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svhoneybee 11-23-2012 09:58 AM

Lithium Batteries
The battery bank on Honey Bee is starting to get a bit tired and we are starting to investigate a replacement.

Lithium batteries (LiFePO4) are now getting to be comparable in price to some of the more common alternatives, the weight saving would be considerable and the life of the Lithium batteries is claimed to far exceed Lead Acid.

It looks as if we can get about 400 amp hours in Lithium for about $A2200. We have a friend who successfully uses them in his house (off grid).

Has anyone out there experimented with these? All relevant threads appear quite old and I think the technology may have moved on in the last few years. Comments?

Trim50 11-23-2012 10:59 PM

Lithium iron phosphate is great...just make sure it comes with a battery management system. Lithium cells can be over charged and catch on fire with out a BMS. Unlike lead acid, there isn't anywhere for the excess charge to go but into heat.

I worked for many years on lithium ion cells, and when they catch fire, you can't put the fire out with water or chemical. They will burn for many hours and will take your boat down with them. However, usage as house batteries is so low level c rate that the cells won't even know you are using them and they should last 10 or more years. Longevity really is the key charatistic that makes Li-Ion a good choice for marine house batteries. Just be sure you do your research and understand what a Li-Ion cell is and how it works before you go swapping from lead acid. Also make sure your solar charge controller has a setting for Li-Ion, else you will be risking a thermal event ;-)

svhoneybee 11-23-2012 11:41 PM

Thanks Trim. I also thought a good BMS was desirable, but got the following response from a retailer who specialises in electric vehicles and sells a good range of Li cells:
A complex BMS is not usually necessary on 12V system as there is only four cells in series so an individual low cell voltage will show up in the overall pack voltage. A low voltage cutoff can be used to protect the batteries from over discharge which is almost always the cause of damage to the LiFePO4 cells.

A 200Ah battery bank will be more than adequate for starting the engine, in most EV's we build, these cells are required to deliver 5C or 5 times their Ah rating which would be 1000A in your case.

You should check that all of the charging source voltages are below 14.5V and they do not have an equalization function set. If possible set chargers to AGM or Gel setting. It is a good idea to monitor cell voltages as they reach fully charged for the first time to ensure the cells are fairly closely balanced.
Also as LiFePO4 has a very flat discharge curve it is almost impossible to tell the state of charge from the voltage unless they are in the top or bottom 10% so some type of Ah counting meter is required if you wish to know how much charge you have left etc."

I might send your comments to him and see what he says. The battery bank is under our bunk and a "thermal event" would spoil my beauty sleep.

Trim50 11-23-2012 11:59 PM

Feel free to send my comments ;) Notice they didn't mention anything about over charge protection. It sounds like their position is that MOST chargers don't produce voltage above that of the Li-ion cell/pack. However, many cruisers attach their solar panels directly into their battery system without a charge controller. In my opinion you are playing with fire without overcharge protection.

FYI, I was working on Li-Ion before most people even knew what it was. We built some of the first cells for the US military and CIA back in early 1990s.

These guys have a good FAQ section:

Mind if I ask who's cells you are buying? Most battery pack builders are just that...they buy wholesale cells from China or Korea and integrate them into a pack. If they don't supply a BMS or VMS, I'd be very concerned about what I'm buying. As you know, a boat is not a car...a bad day at sea is almost always far worse than a bad day on the road.

Trim50 11-24-2012 02:27 AM

Oh yeah...I use Tojan 6V because I can replace them anywhere in the world. When cruising this should be one of your #1 concerns. My friend paid more than the cost of a First class ticket to get his AGMs flown into Fiji from NZ.

My Trojans are 5 years old and doing just fine. Proper care and maintenance is everything. Plus, I carry lead in my keel, so what's a few hundered more pounds.

svhoneybee 11-24-2012 05:03 AM

Ken, considering buying from EV Works in Western Australia (EV Works Pty Ltd). As you can see on their site, their batteries are Chinese, but then what isn't now. Our solar panels have their own regulator, as does our D400 wind generator. I understand what you are saying about sourcing stuff in out of the way places, but there is a lot of gear on the boat that will present that problem. At least with batteries, I could revert to Lead if I had to and flying the Lithium batteries around would be cheaper as they are much lighter (though maybe air freight wouldn't take them) . Like you, I've got lead in the keel, but that's where I prefer it to be. I'll keep exploring BMS options.

delatbabel 11-24-2012 10:38 AM

There was a good article in Cruising Helmsman a short while ago about Lithium batteries. It wasn't one I kept a copy of but IIRC the author also recommended EV Works (WA) as the source. It does seem that they are coming down in price quite a bit, and the weight compensates for many things. About 2 years ago I purchased a new bank of Trojan 105s but I'm guessing that will be my last bank of lead-acids, and I'll switch to Lithium when they are done.

I bought an electric bike recently, it has a battery that's easily liftable with 1 hand, and is 14Ah @ 36V. That equates to 42Ah @ 12v, 5 of those would replace my bank of Trojans quite nicely and use less than half the space.

