Lithium-need dc-dc with balmar?

[vic008]

Is a dc-dc unit needed if running a Balmar mc 614 with a lithium battery? Thank you

 

[Porthandbuoy]

according to the manual the MC-614 regulator has a program setting for lithium.

Balmar MC-614

 

[geem]

Is a dc-dc unit needed if running a Balmar mc 614 with a lithium battery? Thank you

The issue with direct charging of lithium with an alternator is what happens if your lithium battery bms detects a fault and shuts down the battery. This then leaves the alternator with nowhere to dump its charge. The alternator diodes will pop and you then have no alternator output. Considering that the bms will have several fault modes where it can shut down charging, this fault scenario is a real risk. You can add an alternator protector for about £80 but I think these are one time protection devices and not a fit and forget. The quality of the lithium battery and how much information you have available via Bluetooth could reduce the risk of a bms disconnect. Setting the alternator charge voltage well below the bms cut off charge voltage would help.
Set the alternator to say 13.8v at the upper voltage limit and you would reduce the risk of a high voltage disconnect assuming the bms was set for 14.6v. This would reduce the risk of a runaway cell setting off the high voltage disconnect

 

[lustyd]

It is if you also have a Lead Acid starter battery, windlass battery or bow thruster battery.

The smarts help with a charge profile but you shouldn't join lithium with lead as one of them will be at the wrong voltage.

 

[KompetentKrew]

It is if you also have a Lead Acid starter battery, windlass battery or bow thruster battery.

The smarts help with a charge profile but you shouldn't join lithium with lead as one of them will be at the wrong voltage.

I thought you just ran the lithium bank at a slightly lower voltage than optimum, and that this was the way hybrid lithium worked? The lead-acid batteries get 100% charged, the lithium ones never do but they last longer because of it?

 

[Sandyshore]

Mixing two different chemicals is not recommended unless your insurers approve.

 

[geem]

I thought you just ran the lithium bank at a slightly lower voltage than optimum, and that this was the way hybrid lithium worked? The lead-acid batteries get 100% charged, the lithium ones never do but they last longer because of it?

I don't think that works. Optimum voltage for long lithium life is below what lead needs to fully charge. Also contravenes ABYC and ISO standards to mix chemistries.