That’s what I am hoping. Also, it is only 65 AH so there is not much to put back even if it is a bit undercharged. Do you think the internal regulator is enough to dial beck the amperage? I'll check for a temp probe next time I go to the boat.
H49/50 battery replacement
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I don't know the size. I’ll have to check. It's small. It’s probably 50 or 60 amps. The generator is 8k. I didn’t even think about the issue until everything else was set up and I started monitoring all of the systems. Out of sight, out of mind I guess. The generator has a sound shield around it. I think of it as a generator, but it's also a second alternator.
2.5.4
Battery charger
On the engine is an alternator generating 40 Amp 12V.
This current is rectified to charge the battery. The voltage
is regulated at ±14.4V.
This is from the manual.
Battery charger
On the engine is an alternator generating 40 Amp 12V.
This current is rectified to charge the battery. The voltage
is regulated at ±14.4V.
This is from the manual.
The issue is the voltage, what is the absorption voltage for the battery? Most LFP batteries want to be charged between 14.0 and 14.2 volts.
ULTRA-FAST CHARGING
DL rapid charge technology allows for charging speeds of 45 minutes (80 Amps). Recommend for longest life 60A or less (1C), Max continuous 80A (1.5C). 14.4V recommended, 15V max, BMS protection from over charging will cut off at 14.6V. Included is a free 12V 10 A LiFePO4 compatible charger that charges at the recommended 14.4 Volts.
DL rapid charge technology allows for charging speeds of 45 minutes (80 Amps). Recommend for longest life 60A or less (1C), Max continuous 80A (1.5C). 14.4V recommended, 15V max, BMS protection from over charging will cut off at 14.6V. Included is a free 12V 10 A LiFePO4 compatible charger that charges at the recommended 14.4 Volts.
If the battery company says 14.4 is fine, then go with it. If you are concerned about alternator temp, use an IR temp sensor and check the temp at middle of the battery and at the aft end where all the electronics are. If you are pushing 200° F then the alternator is being over worked.
Any voltage regulator should be able to reduce output to 0 amps otherwise it cannot regulate voltage.
No, most likely not. Why? Because internal regulators are dumb and all they do is produce a constant voltage. They do not have remote battery sense wiring. It is the battery acceptance that reduces the amperage with internal regulators, not the regulator. Battery acceptance is like "pushback" and internal regulators work just fine with wet cell technology.
That's why I mentioned the knees. Without wet cell (old) battery acceptance, the essentially infinite acceptance of Lith means you could hit the upper knee right away if the battery is almost fully charged, which most "start" batteries are, because starting an engine takes very little out of any battery.
You need to do some homework on charging Lith. Glad you caught it though.
I guess could use a DC to DC charger in the circuit or add another Balmar regulator unit. I’m not sure I even need the alternator on the generator since I have one on the main engine.
Hayden,
I'm sure you understand that regulators only control voltage and that without battery sense wiring which (most all) internal regulators do NOT have there is no way voltage can be reduced and therefore current. Current is only reduced at ay fixed voltage by the "pushback" (resistance) of battery acceptance, which works well for FLA, but Lith batteries have exceeding low resistance and high acceptance throughout their charging profiles. External regulators with battery sense wires can and do reduce voltage and therefore current.
The LFP has incredibly low resistance when it is below 98% state of charge and then the resistance goes up very quickly as it approaches 100%. That is why the voltage spikes. I little bit of current with a very high resistance will make a very high voltage. All regulators sense the voltage of the battery. An external one usually has the pickup at the battery so there is no line loss and the internal regulator usually senses it at the alternator so there will be lower voltage at the battery. When the battery gets to the set voltage of the regulator [internal or external] it reduces the field current to the rotor and the current output is reduced.
Understood. And that was exactly my point about the knees on Lith. My understanding is that you don't want to hit (or in this case, even worse keep hitting the HVC knee) when charging. Lith don't need to get to 100% all the time. That's all.
Correct, you do not want to hold an LFP for long periods of time at an elevated voltage, but an alternator will not do that because it is not a constant power source. It only charges when the engine is running and only holds the high voltage after it has reached full charge. The BMS will prevent the cells from going over 3.65v which is where they get damaged. Passively balanced batteries like the Battle Born or Dakota need to be held at an absorption voltage in order to let the tiny balance resistor have the time to bleed off some of the extra electrons.
Personally, I do not charge any of my LFP's to anything over 14.0v but I have other ways of balancing them. The last time I read their specs, both BB and Dakota want you to have a certain amount of time at 14.2v for balancing.
On the sealed batteries on my motorhome, I needed to hold the voltage at 13.8v - 14.2v for most of a month in order to get them balanced. Doing this increased the tested capacity from 445Ah to 480Ah.
That is the voltage that most internal regulators limit the voltage to. I would suggest, running the engine with the battery fully charged and use a multimeter to see what the regulator is doing. if it goes above 14.5v it would be better to disconnect the generator alternator and charge its start battery with a DC-DC charger, but I would find that very annoying.
Good point. Does your starting Lithium have a bms, what is it's high voltage disconnect? I'd monitor the charge voltage with a multimeter. If it gets too high and your lifepo4 bms disconnects, it will destroy the diodes in the starter. This is why AGM is still preferred for starter applications, but Lithium can work if the system is well understood and designed.
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Or you could disconnect the genset alternator, remove its battery, and run the genset off the house. We’ve been set up this way for about a year (NL 6kW), but I actually never disconnected the alternator… it seems only about 5A from the 18A alt make it back to the house LFP.
Yep, that is what I said about a dozen posts ago. The start battery just never needs much put back in. For that reason, if it does do a disconnect, it is not likely to cause much of a problem to the alternator. The Diodes will only go boom if the output is near max when it disconnects. with the start battery it will not be cramming much in so will be working less hard.
I tried disabling the alternator on the generator so the new lithium start battery wouldn't fry it, but the generator shut down after about a minute. There must be a sensor that detects alternator function. The generator is a Mastervolt Whisper 8000. The alternator has an internal regulator with just two wires going into the back. I’m not sure if I can fit it with an external regulator. In the meantime, I reconnected the AGM as the starting battery. If I turn off the Parallel Charge Circuit breaker while the generator is running, all is well. The alternator charges the battery at an acceptable rate. I have to flip the breaker back on when the main engine is running in order to allow the main engine alternator to charge. No problem with this alternator since I have a Balmar regulator. If anyone knows how to bypass the Mastervolt alternator sensor, please let me know. Any information on regulating the alternator on the generator would be appreciated as well.
Probably the best course of action is for you to hire a good marine electrician to go over your system and help you understand how all the pieces work together.
Based on my admittedly limited experience with marine generators, the alternator on the generator sole function is to provide current to any electrical devices on the generator such as a electric fuel pump and to charge the generator's start battery. The generator provides AC current which is feed into the AC system on the boat. Part of that AC system is the inverter/charger which then charges the battery. It is not surprising that disconnecting the generator's alternator would cause the generator to stop running.
If the generator is not set up correctly and/or you are not clear on how it works you have a dangerous situation could damage components on your boat or injure someone.
You are in San Diego, there must be some competent marine electricians who can inspect the system and teach you what you need to know to operate it safely and efficiently.
Any alternator shop should be able to remove the internal regulator and bring the brush wires out to connect to an external regulator.