What Battery Types to use for Bow Thrusters and Anchor Windlasses?

[NotCook]

OK, my anchor windlass batteries (2x12V for 124V) are not holding charge - seems reasonable, as they are at least 7 years old. They are size 27. I am not sure what is the right type of battery to replace them - Gel cell, AGM, Lead Acid, "Marine Battery", or what. Anyone know what is the right type for this kind of duty?

Same for Bow Thruster batteries? What is the right type for that duty?

I am NOT assuming what is in the boat now is the right type, hense my question.

Thanks! Brian

 

[Don S/V ILLusion]

Brian
given their age, your assumption is likely correct - time to replace. It would help to know how they are charged (size of charger, distance from charger, wiring gauge, etc. before assuming what batteries are best. For example, Gels and AGMs have somewhat different and critical charge voltage requirements distinct from that of wet cells so your best choice is also a function of what charger you have, if it is compatible with Gels/AGMs, what type batteries are used throughout the boat to avoid having to buy a new charger or alternatively have to replace all the other batteries.

Also, do the thruster and windlass run off the same batteries?

 

[NotCook]

It would help to know how they are charged (size of charger, distance from charger, wiring gauge, etc. before assuming what batteries are best. ...what type batteries are used throughout the boat to avoid having to buy a new charger or alternatively have to replace all the other batteries.

Also, do the thruster and windlass run off the same batteries?

Hi Don, Well, I have 8 batteries total. 2 4D Gel house batteries, on a Xantrex 3012 (30 Amp, 12V) charger (I should have got the 50 Amp. Won't make that mistake again.) Anyway, the various batteries are individually configured on the Zantrex. 14.1V for the Gels, 14.6 (? I think) for the lead acid starting batteries. You select the program appropriate to the respective battery.

The 24V sets are charged off their own 24V 30 Amp charger. There is a set for each. The bow thruster batteries are up by the bow thruster, and I have a 6AWG cable running up there from the charger - overkill for 24 V. So, no problem on getting the juice to the battery.

The anchor windlass batteries are in the engine room, about 45 feet away. Not sure what the cable is going to it. I'll have to check one of these days. But, it is 24V, so it doesn't need the same large guage as 12V (an advantage of 24V).

I am more concerned about what is the right type battery for the respective jobs. If the right battery requires a different charger, I'll get a different charger, just as I did for the new house batteries. So, my question is, what is the right battery type for those jobs?

 

[Ron20324]

Deep cycle.

 

[Don S/V ILLusion]

Brian
Nice to see someone asking for opinions who obviously already has done his homework.
I think you already know or can easily find for yourself what the various pros/cons are with each type battery and also probably know the answer is largely a matter of opinion as there is no single right or wrong answer.
If you are adverse to the routine inspection and maintenance wet cells require or have them in relatively inaccessible locations, your choice may be influenced by that. If, however, you have no issue with the above and want to be economical, the answer is equally obvious. None of the three types are uniquely suited to your intended uses or are any a bad choice.
Given the charging isource doesn't dictate type, it seems to me it all comes down to one thing - how fast do you want/need to recharge? If time is an issue, go with AGMs which can take a faster charge.

RON - all of them would be deep cycle

 

[Ron20324]

Well, Duh... according to his last sentence, apparently my answer was the only correct one in any of the replies even though it didn't answer his post.

 

[cat38skip]

Not to be tossing a boot into the works here and the 24V application may make my comments a moot point, but I was of the impression that for high amperage draw applications, a deep cycle battery is not the power source of choice, as they are designed to release power over a long period of time and can sustain a long deep discharge and recharge without damage. A starting battery or dual purpose marine battery is designed to release high amperage in short bursts without overheating. The drawback to the starting or dual purpose battery is that it cannot sustain a deep discharge and recharge without losing lifespan....Someone with some serious battery application and engineering experience please chime in !!!!

