Dead Battery

KZW

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May 17, 2014
831
Catalina 310 #307 Bluewater Bay, FL
Curt, as JK said, go with the four Duracell golf cart batteries. Replace the OEM dumb charger with a smart charger. Take the lid off the battery compartment for easy access. You will need to change up the bracing a bit. Be advised the conduit for the charger wire under the rear bunk splits under the bunk (at least on my boat) you will need to feed the charger wire, then lift up the bunk and pass the wire into the conduit that runs under the deck next to the head and into the battery compartment. The wire on my charger wasn't long enough.
The hardest part about swapping out the batteries is lifting those 4Ds and getting them off the boat. They are unbelievably heavy.
I made a template of the batters, went to the local West Marine, used their heavy duty crimpers, and made the connection cables in the store. They folks in the store were most helpful!
You will be very glad you did this mod. I am not a mechanic and managed the whole thing in an afternoon. A person who knows what they are doing (not me) could do it in less than two hours. Serious cruisers may add an engine starting battery, separate from the four golf cart batteries. That is the ultimate way to go, but I've not had an issue with my casual cruising.
The only big draw on my boat is the refrigerator. All interior and exterior lights are LEDs.
 
Oct 3, 2011
825
Anam Cara Catalina 310 Hull #155 155 Lake Erie/Catawba Island
If Curt replaces his two 4D batteries with two 4D batteries-from flooded to gel does he replace the OEM charger?
If he goes from 2 4D flooded batteries to 4 GC gel batteries, does he replace the charger?
aside from changing the designation on the charger.
We have two interstate gel batteries 4D that are at least 7 years old- weigh 97 Lbs each, each produce 1250 Amps with 295 reserve capacity. They are also aligned correctly according to MaineSail. (Bow to Stern)
Each battery is $234.
Like KZW we only really draw our fridge and VHF the rest of our lights are all LED except steaming light (Only use that when you are running anyway)
and we are plugged in at a dock most of the time, when not sailing or anchoring-small percentage of the time.
 
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Nov 18, 2010
2,441
Catalina 310 Hingham, MA
If Curt replaces his two 4D batteries with two 4D batteries-from flooded to gel does he replace the OEM charger?
If he goes from 2 4D flooded batteries to 4 GC gel batteries, does he replace the charger?
aside from changing the designation on the charger.
In short, yes. The original Flyback charger is a "dumb"-smart charger. Its essentially the "egg timer" charger that MS has talked about before. So upgrading the charger, if you use it often, is definitely worth it.

We have two interstate gel batteries 4D that are at least 7 years old- weigh 97 Lbs each, each produce 1250 Amps with 295 reserve capacity. They are also aligned correctly according to MaineSail. (Bow to Stern)
Gel and AGM batteries don't have to be aligned. That's one of the benefits of them.

I am not aware of Interstate making any gel batteries. But I could be off.

As far as the specs you are quoting, 1250 Amps is actually the Cranking Amps and doesn't matter much for small diesels like ours. The 295 reserve capacity is at 25 amp draw. This is not what you want to look at. From MS's post on deep cycle batteries, "Ampere Hours (Ah's) and Reserve Capacity / Reserve Minutes (RC) are not one in the same nor are they interchangeable. You buy house bank cycling batteries based on the Ampere Hour rating at the 20 hour rate not the Reserve Capacity or Reserve Minutes rating."

For the Interstate 4D batteries, the Ah ratings I have seen published are 150-160 Ah (so only 75-80 Ah usable capacity). So for comparison, 2 of the EGC-2 Duracell batteries from Sam's Club (Deka batteries with a different sticker) wired in series for 12 volt will give you a capacity of 230 Ah (115 Ah usable capacity). Again, you can put 4 of the golf cart batteries in the same footprint as the 2 4D batteries with the proper orientation. So you can be simple and keep the two banks as its setup and just gain the Ah in each bank or get more involved and make one large bank of golf cart batteries and then a reserve bank of a Group 24 or something similar.

To be honest, I have eliminated my reserve bank temporarily. My Group 24 was bad so I just didn't install a reserve bank. I purchased a small lithium ion jumper pack and I can actually start my boat off just the jump pack. I will add a reserve bank again when we get ready to leave STT to cruise some more.

Each battery is $234.
The Duracells are $118 each in Boston, so more Ah for the same price.
 
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May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
If he goes from 2 4D flooded batteries to 4 GC gel batteries, does he replace the charger?
aside from changing the designation on the charger.
[/QUOTE]

Most people don’t and don’t get the full life out of them. And don’t forget the alternator charge profile it needs to be changed also

[WUOTE]Q
We have two interstate gel batteries 4D that are at least 7 years old- weigh 97 Lbs each, each produce 1250 Amps with 295 reserve capacity. They are also aligned correctly according to MaineSail. (Bow to Stern)
[/QUOTE]
Go reread the article. I believe he advocates Port-Starboard

Les
 
Nov 16, 2012
1,037
Catalina 310, 2000, #31 31 Santa Cruz
If he goes from 2 4D flooded batteries to 4 GC gel batteries, does he replace the charger?
aside from changing the designation on the charger.

Most people don’t and don’t get the full life out of them. And don’t forget the alternator charge profile it needs to be changed also

[WUOTE]Q
We have two interstate gel batteries 4D that are at least 7 years old- weigh 97 Lbs each, each produce 1250 Amps with 295 reserve capacity. They are also aligned correctly according to MaineSail. (Bow to Stern)
Go reread the article. I believe he advocates Port-Starboard

Les
Les, most flooded batteries are better Port to Starboard, but the 4D (and 8D) are special, and ideally should be bow to stern. But in Alan's case they are gel batteries, so the orientation doesn't matter (like Jessie said), although I don't know how he got 4Ds to fit that way in the C310!

Unless Curt (or a PO) has upgraded the alternator it probably doesn't have a charge profile.
 
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Feb 6, 1998
11,665
Canadian Sailcraft 36T Casco Bay, ME
Unless you plan a major upgrade to the charging system, GEL's are not the way to go. GEL batteries are tremendous cycling batteries (speaking specifically in regards to Sonneschein & East Penn) but they need the right charge voltage if you want the life expectancy you paid for.
 
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Oct 3, 2011
825
Anam Cara Catalina 310 Hull #155 155 Lake Erie/Catawba Island
Is Curt going to have to change his Alternator/regulater?
Mainesail has a great battery charger.
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
If your running Gels doing both charger and voltage regulator is required for getting the most out of them. Depending on the alternator (availability of a regulator delete kit) you might also have to replace it also. Balmar alternators have a special internal regulator that plays nice with an external max charge VR - so removing the internal one is not necessary.

Les
 
Oct 3, 2011
825
Anam Cara Catalina 310 Hull #155 155 Lake Erie/Catawba Island
Thanks, I hope I have not hijacked the thread but helped Curt answer some questions he might not have asked and it has helped me also.
Thanks again