AGM batteries

[Shoyrtt]

I'll second that! I learned the hard way am am taking back my lithium and switching to FireFly. No reworking the charging system and will outlive my ownership of the boat (slightly cheaper also).

What exactly was your experience? Which lithium batteries did you have? Which charger/inverter? How about your battery monitors? I have had zero issues so far.

 

[Flyguy1967]

What exactly was your experience? Which lithium batteries did you have? Which charger/inverter? How about your battery monitors? I have had zero issues so far.

I discovered I need a DC-to-DC Converter otherwise you will burn out your alternator and best off with a seperate charger made to charge lithium batteries for the lithiums.

I have wet cell D8's for my starting batteries and back-up for my DDEC and AGMs for my bow and stern thrusters. Consequently charging the different battery chemistries is a bit more work and money. Although the lithium batteries can take a ton of abuse and still bounce back, you can get close to the same with the FireFlies without re-working the entire charging system.

Here is a good explanation.

 

[ttmott]

I discovered I need a DC-to-DC Converter otherwise you will burn out your alternator and best off with a seperate charger made to charge lithium batteries for the lithiums.

I have wet cell D8's for my starting batteries and back-up for my DDEC and AGMs for my bow and stern thrusters. Consequently charging the different battery chemistries is a bit more work and money. Although the lithium batteries can take a ton of abuse and still bounce back, you can get close to the same with the FireFlies without re-working the entire charging system.

Here is a good explanation.

I think the Lithium brings more good than negative but the investment doesn't stop at the batteries as you found out. The batteries will demand almost unlimited current during the bulk charge mode and that will smoke alternators that do not have temperature monitoring and a good charge controller. The DC to DC converter however doesn't solve the issue with current demand. Now these batteries can be charged traditionally provided you can alter the charge voltages (like with a DC to DC converter) with a bulk mode then absorption mode then float mode which really is a waste of one of the great features the lithium bring to the table. That is they don't need to go through the hours and hours in absorption that the lead acid batteries do; you can hammer them with high current in bulk mode then go straight to float.... So, your generator or engine run time to recharge the house bank is two hours rather than six - that is big... I think the right way do do this is with dual alternators on the engines.
Note below in the design I'm implementing there are Balmar alternator controllers and Sterling APD (Alternator Protection Devices) for the main engine alternators which not only sets the charge voltages but also maximum current based upon the temperature of the alternator; I have 120 Amp alternators. The APD's are there to protect the alternators should the battery system or main disconnect switch trip the alternators off line during operation. But note also that the Lithium bank is also the main engine starting bank.

 

[mobocracy]

I got the AGM's for both my 400DA and later my 52DB at Batteries+. The Group 27 AGM's in the 400DA had a 5 year replacement warrantee; I think they were called "X Power". The 8D's on the 52 have a 3 year. The 52 is being changed over to lithium later this year.
A word of warning regarding lithium - the charging system must be designed around the batteries. They are not plug and play. Consideration for protection of the alternators as well as a dedicated lithium specific charger is required. The lithium technology is however safe but needs to be implemented correctly.
Tom

I've heard mixed messages about LiFePO lithium batteries being plug and play, with some including basic BMS at the individual battery level for a greater level of general compatibility with 12v systems, although none of the installs I've read about are drop-in replacements, they all seem to include installing sophisticated LiFePO aware BMS or at least fine-grained configuration of chargers to meet LiFePO charging needs.

The biggest factor I've read about in specific marine installations by live-aboard bloggers is that LiFePO is more heat sensitive than lead acid batteries and isn't that viable in hot engine rooms. I think in both more detailed writeups the folks involved ended up moving their LiFePO battery banks from the engine rooms to cooler locations elsewhere in the boat.

 

[ttmott]

I've heard mixed messages about LiFePO lithium batteries being plug and play, with some including basic BMS at the individual battery level for a greater level of general compatibility with 12v systems, although none of the installs I've read about are drop-in replacements, they all seem to include installing sophisticated LiFePO aware BMS or at least fine-grained configuration of chargers to meet LiFePO charging needs.

The biggest factor I've read about in specific marine installations by live-aboard bloggers is that LiFePO is more heat sensitive than lead acid batteries and isn't that viable in hot engine rooms. I think in both more detailed writeups the folks involved ended up moving their LiFePO battery banks from the engine rooms to cooler locations elsewhere in the boat.

You are exactly right; there is a correlation between temperature and battery life. Another drawback is in very low temperatures the batteries cannot be charged at a high amperage rate. The arrangement that will be done on my boat is the batteries will be located under the solon sofa. From a weight perspective the 1000 Ah bank weighs about the same as the two 8D's on the same side of the boat; so the boat will remain balanced.