 

[Allan12210]

My .02 worth would be to agree with cat38skip about using starter batteries for the high amperage short duration draw. I would also combine the two banks into a series/parallel arangement still outputting 24V for both the bow thruster and windlass so usage would not pull the bank down appreciably, avoiding the lifespan problem.

Just for extra input, not related to your original question: With that 30A house/starter charger, I might consider putting all the outputs on the house bank to charge first, then use an echo charger or battery combiner to charge the starting bank when the house is full. Same for the alternator...directly to the house bank and let the combiner deal with the starter bank.

Allan

 

[alexco38]

The best way is to locate the batteries closer to the consumming equipment. You charge the batteries with much less current than the windlass and bow truster draws. The cable could be much smaller from the alternator (e.g. a 10 AWG) while the battery to the windlass and bow ctruster could be as big as a 0 or 1 AWG. I would use a welding or automotive starter cable to reduce voltage drop.

Shore power charger is cheap enough to use a dedicated one for the bow batteries. Definitly use a starter battery for those purpose. Again, put the charger near the batteries. There is less current thus less voltage drop on shore power cord.

Hope this help.

 

[NotCook]

Allan, I like the idea of being able to combine the two sets of 24V banks. I'll have to consider that. I haven't looked a lot at the echo charger approach. My main engine and genset starting batteries are sealed lead acid automotive starter batteries. would this still be effective, considering that the house batteries are gel? Also, I am not sure if I can connect my gel house batteries to the main engine alternator, though I have wanted to explore that. I'm afraid it would over voltage the gels. I do have an Hehr voltage regulator with the ability to adjust the voltage output. If I lowered it to 14.1, would it charge the start batteries to the appropriate full level?

Alexco38, I would think a small cable to the batteries 45' away would cause too much of a voltage drop, and would result in the batteries nto getting fully charged.

To be clear, my concerns are not related to be charged with shore power. My objective is extended cruising. We seldom spend time in a slip. Charging on teh hook or underway is usually accomplished from the 50 Amp 220V genset, or wind and solar (in any combination). Don, to your point, quick charging IS an important issue. The normal charing routine is to run the genset only for 1 hour in 24, to run the refridgeration. Unfortunately, it is all 110V.

It is sounding like I am looking at a choice of an automotive battery or an AGM.

Thanks for all the input so far.

 

[Don S/V ILLusion]

I have to disagree with the use of a start battery(ies) in this use. These batteries are designed for a specific purpose of short discharge intervals and prolonged recharge rates. Although a bow thruster might come close, adding the windlass draw which is fundamentally different than automobile battery technology is intended for plus the duty cycle of a windlass in use makes deep cycle designed batteries a much closer match.

As the biggest advantage AGMs have is their ability to accept huge bulk charging rates, it seems like this would be your best option if your budget allows.

 

[Don S/V ILLusion]

Upon further examination I would have to defer to Nigel Calder who recommends that the installation of a battery bank to operate the windlass/bow-thruster is flawed. The argument being that most of the time one operates those devises the engine is running. When the windlass is turned on the engine driven alternator will go into high output, resulting in high charging currents. Therefor the cables to the battery will need to be rated for the maximum output of the alternator. Thus the cables must be sized accordingly. He further cautions that the batteries up forward will see lower charge voltages with a resultant constant undercharge.

 

[NotCook]

Don, Good advice. In my case currently, my main engine alternator only services my main engine and genset starting batteries. I'll have to look into what it would take to have is service all 6 batteries other than the house gels. However, as Nigel Calder says, maybe I shouldn't have a separate bank for the windlass anyway...

Clearly, having so many different batteries for different purposes are a mixed blessing!

PS: I ran across another "Nigel Calder", other than the boating guru. He works at Sunforce, source of wind and solar power products. I was excited to be corresponding with "Nigel Calder", then he informed me that he was not "that" Nigel! I tried not to show TOO much disappointment in my response!