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Boat batteries

Old 06-10-2019, 06:25 AM
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Default Boat batteries

Boat that I bought has two 12 volt cranking batteries. One is also used as the house battery supplying power to lights, fish finder, radar, etc...shouldn’t the house battery be at least a dual purpose battery or deep cycle?
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Old 06-10-2019, 06:29 AM
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Yes. One should be deep cycle, (house), and the other cranking. Just be sure both batteries are the same..ie: glass mat, gel, etc. You do not want to mix battery types.
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Old 06-10-2019, 06:31 AM
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Originally Posted by tmise View Post
Boat that I bought has two 12 volt cranking batteries. One is also used as the house battery supplying power to lights, fish finder, radar, etc...shouldn’t the house battery be at least a dual purpose battery or deep cycle?
https://www.thehulltruth.com/search.php
https://www.westmarine.com/WestAdvis...torage-Battery

short version: you need to make sure your engine has what it needs. some engines can be damaged by incorrect battery/specs. best to have a separate house bank and starting bank, ability to parallel. on a smaller boat that may not make sense though. since you have radar this doesnt sound like a small boat. i would review your setup.
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Old 06-10-2019, 07:15 AM
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Mystery has it. Check your motor guidelines.
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Old 06-10-2019, 07:44 AM
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Originally Posted by mystery View Post
https://www.thehulltruth.com/search.php
https://www.westmarine.com/WestAdvis...torage-Battery

short version: you need to make sure your engine has what it needs. some engines can be damaged by incorrect battery/specs. best to have a separate house bank and starting bank, ability to parallel. on a smaller boat that may not make sense though. since you have radar this doesnt sound like a small boat. i would review your setup.
Boat is a 20’ cc with a 4.3 liter V6 stern drive. There is a battery selector switch.
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Old 06-10-2019, 09:16 AM
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Personally, I would want two batteries that each one, alone meets the engines starting requirements. After that is met a deep cycle is preferred.
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Old 06-10-2019, 09:22 AM
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Originally Posted by D.M.D. View Post
Just be sure both batteries are the same..ie: glass mat, gel, etc. You do not want to mix battery types.
I think that is true if they are in the same bank, but house vs starting are two different banks.

In the same bank the battery characteristics would definitely affect the drain rate etc and could cause issues but in separate banks the drain rate etc is not relevant.
If this is not correct then please explain, why they would have to be the same type.
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Old 06-10-2019, 10:24 AM
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Originally Posted by whitey436 View Post
I think that is true if they are in the same bank, but house vs starting are two different banks.

In the same bank the battery characteristics would definitely affect the drain rate etc and could cause issues but in separate banks the drain rate etc is not relevant.
If this is not correct then please explain, why they would have to be the same type.
i think i have three or four different types of batteries on my boat

of course not mixed within a single bank

some chargers are OK charging different types
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Old 06-10-2019, 05:28 PM
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One starter battery, one deep cycle. Buy the dual battery switch from Blue Sea with combined power option in case of emergency can draw from both batteries to crank motor.
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Old 06-12-2019, 08:55 AM
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This is a timely post with similar question. My boat has twin 2011 F150s and is configured with 3 batteries, port, starboard and house. All three are flooded, cranking/starting batteries (spec'd from factory). Battery panel consists of a house switch and engine switch (both blue sea 6011). The boat has a number of electrical components (chartplotter, vhf, stereo, bilge, head, raw and fresh wash downs, livewell, lights). I've never had any issues with current configuration, but click-click-click is always on my mind if we spend a day at the sandbar.

Was planning to replace the house with deep cycle and was told by boat mfg that deep cycles are not made to be charged by the outboards and would need an onboard battery charger. boat is racked, so shore power is not an option.

Is it true that deep cycle batteries shouldn't be charged by outboards?
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Old 06-12-2019, 09:52 AM
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Originally Posted by jdibber View Post
Is it true that deep cycle batteries shouldn't be charged by outboards?
on its face, nonsense.
with separate cranking batteries for each engine,
using a cranking battery as a house battery is plain silly.

Presumably the engine Aux outputs go to the house battery?
A 'deep cycle' will accept charging current just the same as a cranking battery.
The outboard's alternator doesn't know the difference.

Now whether the house battery has time to get fully charged
during the trip back to rack storage after a day at the sandbar,
is another question.
But that is an issue regardless of battery "type".

By the way, if the batteries are properly arranged,
you shouldn't have to worry about "click-click-click"-
unless you change a switch to combine them,
your house load can't run down your engine cranking batteries.
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Old 06-12-2019, 02:41 PM
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Thanks, FWPRATT. So what is the typical setup in this case, where charging is dependent on the outboards (get a battery monitor and cruise around until 100%)?
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