Batteries

NoGin · Jul 21, 2009

I need to replace my 4 batteries on board as they are all dead!

Here is a quick synopsis of my needs:

*29 foot Thompson with twin Mercs
*I am on a mooring
*Use approx 60 amp hours on a typical day trip
*Use approx 100 amp hours on a late evening trip
*Overnight trips will be at a slip with shore power and my house battery charger maintaining the batteries
*I run GPS/Chartplotter, Radar, refrigerator,water pump, radio, then your typical bilge pumps and blower as needed plus nav/interior lights after sun down.

1. Do I really need 4 batteries?
2. What size batteries should I have?
2. What brand names do you recommend?

Thanks guys!

NoGin · Jul 21, 2009

Re: Batteries

Bump ~ Need advice asap as I want to go buy the batteries today and get her going!

JustJason · Jul 21, 2009

Re: Batteries

I think you should go and get your charging system fixed/converted before you shell out 400 bucks for batteries.
If you just need to get an engine going for testing, buy 1 maring starting battery.
There's 100 different ways you can configure your batteries. If it were me I would do 2 starting batterys, 2 deep cycles, 2 isolators, 2 1/2 all off switches for the starting batterys and maybe 2 on/off switches for the deep cycles.
Buy the biggest ones you can afford/fit in the boat.
But really, I know what you said about the $60 meter, getting these engines to charge the batt's is going to be pricey.

NoGin · Jul 21, 2009

Re: Batteries

I don't mind shelling out the dough for good parts. I do have a problem shelling out big dough for tools that I will just use for this one time and maybe again in the future. I am not a mechanic and don't pretend to be. I will invest what ever money it takes to make my boat the best it can be.

Do you think my charging system isn't working or maybe that my batteries and 75% of all cells are dead which is why they weren't taking the charge?

NoGin · Jul 21, 2009

Re: Batteries

Heard from many people not to mix different kinds of batteries rather to stick with all deep cycle batteries ? ? ? ?

NoGin · Jul 21, 2009

Re: Batteries

Just got a quote from a local marine supplier for the Deka Group 31 Deep Cycle battery for $150.00 each. Is that good? He said I can run well with just 2. ? ?

JustJason · Jul 21, 2009

Re: Batteries

You don't want to be starting your engines with a deep cycle, it's a sure way to kill a new battery.
You also don't want to use a starting battery to run accessories for a long time, they will do it, but deep cycles are designed to do it better.
Yes you can mix and match.

Do you think my charging system isn't working or maybe that my batteries and 75% of all cells are dead which is why they weren't taking the charge?

I don't know... I'm not in front of the boat.

I do know this though... if you have a dead battery, you can jumpstart the boat with a good battery and then take it away and let it run on the dead one. If you put your meter on the battery and you get less than 14VDC you have a charging issues, good battery or bad.
If you get 14 VDC then the charging system is working, wether the battery is taking the charge or not.

rbh · Jul 21, 2009

Re: Batteries

good morning joe-
replace your dead and dieing batteries with a good group 27 battery (deep cycle) as your old batteries will pull down the new ones.
rob

NoGin · Jul 21, 2009

Re: Batteries

Thanks guys.

JustJason - Great info on the charging system. I had no idea that the batteries should show 14 while the boat is running even though the batteries are bad. That being the case, my charging system is definately not working!

Is Deka a good brand? I am also looking into the Interstate batteries...

NoGin · Jul 21, 2009

Re: Batteries

Time for a good laugh! Amateur hour is upon us...

This is how I have the batteries set up now but with all deep cycle. Is this how I should keep them having the deep cycle and cranking batteries jumped together?

bruceb58 · Jul 21, 2009

Re: Batteries

Personally, I would have a start battery for each engine and a set of 6V Trojan deep cycle batteries in series hooked up to one/both engines with ACRs(automatic charge relays). These batteries would be your house batteries and you would have at least just your refer on these. You don't ever want to discharge a battery more than 50%. If you are pulling 100 amp hours, you need a 200 amp hour capacity.

A 27 series deep discharge battery is just not going to cut it if you really have a 100 amphour draw. 27 series batteries are in the neighborhood of 75 Ahr...maybe. Even with two in parallel you wouldn't want to draw more than 75 at a time.

If it were me, I would get two of these and put them in series:
http://www.batteriesinaflash.com/in...nfo&products_id=4010&language=en&currency=USD

This would be a way to hook up.
http://bluesea.com/viewresource/685
In your case, don't use the switch or battery on the left. The house battery would be two 6V in series(Trojan 6V) or 2 12V batteries in parallel. This shows an ACR between the house and the one engine. You can add a second ACR to the other engine for more charge capacity but that depends a lot on the output of your alternator.

You also need an onboard charger to charge them up when you get home.

NoGin · Jul 21, 2009

Re: Batteries

Thanks Bruce. Someone else told me to use these 6 volt go-kart type batteries in series for the house. I actually just got off the phone with Deka. They recommended using 2 cranking batteries which are a 24 series at 820 MCA and 2 of their largest group 31 batteries rated at 105 ah @20amps.

The Deka deep cycles are $141 each. How are the trojans?

bruceb58 · Jul 21, 2009

Re: Batteries

Trojans are expensive but worth it. You just have to keep on top of them and keep the water up in them and they will last a long time. Also, don't discharge them over 50% but that goes for any battery. Typically, 12V is the point at which a battery is at 50%.

Two 6V is preferred over 2 12V in parallel.

I updated my previous post so take a look at it.

rbh · Jul 21, 2009

Re: Batteries

Joe-
the batteries are not going to run all your appliances for a long time that is why you have a ac generator or you run the engine that has the house side hooked up.
rob

NoGin · Jul 21, 2009

Re: Batteries

No Trojan distributors on Long Island.

bruceb58 · Jul 21, 2009

Re: Batteries

Talk to RV or golf cart distributors in your area. Golf cart distributors are your best bet becuase they have more volume than anyone.

Did you call up Trojan directly?

NoGin · Jul 21, 2009

Re: Batteries

bruceb58 said:
Talk to RV or golf cart distributors in your area. Golf cart distributors are your best bet becuase they have more volume than anyone.

Did you call up Trojan directly?

Great advice Bruce! Just go off the horn with a local golf kart shop who has the T 105 in stock for $124 ea. ! think I will go with 2 of these and 2 of the Deka cranking batteries. What do you think?

bruceb58 · Jul 21, 2009

Re: Batteries

I think that is great. Now you just need to get cables and switches to hook all of this up. Don't wire it up like you had it shown. They all need to be isolated through switches. Then use an ACR to get the house battery charged. Don't use a diode based isolator or you will never get those Trojans charged all the way and you will be buying new batteries in a couple years.

bruceb58 · Jul 21, 2009

Re: Batteries

If you want to get some cables made at good prices, get them from this guy on ebay. I have had many cables made up by him.

http://shop.ebay.com/merchant/genuinedealz_W0QQ_dmdZ1QQ_ipgZ50QQ_sopZ12?_rdc=1

NoGin · Jul 21, 2009

Re: Batteries

I currently have 2 battery switches of which one is heavy duty. The diagram you sent me has 3 battery switches. Should I use my 2 and add another? Any suggestions with isolators?

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