DC to DC charger - not needed for boats with proper alternators.

[Simi 60]

Originally Posted by CaptainRivet

You want it simple and cheap.
Derate alternator to 70% with resistor on field wire.
Take an Victron argofet splitting diode, input alternator and connect output LFP and starter
Simple, cheap and fits your needs.
Your BMS shuts the alternator down when LFP full, the lead is cut off and surge protection, the voltage drop on argofet is enough to reduce voltage so its not to high for LFP

You've already lost me
And I certainly don't want BMS being my first line of defence.

What sounds simple to you is not for me - I would need to get a sparky on board and likely $700 gone in the blink of an eye

Or get dc2dc , do it myself and BMS and sparky don't need to get involved.

Originally Posted by CaptainRivet

Alternator does bulk, absorption done by solar.
You don't need 3 stage alternator charge and LFP takes itsself whats needed.

For us it's always 2.5kw of solar does bulk AND absorption

Alternator charging is just a bonus used in the days we move.
We have lived without it for the past seven years of full time cruising
We often don't move for over a week or more.
So clearly not essential for us.

But, if we could get 70amps @ 24v coming in from from Sterling dc2dc x2 and a new Delco Remy 33si alt for $1000 , be mad not to grab it.
And we did

[CaptainRivet]

Originally Posted by Simi 60

You've already lost me
And I certainly don't want BMS being my first line of defence.

What sounds simple to you is not for me - I would need to get a sparky on board and likely $700 gone in the blink of an eye

Or get dc2dc , do it myself and BMS and sparky don't need to get involved.




For us it's always 2.5kw of solar does bulk AND absorption

Alternator charging is just a bonus used in the days we move.
We have lived without it for the past seven years of full time cruising
We often don't move for over a week or more.
So clearly not essential for us.

But, if we could get 70amps @ 24v coming in from from Sterling dc2dc x2 and a new Delco Remy 33si alt for $1000 , be mad not to grab it.
And we did

Who is Sparky?
Why lost?
its super simple and cheap:
Measure field current in full throttle output and what is needed for 70% derating. Calculate R=U/i what you need for a resistor to get the needed voltage drop. Buy the calculate resistor, max 5 Euro and solder it into the field wire.
argofet connect input and output done, nothing to adjust.
100A Argofet is 100$, so 105$ spend +alternator=500$

No sterling helpline or support needed.


Your BMS=Battery management system is there to manage your battery and shut off when end of charge value is reached. Its the onlybdevice who can do this based on cell voltages in your system, so the go.to device to do it.

[tanglewood]

Originally Posted by Uncle Bob

Hey, come on, the entertainment value in these posts is well worth it.

I agree. I read them for the same reason I like watching train wrecks and other disasters on YouTube.


Being SOOO certain you are correct about everything blocks one from learning when they might not be quite so correct. I agree the whole "your alternator only works with LFP because your wiring is bad" is total rubbish.

[CaptainRivet]

Originally Posted by tanglewood

I agree the whole "your alternator only works with LFP because your wiring is bad" is total rubbish.

Well you can ask Marine how to, Terry T1 or any other very experienced installer what is the major reason a standard alternator didn't fry (and set the boat on fire) when boat owner connect the alternator directly to LFP bank.
And this will be the answer: undersized or broken cable and/or incorrect or corroded connection resuced many boat owners asses and boats from.frying and burning alternators.
Why: this (bad wiring) presents a high resistance to alternator that limits output current of alternator.
Facts nothing else. What else is there between a standard alternator and the LFP other then cable and connection that can create a high resistance?

And guess what do you think the boat owner states: why you need DC2DC or external regulator, on my boat it works since 6,9,15,30...month perfectly.

And that happens more often then you think as commercial and marketing of a lot of drop in manufacturer state you can simply replace your lead with LFP drop in...

[Simi 60]

Originally Posted by CaptainRivet

Who is Sparky?

Electrician

Why lost.?

Because I built boats as a trade
I was not an electrician

its super simple and cheap:
Measure field current in full throttle output and what is needed for 70% derating. Calculate R=U/i what you need for a resistor to get the needed voltage drop. Buy the calculate resistor, max 5 Euro and solder it into the field wire.
argofet connect input and output done, nothing to adjust.
100A Argofet is 100$, so 105$ spend +alternator=500$

No sterling helpline or support needed.