Trim50 11-24-2012 11:01 AM

I must be honest and admit that I have been considering the conversion to Lithium before the start of our next cruising leg into Indonesia.

I presently carry fourteen (14) 105s onboard ;-)

If I do go Li-Ion, I'll likely build my own 1000Ah system.

Take a look at Bill Joy's yacht Ethereal, he went Li-Ion in a big way especially since he helped venture fund several battery companies. Unless he has swapped-out, his battery packs were built from lots of parallel strings of 26700's to produce 400 kWh battery bank.

SuperYacht of the Week: Ethereal, a journey of innovation and development - SuperYacht of the Week -

Before you spend your hard earned Aussy dollars, do a search on Alibaba for Li-Ion...EV Works doesn't even change the artwork ;-)

svhoneybee 11-25-2012 06:10 AM

That Cruising Helmsman article was in the August edition. It was quite a good read, but it was mostly about the installation process. I'd like to hear from someone who did it a few years ago, but maybe nobody much has. The author was installing the batteries in a cat and was naturally interested in the weight reduction as much as anything else.

Trim50 11-25-2012 06:16 AM

Contact Frank on S/V Tahina. I helped him with his Li-Ion while in New Caledonia...that was a year ago and he seems very pleased thus far.

Lithium Ion Batteries for Boating | Tahina Expedition

Our new batteries cost about $6K New Zealand dollars including shipping to New Caledonia. I'm sure they are cheaper now. The link to the guy I bought them from is in that post I sent you before: Batteries On Board | Tahina Expedition
The batteries are Li Iron Phosphate Yttrium - per the link: Winston Battery Limited
Our setup was for 600 AH at the 10-hour rate (or 780 at the 100-hour rate) configured in the 12V arrangement.

This is far more useful hours than our previous 735 AH of AGM batteries. Most important for us was getting the upgrade for our solar regulator Solar Power Boost | Tahina Expedition Made a HUGE difference to our charging times and need for charging.

svhoneybee 11-26-2012 12:45 AM

This has been a very useful discussion for me. Lots of good information and some interesting references as well.
At this point, I'm thinking of two banks of 4 Thundersky 3.2v 200AH LiFePO4 cells.
Despite the EV Works recommendation, I'm inclined to go with a BMS, so the next question is, which one?
Inputs are 170 watts of solar, a D400 wind generator and an 80 amp generator on our Yanmar diesel.

Trim50 11-26-2012 12:53 AM


I'm working on that answer now for my project battery system.

I thought about it more and more, and in reality there probably won't ever be an issue if your voltage supplies never exceed 14.5 Volts, however I've set-a-fire thousands of batteries in my years of testing (including LiFeP), and I'd really kick myself if one day I came home to the boat to find it parked at the bottom of the anchorage due to my failure to follow my own wisdom.

Did you check Alibaba prices? Maybe we could look into a group buy if enough people are seriously interested.

svhoneybee 11-26-2012 01:26 AM

The only thing I could find on Alibaba was someone based in Poland and near as I could tell, their price wasn't different (maybe even more ) to EV Works. Certainly EV Works reduces their price for bulk buys. See EV Works Pty Ltd
Buying in bulk would be easier if we were in the same State. How about dropping down for the Wooden Boat Festival?

Trim50 11-26-2012 01:36 AM

Take a look here 1000Ah
Lithium-ion Battery 1000ah - Buy Lithium-ion Battery 1000ah,Lithium-ion Battery 1000ah,Lithium-ion Battery 1000ah Product on

Put 4 of these together and you'll be set for life.

Or be more conservative...

Also, it is important to know that the BMS/VMS needs to be specific to the battery chemistry. LiMnO, LiCoO, LiFeP and LiPO are all completely different beasts.

Trim50 11-26-2012 01:57 AM

We are living in Melbourne and the boat is sitting on the hard in Bundy.

When is the wooden boat festival?

Trim50 11-26-2012 02:15 AM

OUCH!!!! $1050 for 2 people and a car just to get there...and that is the cheap seats.

svhoneybee 11-28-2012 12:47 AM

Ken, If you want to see the WBF (& it really is great) fly over. If you are desperate for a bed, we could probably put you up and we live a half hour walk from the Dock.

Back to Li batteries. There is in the December Cruising Helmsman a response to the August article from Rod Dilkes of EV Power. Strongly recommends a BMS & details why with a nice pic of an exploded cell. Looking at their website, they seem to offer a more comprehensive approach (also more expensive) with matching cells and BMS. I've sent them an enquiry and will share the response.

Auzzee 11-28-2012 02:22 AM

I can thoroughly recommend the Wooden Boat Festival in Tassie. Went there a few years back. Good fun, good boats, good environment, good beer (Boag's is about as good as it gets), and more beards per square mile than anywhere this side of Portsmouth.

Trim50 11-28-2012 04:25 AM

What was the fit bird to beard ratio?

Auzzee 11-28-2012 07:56 AM

Lots of pretty flash blokettes about. But they seem to be attached to blokes with cable knit pullovers. Still, it's a great place to perve!

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