stock yanmar (valeo) 125amp alternator charging lifepo4

[ers61]

sailors who used this alternator without a dc2dc charger or any other alternator modifications

could you share your experiences ? did you burn your alternators like said ?

there is a lot info already with people using dcdc s or balmars or alternator regulators. i wonder how is people not using them doing ? how is your setup ?

[donradcliffe]

I have one data point.

Boat with old 2 cylinder upgraded to internally regulated 85 amp alternator, ground and B+ wires not upgraded.
200 amp hr drop-in lifepo4.
300 watts flexible solar.

First test--depleted battery to 50 % SOC and fired up engine

Result-- 20 amps of charging current, dropping to 12 after 0.5 hours.
Alternator stayed cold enough to keep your hand on it.
Wire connections remain cold.

Ran extra #6 wires from alternator case to engine ground and B+ to Starter Terminal

Second test SOC 40%.

Result-- 40 amps of charging current, dropping to 30 after 0.5 hrs.
Alternator and connections warm, but not hot.

Now maybe I could have burned out the alternator if I had upgraded all the connecting wire to 2/0, but I was happy with 40 amps, and there was no stress on the electrical system. Battery never went below 50% SOC all the way to and from Hawaii.

[ers61]

Originally Posted by donradcliffe

I have one data point.

Boat with old 2 cylinder upgraded to internally regulated 85 amp alternator, ground and B+ wires not upgraded.
200 amp hr drop-in lifepo4.
300 watts flexible solar.

First test--depleted battery to 50 % SOC and fired up engine

Result-- 20 amps of charging current, dropping to 12 after 0.5 hours.
Alternator stayed cold enough to keep your hand on it.
Wire connections remain cold.

Ran extra #6 wires from alternator case to engine ground and B+ to Starter Terminal

Second test SOC 40%.

Result-- 40 amps of charging current, dropping to 30 after 0.5 hrs.
Alternator and connections warm, but not hot.

Now maybe I could have burned out the alternator if I had upgraded all the connecting wire to 2/0, but I was happy with 40 amps, and there was no stress on the electrical system. Battery never went below 50% SOC all the way to and from Hawaii.

thanks for your reply, how long have you been using it like this ? did you have longer engine hours after your setup ? or was just testing?

[CaptainRivet]

Originally Posted by ers61

sailors who used this alternator without a dc2dc charger or any other alternator modifications

could you share your experiences ? did you burn your alternators like said ?

there is a lot info already with people using dcdc s or balmars or alternator regulators. i wonder how is people not using them doing ? how is your setup ?

It will burn sooner or later, it’s physics.
The internal resistance of LFP is 10-20milliOhm, basically a short that you are charging and the resistance your regulator for lead acid batteries see is your cabling,connection and fuses.
If you are lucky they are underrated and connection corroded presenting a high resistance to your lead acid regulator and limiting the output current and protecting your alternator…and your engine room is very well ventilated offering a very good cooling environment.
That’s what have saved thousands of alternators from immediately burning up when newbies or unqualified installers put in drop in LFP without taking care about the alternator.
Well and if your LFP shuts off during full load the spike kills your rectrifier and diodes in your regulator….

There is only one setup that works, having a charge splitter diode eg Victron Argofet and having a lead acid battery connected too acting as load dump and resistance in the circuit. That will still put a lot of stress on your Valeo alt and you can count for less lifespan=earlier overhaul.

[CaptainRivet]

Originally Posted by donradcliffe

I have one data point.

Boat with old 2 cylinder upgraded to internally regulated 85 amp alternator, ground and B+ wires not upgraded.
200 amp hr drop-in lifepo4.
300 watts flexible solar.

First test--depleted battery to 50 % SOC and fired up engine

Result-- 20 amps of charging current, dropping to 12 after 0.5 hours.
Alternator stayed cold enough to keep your hand on it.
Wire connections remain cold.

Ran extra #6 wires from alternator case to engine ground and B+ to Starter Terminal

Second test SOC 40%.

Result-- 40 amps of charging current, dropping to 30 after 0.5 hrs.
Alternator and connections warm, but not hot.

Now maybe I could have burned out the alternator if I had upgraded all the connecting wire to 2/0, but I was happy with 40 amps, and there was no stress on the electrical system. Battery never went below 50% SOC all the way to and from Hawaii.