It doesn't matter to me
I have gone the way I have

Your BMS=Battery management system is there to manage your battery and shut off when end of charge value is reached. Its the onlybdevice who can do this based on cell voltages in your system, so the go.to device to do it.

The rest of the world would suggest that BMS is the LAST line of defence, not the first.

[CaptainRivet]

I know you done your way, just want to post the cheapest and simplest solution this can be done.
Or a fallback if your DC2DC dies...argofets 100A you get used for 20bucks, good to put into your spare parts box as emergency solution. Not everyone can rely on a genny.

Originally Posted by Simi 60

The rest of the world would suggest that BMS is the LAST line of defence, not the first.

1)the BMS is first line that manages the bank daily operations as its the most precise and the only source in your whole system that knows your cell voltages and is able to manage your bank on cell AND total voltage. Why do you think BMS has an "end of charge" parameter=> stop charging
Every,even cheap BMS eg Daly, has that. Its also the only device that sees all charging devices in total. And this is normal operation and not "lines of defence.
2)your charge sources individually decide about the stages bulk, absorption based on total voltage they see (some installations 10m+ away the MPPT ) but BMS should steer your charge by remote/CAN (thats the better way) or simply disconnect (simple way, works too) when to stop because of 1). Again even the cheap daly BMS does exactly that.
3)your 1st line of defence is again the BMS (which throws an Overvoltage disconnect based on cell and total voltage) or your charge sources (which disconnect based only on total voltage), depending on your system design. I prefer to have the BMS 1st line as its the most precise and 2nd line the charge sources as it has some error+only total voltage. But you can do it the other way around, both ways work.
4) last line of defense BMS: what happens in your installation if your BMS fails?
=>as Jedi suggests i have a BMV 712 including midpoint measuring on the middle cells as my last line of defence in case the BMS fails. It disconnects based on total voltage and on cell deviation of cell pack 1+2 and 3+4. The shunt is directly on the negative pole of my bank, so measurements are as precise as BMS, just not on cell level.
The BMV712 also delivers as added value all data to Cerbo GX which can then
A)compare BMS (my electrodacus BMS has a total and a load shunt on positive pole of bank) with BMV and throw an alarm if deviations are to big as one of the defence lines. Thats planned as cerbo integration of my BMS is in development.
B)delivers to all charge sources (except DC2DC) the total battery voltage at the poles of the bank to correct the error of cabling caused. I have also old MPPT that are not smart...so they can work better on the stages and cut off.
Plan to do all sorts of automations where cerbo makes your life much easier.

[CaptainRivet]

I know you done your way, just want to post the cheapest and simplest solution this can be done.
Or a fallback if your DC2DC dies...argofets 100A you get used for 20bucks, good to put into your spare parts box as emergency solution. Not everyone can rely on a genny.

Originally Posted by Simi 60

The rest of the world would suggest that BMS is the LAST line of defence, not the first.

The BMS is
1)the first line that manages the bank daily operations as its the most precise and the only source in your whole system that knows your cell voltages and is able to manage your bank on cell AND total voltage. Why do you think BMS has an "end of charge" parameter=> stop charging
Every,even cheap BMS eg Daly, has that. Its also the only device that sees all charging devices in total. And this is normal operation and not "lines of defence. Thats why its called Battery management system and not Battery rescue system or alike. A modern and good BMS manages the bank to optimize charge/load/lifespan AND makes sure its safe.
2)your charge sources individually decide about the stages bulk, absorption based on total voltage they see (some installations 10m+ away the MPPT ) but BMS should steer your charge by remote/CAN (thats the better way) or simply disconnect (simple way, works too) when to stop because of 1). Again even the cheap daly BMS does exactly that.
3)your 1st line of defence is again the BMS (which throws an Overvoltage disconnect based on cell and total voltage) or your charge sources (which disconnect based only on total voltage), depending on your system design. I prefer to have the BMS 1st line as its the most precise and 2nd line the charge sources as it has some error+only total voltage. But you can do it the other way around, both ways work.
4) last line of defense BMS: what do you do if your BMS fails?
=>as Jedi suggests i have a BMV 712 including midpoint measuring on the middle cells as my last line of defence in case the BMS fails. It disconnects based on total voltage and on cell deviation of cell pack 1+2 and 3+4. The shunt is directly on the negative pole of my bank, so measurements are quite precise.
It also delivers as added value all data to Cerbo GX which can then
A)compare BMS (my electrodacus BMS has a total and a load shunt on positive pole of bank) with BMV and throw an alarm if deviations are to big as one of the defence lines. Thats planned as cerbo integration of BMS is in development.
B)delivers to all charge sources (except DC2DC) the total battery voltage at the poles of the bank to correct the error of cabling caused. I have also old MPPT that are not smart...so they can work better on the stages and cut off.
C)plan to do all sorts of automations where cerbo makes your life much easier.

