# Starting Battery vs. House Battery



## GarrettK (Aug 9, 2004)

I''ve done a bit of research and am still a bit confused on this.

My plan is to have a 3 battery system in my new to me Pearson Wanderer. It will consist of 2 banks, the first being a single battery for the motor, and a two battery bank (house batteries) for all other electronics.

The house batteries will be deep cycle batteries. The question revolves around the selection of the motor battery. From my research, I''m better off having 3 identical batteries (from a charging aspect), but for a starting aspect, I don''t want this to be a deep cycle battery (or am I wrong)?

Basically, is there a problem using a deep cycle battery as a starter battery for the motor? If it matters, the motor is a 25 hp Universal diesal.

The electrical system on this boat is a nightmare and I''m basically going to gut it and start over, but want to get it right the first time.

I''m currently working my way through Nigel''s book on electrical systems, but have this one question (for now).

Garrett


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## TSOJOURNER (Dec 16, 1999)

Good plan on the battery set up, however a slight improvment could be made. 
First, the starting battery should be just that, a Group 24 or 27 will be fine for the Universal 25, had one on my last boat. If you can, use 6v golf cart batteries for the house system Trojan T-105''s, you will need 4. Each bank is connected in series to have 2 banks of 12v capable of very deep discharges and multiple ones. Should get 5 years from the set up. Next, the 35amp alternator on the Universal is too small to charge these batteries fully or any other mix you might come up with. I used a new 105AH alternator and a smart regulator. That is the max you can turn with a single pulley set up, and at that you need to use a Gates Brand belt. When the altrnator kicks in, you''ll take about 300 rpm off the cruise. It''s noticable. This set up served me well running everything on the boat, refer, etc. Good luck.


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## RichardElliott (Sep 24, 2001)

I''ve been very happy with the Optima AGM deep cycle batteries for both uses with a Universal 25hp diesel. They do not require water top off.


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## TSOJOURNER (Dec 16, 1999)

They don''t require water ever thats true but like anything else it''s a trade off they don''t have near the storage capacity of a flood battery. Each must decied, based on thier boat power needs just what type battery bank is the best for thier curcumstances


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## Jeff_H (Feb 26, 2000)

Jim, I believe that AGMs have a much greater storage capacity and are longer lived than a flooded battery but they are more expensive and require proper charging and voltage control. 

Jeff


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## TSOJOURNER (Dec 16, 1999)

Garrett asks a very good question.

I agree Group 24/27 batts for starting & T-105''s for house would be a good choice and is exactly the setup I''ll use to replace my current 2 banks of group 27''s.

But what about the different charging profiles/characteristics of the the two different types of batteries? Would a multi-stage smart charger (i.e. Xantrex Trace 20, etc.) handle charging the two different batteries appropriately? Or would you need 2 independent chargers to charge the different batteries properly?


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## TSOJOURNER (Dec 16, 1999)

I have the same set-up including the Xantrex. The charger is also smart enough to tell when one bank is up and then divert extra amps to the lower banks until all are charged. I''ve had this set-up for two years and it is great.


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## GarrettK (Aug 9, 2004)

Boatbum,

Thanks for the reply. That was going to be my next question, but mmcoy beat me to it.

So if I understand this correctly, I want to use a 24/27 size/style battery for starting (as bank 1) and then 2 105''s for my house battery (bank 2) and a 3-stage charger will adequately charge the banks even if they are different types.

I''m sure I''ll come up with more questions as I start this project.

Garrett


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## jack_patricia (May 20, 2001)

Garrett, there isn''t a different ''charging profile'' in the different form factors of conventional flooded batteries you are considering; they will charge similarly because the battery chemistry is (or should be) the same.

As you continue to work your way through Calder, I think you''ll find him also raising the question of ''battery switch management'' and whether you want that variable added to your new system. With the same basic question in front of me (but for a larger boat which needed, I felt, a larger house bank), I opted for a single house bank of 4 x 6V T105''s and a Group 27 start battery (all flooded). But the wiring plan I selected allows me to *never* need to change the battery selector switch so long as all batteries and circuits are performing properly. Consequently, I never risk e.g. running a start battery down along with the house bank because I forgot to switch back from ALL to e.g. ''1'' after doing a charge. I can start off the house bank, should that battery fail, by moving the Selector to ''2''...but otherwise, nothing changes, ever. I find this utility (and protection for self-inflicted wounds) to be very useful in the real world. It''s downside is that one needs to add an in-line sense circuit of some kind that can allow charging voltage to reach the start battery whenever the alternator is putting out...so that extra cost is the price of the simplier, more user-protected set-up.

If this interests you, visit www.jackrabbitmarine.com or give the folks there (in CT) a call and put your hands on one of Jack Csenge''s simple 12V block diagrams showing how this is set up. (This will be free, BTW). It''s simple, clever, and totally consistent with the wiring recommended for more sophisticated DC circuits (as e.g. adding wind power, an inverter/charger) at a later date.

What you doing is painful - to the wallet, the back and the hands. But it''s exactly the right kind of thing to do with an older boat, and you''ll forevermore be thankful you put your time, grit and money into this project. Good luck to you.

Jack


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## GarrettK (Aug 9, 2004)

Woosh,

Thanks a lot!!! The diagram sounds exactly like something that I''ve been considering, but have been unbable to actually find a daigram showing the layout.

