Short term smart solution, or false economy?

[GILow]

Hello Electrical Cruising types,

I have a medium term electrical plan for our boat, based on a lot of reading, thinking and testing.

The plan assumes we will do some serious coastal cruising in, maybe, three or four years, and until then it's all weekender stuff with the odd, very infrequent, longer journey of a few weeks to a month. Our boat has relatively light power consumption, the fridge/freezer is a very efficient compressor type, the autopilot will mainly give way to windvane, lighting has all been converted to LED (interior and navigation), no power winches, one electric anchor windlass, basic electronic instruments and a mid sized chart plotter.

Our current, 5 year old, 400AH battery bank is pretty well kaput, thanks to being left on a $20 battery charger for a year or more. It has a useable capacity in the realm of 20 - 30AH at most which I can get away with for day sailing only.

My electrical plan is for (up to) 400AH of Lithium batteries, combined with 300W of solar with suitable MPPT controller, our existing Aerogen 6 wind generator and the currently fitted good quality 100Amp alternator. The engine, FWIW, is 24V and has its own alternator and battery bank. (This means, whatever house bank I create must be able to be reconfigured to provide 24V for emergency starting.)

Now, in the middle of this, a reasonably reputable supplier has just advertised 220AH 12V flooded Lead Acid batteries on their site for $289, and I am asking myself, given my timelines, if it would be smart to put two of those in now, with the existing setup (Approx 100W of solar with a PWM controller, the Aerogen, the 100Amp alternator and a good quality shore charger)

Is it a false economy, I wonder, to use this cheap flooded bank till we get "serious" and maybe also get a lower price on the Lithium bank later, but at least not worry about ruining a good battery bank from it sitting at the pen unused all week.

Thoughts...?

Matt

[raybobsky]

my employer has determined it is not cost effective to replace the sealed deep cycle batteries and instead getting better reliability for less money with a simple lead acid battery. couldn't believe it but I have seen the results.


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[skipmac]

Hi GILow

First some advise. Splurge and get the $25 charger and your batteries will last longer.

So what kind of lithium battery? There are several different varieties. Are you referring to LiFePO or some other lithium chemistry? Regardless, all of them are a really big investment up front. The advocates say the with the greater usable capacity and additional charge cycles they are cost effective but the thousands up front make me nervous.

I think LiFePO is great technology and at some time may switch but I have too many other boat projects to work on for now and I am just not willing to take the time it really needs to learn the proper care and feeding of a LiFePO battery bank. The technology is definitely not plug and play, install and forget it. Try that and you may be in for a very expensive lesson.,

I just went through the same decision process and decided to stay with FLA for now. Not sure what options you have in Oz but in the states I went with 6 X 6V 220 amp hour golf cart batteries. Cost $90 each so $180 for 220 amp hours at 12V. A little more wiring to connect but a whole lot easier to handle than the 12V monsters.

[skipmac]

Originally Posted by raybobsky

my employer has determined it is not cost effective to replace the sealed deep cycle batteries and instead getting better reliability for less money with a simple lead acid battery. couldn't believe it but I have seen the results.

Not sure what you mean by a simple lead acid battery. Do you mean a regular acid filled lead battery just not deep cycle? What's the application your employer uses them for?

[MarkJ]

Get the cheap bank now because in 3 or 4 years time they will be shot and the good batteries will be cheaper.

[roverhi]

Just paid $89 for 6 volt, 220 amp golf cart batteries at Costco. Know there seems to be an Oz tax on everything for the privilege of forever being upside down but would think there would be cheaper batteries than what you are contemplating. If you get even occasional winds into the 20k range and a little sun, seems like your wind gen/solar would keep the batteries charged until you can spring for more solar panels if you are talking just weakend use.

I'd go for the golf cart batteries for ease of schlepping. Just replaced two on my boat and wouldn't want to have lifted more weight than each of those batteries onto the boat from the dinghy. For 24v you'll need to wire four in parallel but you'd need that many to get 440 amps at 12v. Can't see why anyone would go with a 4D or 8D 12v battery unless they know they will never have to move them around.

[GILow]

Originally Posted by skipmac

Hi GILow

First some advise. Splurge and get the $25 charger and your batteries will last longer.