[tanglewood]

Originally Posted by CaptainRivet

I know you done your way, just want to post the cheapest and simplest solution this can be done.
Or a fallback if your DC2DC dies...argofets 100A you get used for 20bucks, good to put into your spare parts box as emergency solution. Not everyone can rely on a genny.



1)the BMS is first line that manages the bank daily operations as its the most precise and the only source in your whole system that knows your cell voltages and is able to manage your bank on cell AND total voltage. Why do you think BMS has an "end of charge" parameter=> stop charging
Every,even cheap BMS eg Daly, has that. Its also the only device that sees all charging devices in total. And this is normal operation and not "lines of defence.
2)your charge sources individually decide about the stages bulk, absorption based on total voltage they see (some installations 10m+ away the MPPT ) but BMS should steer your charge by remote/CAN (thats the better way) or simply disconnect (simple way, works too) when to stop because of 1). Again even the cheap daly BMS does exactly that.
3)your 1st line of defence is again the BMS (which throws an Overvoltage disconnect based on cell and total voltage) or your charge sources (which disconnect based only on total voltage), depending on your system design. I prefer to have the BMS 1st line as its the most precise and 2nd line the charge sources as it has some error+only total voltage. But you can do it the other way around, both ways work.
4) last line of defense BMS: what happens in your installation if your BMS fails?
=>as Jedi suggests i have a BMV 712 including midpoint measuring on the middle cells as my last line of defence in case the BMS fails. It disconnects based on total voltage and on cell deviation of cell pack 1+2 and 3+4. The shunt is directly on the negative pole of my bank, so measurements are as precise as BMS, just not on cell level.
The BMV712 also delivers as added value all data to Cerbo GX which can then
A)compare BMS (my electrodacus BMS has a total and a load shunt on positive pole of bank) with BMV and throw an alarm if deviations are to big as one of the defence lines. Thats planned as cerbo integration of my BMS is in development.
B)delivers to all charge sources (except DC2DC) the total battery voltage at the poles of the bank to correct the error of cabling caused. I have also old MPPT that are not smart...so they can work better on the stages and cut off.
Plan to do all sorts of automations where cerbo makes your life much easier.

You are assuming a BMS that tells you when to stop charging, but the vast majority of LFP installations are drop in batteries where there is no such communications from the BMS. I agree that's not optimum, or even desirable, but it's the reality of the market and drops-in are going to grow in market share, not shrink.

[wholybee]

Originally Posted by tanglewood

You are assuming a BMS that tells you when to stop charging, but the vast majority of LFP installations are drop in batteries where there is no such communications from the BMS. I agree that's not optimum, or even desirable, but it's the reality of the market and drops-in are going to grow in market share, not shrink.

There are clearly two opposing trains of though on the purpose of the BMS, and what level of control it should have.

I have seen zero evidence that having the BMS control everything offers any advantage. If the BMS and balancer are keeping the cells in balance, then any good charger that only has access to the pack voltage will work exactly as well as a device that has access to the cell voltages. If the cells go out of balance, then something is wrong, and the BMS will notify you of that.

Having the BMS control everything does not increase the cycle life of the cells. It does not allow for faster charging, or more capacity, or offer any advantage that anyone has shown. It is more complicated. It is more expensive. One of the amazingly great things about LFP is that I don't have to worry about my batteries anymore. Keeping the system simple is a virtue.

That doesn't mean the BMS should not connect to an alternator regulator. For the purpose of shutting down charging before a disconnect, not to tell the regulator how to do its job. A few drop-ins now do this, as well as many external BMS's. That is a great feature, but if you choose to use a DCDC charger that isn't even necessary.

I know there are a few very outspoken users that insist a BMS should control everything, but honestly, why?

[newhaul]

Originally Posted by wholybee

There are clearly two opposing trains of though on the purpose of the BMS, and what level of control it should have.

