Best Way To Charge Lithium

[HarrisonM]

Hello:

I am just about to put in new Lithium batteries and a Victron System. When I do this where is the best place for the alternator to charge to? I think it should goto the Lynx Distributor where the batteries (HOUSE BANK) are connected, so the lithium will get the full load. (I have at 170 AMP Balmar alternator) I also have a start battery and a separate bank for the windless, winches, and bow thruster. I was going to use 2 separate DC to DC chargers to keep them charged.

Any input helpful

[fxykty]

Originally Posted by HarrisonM

Hello:

I am just about to put in new Lithium batteries and a Victron System. When I do this where is the best place for the alternator to charge to? I think it should goto the Lynx Distributor where the batteries (HOUSE BANK) are connected, so the lithium will get the full load. (I have at 170 AMP Balmar alternator) I also have a start battery and a separate bank for the windless, winches, and bow thruster. I was going to use 2 separate DC to DC chargers to keep them charged.

Any input helpful

What you describe is standard practice. The alternative is to direct the alternator charge to the start and/or windlass battery and use DC-DC chargers to charge the LFP battery. That does lose some efficiency, but simplifies the install.

Otherwise, any charge source that must be connected to a battery while operating (such as your alternator) should have an automatic turn off switch that operates before the BMS disconnects the LFP battery due to over charging (think about a long day of motoring under windless sunny skies). Hopefully your BMS has a shut down relay that is triggered before the BMS disconnects the LFP battery. If so, connect that relay to your alternator’s or alternator regulator’s ignition wire (alternatively, you could connect to your field wire). The alternator/regulator is safely turned off by the relay before the LFP battery disconnects.

[Pete7]

This is how we did our installation, all charging and discharging circuits via a Power In which is the cheap version of the Lynx and with 4 extra bolts creates a fuse box. Its neat and and all in one place.

I used the lugs on the end which you might be using for the Lynx shunt as ports for the inverter. There are two other spare connections available at the other end for heavy cables if required.

[CarlF]

Take a look at the new Argo Zeus alternator regulator. It gives you much more information and control over alternator charging via bluetooth on your phone. Besides voltage it measures amps so can shut down the alternator if amp are getting too high.

The usual worry is what happens if your lithium battery BMS shuts off while the alternator is running. This can damage the alternator just like turning off the main battery switch underway. But this risk can be managed. I expect you know most of the following….

1) In three years I’ve never come close to a BMS shutoff on my lithium bank. I do three things 1) the alternator charge voltage is 14.1v which is well below the battery manufacturers recommended 14.4v. I have the solar panels do the last little bit to 14.4. 2) I have four batteries each with 200 amp maximum charge/discharge. This means the BMS won’t shut down until over 800 amps which won’t happen. 3) The battery cables are “equal length” to be sure the batteries charge and discharge equally.

2) If your batteries have “communication” then they can shut off the alternator before the BMS shuts off the battery. Unfortunately most lithium batteries do not have this sort of communication

3) I installed a Balmar Alternator protector

4) The DC-DC chargers you plan to install will also absorb a surge into the start and windlass batteries likely with no damage.

[smj]

Don’t know if this would be of interest.
https://www.emilyandclarksadventure.com/bbms
You can use the older standard LA charging sources so may be a savings there. My friend uses one and speaks very highly of it.

[Ryban]

There's a very long discussion on the topic of LA + LFP charging here too, that you might find helpful:
https://www.cruisersforum.com/forums...ps-283451.html

But more or less the replies above provide sufficient information.

[hjohnson]

This topic has been discussed and argued ad nauseam both here and on other forums.

The ling and short of it boils down to which batteries/BMS you are using, and which alternator regulator you are using.

If your BMS can signal to the alternator to shutdown before the battery goes into an alarm state (either via relay closure or CANbus), and your regulator can adequately protect your alternator from overheating and burning itself out, then going directly to the lithium bank is going to get you the most power safely.

If your BMS only has, say, Bluetooth capabilities, or you just have a dumb alternator with internal regulator, then you’re better off with a DC to DC charger.

[HarrisonM]

Thanks all... Very helpful...

[CaptainRivet]

Originally Posted by fxykty

What you describe is standard practice. The alternative is to direct the alternator charge to the start and/or windlass battery and use DC-DC chargers to charge the LFP battery. That does lose some efficiency, but simplifies the install.

Otherwise, any charge source that must be connected to a battery while operating (such as your alternator) should have an automatic turn off switch that operates before the BMS disconnects the LFP battery due to over charging (think about a long day of motoring under windless sunny skies). Hopefully your BMS has a shut down relay that is triggered before the BMS disconnects the LFP battery. If so, connect that relay to your alternator’s or alternator regulator’s ignition wire (alternatively, you could connect to your field wire). The alternator/regulator is safely turned off by the relay before the LFP battery disconnects.

Sorry your alternative makes 0 sense here. He has a 170A alternator to charge the 2-5AH the starter/bowtruster need and then use 3x 50A or 2x60A DC2DC chargers...makes 0 sense, has additional losses and complicates the install plus adds additonal failure points eg. Lead died due to internal cell short, how do you charge house with alternator...you cannot via DC2DC?


The hints regarding alternator cut off are a good point and should be followed.

