Alternator burn out charging lithium

[Martin S]

It is a good question and one everyone should ask when installing lithium batteries. If you do some more research on the web you will find there are other solutions. It is worth reading everything you can on Lithium installations. Look at “Marine how to” site and also Sterling power. You will find a battery to battery charger and an alternator protector is another way to go.

[SV-NoBadDay]

I got that one - with all due respect

Thank God for google

[RaymondR]

Originally Posted by Stu Jackson

WADR, huh?!?


The internal regulator measures the V at the back of the alternator, and is preset, usually not adjustable. So, let's say it is set for 14.2V.


The AO goes out and to an isolator that drops let's say 0.7V. 14.2 minus 0.7 = 13.5V.


That's the highest V that can get to the batteries (neglecting voltage drop completely ford this discussion).


All that will happen is that the batteries will be woefully undercharged, and NOT "causing the regulator to wind back the alternator output." That will simply not happen, it is not how it works.

With an alternator fitted with a regulator which "sees" the voltage at the output what it "sees" is the battery voltage, say 12.6V and the diode voltage drop, say 0.6V for a silicon diode, equals 13.2V and the regulator will wind back the output accordingly whereas without the diode it will only "see" 12.6 and respond with a higher amps output.

The best solution to the problem of big charge capacity battery banks is a large alternator which has temperature control which responds to heating by reducing the current output enough to reduce the heating to an acceptable value.

I have used a SS push bike spoke as a series resistance to limit the alternator output of alternators without any sort of temperature control when I used it on depleted house batteries.

[Stu Jackson]

Originally Posted by RaymondR

With an alternator fitted with a regulator which "sees" the voltage at the output what it "sees" is the battery voltage, say 12.6V and the diode voltage drop, say 0.6V for a silicon diode, equals 13.2V and the regulator will wind back the output accordingly whereas without the diode it will only "see" 12.6 and respond with a higher amps output....

I knew you were going to do this.


First you said internally regulated alternator. This by definition, means a regulator that can ONLY "see" the voltage of the AO and only AT the AO.


Maine Sail has taught us that the voltage AT the battery bank can be much less because of voltage drop in the wiring between the AO and the battery bank.



That is the reason there is a separate voltage sense wire on external regulators.


This: "...With an alternator fitted with a regulator which "sees" the voltage at the output what it "sees" is the battery voltage..." is PLAINLY INCORRECT. Internal regulators rarely if ever have external battery sense. At rest or during operation there is a voltage drop between the AO point and the battery bank.


Also "...and respond with a higher amps output." is simply not how alternators work. The output of any alternator at any given voltage is determined by the acceptance of the battery bank and the size of the alternator. The "any given voltage" should be the appropriate charging voltage at the appropriate stage of charging.

[Stu Jackson]

Originally Posted by SV-NoBadDay

Hi Stu, no sorry i didn't look. Would you have a link or the title for me to search for it?

Paul

Paul,, look at the titles of the threads in this section of the forum. Choose the one(s) that have multiple pages.


And read Maine Sail's excellent analysis, link previously posted by someone else, thx.

[Hermia II]

You are perfectly set for using a Mastervolt Charge Mate Pro 90, which will limit the surge to the Litium batteries to 90A. Problem solved.
https://www.mastervolt.com/products/...e-mate-pro-90/

[RaymondR]

Originally Posted by Stu Jackson

I knew you were going to do this.


First you said internally regulated alternator. This by definition, means a regulator that can ONLY "see" the voltage of the AO and only AT the AO.


Maine Sail has taught us that the voltage AT the battery bank can be much less because of voltage drop in the wiring between the AO and the battery bank.



That is the reason there is a separate voltage sense wire on external regulators.


This: "...With an alternator fitted with a regulator which "sees" the voltage at the output what it "sees" is the battery voltage..." is PLAINLY INCORRECT. Internal regulators rarely if ever have external battery sense. At rest or during operation there is a voltage drop between the AO point and the battery bank.


Also "...and respond with a higher amps output." is simply not how alternators work. The output of any alternator at any given voltage is determined by the acceptance of the battery bank and the size of the alternator. The "any given voltage" should be the appropriate charging voltage at the appropriate stage of charging.

Bosch internal regulators commonly have a external voltage sensing terminal in the plug with the terminal to the ignition switch connection.

And what the regulator does is back off the output as the battery voltage rises.

The statement:

"With an alternator fitted with a regulator which "sees" the voltage at the output what it "sees" is the battery voltage, say 12.6V and the diode voltage drop, say 0.6V for a silicon diode, equals 13.2V and the regulator will wind back the output accordingly whereas without the diode it will only "see" 12.6 and respond with a higher amps output."

is basically correct, it is just dumbed down for the non alternator tech savvy. I guess I did not dumb it down enough.

