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-   -   What be a high capacity battery, and which with thickest plates? (http://www.cruisersforum.com/forums/f14/what-be-a-high-capacity-battery-and-which-with-thickest-plates-144406.html)

tat 12-04-2015 08:45

What be a high capacity battery, and which with thickest plates?
 
I'm looking to buy a flooded deep-cycle battery.

Although I will not use a lot of amps, usually, I want a high capacity battery so that I will not need to discharge it much before I am able to recharge it (with a Honda 900watt silent generator and a 40amp unsmart charger), so it will mean I will have the capacity if I need it, but be able to keep it in good shape as I will not drain it too deep, usually.

So what would be a high capacity battery?

Also, I want to get a battery with the thickest plates. Do you know? How would I know, please?

Cheechako 12-04-2015 09:10

Re: What be a high capacity battery, and which with thickest plates?
 
You may be overthinking it, but generally I think golf cart batteries have thick plates. But they are 6 volt so it takes 2. A good deep cycle battery will have "thick" plates. Only way I know to tell would be to compare weights. Each time a battery is discharged and charged it gives off some of it's plate material. So deep cycle batteries have thick plates apparently...(all second hand knowledge).... But you say you don't intend to discharge it much, so if that's the case... not sure you need a deep cycle battery...

Andina Marie 12-04-2015 09:14

Re: What be a high capacity battery, and which with thickest plates?
 
Once upon a time battery manufacturers would specify the amp-hour capacity of their batteries, even though the capacity is a function of load. Sift through their specs and purchase the largest capacity they appear to have for the space and weight you have available. The "deeper" the cycle the thicker the plates but that is all you can use for a guide, they don't give internal specifications.

goboatingnow 12-04-2015 09:43

Re: What be a high capacity battery, and which with thickest plates?
 
Tubular traction batteries are best, but very pricey. After that it's a crap shoot


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newhaul 12-04-2015 09:44

Re: What be a high capacity battery, and which with thickest plates?
 
Two 6v golf cart batteries is m2cw will give you about 200 ah for about 100 ah usable and the thickest plates for the money. Golf shops sell used ones with 80% of life left in them for less than half of new units ( usually less than a year old)

denverd0n 13-04-2015 05:20

Re: What be a high capacity battery, and which with thickest plates?
 
You need to start by getting some concept of your electrical usage. "What would be a high capacity battery" depends entirely on how much you need/want to use. If you are only powering a few LED lights then what constitutes a "high capacity battery" for you will be completely different than for someone who runs lights, a stereo, full suite of instruments, an electric head, pressure water system, a refrigerator, and so on.

sainted 13-04-2015 07:56

Re: What be a high capacity battery, and which with thickest plates?
 
Generally, Trojan T105 6V golf cart batteries give the biggest bang for the buck. They have a capacity of 225 amp hours and will last for years if properly maintained (keep distilled water in them and keep them charged).

In my neck of the woods, they sell for about $120 per battery at my local golf cart shop. You can get them delivered for about $150 per.

A previous poster is certainly right, too, that you need to know your electrical demand to properly size your battery bank. A 225 amp bank (two six volt T105s wired in series) will give you about 110 amp hours if discharged to 50%, the recommended discharge level before charging. Two banks will obviously double that.

Best of luck.

Isabella Jane 17-04-2015 19:02

Re: What be a high capacity battery, and which with thickest plates?
 
Something that has bothered me for a while: how do I know what percentage discharge my 100 Ahr deep cycle battery is when it's voltage is say,11.8? What's the lowest voltage I should allow?
Sorry if this off topic but I hope it is a relevant question here.
Thanks!
Pete
On the Gippsland Lakes,
Australia

Roy M 17-04-2015 19:24

Re: What be a high capacity battery, and which with thickest plates?
 
2 Attachment(s)
I use 4 six volt batteries in my house bank. They are the L16 style which means they are TALL, around 18" with the special Hydrocaps which convert the produced gases from charging back into water to reduce maintenance. This format gives me a nominal 740 amphours. I chose this so as to have a sufficient capacity to allow me to have a substantial reefer and freezer. Ideally, you don't want to use more than one-half of your battery capacity in order to get the best longevity from your bank. I have a separate battery for my engine start and windlass draw.

newhaul 17-04-2015 19:56

Re: What be a high capacity battery, and which with thickest plates?
 
Quote:

Originally Posted by Isabella Jane (Post 1803270)
Something that has bothered me for a while: how do I know what percentage discharge my 100 Ahr deep cycle battery is when it's voltage is say,11.8? What's the lowest voltage I should allow?
Sorry if this off topic but I hope it is a relevant question here.
Thanks!
Pete
On the Gippsland Lakes,
Australia

Here's a chart to help answer your questions http://i168.photobucket.com/albums/u...2Dec051817.gif hope it helps

Isabella Jane 17-04-2015 23:42

Re: What be a high capacity battery, and which with thickest plates?
 
Thanks Newhaul. Just what I needed. Appreciate your help to a (very) newby.
Cheers from me!

newhaul 18-04-2015 07:01

Re: What be a high capacity battery, and which with thickest plates?
 
Quote:

Originally Posted by Isabella Jane (Post 1803330)
Thanks Newhaul. Just what I needed. Appreciate your help to a (very) newby.
Cheers from me!

Being a newby is nothing to scoff at my last name is Newby and I used to own a small trucking company ( newby hauling) aka newhaul. And you are very welcome. Glad to help when I can.
One thing I forgot to mention take the voltage readings with at least a 30 minute rest period after heavy use or charging to allow the voltage to stabilize ( large load items like a refer or autopilot)

tat 18-04-2015 22:35

Re: What be a high capacity battery, and which with thickest plates?
 
Quote:

Originally Posted by Isabella Jane (Post 1803270)
Something that has bothered me for a while: how do I know what percentage discharge my 100 Ahr deep cycle battery is when it's voltage is say,11.8? What's the lowest voltage I should allow?
Sorry if this off topic but I hope it is a relevant question here.
Thanks!
Pete
On the Gippsland Lakes,
Australia

This is what i wanted to know, and in a book I found a table. Like the link posted, it shows the rested state of charge and the capacity %, but also seems to show the state of charge when the batteries are/have been in use. The rested charge is just to see if you have charged them enough. But we also need to know how much we have got left in them before we need to charge again.

It was a table in the book called Essential Boat Electrics by Pat Manley. I've just 'looked inside' on Amazon and near the back in the useful tables is the chart for this. I'm going to cut it out and stick it next to the volt/amp meter.

For instance, the rested figure is 12.8v for 100%, but 100% after a few days is actually 12.5v. It is the 'after a few days' capacity we need, not just the rested after charging figure.

According to this chart in the book, your battery, reading 11.8 volts, if not a load on it when you took the voltage would be down to 30% capacity. The chart recommends that you should re-charge at 50%, which is a reading of 12.0v. Or, if you had a 5amp load on it when you read it, then 11.9v, or if you had a 10amp load on it when you read it, then 11.7v.

Cheechako 19-04-2015 08:17

Re: What be a high capacity battery, and which with thickest plates?
 
It's all over an internet search:

darylat8750 19-04-2015 08:37

Re: What be a high capacity battery, and which with thickest plates?
 
http://www.cruisersforum.com/forums/...1&d=1429456625

This is the chart I have by my volt meter. However I colored it yellow at 12.06 volts. Any one on the boat knows that we want to do something about it before it gets to yellow.

As others have stated you need to figure out your usage.

Best value in deep cycle batteries seem to be Duracell 6 volt golf cart batteries at Sam's Club if you live in a state where Sam's carries them.


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