The only correct and also sensefull way here is connect it to lynx distributor to directly charge the LFP house with the 170A balmar.
I assume he has lead starter and bow truster, then you need to use small DC2DC chargers to charge/top up the bowtruster and start batteries. The 18A Victron (offers no communication anyhow) or the 20A renogy DC2DC charger is sufficent for the starter and also small bowtruster. If it's a bigger bowtruster I would use the 40A renogy DC2DC, so you can recharge them faster. No reason to use expensive victron here as no communication anyhow and use cheaper plus cooler running renogy. Yes if money plays no role you can use the Victron XS 50A DC2DC which has communication but that's triple you need to spend with renogy.

An even simpler install you could achieve by swapping starter and bowtruster to lithium too.
In this case you just connect the house directly but starter and bowtruster LFP via a victron ArgoFET to the lynx distributor and they get charged in parallel by all charge sources you have incl. the alternator. An argofet because like this they cannot be depleted by the house but only charged.
You could even spare yourself one battery bank and eg start from the house lithium as you still have the bowtruster battery as emergency start or use bowtruster from house so enlarge the total capacity of the house.
What makes sense depends where your LFP house is located and which battery is closer, most likely the starter and you should have anyhow a cable running to it so in emergency case you can start from house. So it's simply deleting the lead starter and take out the switch.

[CaptainRivet]

Double post

[knutmi]

Why do everyone suggest DCtoDC chargers? I have been charging AGM and Lifepo4 bank from 115A alternativ for 5 years. I have a Victron Argofet who separate the two banks.
0 problem.
My alternativ dont burn and I always have fully charged batteries.
Why slow down charging, when I always want it to be fast. BMS is as safe as a AGM battery. BMS also slow down charging as AGM do when its nearly fully charged. Just watch your battery meter, V and A, they dont lie.

[CaptainRivet]

Originally Posted by knutmi

Why do everyone suggest DCtoDC chargers? I have been charging AGM and Lifepo4 bank from 115A alternativ for 5 years. I have a Victron Argofet who separate the two banks.
0 problem.
My alternativ dont burn and I always have fully charged batteries.
Why slow down charging, when I always want it to be fast. BMS is as safe as a AGM battery. BMS also slow down charging as AGM do when its nearly fully charged. Just watch your battery meter, V and A, they dont lie.

Exactly what ia always suggest with the 115A Mitsubishi too IF you wanna keep lead.
The only thing you need to do is run seperate cable for the starter directly to starter battery as you cannot use the alternator charge cable in reverse due to the argofet.
And if you need conversion from 12 to 24V connect after the argofet an 12 to 28.0V DC2DC converter and via its remote the BMS, the easyas alternator relay or a BMV702/712 ( if your BMS like dropins cannot) can switch/on off charge.

Only requirement your alternator needs internal temp protection to be able to do this which the 115A Mitzi and 125A Valeo has, that's found on most of the 3 and 4 cylinder when they have a serpentine belt drive.

[CarinaPDX]

Originally Posted by CaptainRivet

Only requirement your alternator needs internal temp protection to be able to do this which the 115A Mitzi and 125A Valeo has, that's found on most of the 3 and 4 cylinder when they have a serpentine belt drive.

The point of using a Nordkyn VRC-200 external regulator with the Mitsubishi 115A alternator is it that works by manipulating the internal regulator's voltage sense, and thus leaves intact the temperature protections of the internal regulator. This is preferable to attaching a temperature probe to the alternator and expecting the external regulator to manage the alternator temperature.

Greg

[CaptainRivet]

Originally Posted by CarinaPDX

The point of using a Nordkyn VRC-200 external regulator with the Mitsubishi 115A alternator is it that works by manipulating the internal regulator's voltage sense, and thus leaves intact the temperature protections of the internal regulator. This is preferable to attaching a temperature probe to the alternator and expecting the external regulator to manage the alternator temperature.

Greg

That's correct. To add to that the following points:
1) it keeps the volvo D+ connection to MDI box, so you don't need to hack that as you need to do with all the external regulated alternator. Without hacking MDI engine won't start anymore and doing that also voids the engines warranty
2) you can additionally use external temp probe, one VSR 200 can handle 2 additional probs means you stick one on alternator no1 and install a 2nd 115A Mitzi+ stick 2nd temp probe on that and one VSR200 controls both alternator on the same engine using internal and the external temp prob so the VSR 200 can actually see the delta from stator and case temp on both (so knows exactly when cooling capability is exceeded=always safe max output) and regulate them more precise+safe then any external regulation ever can.
3) Thats 170A charge constant, modifying gearing gets you to 200A, from 2x115A Mitzi each costing 250Euro if using reman ones+plus one VSR200.
A tip here: I keep the org alternator geared original (around 2:1) but gear the 2nd 3.3:1 which is easy as you an choose crankpulley to your liking, no waterpump pulley that needs to be adjusted too. The 2nd is better cooled due to its location then 1st but is also loaded with higher temp as it delivers already 85A at 1400RPM and 95A at 1800 and around 105A at 2300. Like this the 2nd is quite equally tempwise to the original, which is good as the VSR regulates the hotter of the 2, the other follows automatically.

Plus you have redundancy and warranty on the engine stays intact.