How is your lead acid starter battery connected to the alternator?
20A at 50% SOC from a 85A alternator, that’s very low which means your lead acid alternator regulator sees a high resistance to limit the charge current to 20A then to 12A, I guess from the lead starter that was full.

[hjohnson]

Originally Posted by ers61

sailors who used this alternator without a dc2dc charger or any other alternator modifications

could you share your experiences ? did you burn your alternators like said ?

there is a lot info already with people using dcdc s or balmars or alternator regulators. i wonder how is people not using them doing ? how is your setup ?

It will work fine, with a little work. I was gifted with an 85A Mitsubishi off of a 4 cylinder Yanmar. Took it to my local alternator shop, and had them rebuilt it, and convert it for external regulation. They also replaced the diode pack with that would normally be used on a 120A alternator (along with me bearings etc…)

I then added an external regulator that monitors the alternator temperature (and integrates with my power system) and it’s worked a test for well over a year.

If you just stick with the internal regulator, you will burn it out in short order.

[donradcliffe]

The boat mas modified for the Pacific Cup, but had enough solar to meet its needs on most days at sea. The racers were only running Led lighting an a refrigerator, and they only ran the engine for about 5 hours over a 12 day passage. I added a tiller pilot for the return, and used 15 gallons of fuel out of the 60 I brought.

The existing lead acid starter battery had a relay that combined it when the voltage was over 13.4vc which whenever the engine was on, and most days when there was good sun.

[CaptainRivet]

Originally Posted by donradcliffe

The boat mas modified for the Pacific Cup, but had enough solar to meet its needs on most days at sea. The racers were only running Led lighting an a refrigerator, and they only ran the engine for about 5 hours over a 12 day passage. I added a tiller pilot for the return, and used 15 gallons of fuel out of the 60 I brought.

The existing lead acid starter battery had a relay that combined it when the voltage was over 13.4vc which whenever the engine was on, and most days when there was good sun.

Oops paralleling a lead and an LFP unprotected via a relay is very dangerous and a big NoGo.

[donradcliffe]

Its more dangerous to spread misinformation.

You reminded me I have had the same setup in my RV for three years now. A 200 amp hour LFP is paralleled with the start battery and 180 amp alternator through a VSR from Yandina. The relay automatically closes at 13.4 volts, but I can manually close it or open it with a rocker switch. The highest measured current into the LFP has been 65 amps.

[CaptainRivet]

Originally Posted by donradcliffe

Its more dangerous to spread misinformation.

You reminded me I have had the same setup in my RV for three years now. A 200 amp hour LFP is paralleled with the start battery and 180 amp alternator through a VSR from Yandina. The relay automatically closes at 13.4 volts, but I can manually close it or open it with a rocker switch. The highest measured current into the LFP has been 65 amps.

well consider yourself lucky paralleling FLA and LFP and nothing happened so far and only 65A were floating into LFP if the starter is at 13.8V while LFP is at 11.8V then the party starts with melted cables in best case...i melted several during my car stereo times....
its dangerous especially if you don't know where the issue is...as long as LFP and FLA are close in voltage all is ok, the problem starts when one is low and the other high....and boats normally have bigger banks then RVs=more current floating plus a boats starter is always full, a cars/RV seldomly. Thats also why you never use VSR in a boat when using different chemistries, a spliiting diode (eg argofet) is the way to go in this case.


watch this video: he developed a device that let you mix lead and lithium. He also explains the problems mixing them. his device only connects them together if they have the same voltages...

https://www.youtube.com/watch?v=tAuPfgZgXec

[HeinSdL]

Originally Posted by CaptainRivet

well consider yourself lucky paralleling FLA and LFP and nothing happened so far and only 65A were floating into LFP if the starter is at 13.8V while LFP is at 11.8V then the party starts with melted cables in best case...i melted several during my car stereo times....
its dangerous especially if you don't know where the issue is...as long as LFP and FLA are close in voltage all is ok, the problem starts when one is low and the other high....and boats normally have bigger banks then RVs=more current floating plus a boats starter is always full, a cars/RV seldomly. Thats also why you never use VSR in a boat when using different chemistries, a spliiting diode (eg argofet) is the way to go in this case.


watch this video: he developed a device that let you mix lead and lithium. He also explains the problems mixing them. his device only connects them together if they have the same voltages...

Returning to this earlier thread, I watched that video with interest. In the video, the presenter (Clarke?) makes the point that you should first make the connection LFP-FLA via a power resistor, until the current has dropped off to something close to 0. Would an alternative be to measure the battery voltages at the point where the connection is made and then only connect once the two voltages are the same? That should be fine too? For a 300Ah LFP + 240Ah AGM combo, how close should the voltages be to make the connection?

