In my opinion, 2 6V GC-2 Golf cart batteries in series are far superior to 2 12V Group 27's or a single 8D. * They are lighter to handle individually than the 8D. *Provide slightly more AH's. They are durable. *Think of the environment in which they are designed to perform. *They are driven hard during the day by golfers who know little and care less about batteries. *They are subjected to heat, shock and often times not fully recharged by the time they are called back into service the next day. *It takes a lot of juice (amperage) to haul two extra large golfers up hill with excessive club bags and a cooler of adult beverages. *And they do it day after day. *Because of economy of scale, they are an exceptional value at $75~90 each. * There are a lot of electric golf carts and other stuff using them. *There are advocates of gel cell and AGM batteries and they do offer some advantage (a higher acceptance rate) but in my opinion, the extra cost is not justified. *The plain flooded wet cell batteries are way (half of less) cheaper. *If charged with a 3 stage charger of appropriate size and equalized periodically, they will last for years, and very seldom need water. * Estimated life is 700 cycles, but can go farther depending on how far they are discharged before recharging. *Never discharge below 50%.
Based on your described useage *I would recommend 4 GC-2's in two banks. *Multi bank chargers can have problems properly charging two battery banks of disimiler sizes. *I used this in my old boat. *I wired the engine and house loads together with a battery switch to select either or both banks. *If you think you EVER might be tempted to switch batteries with the engine running, get a battery switch with an alternator field wire disconnect to prevent blowing the alternator. * With this setup I powered a small Norcold reefer, a 1800 watt inverter to run my coffee maker, toaster, microwave, fans, cabin and anchor lights. *At first, I would run from one bank only so as to have a fresh bank to crank the engine. *After realizing that I could crank the engine no matter how discharged the batteries were, I switched to the both position and never messed with it. *I do monitor my battery voltage closely. *I can easily get two days use without running the engine. *The engine has a 150 amp alternator. but has only a single stage voltage regulator so I probably never get much over 100 amps from it, and then not for long, as the regulator starts to slow the charge rate quickly. * I have a 20amp 4 stage (w/ eq. cycle) charger running from shore power. *This is less than 5% total capacity). *It is slow, but my boat sits for a few days between useage, and slower charging helps battery life. *I get about 6 years battery life with this setup. * *
I haven't figured out how I want to configure my batteries for my new to me trawler. *One thing is certain, the genny will have its own independent battery. *My house loads will be higher, bigger 120v only fridge, electric head, more lights etc. * Currently I have an 8D house battery, a Group 27 cranking the twin diesels. *I am sure the 8D is inadequate. *
There are probably as many opinions as boaters here. *That is a good thing. *But in my engineering experience, simpler is always better in the long run. *I fix my own stuff.*

When the engine is operating the ACC terminal connects the house set to the alternator and start batt to charge them.

The ACC position is what closes the solenoid , joining the engine batts to the house bank.

I agree that 6V golf carts make a great cheap system .

IF you value the batts , and will be working them at anchor ,bogartengineering.com , E - Meter or one of the other SOC units is a MUST!!

If you add an inexpensive Yandina Combiner between your battery banks, both banks will charge after the first bank reaches 13.2V. This way, there would be no need to connect to the start switch ACC position. A single-bank shore charger would charge both, or a single alternator would charge both while underway.

I prefer the 6V GCs to the 12V 31s. I just replaced 2 8Ds with 6 GCs. I got about a 50% Amp Hr increase in the same footprint. I appreciate the lighter battery weight when manhandling them into and out of position in the ER.

Here's a schematic of my recently revamped electrical system. Granted, it's got 2 engines/starters/alternators, but maybe it'll help in planning your system. So far, everything is working perfectly.





-- Edited by FlyWright on Thursday 24th of March 2011 04:21:46 PM


-- Edited by FlyWright on Thursday 24th of March 2011 04:22:44 PM