I have seen zero evidence that having the BMS control everything offers any advantage. If the BMS and balancer are keeping the cells in balance, then any good charger that only has access to the pack voltage will work exactly as well as a device that has access to the cell voltages. If the cells go out of balance, then something is wrong, and the BMS will notify you of that.

Having the BMS control everything does not increase the cycle life of the cells. It does not allow for faster charging, or more capacity, or offer any advantage that anyone has shown. It is more complicated. It is more expensive. One of the amazingly great things about LFP is that I don't have to worry about my batteries anymore. Keeping the system simple is a virtue.

That doesn't mean the BMS should not connect to an alternator regulator. For the purpose of shutting down charging before a disconnect, not to tell the regulator how to do its job. A few drop-ins now do this, as well as many external BMS's. That is a great feature, but if you choose to use a DCDC charger that isn't even necessary.

I know there are a few very outspoken users that insist a BMS should control everything, but honestly, why?

Exactly it's KISS on my vessel I don't want to think when I'm sailing . Dumb bms and a dc/DC for when I'm running the iron wind . Which is as rarely as I can .
Alternator is a backup to the backup charge source.

[CaptainRivet]

Originally Posted by wholybee

There are clearly two opposing trains of though on the purpose of the BMS, and what level of control it should have.

I have seen zero evidence that having the BMS control everything offers any advantage. If the BMS and balancer are keeping the cells in balance, then any good charger that only has access to the pack voltage will work exactly as well as a device that has access to the cell voltages. If the cells go out of balance, then something is wrong, and the BMS will notify you of that.

Having the BMS control everything does not increase the cycle life of the cells. It does not allow for faster charging, or more capacity, or offer any advantage that anyone has shown. It is more complicated. It is more expensive. One of the amazingly great things about LFP is that I don't have to worry about my batteries anymore. Keeping the system simple is a virtue.

That doesn't mean the BMS should not connect to an alternator regulator. For the purpose of shutting down charging before a disconnect, not to tell the regulator how to do its job. A few drop-ins now do this, as well as many external BMS's. That is a great feature, but if you choose to use a DCDC charger that isn't even necessary.

I know there are a few very outspoken users that insist a BMS should control everything, but honestly, why?

Every professional BMS and a lot of consumer BMS take more and more control over the battery management and also about security.
High quality drop ins communicate via CAN or/and BT, only the cheap amazon, aliexpress and chinese stuff has rudimentary 5$ BMS that are the real problem and actual not a BMS that has the security levels necessary for a boat.

The BMS has as only the 100% control based on cell voltage and total voltage directly at the cells with minimum losses but even here the balance cables have some.
Every charge source has already measurement mistakes/incoorect values through cable and connection losses and on the other side the BMS steers on mV base. The further away the bigger the inconsistencies.

Its also wrong that the BMs can do nothing about optimization of battery: Tao and REC BMS (think batrium too) for example can cycle the bank much deeper and only request a 100% charge every 2 weeks (adjustable) means instead of 14 mini cycles daily that tries to charge every day from 90 to 100% for 14 days it does one cycle from 100 to 20% and back to 100 in 2 weeks. Good for a bank with a lot spare capacity for couple bad days.
Just to mention one of many other.
An active balancer that actually covers up when devations getting too big is not always the guarantee that a bank does well. Again here is optimazation possible, a passive balancer that evens out little deviation gives BMS much better information about the real state of a bank. Only if devation is bigger the BMS starts an active balancer that gets bank back to balance.

As most of capacity is between 3.1 and 3.3V several inconsistencies due to connections and cables add up so the external sources can actually not steer charging process properly as what they measure has already more error then the 0.2V between 3.1V and 3.3V...

Many boats have serveral charge sources.
you cannot take a small 30ft boat with 2 solar panels, 1 Mppt, a DC2DC and 1 or 2 drop ins as reference.

Switching off charge sources by BMS without communication can be done or is done by most conaumer FET BMS, Victron MPPT don't care as well as DC2DC charger. If you have alternator directly connected you need to take precautions to protect it and bank from surge and shut off under load.
A BMV takes care about last resort switch off, for drop ins you cannot use midpoint and therefor cell deviation detection.

[CaptainRivet]

Originally Posted by newhaul

Exactly it's KISS on my vessel I don't want to think when I'm sailing . Dumb bms and a dc/DC for when I'm running the iron wind . Which is as rarely as I can .
Alternator is a backup to the backup charge source.

