Not your typical battery question

thetoddjohnson

I've seen many threads where people have been advised that they are trying to use batteries that are not appropriate for golf carts. I have the opposite question. Would a golf cart battery be an appropriate battery for use as the house battery on a boat? I have a 2 year old boat and the house battery (the one that is used to power the lights, VHF, chartplotter, GPS, etc) is dead. The other battery is exclusively used to start the engine, and that battery is fine. Both batteries are the same. (Deka Marine Master 27M6) I’m thinking that the house battery should be a deep cycle, wet cell, battery, rather than one that has "high reserve starting capacity".

Any thoughts?

TJ

BGW

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scottyb

Keep in mind the charging needs of a GC battery - you will need a golf cart charger or similar algorithm.

93yellowclubcar

Get an RV battery. They're deep cycle wet cell batteries that are made for doing way more than what you're describing, should work nicely for your house battery.

pachanga90

Yep,They always use Marine Deep-Cycles for "House-Batteries",since they get drawn-down and recharged often.This cycling will ruin a cranking-battery.

sunking

Golf cart batteries are default standard for RV's/boats (house batteries), and renewable energy applications.

There are basically 3 categories of lead acid batteries.

SLI aka Cranking batteries are constructed with multiple thin sponge like texture plates to maximize surface and minimize internal resistance. That allows a starting battery to deliver very high Cranking Amps and very high charge rates. If pressed into cycle service the plates corrode quicly and you may get 50 cycles if you are lucky.

Deep Cycle and I mean a true Deep Cycle batteries high thick heavy plates that enables them to be cycles many many times. Some of the high end batteries like Rolls can get up to 5000 cycles to 50% DOD. The down side to a true Deep Cycle is the plate construction results in higher internal resistance which limits it current discharge and charge rates. Typically C/8 where C = the battery 20 hour rated capacity. So for a 225 AH battery you only can take around 30 amps. You can certainly discharge at a higher rate but the voltage will collapse.

Hybrid Batteries try to be both SLI and Deep Cycle. It cannot do the job as well as its counter part, rather a trade-off between the two. This is what your golf cart battery is a HYBRID. It has other marketing names it goes by like Marine Deep Cycle, RV, Leisure, and Floor Machine. All are hybrids with a Marketing Names.

Now for you Trojan fans who will swear the T-105 is a Deep Cycle consider this. Trojan also makes a T-105RE battery which is a true Deep Cycle Battery. Two important differences between the two batteries. The T-105RE weighs 67 pounds vs 62 for the T-105 which means the T-105RE has heavier thicker plates for longer cycle life. Second point is warranty for the T-105RE is 24/60 vs 12/24 for the T-105.

But do not go off and use a T-105RE in your cart. You will not be happy because it is not a hybrid that can deliver those high start-up currents the motor pulls at low speeds while accelerating from stop to cruise.

Now if you really want High Torque, use a 6 volt AGM 200 AH batteries. You wil have a stronger cart using AGM vs Flooded. The reason as I alluded to earlier. Internal Resistance. AGM batteries have a much lower internal resistance which means more current and less voltage sag. Not only will you gain torque, but a little extra speed because the voltage runs a little higher without sag you get from flooded batteries. The ultimate today though if you can afford them is LiFeP04 aka LFP EV batteries.

Andy4639

sunking

Depends on the size of the boat. Get into larger boats like a ship, and you will see 2 volt 3000 AH cells configured for 12 and 24 volts.

Don't get any ideas, those 2 volt 3000 AH batteries weigh 285 pounds each.

In the Navy on the sub I served on had 200 2-volt 6000 AH cells configured for 400 volts to get us to the surface in the event the fire went out in the reactor.

hookm

What he said,a good deep cycle will last a long time.Get a battery swich if you don't have one & charge it while you're running,then swich it to the starting battery when you get to your destination

Andy4639

Wylie_Tunes

I see that this question is a few months old, but i wanted to offer some thoughts since its right up my alley.

If your goal is to spend any amount of time powering house loads while at anchor, a deep-cycle will absolutely do a better job then a cranking battery.

You would need 2 6V GC's wired in series in order to get a usable 12V for your house loads. This is a great way to go if you have space and your budget allows. But, before making that decision, you need to figure out how many Ah is needed to do the job. Whats your average load and how long do you need to battery to last, staying above 12V. 2 or more batteries cycled shallower, last longer then a single cycled deeper.

The next thing to consider is your dual battery setup: how is it configured, type of switch you have and do you have an on-board battery charger. The later is very important in regards to battery life. Alternators make for poor battery chargers. When depleting a house battery while at anchor, you should rely on shore charging to replenish it, NOT the alternator.