On 1/12/2020, at 9:00 AM, Ken Powers SV Aquarius <ken@...> wrote:

You asked for opinions.....

With new solar, and lithium batteries the future of gensets has almost come to an end.  You can put 2KW of solar on deck with 900AH of LiFePO4 batteries (at 24V).  This would life better than getting a new GenSet.

Keep the genset though, you might use it about 50 hours per year, max, with the set up above.   And you might even get another 10 years of life out of that Onan.  Onan's are very good gensets!

Ken
Aquarius
SM2K#262

FWIW, I would proceed exactly as suggested on Aquarius 

On Nov 30, 2020, at 10:59 PM, Karen Smith via groups.io <karenharmonie@...> wrote:

This year we decided to bite the bullet and replace our Onan.  Not because of intrinsic reliability issues, but because of a lack of spare parts availability from Onan.  We had several major routine maintenance issues coming up, and it was clear that parts just were not going to be available.

We looked at deck mounted, "walk-on" solar panels, but at a cost of about $10 a watt (!) the cost was very unattractive for a solution that still wasn't sufficient to meet all our needs.

You can find a detailed description of our logic and design process here:

https://fetchinketch.net/boat-projects/power-to-the-people/

The short form answer:  We analyzed how we use our boat, and our electrical needs, and came up with what has seems to be a very good solution for us.  A DC generator from Whisper-Power.  It is smaller, lighter, and much more efficient than the Onan (Light enough that the permanent list to port is GONE!).  It is the last piece of a long, steady modernization of our boat's electrical system.

With the addition of this generator, and a Victron Cerbo GX monitoring system, we finally see our systems set for comfortable, simple, extended off dock cruising for the foreseeable future.

Maybe the next time we need batteries (in 8 to 10 years), we will jump to a Li system, but for now we are staying with our Firefly Batteries that seem to give us 90% of the benefit for 50% of the cost.

Bill Kinney
SM160, Harmonie
Fort Lauderdale, FL, USA.

Alex,

Yes, I am still a fan of Firefly batteries, but a caveat or two is worth mentioning.  Like any relationship, there has been a bump or two in the road.

Twice we have had a battery develop an internal short.  The first time we discovered it quickly, and it was immediately replaced by Firefly.  The second time, our monitoring system wasn't good enough to catch the issue, and we developed a chronic imbalance where half the bank was overcharged, and the rest undercharged.  By the time the issue was apparent, permanent damage was done to all the batteries.  Firefly stepped up an replaced the whole bank within the terms of the warrantee--keeping us happy.

We learned. It is quite likely that if we had seen the issue early on a minor change in charging procedure might have alleviated the issue, but we'll never know for sure. We have since significantly upgraded our electrical system monitoring system, and a minor imbalance is not going to sneak up on us again.

As for running A/C from the batteries, sure it's possible.  One of our A/C units draws about 850 watts when running. That's about 4 times our normal house load.  That is easily supplied by our 8 battery bank and 3kW inverter. In the absence of any solar power, we'd need to run the generator twice a day for 3 hours instead of once a day for 90 minutes.    It is important to remember that it doesn't matter what kind of batteries you have or the size of the bank.  Batteries do not make power they just store it.  A bigger bank means you can reduce the number of times you start the generator, but your total run time will be about the same.

All that said, in 5 years of full time cruising we have run the A/C units while away from shore power exactly once, so it was not a priority in our design decisions.  If your plan is to run A/C units regularly off the grid, a larger system than we have might be needed.

Bill Kinney
SM160, Harmonie
Fort Lauderdale, FL, USA

On Wed, 2 Dec 2020 at 5:17 pm, Dean Gillies

<stella@...> wrote:

I hear and read about so many cruisers with defective Firefly batteries. Its also clear that the manufacturer has usually replaced them under warranty after sending the customer through some testing hoops.

I have also heard the stories about previous production problems that are now 'fixed'. What evidence is there of this fix? Is there anyone on this forum that can report an incident-free experience with Firefly batteries for say two years or more? If not then I'd have to suggest that the jury is still out on reliability of Firefly batteries. 

it's good that the company has been honouring the warranty, but personally I'd prefer not to interrupt my cruising season trying to manage the logistics of getting specialist batteries replaced. 

I'm still considering my battery replacement technology.

Cheers, Dean
SV Stella A54-154

 

I hear and read about so many cruisers with defective Firefly batteries. Its also clear that the manufacturer has usually replaced them under warranty after sending the customer through some testing hoops.

I have also heard the stories about previous production problems that are now 'fixed'. What evidence is there of this fix? Is there anyone on this forum that can report an incident-free experience with Firefly batteries for say two years or more? If not then I'd have to suggest that the jury is still out on reliability of Firefly batteries. 

it's good that the company has been honouring the warranty, but personally I'd prefer not to interrupt my cruising season trying to manage the logistics of getting specialist batteries replaced. 

I'm still considering my battery replacement technology.

Cheers, Dean
SV Stella A54-154

 

Thanks Matt, much appreciated. 

Did you install Firefly batteries in your new A50 or did you make the leap to Lithium?

Cheers, Dean
SV Stella A54-154