A BMS that takes the full control over your whole system is kiss. One device you have to check...not many and actually BMS does all automatically so you don't have to check it at all after you done a complete stress test of your install and know everything is adjusted as should be and working.

Take eg electrodacus: it controls everything very safely with switching of charge and load via their remote function.
So all you need is an electrodacus, 1 or 2 shunts, a Victron MPPT and DC2DC or regulated alt plus 1 Battery protect for switching on/off your legacy load system.
It controls your whole charge and load at one single point directly on the battery on cell and total battery voltage, in&outgoing AH and A without carring current and no need for expensive high current relay as its switching on the low and not the hot side. Remote function is heavly tested at Victron factory and need to last 10 years as you have garauntee.
Simple and very save.
BMS carries no current so no problem using it on a single hybrid starter and house bank as BMS cannot be damaged by surge.
With a BMS controlling everything you don't need an extra starter battery if you have the right cells or bank size that support the surge of a starter. And if you have 2x200AH lithium instead 200AH lithium and 110 or 200AH lead, you have double capacity and definitely enough to start each 4 zylinder diesel on the market for a leisure sailingboat till 60ft.

Wanna have it starting every time, put LVC of BMS at 3.0V and everything gets cut off at 3 0V except of starter and it will always start your engine. You can set a 2nd LCV threshold at 2.5V in BMS (actually set already) that cuts then everything off. The hybrid you constantly using so you know it works. The lead starter thats constantly trickle charged can gas out or run dry but still shows you full voltage without load but if you wanna start it breaks together as it cannot support the load anymore.
Again thats KISS...

An very expensive blue system relay has 300 cycles due to manual and is never tested what are 300 cycles in operations....if its switching 3 times in 3 years are this 3 cycles? Definitely not.

[newhaul]

Originally Posted by CaptainRivet

A BMS that takes the full control over your whole system is kiss. One device you have to check...not many and actually BMS does all automatically so you don't have to check it at all after you done a complete stress test of your install and know everything is adjusted as should be and working.

Take eg electrodacus: it controls everything very safely with switching of charge and load via their remote function.
So all you need is an electrodacus, 1 or 2 shunts, a Victron MPPT and DC2DC or regulated alt plus 1 Battery protect for switching on/off your legacy load system.
It controls your whole charge and load at one single point directly on the battery on cell and total battery voltage, in&outgoing AH and A without carring current and no need for expensive high current relay as its switching on the low and not the hot side. Remote function is heavly tested at Victron factory and need to last 10 years as you have garauntee.
Simple and very save.
BMS carries no current so no problem using it on a single hybrid starter and house bank as BMS cannot be damaged by surge.
With a BMS controlling everything you don't need an extra starter battery if you have the right cells or bank size that support the surge of a starter. And if you have 2x200AH lithium instead 200AH lithium and 110 or 200AH lead, you have double capacity and definitely enough to start each 4 zylinder diesel on the market for a leisure sailingboat till 60ft.

Wanna have it starting every time, put LVC of BMS at 3.0V and everything gets cut off at 3 0V except of starter and it will always start your engine. You can set a 2nd LCV threshold at 2.5V in BMS (actually set already) that cuts then everything off. The hybrid you constantly using so you know it works. The lead starter thats constantly trickle charged can gas out or run dry but still shows you full voltage without load but if you wanna start it breaks together as it cannot support the load anymore.
Again thats KISS...

An very expensive blue system relay has 300 cycles due to manual and is never tested what are 300 cycles in operations....if its switching 3 times in 3 years are this 3 cycles? Definitely not.

Ok since you quoted me I assume your comments are mainly to my setup.

Westerbeke 10-two diesel a 350cca Fla start battery. 75 amp alternator. Still deciding 40 or 60 amp b2b to charge the 250ah lifepo4. 1p4s with 300 amp Daly bms . currently 200 watts solar ( adding 400 this fall -winter. 40 amp tracer MPPT . 2500 watt inverter charger . fully adjustable from 11v to 15v, 1amp to 120 amp output. . also carry a small lfp jump pack that can start my truck t444e diesel engine. Just in case. but that's just my maritime engineer kiss system .

[CaptainRivet]

Originally Posted by newhaul

Ok since you quoted me I assume your comments are mainly to my setup.

