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On my fourth alternator....??

This video is interesting.


I have a DC-DC 40A working very well, but I'd be interested to hear other members' opinions on this approach.
Most that I've seen my alternator (2004 Ford E450 v10) push was 85 amps. The only time I would be worried about over heating the alternator would be Arizona heat and idling for long periods or during extended heavy loading from a DC appliance or DC to AC inverter powering air conditionor.
 
Most that I've seen my alternator (2004 Ford E450 v10) push was 85 amps. The only time I would be worried about over heating the alternator would be Arizona heat and idling for long periods or during extended heavy loading from a DC appliance or DC to AC inverter powering air conditionor.

There are going to be different consideration for alternator charging for RV vs. marine applications. And in the marine world ( this is a marine post btw) difference based on boat size, type and usage.


Sail Boats: typically small case alternators with terrible air flow and limited motor run time (because we are sailing), so milking every amp from the limited motor run time is a priority.

Small power boat: same as above, but a lot more engine run time, therefor DC-DC solution might be OK

Large Power Boat: large case alternator, better air flow, potentially lots of motor run time

RV: large case alternator, lots of air flow, perhaps lots of run time (depending on owner use case)


But of course, If you have tons of solar and are in a sunny place, that also impacts your alternator solution and dependacy on this charging source.
 
Victron FTW.
Friends don't let friends buy renogy. PERIOD

As so well explained already, you need a regular starting battery for your engine, isolate your house circuit with the lifepo4 battery(s) and a Victron DC to DC charger. Live happily ever after.

Got a solar panel and charge controller too? Or do you plug in. Unless you motor every day you may want to consider an alternate charge source for your house batteries.

Don't listen to BB. They make a nice battery, but tend to over-simplify on the ancillaries and applications.
Agree that the Renolgy 40amp DC-DC has a bad reputation.

I should note that I also had a failure with a Victron 30amp.

The remote on/of would not function. Seems to be an issue based on the Victron community.

I replaced it with the Victron 18amp version - and that is working fine.

If you buy the 30amp, check the remote function immediately after purchase - so you can return if you get a dud.

I have a nice blue paper-weight now... would also be a good door-stop
 
Most that I've seen my alternator (2004 Ford E450 v10) push was 85 amps. The only time I would be worried about over heating the alternator would be Arizona heat and idling for long periods or during extended heavy loading from a DC appliance or DC to AC inverter powering air conditionor.

So is your vehicle alternator charging the EG4 Lifepower directly, no current limiting device? Wondering why does it not draw more when the SoC is low?
Is it a "smart" alternator that limits the current?
 
I watched most of it. Nothing new, and he missed some points, which have all been addressed on this forum before. First, yeah, a 180A alternator can put out 180A, but for how long without overheating? That is why the conservative 40A or 80A limit for charging a large bank.
Second, a new alternator from Mercedes certainly has a temperature sensor in it, to limit output if it starts to overheat. So, thats the safety you need for a direct to LFP charging. Not all alternators have this. You need to know what you have before doing this.
Lastly, airflow around the alternator makes a huge difference. In an RV or van, the engine fan is moving tons of air, pulling it from outside, and cooling everything in the engine bay. Driving down the road at 60 mph, there is even more. Engines on a boat have no fan, and are completely enclosed, with minimal airflow to run the engine. So everything will get very hot. A blower can be installed with a hose to bring in outside air. That helps alot, but still isn't as much cooling as an RV.

Lots of people charge LFP directly from an alternator even on a boat. You just need to know if your alternator can take it, and if you need more cooling, or if you need to upgrade.
 
I watched most of it. Nothing new, and he missed some points, which have all been addressed on this forum before. First, yeah, a 180A alternator can put out 180A, but for how long without overheating? That is why the conservative 40A or 80A limit for charging a large bank.
Second, a new alternator from Mercedes certainly has a temperature sensor in it, to limit output if it starts to overheat. So, thats the safety you need for a direct to LFP charging. Not all alternators have this. You need to know what you have before doing this.
Lastly, airflow around the alternator makes a huge difference. In an RV or van, the engine fan is moving tons of air, pulling it from outside, and cooling everything in the engine bay. Driving down the road at 60 mph, there is even more. Engines on a boat have no fan, and are completely enclosed, with minimal airflow to run the engine. So everything will get very hot. A blower can be installed with a hose to bring in outside air. That helps alot, but still isn't as much cooling as an RV.

Lots of people charge LFP directly from an alternator even on a boat. You just need to know if your alternator can take it, and if you need more cooling, or if you need to upgrade.
Yes, I researched the hell out of the question, on the forum and elsewhere. Decided there was no way I'd chance charging my 280Ah lithium battery directly from my 160A "dumb" vehicle alternator. Also the DC-DC ensures the right charging voltage is applied over the long wire run. Thanks.
 
There are going to be different consideration for alternator charging for RV vs. marine applications. And in the marine world ( this is a marine post btw) difference based on boat size, type and usage.

On that note I'll see myself to the door.

See my comment at the bottom of this post.
 
So is your vehicle alternator charging the EG4 Lifepower directly, no current limiting device? Wondering why does it not draw more when the SoC is low?
Is it a "smart" alternator that limits the current?
Directly through a factory Solenoid. Just remember that the wire size, length and maximum voltage are the limiting factors in my RV. If you connect the two systems with a thick cable that is short, it could result in a perfect storm where you can melt a "dumb" alternator.
 
Alternator diodes generate a lot of heat when high output current is maintained. Diodes are often press fit into alternator metal case for heat transfer to alternator casing.