[Pete7]

Hein, I don't even bother matching the voltages when combining the lead acid and LFP.

My set up has changed quite a bit over time. Initially with a single 120Ah LFP and 2 x Trojan 85Ah flooded lead acid. Today I have 1 120Ah and 1 x 100Ah LFP and a single 85Ah Trojan. When not on board the LFP is isolated, leaving the solar to charge the single LA which powers the bilge pumps. Once on board I just turn a large battery switch and let the batteries balance out. There is normally a flow starting at 10A but dwindles down to nothing over a few minutes. I haven't tried with either deeply discharged.

I have a power resistor but that is more for pre-charging the inverter before first use if it hasn't been on for a while.

It all works well, but my Trojans were quite new hence I wanted to make use of them. What won't work is old lead acid batteries particularly if then then develop an internal short.

The point is the LA sits at float all day long not doing much, but isolating the LFP means they can sit at 50=70% without being constantly floated. Whilst unlikely to get below 5'c temperature is another reason to put the LFP to sleep.

Pete

[HeinSdL]

Thanks Pete, also for the PM.

[CaptainRivet]

Originally Posted by HeinSdL

Returning to this earlier thread, I watched that video with interest. In the video, the presenter (Clarke?) makes the point that you should first make the connection LFP-FLA via a power resistor, until the current has dropped off to something close to 0. Would an alternative be to measure the battery voltages at the point where the connection is made and then only connect once the two voltages are the same? That should be fine too? For a 300Ah LFP + 240Ah AGM combo, how close should the voltages be to make the connection?

You have a powerfull lead and wanna compromise it with a an AGM. What clarke is doing is getting the worst of both world...first also thought this is a great solution (you will find a thread on that here if you look for it if you wanna know why).
If you desperately wanna combine lead and LFP get an X2-BMS. It uses correctly the lead as backup and dumb load and deal with charging of both correctly.
If Pete gets a battery related damage claim, worst case boat burned down, the insurance will bail easily out as it is forbidden by ISO (for European registered boats, quite sure UK will also require ISO after brexit but check with your insurance) and ABYC (for US registered boats) to directly combine 2 different chemistries with LFP.
Pete done right would be 2 ways possible:
1)Connect a argofet splitting diode directly to main bus or if you have sperate buses to charge bus. Then connect LFP to one and lead to the other output. As soon as there is charge both batteries get charged.
2)use a DC2DC 12Vto12V converter with adjustable voltage and set it to float voltage of your trojan. The converter tops up the trojan from the LFP. You can also use a DC2DC charger but a converter is cheaper and enough. It can be a 5A DC2DC, thats enough for a 85AH trojan, for a 240AH AGM use the 18A or 20A ones.
Pete has very small batteries and FLA has a very high resistance so lets say its acceptable to do as the FLA protects itself and high resistance limit the current, with the knowing the insurance consequences...a 300AH LFP and 240AH AGM is a totally different story, the current that can float here if eg AGM is low is huge and exponentially more risk, an absolute noGO

[CaptainRivet]

Originally Posted by ers61

sailors who used this alternator without a dc2dc charger or any other alternator modifications

could you share your experiences ? did you burn your alternators like said ?

there is a lot info already with people using dcdc s or balmars or alternator regulators. i wonder how is people not using them doing ? how is your setup ?

just read its the 125AH valeo on newer yanmar, so the one that has already a serpentine belt from factory, correct?
If yes that has an internal temp control which means it can protect the alternator. its not as conservative as the Mitusbishi 115A one but still works sufficent.

you can charge LFP with it with a victron argofet and a lead starter in parallel and put a disconnect relay between argofet and LFP house so the BMS can cut of the alternator at 13.8-14V. the lead starter will protect the alternator and installation from a surge.
Alternative you can get the Nordkyn VSR 200 which will control the 125AH valeo without any modification via its sense wire means keeping the internal temp control intact. i assume you now get around 60A, with the VSR its around 85-90A as Nordkyn VSR can steer the internal temp control more efficently.
it doesn't make sense to modify this alternator to external control as you loose the internal temp control which measures the stator temp with an external regulation that just measures case temp plus the alternator will deliver 5-10A more then when steered via Nordkyn VSR200. more costs, complex for 5 A gain, not worth it.