Yeah, seriously, what a tragedy. The PO put in 400AH combo of AGM and Lead/Cadmium (? I think it was Cadmium). Must have cost him around AU$1000 at the time. Regardless of the pros and cons of combining the two chemistries, he then went to Bunnings and bought the $20 charger and left it connected all year round.

That charger is now in the shed where it is borrowed from time to time by neighbours who forgot to turn off their car interior lights.

The new charger is a tad more sophisticated... and cost rather a LOT more than $20.

Matt

[GILow]

Originally Posted by MarkJ

Get the cheap bank now because in 3 or 4 years time they will be shot and the good batteries will be cheaper.

This is sort of what I was wondering, but whenever I see a cheap solution that looks attractive, I feel I am just kidding myself. So that's one vote at least in favour.

[kmacdonald]

I vote for 4 6V golf cart batteries from Sams. If you are a weekend sailor they will last a least 5 years.

[GILow]

Originally Posted by roverhi

Just paid $89 for 6 volt, 220 amp golf cart batteries at Costco. Know there seems to be an Oz tax on everything for the privilege of forever being upside down but would think there would be cheaper batteries than what you are contemplating. If you get even occasional winds into the 20k range and a little sun, seems like your wind gen/solar would keep the batteries charged until you can spring for more solar panels if you are talking just weakend use.

I'd go for the golf cart batteries for ease of schlepping. Just replaced two on my boat and wouldn't want to have lifted more weight than each of those batteries onto the boat from the dinghy. For 24v you'll need to wire four in parallel but you'd need that many to get 440 amps at 12v. Can't see why anyone would go with a 4D or 8D 12v battery unless they know they will never have to move them around.

I'll double check the prices, but things in Oz are a tad pricey, AU$289 for 220AH from a reputable supplier is as good as I have seen for a while.

I am interested that you seem to be feeling that 300W of solar is not enough?

Matt

[skipmac]

Originally Posted by kmacdonald

I vote for 4 6V golf cart batteries from Sams. If you are a weekend sailor they will last a least 5 years.

I vote the same but they don't have a Sams in Australia.

[roverhi]

Have 260 watts of solar. On the sail from SF, had overcast for 10 plus days and 220 amps of battery got down to 12volts before the sun began to shine. Even then, they were slow to charge the batteries back up. Ran a plotter and AIS 24/7, occasional use of computer and Ham radio, lights are all LED, no refrigeration. If you always sail where it's sunny and your ice box is well insulated, might get by with 300 watts of solar especially in conjunction with the wind gen.

[GILow]

Hmmmm. Relevant stats there thank you. 300 watts is real easy on our boat. Any more gets tricky.


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[Stumble]

I would go with the cheapest FLA's you can get for now, and wouldn't add solar right now. Particularly since you know in a few years you will need to completely reconfigure the electrical system in a few years. Instead I would get a really good battery monitor and really work out what your consumption is over the next few years.

This way in a few years when you do the major upgrade you will have a base of good information, and it won't hurt so much to toss away the stuff you have. And a few years down the road the price for LIFEPO's and solar cells should be a good bit cheaper than they are today.

[GILow]

Originally Posted by skipmac

...I think LiFePO is great technology and at some time may switch but I have too many other boat projects to work on for now and I am just not willing to take the time it really needs to learn the proper care and feeding of a LiFePO battery bank. The technology is definitely not plug and play, install and forget it. Try that and you may be in for a very expensive lesson.,

I just went through the same decision process and decided to stay with FLA for now. Not sure what options you have in Oz but in the states I went with 6 X 6V 220 amp hour golf cart batteries. Cost $90 each so $180 for 220 amp hours at 12V. A little more wiring to connect but a whole lot easier to handle than the 12V monsters.

Thanks Skipmac, it seems that you are advocating holding off on the Lithium for now.

The economics are a bit different for me, mainly because everything is so darn expensive here. If I could buy at your prices it would be a no brainer for me, I'd get the golf cart batteries or equivalent, as you suggest, and then look at replacing them later IF Lithium looks attractive. As it is, the price on the FLA was as good as I have seen in a while, and does make me think its the way to go.

At least now, what I am doing, is ensuring each new component I purchase is compatible with Lithium chemistry, so at least I will have the option of going that way later.

Matt