Auto alternators get some air flow to help cool their casing. A boat with an inboard engine heat exchanger only cools the engine block and the alternator does not usually get much air flow to help cool it. Make sure you have a good-sized cooling fan behind the alternator pully to help circulate air through alternator. Some replacement alternators do not come with pully fans.

Alternators are usually designed to be self-limiting on their output current by core magnetic flux saturation on their rotor field winding. But this self-current limiting may be based on having some air cooling for their diodes.
 
This video is interesting.


I have a DC-DC 40A working very well, but I'd be interested to hear other members' opinions on this approach.
No idea how much voltage drop between his alternator/battery and the lithium batteries. That may be the main reason that is causing the current to be at 80A.
 
In the past, I was using a second battery in Grand Cherokee WG. These are known to have not the most reliable charging system. To avoid overloading the alternator I've calculated the proper wire size to limit the charging current with a fully empty 2nd battery to 20A.

This would be a lot easier to achieve with a LiFePo4 battery. So just calculate the required voltage drop, then the wire size at the desired max current and you'll be good to go. The disadvantage is the lack of control over the charging current. As the 2nd battery gets charged the charging current will drop significantly. To work around this I used a step-up converter that supported CC/CV settings. In Aliexpress two 10A step-up CC/CV converters were like $20 with shipping included.
 
I run lithoum house batteries and agm starter
My trial and error has taught me this...
No lithium Iron is drop in on a boat, and almost none can be used as a starting battery, those that can are super expensive.
Fuses are a must
3 choices:
Victron DC-DC charger is the best
Renogy 20A & 40A chargers are cheap but not moisture proof
Xantrex echo charger is good if 18A is enough for you, this option is rarely mentioned but a good one.
Most outboards especially older ones only output like 35-65 Amps so a 40A or 60A charger is too much in my case.
Put down a rubber mat to help absorb shock. Lifepo4 batteries have boards inside that don't do well with being hit for 8 hours at a time.
 
Even though my 160A alternator seems fine (so far) to charge the lithium battery at 40A, I'd like know how much hotter than normal it gets. I had considered using a non-contact thermometer to measure surface temp after charging at full load, but I think mounting a thermocouple and reading real-time might be better.

My multimeter came with this styleTC1.jpg

but I'll try one of theseTC3.jpg

Should screw mount to the surface to optimise heat transfer. Anybody else tried such a method?
 
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This video has some good info on the subject:
Sadly, Clark has little clue what he is talking about in regards to the ABYC. Manufacturers do not run the show nor do they write the standards.

The #1 failure of Alt’s we have seen with LFP is Heat damage, then diodes..(ex marine alternator manufacturer) Alts like those tiny Hitachi’s try to self protect by reducing charge voltage as they heat up. This often result in almost no charging at all However, if you are routinely cycling to 80 or 90% DoD then they can cook pretty easily.

The worst thing you can do to a stock alt is to improve upon the crappy factory wiring. It is loaded with voltage drop which is also helping to protect a stock alt.

Best way to protect against heat damage is an external regulator such as Balmar or Wakespeed. Balmar also makes an excellent “Alternator Protection Module” which deals with Load dumps.

An ARGOFET an APM and an external regulator and you can charge LFP with your alt with zero issues. You can also use an APM and DC to DC but charging will be slow..
 
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The worst thing you can do to a stock alt is to improve upon the crappy factory wiring. It is loaded with voltage drop which is also helping to protect a stock alt. Best way to protect against heat damage is an external regulator such as Balmar or Wakespeed. Balmar also makes an excellent “Alternator Protection Module” which deals with Load dumps”. An ARGOFET, APM and an external regulator and you can charge LFP with your alt with zero issues.

This has been my position for why those that claim they don't need DC-DC chargers because they've never blown up a stock alternator.

That 0.8-1.0V drop causes the alternator to throttle back its output before it cooks.
 
This has been my position for why those that claim they don't need DC-DC chargers because they've never blown up a stock alternator.

That 0.8-1.0V drop causes the alternator to throttle back its output before it cooks.
We Unfortunately folks get frustrated their 80A Hitachi is only putting 12-15A into the LFP bank so they upgrade the alt B+ & B- wires and cook goes the alt. We had a recycle bin in our shop full of cooked stators.
We first started seeing heat damage when AGM’s hit the scene. then when FDC & AGM banks kept getting bigger and bigger Heat damage continued. Then LFP Hit big for us back in 2011, all custom built packs or Genasun back then and luckily we already knew how to deal with it..
 
My Bosch AL170X never seems to go above 40°C supplying `75A to a 4s2P 460Ahr bank. (Too big for my needs)
200A Argofet splitter. Planning on a small adjustable buck to periodically give start LA a bit of a nudge.
MC618 set to 55% (bottom setting as only 1 V belt)
Factory cooling cowl on back of alt to saloon air.
Porsche 944 factory cowl can be rotated to exit outside. (with a bit of fg mod to cowl)
Good thing is I have a 12v fan I can mount to force air in if necessary.
 

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My Bosch AL170X never seems to go above 40°C supplying `75A to a 4s2P 460Ahr bank. (Too big for my needs)
200A Argofet splitter. Planning on a small adjustable buck to periodically give start LA a bit of a nudge.
MC618 set to 55% (bottom setting as only 1 V belt)
Factory cooling cowl on back of alt to saloon air.
Porsche 944 factory cowl can be rotated to exit outside. (with a bit of fg mod to cowl)
Good thing is I have a 12v fan I can mount to force air in if necessary.
With BLM cutting field potential that much I would not expect that alt to over heat. the Al170x is typically a 115- 120A alt depending on who did the reman and what stator they used. You’re running it at approx 65% of its potential so yes it will like that and lead a long life.
 
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