Nigels book seems very thorough, but I don''t quite know enough about electricity to feel 100% confident about a set up that I design. I''ll be getting in touch with them very soon.

Thanks again,

Garrett


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## TSOJOURNER (Dec 16, 1999)

Whoosh, again you come thru. Thanks for the pointer to Jackrabbitmarine. 

I do wish I''d known about them a couple weeks ago as I just purchased 25'' of battery monitor cable from Zantrex for about $50 for my new Link 20 (when I could of bought the 6'' I actually needed from Jackrabbit marine for $2/ft).

But after perusing their site I think in the end they''ll save me $$$ (or at least the impending headaches trying to figure out the rewiring of a dual 12v/110v/dual bank system). 

I too want to incorporate Calders ''no battery switch needed'' approach for the same peace of mind but found his description of how to do it rather confusing (and I''m somewhat knowledgable when it comes to electrical/electronic circuits). I''m sure the block diagrams from Jackrabbit will make it clear what exactly is going on.

Again, thanks


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## GarrettK (Aug 9, 2004)

I talked to Steven at jackrabbit marine yesterday afternoon, and apparently they don''t have any block diagrams that they just give away. He was offering to design a system for me, but at a cost of about $200.

I''m debating on what to do now. Apparently Jack Csenge has retired and no longer works there. Lucky guy!

Does anyone know of a place where you can buy pre-designed block diagrams for less than the $200 they were talking about?

Garrett


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## efatzinger (Nov 30, 2000)

Try poking about in the http://www.amplepower.com site. Particularly in the Primer and wiring diagrams area.


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## ianl (Oct 12, 2002)

Garrett,


I''m also interested in finding a block diagram. Did you find one or did you use Jackrabbit''s service?


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## GordMay (Dec 19, 2002)

Blue Sea Systems ( http://www.bluesea.com ) has about a dozen different block diagrams at:
http://www.bluesea.com/Article_detail.asp?Section_ID=154&id=178

Including:
PN 8062 Switch Panel with Circuit Breaker
PN 8080 DC Parallel Battery Switch Panel
PN 8083 DC Power Distribution Panel
PN 8280 DC Parallel Battery Switch Panel
PN 8281 DC Parallel Battery Switch Panel
PN 8280 DC Parallel Battery Switch Panel
PN 8370 DC Parallel Battery Switch Panel
PN 9001e Battery Selector Switch
PN 9002e Battery Selector Switch
PN 9003e Battery Isolation Switch
PN 9004e Battery Isolation Switch
PN 9005 Mini Battery Disconnect Switch 2 Position, OFF-ON with Key
PN 9006 Mini Battery Disconnect Switch 2 Position, OFF-ON with Knob
PN 9012 E-Series Electronic Switch
PN 9112 Automatic Charging Relay with Emergency Parallel Capacity

Attwood ( http://www.attwoodmarine.com )also has a few drawings at:
http://www.attwoodmarine.com/Products/Install_Instructions/19352rb-english.pdf

HTH,
Gord


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## TSOJOURNER (Dec 16, 1999)

Thanks for the link(s).

Any idea which one of those diagrams accomplish what WHOOSH was describing?


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## GordMay (Dec 19, 2002)

I think the drawings and Caulder’s texts should provide sufficient information for anyone competent to design & install their own electrical system.

Additional guidance might be useful, in the form of an on-site consultation or supervision /w a QUALIFIED marine electrician (caution: many who claim to be, are not IMHO). 

Still nervous? Contract the work out. 

Respectfully,
Gord


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## GordMay (Dec 19, 2002)

Some additional BATTERY WIRING DIAGRAMS:
http://www.homestead.com/dolphinmarineservice/Ele1.html
http://www.homestead.com/dolphinmarineservice/Ele2.html


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## TSOJOURNER (Dec 16, 1999)

I have two AGM''S that I love they stay charged and can be turned any way you want but upside down. My cranking battery is led acid group 31 from Sams so when it starts to get weak I will trade it in and it is a marine battery. The system works well I have a switch to isolate all three from the ALT and Charger which is a Xantrex 20+ I also have the remote panel and heat scensor. I can switch the switches to charge the two AGM batteries or the Led acid battery sometimes all at once and I have had no problems yetwith charging the combined banks all set on AGM. I have not charged the batterys all on led acid for fear of overheating. The Cranking battery does nothing but crank so I dont see it as needing much more than the low voltage boost it gets from the AGM type charge. I can however set it to the led acid cook off which will shake the scale that builds up on the plates off. In the five months the system has been working It has not failed once,I ran my Cafamo fans two of them and my lights for two days all but a couple of hoursand by the end of day two my batteries were at 11.75 I was very happy with that test.
The other test was my cranking battery. I left Key west for Tampa and had been doing allot of motoring for three days in the calm water they get down in Conch ville and thought I should charge the battery for the engine since we were crossing some open water. When we arived at our destination I found that the wire to the battery from the ALT had been left undone while doing some other maintanance ( the wites to the AGM''s were still connected). So the battery still had lots of juice reading at 12.45, so it had only used a very small amount of juice in about six days.I will would like to have all three batteries AGM''s but sometimes the pocket has a hole in it where the money falls out, Or is it that the boat just suckes it out hole or not.


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