Westerbeke 10-two diesel a 350cca Fla start battery. 75 amp alternator. Still deciding 40 or 60 amp b2b to charge the 250ah lifepo4. 1p4s with 300 amp Daly bms . currently 200 watts solar ( adding 400 this fall -winter. 40 amp tracer MPPT . 2500 watt inverter charger . fully adjustable from 11v to 15v, 1amp to 120 amp output. . also carry a small lfp jump pack that can start my truck t444e diesel engine. Just in case. but that's just my maritime engineer kiss system .

No not mainly your setup. Yours has already several charge and load sources and its not kiss.
You definitely need a Victron BMV as last resort with midpoint on your cells as jedi suggests as daly is not really the reliablest BMS and missing a last resort in case Mosfets fry close. Also 250AH bank with 2500W inverter plus rest load means you stress the cells quite high with 1C.
This is exactly the prime example where a hybrid bank with 2 batteries each 250AH 0cells that has then 400-500AH the whole system would profit, instead 1 service with 250 and one lead starter.
Another buddy boat a moody 33 decksalon has very close setup to yours but Victron MPPT and multi 2000VA, also daly 300A BMS.
3 month ago i helped him to replace daly with electrodacus BMS that now shuts all Victrons off via remote and made one hybrid bank of 8x 200AH calbs due to space constrains. No mosfets that can fry, the cells now are max loaded 0.4C instead 1C and mitsubishi 115A alt without any mods is steered via Nordkyn VSR200 regulator directly via BMS. One set of parameters that steers and controlls all, thats real kiss.
Now its kiss. Supereasy to test and troubleshoot, simply switch the EXTIo that switch load and charge on/off and you can see on optocoupler glowing red or stay dark if that works or not.

Did you switch off your tracer MPPT under full load on battery side? Victron survives that but other don't or only over a periode?
DC2Dc i suggest 40A as 60A is too high for a 75A alternator even at perfect cooling. Assume you wanna take renogy one, i think their 60A you can also switch down to 30A Limit, check it as that would be worth trying then.

[CaptainRivet]

Originally Posted by newhaul

Ok since you quoted me I assume your comments are mainly to my setup.

Westerbeke 10-two diesel a 350cca Fla start battery. 75 amp alternator. Still deciding 40 or 60 amp b2b to charge the 250ah lifepo4. 1p4s with 300 amp Daly bms . currently 200 watts solar ( adding 400 this fall -winter. 40 amp tracer MPPT . 2500 watt inverter charger . fully adjustable from 11v to 15v, 1amp to 120 amp output. . also carry a small lfp jump pack that can start my truck t444e diesel engine. Just in case. but that's just my maritime engineer kiss system .

No not mainly your setup. Yours has already several charge and load sources and its not basic, simple and not kiss anymore.
You definitely need a Victron BMV as last resort with midpoint on your cells as jedi suggests as daly is not really the reliablest BMS and missing a last resort in case Mosfets fry close. Also 250AH bank with 2500W inverter plus rest load means you stress the cells quite high with 1C.
This is exactly the prime example where a hybrid bank with 2 batteries each 250AH 0cells that has then 400-500AH the whole system would profit, instead 1 service with 250 and one lead starter.
Another buddy boat a moody 33 decksalon has very close setup to yours but Victron MPPT and multi 2000VA, also daly 300A BMS with 4x200AH calb and 140AH lead starter.
3 month ago i helped him to replace daly with electrodacus BMS that now shuts all Victrons off via remote and made one hybrid bank of 8x 200AH calbs. No mosfets that can fry, the cells now are max loaded 0.4C instead 1C and mitsubishi 115A alt without any mods is steered via Nordkyn VSR200 regulator directly via BMS. One set of parameters that steers and controlls all, one battery chemistry, thats real kiss.
Supereasy to test and troubleshoot, simply switch the EXTIo from 0 to 1 or back 0 that switch load or charge or SOC based sources on/off and you can see on optocoupler glowing red or stay dark if that works or not.

Did you switch off your tracer MPPT under full load on battery side? Victron survives that but other don't or only over a periode?
DC2Dc i suggest 40A as 60A is too high for a 75A alternator even at perfect cooling. I think if renogy their 60A you can also switch down to 30A Limit, check it as that would be worth trying then as you get a 30 and a 60A in one.