None of these were particularly great solutions.
The alternator output method relies on a temperature limitation.
The DC-DC converter has high losses.
The Sterling APD (have one sitting here on the shelf) had other issues, which don't come readily to mind.
The the last boat, the "least bad" choice was the DC-DC converter, for my application. Still wasn't particularly happy with it.
Had a couple of phone conversations with Clark (YouTube video posted above), about his bank manager. It appears to be the most elegant solution, but still requires a Lead Acid battery in the mix, to act as the 'shock absorber' when the LI BMS shuts off the charge.
Also spoke to the founders of BattleBorn (DragonFly Engineering) about the charging issue. At the time, they were working on the WakeSpeed controller. I have no experience with it, so can't opine. Maybe somebody else does.
ey were working on the WakeSpeed controller. I have no experience with it, so can't opine. Maybe somebody else does.[/QUOTE]
I'd like to discuss this some more but out of the Cat 3116 thread -
@SCFoster - I really don't understand technically what you are getting at -
The good/bad on lithium batteries is their capability of a high rate of charge. The good is they charge quickly, like 100 amps until they are 100%. The bad is using a standard engine alternator will cook as the batteries have nearly zero resistance and will allow pretty much unlimited current flow. So, if you want to have the capability to charge a Li battery bank using the boat's engine alternators the alternator needs to either be capable of the current or be tempered so is isn't damaged by heat. The highest efficiency is at that point of output where thermal conditions will not damage it. The second part is to allow a bulk charge until the battery bank is essentially 100% charged and to minimize the charge period. An engine alternator bo-haus enough to manage the battery current you are into custom alternator installations with multiple drive belts. The best solution is to have an external programmable field controller that can charge to the desired voltage, have the desired charge profile, and monitor the alternator temperature to extract the highest output. The Balmar Regulators do exactly this. What is your solution?
The second most important thing is to protect the alternator should the Li battery's BMS trip it off line. Without a buffer the alternator will certainty go high order and self-destruct. You could do an adjunct SLA battery as the buffer but then you are back to compromising the charge profile and voltage for the Li battery; a poor solution in my mind as some of the desired features of the Li battery are not used. The Sterling APD is a simple inert device that should a BMS trip occur the voltage surge will be absorbed. I think it is a perfect solution to the quandry. Can you explain why not?
I to was working with Battleborn Batteries and trying to technically use the Lithium battery as a starting bank as well as the house bank; a fellow at Battleborn named Denis Phares was working with the engineering company I had designing the system. They laid out the system as I outlined above. So I'm curious why they seem to have changed their technical position. Know why?
Thanks
Tom