[Nicholson58]

Originally Posted by Stu Jackson

Yes, you should get an external regulator.


Have you already installed the Liths?


The reason is simple: only an external regulator, preferably with temp sensors, will allow you to dial back the AO so it doesn't burn up due to the high acceptance of Liths.


It's also true for AGMs.


You should also get rid of the isolators, which drop Voltage thru them by ).7 to 1V.


WADR, it appears you could use some reading on this subject. Try marinehow.com Is for Sale.

This is totally spot on correct. We burned out our big alternator on a large firefly AGM bank. I have since dialed my Balmar external controller to 80%. Unless your alternator is rated for continuous full load output it must be limited.

And, yes, you need an external regulator. Make sure it has a program for lithium charging. This will have zero float.

https://marinehowto.com/lifepo4-batteries-on-boats/

[Gary Bode]

Different battery chemistries have different charging profiles. Use an external regulator for your lithium if you have a mix of chemistries. Victron makes a regulator that goes between your alternator and lithium.

[Brickwede]

Hey, I had nearly the same problem last year.
And that was my solution. I switched from 600Ah AGM to 400Ah LifeYPo4 and use now only one akku type. When you use differen types of akku you need a B2B loader for each akku type. And a kind of switch which akku you like to use for servicing. But didn't make it so complicated, think simple. Use only one type of akku.

Two times B2B Loaders 60A from two 80A engine alternators in sum 120A;
Solar Panel 30A;
Shore Power 60A;
5kW 230V generator supplies shore power 60A and 35A from generator alternator 40A (generator use starter akku from BB-engine); in sum close to 100A;
It works fine since installation.
I use WINSTON LiFeYPo4 with extended temperature range: -35°C up to 85°C.

[SailDutchman]

When charging LiIon or LiFePo batteries yes you most likeley are goiing to fry your standard alternator if you do not take any measures. a couple of years back I learned a lot from user MaineSail. Go visit his website at marinehowto.com/category/electrical/ you will learn a lot and avoid many costly mistakes. I'm using a Balmar Mc-614 MC Regulator and have had zero problems since. It use it with max current reduced to about 70% and even after 60 minutes at any throttle position my alternator has a very warm but not to hot Temp.

[skenn_ie]

Originally Posted by Stu Jackson

You should also get rid of the isolators, which drop Voltage thru them by ).7 to 1V.

Use either voltage-sensitive relays or a new device, an Ideal Diode. These actually consist of two semiconductor devices, a controller and a MosFET. You can buy modules which have both. They keep a very low (35mV) forward drop, while blocking reverse current.

[Stu Jackson]

Originally Posted by skenn_ie

Use either voltage-sensitive relays or a new device, an Ideal Diode. These actually consist of two semiconductor devices, a controller and a MosFET. You can buy modules which have both. They keep a very low (35mV) forward drop, while blocking reverse current.

Thx for the helpful and informative input on available newer technology.


I think that most people who post here with questions about their systems and mention isolators have a long way to go before they even think about Ideal Diodes, though. My experience here and on many other boating forums is that they rarely have a clue if they still have isolators and mention them, and they are invariably the OLD isolator types.

[skenn_ie]

There are ways to split the charge that does bring the batteries up to maximum.
1) Add a diode to the feedback circuit so that the alternator output is 0.7V up on standard, then use a diode splitter. Some external regulators have several slightly different o/p voltage options
2) Bring the 3-phase AC output out to a 2nd high-side rectifier (3 power diodes), then take the rectified output to the 2nd (or 3rd, or 4th) battery bank.
3) Use voltage sensitive relays between alternator and each bank.
4) Use Ideal Diodes. This is the simplest solution.
5) Use a battery-to-battery charger. These boost the output voltage from your primary bank to a charging voltage for the other, ONLY when the primary is well "up". This is the safest in terms of battery state, as it makes sure that your primary is well charged, AND has charging current available, before current is supplied to the secondary.

[kmacdonald]

Originally Posted by Stu Jackson

Thx for the helpful and informative input on available newer technology.


I think that most people who post here with questions about their systems and mention isolators have a long way to go before they even think about Ideal Diodes, though. My experience here and on many other boating forums is that they rarely have a clue if they still have isolators and mention them, and they are invariably the OLD isolator types.

It's called an automatic charge relay. Blue Seas makes them. They have been on the market a long time.
If you have a lead acid starting battery and LiFePO4 house bank use a B toB charger with the LA connected to the alternator. Limit current with the B toB charger.

The ACR works great with lead acid start and house banks.
Virtually no voltage drop across ACR.