Anyone using Mastervolt Lithium Batteries?

[HKTim]

Regarding economics, the option to add a genset on my boat was US$30,000. While it won't be right for everyone, I think a combination of good alternators and solar plus a lithium bank will be a plausible genset replacement for some people.

[SVNeko]

Originally Posted by HKTim

Regarding economics, the option to add a genset on my boat was US$30,000. While it won't be right for everyone, I think a combination of good alternators and solar plus a lithium bank will be a plausible genset replacement for some people.

Especially on a catamaran, where you have redundancy in the event one engine goes out and to keep hours to a reasonable amount.

[John Holbrook]

LC If lithium batteries are too expensive you could try Firefly batteries. They are about $500 for the 110amp/hr version so $5000 for 1,100 amp/hr bank. They can be discharged to 20% without damage, charged fast and are not as sensitive as lithium.

Jaguar says they want half of their cars to be electric by 2020, Mercedes and VW are launching many electric cars over the next few years, etc, etc. Battery technology is improving rapidly and like LCD TVs the price will come down.

HK Tim says he wonders if he needs a generator on his next boat. I'm thinking will a 10kva generator have enough power to recharge a large battery bank in 60 minutes or whatever a Tesla can recharge in. It maybe that the HP of the main engine is needed to do that.

Originally Posted by Lamb Chops

Ok, I started to get really excited reading this thread! Particularly the idea about running my AC unit off battery power over night. I think the idea of cooling the cabin first with the genset is a great one but two factors caused me to have a lot less interest...



1) The cost - a single 360ah battery is $6.3K!

2) Anyone heard about the Samsung Note? Given the issues with high density lithium batteries I think I would be very tempted to wait a bit longer to let the problems with fire sort themselves out. A battery fire on a sailboat would be let's just say a bit of a bummer!

[Lamb Chops]

Thank you for the pointer to firefly! I'm assuming you mean this...

http://www.bruceschwab.com/advanced-...asis-group-31/

Pretty impressive! I just replaced my entire house system with Lifeline but next time I will definitely consider this and LiFeP04

I didn't do a comparison but I'm assuming the weight of the Firefly is still pretty comparable to regular AGMs?

[Lamb Chops]

I just checked... they actually weigh a bit more $75lbs vs 64llbs for LIfelnie GPL31. Not a biggy really since you can probably also live with a smaller house array given the deeper discharge time. I wish I had know about these before I purchased my lifelines!

[John Holbrook]

Thinking aloud...

On the Fireflys they suggest the sweet spot is between 20% and 80% meaning you can run them down to 20% without damage and bulk charge them back up to 80% quickly. 80% to 100% takes a lot longer and is fine with solar say but running a genset or main engine just to charge the batteries wouldn't be efficient.

On a 1,100amp bank of fireflys you would have 660amps usable in the sweet spot and 220amps more if you topped the batteries to 100%. If your aim is to run aircon overnight it is a reasonable bet that you are in a hot location and could get that last 220amps from solar panels.

Each 110amp firefly battery can accept a max charge of 250amps, so a 1,100amp bank 2,500amps. Not practical I know but in theory a 40kva genset could recharge the sweet spot 660amps in 16 minutes. Today what may be practical is putting two 200amp alternators on your main and recharging in circa 100 minutes - maybe a lot less if you have solar and aren't running your aircon.

If you are motoring around there are no extra engine hours but extra load. On say a 57hp Yanmar at 2200rpm the engine makes 50hp, the prop aborbs 21hp and two 200amp alternators on bulk charge would use 6hp each, total 33hp so the engine would not be overloaded. Btw the Yanmar 57hp comes standard with a 125amp alternator and a second 125amp alternator is optional.

If you are stationary and run the engine in neutral at say 1000rpm and used a 3.0 to 1.0 ratio on the serpentine pulleys the alternators would spin at 3000rpm and use circa 12hp of the 20hp the Yanmar 57hp makes at 1000rpm. I don't know if this would place enough load on the engine to bring it to the correct operating temp and also burn the fuel properly to prevent glazing of the engines bores. So a question for the experts.

[HKTim]

John, to get back to your questions from yesterday:

1. Fridge is 4.88 amps but I assume only about 40% cycling ON time, so really average of 1.95 amps through the night. I've never run the air con and the fridges separarte through the night so this is just an estimate for the cycling. Similarly, the air con is 83.25 amps but cycling on is assumed to be about 35-40%. This is what it takes to reverse out the cycling for both air con and fridges given the known amps for each unit as supplied by the manufacturer vs what I can see is the actual amps consumed over a set period of 8 hours.

2. The master cabin does take up the entire starboard hull. I have shut the door to the main saloon and the the starboard master head though. But its still a pretty large space. I take your point that blocking off a smaller area in the cabin could improve efficiency further.

3. I am in the process of installing a new set of Mastervolt 130 amp alternators. Once they are installed I will update everyone on how much charge they actually produce at various RPMs. These alternators though are designed to produce quite high output at low RPM. The sales literature says that at 2000 RPM you should have 115-120 amps. So in theory with both engines running for an hour, you should be getting 240-300 amps into the house bank. If you are consuming approximately 40 amps for 8 hours through the night, you should be able to use the engines to recharge the house in about 1.5 hours or less at 2000 RPM. Add solar and you can adjust down accordingly.

Tim

[HKTim]

Forgot to mention that I had set the temperature to 25 C in the cabin for the tests described above.

[rwidman]

Originally Posted by John Holbrook

...............Jaguar says they want half of their cars to be electric by 2020, Mercedes and VW are launching many electric cars over the next few years, etc, etc.............

Cars are not at all like boats. Cars often spend a lot of time stopped for traffic. Boats do not. Cars spend a lot of time coasting down hills. Again, boats do not. Cars can be setup to use regenerative braking (slowing the car generates electricity to recharge the battery), boats do not have brakes, Cars are usually parked where the batteries can be recharged. Unless you stop at marinas every night, you won't be able to do this on a boat.

If your plan is to putt around the harbor all day and return to the dock at night, an electric powered boat may work. For cruising, it probably won't.

[John Holbrook]

Tim thanks for the info. Are you installing your new alternators in addition to your existing alternators or as replacements for your existing alternators?

Originally Posted by HKTim

Forgot to mention that I had set the temperature to 25 C in the cabin for the tests described above.

[John Holbrook]

rwidman If you wish to quote me please quote me in context with what I was writing about.

No one in this thread about an electrically powered boat. It would be helpful if you read the thread before contributing.

Originally Posted by rwidman

Cars are not at all like boats. Cars often spend a lot of time stopped for traffic. Boats do not. Cars spend a lot of time coasting down hills. Again, boats do not. Cars can be setup to use regenerative braking (slowing the car generates electricity to recharge the battery), boats do not have brakes, Cars are usually parked where the batteries can be recharged. Unless you stop at marinas every night, you won't be able to do this on a boat.

If your plan is to putt around the harbor all day and return to the dock at night, an electric powered boat may work. For cruising, it probably won't.

[rwidman]

Originally Posted by John Holbrook

rwidman If you wish to quote me please quote me in context with what I was writing about.

No one in this thread about an electrically powered boat. It would be helpful if you read the thread before contributing.

Dude! I responded to what you posted. I quoted you. Perhaps it is you who didn't read the thread before posting.

[HKTim]

John. I am adding the mastervolt alternators as the secondary alternator on each engine. Keeping existing factory installed primary alternator which will only be for charging the start batteries.