What size DC-DC chargers are you using?

200ah in canopy, 600ah in van. Fed by 200w panel on canopy, 700w on van (when it works- having it looked at tomorrow!). I have a300w panel to use remotely for either.

Loads vary, 60lt fridge in canopy (usually fine with existing dc-dc and solar), van loads vary, but 75l fridge constantly.

Cheers,
Mark

I can't imagine that you would ever need more than you have.
I might move the existing DC-DC charger to the van and be able to charge the canopy battery direct from the alternator.
Cheers,
Peter
OKA196 motorhome

No, leaving it as is, for now. Simply looking to get an idea of alternator capacity. I agree, particularly the van solar being more than adequate... if it works!

Cheers,
Mark

I wouldn't be too concerned about the brushes wearing out, it is the heat generated and the flexing of the stator windings with the high energy of the magnetic forces at play that will lead to a shortened alternator life.
I'd be leaving your settings as low as possible then increasing it if ever required.

QLD
Yes that too, plenty of magnetic vibes happening.
His vehicle also has/most likely has, ELECTRIC steering and lots of steering in hilly terrain will be using MORE amps to drive the steering motor. Not sure when they changed to Electric PS!

Good point. I know nothing about electric power steering as I got out of the light vehicle side of the industry just as they were being introduced, I saw it as a step towards autonomony. All of the autonomous machines I have been maintaining for almost a decade and a half are electric over hydraulic so they have minimal ELV electrical consumption and most come STD with a 90 to150 amp alternator (24v).
The point I was getting at is under conditions when the vehicle is operating under full electrical load there isn't much left to supply the draw of the DCDC units, if the alternator saves itself by derating it wouldn't take long to completely drain the start battery.

LifePo4.

Cheers.

Mark I think that people that have high output alternators and DC charges those that need a lot of power in a short period to charge many batteries in a quick period
, people that are doing long days of driving would not necessarily need fast charging as well as they wouldn't be using a lot of accessories depleting their batteries .
keep in mind the DC charger will only be at its full rate while the unit is still cool and Will throttle itself back when it starts to get hot and also throttle back as it goes through its charging stage of bulk absorption and float.

Note: I thought the principal of a DC charger was not only to give the battery a proper charging but also to protect the alternator ?

Regarding solar . I just recently wired my solar array to series after seeing a tip on YouTube , buy way of increasing the time that the panels will produce power .. I.e higher voltage keeping the panels charging earlier in the morning and later in the evening , but this comes at a cost if in a shaded area they don't work as well . this system apparently is good if adding extra panels to a caravan where running extra wires is a problem .
Cheers .

The primary purpose of a DC-DC charger is to boost the charging voltage to overcome the voltage drop from long cables from the alternator to the van battery, and they do that well.
If you have not got excessive voltage drop, then there is little value in spending lots of $$s on a DC-DC charger because the alternator voltage output is designed to be ideal for battery charging (including LiFePO4) and the charge rate will be much less constrained.

I used to charge our 400Ah of AGMs direct from the alternator from time to time. The initial charge rate was about 70A from the 85A alternator (plus whatever solar was available). That rate would drop off fairly quickly (as is the case with lead acids).
Providing the charge voltage offered is not excessive (and an alternator is not), lead acid batteries self regulate the charge rate.
There was never an issue with either the batteries or the alternator.

Since then I have increased the solar and changed to a 320Ah LiFePO4 battery. I have not needed to charge them from the alternator, but have a couple of times (from about 50% SOC to near full), "because I could". Again, the charge rate dropped off initially as charging progressed (but I don't have the actual rates). And again, no issues for the battery or the alternator.

The maximum charge rate for Li is typically a limitation of the BMS rather than the battery itself. 250A is common.
Cheers,
Peter
OKA196 motorhome

SCUBADOO
Maybe your vehicle has FAR MORE airflow than the modern dual cab utes with 3 heat delivery cores to the airflow. Therefore the ALTERNATOR TEMP and the AIR temp flowing through it could possibly be significantly cooler than a HIGH heat stressed ute engine bay. Unless having to charge the whole battery pack from low discharge, would mean less total heat generated for the time it takes for amp flow to reduce.
So your system works OK!

Silkwoods situation might be quite the reverse of yours and causing lots of heat energy inside the ALT for a long time.

It's always good to hear of people's personal experiences of one or maybe two practical experiences but you seem to think that every machine out there will behave like yours has done. Do you even know what the duty cycle spec is for your alternator is and how far through the designed tolerance buffer you pushed it doing things you have done? Ignorance is bliss. A 100 amp alternator in a light commercial is vastly different to a 100 amp alternator in a passenger vehicle.
When people seek professional advice they trust the advice is based on sound knowledge and experience of similar systems, not just "I have done it a couple of times and gotten away with it so I'm an expert". Also the professionals giving the advice are legally liable for any expense or injuries coming from their advice, not a lot of people know that when banging on about shit in forums. Are you willing to take legal responsibility if someone does as you have advised them in writing they can do and comes to grief because you had no idea of their circumstances? You better take out a professional liability pollicy just in case.

Seeking professional advice on a forum. Who in their right mind?

"but you seem to think that every machine out there will behave like yours has done" .
Your mind reading words, not mine.

From my last post:
"Entirely your decision but I will tell you like it is for us."

I don't give advice on forums. Friends and professionally - occasionally.

Just facts, opinions and what I have done.
Others are free to read, follow or ignore. I care not.



OT
Despite the many doomsayers that abound on these forums I have thankfully gathered more than a few great ideas over the last 11 years of fulltime travel.
Like many others my alternator is still charging the battery with no DC-DC charger involved.
Our domestic 255l Samsung fridge compressor and associated tubing has not shaken to pieces on corrugated and potholed roads.
Our 4 cell 300Ah LiFePO4 battery has both started the truck engine perhaps a few thousand times and powered the motorhome without self destructing because there is no internal BMS or cell balancing.
The 3x 270W solar panels mounted without holes in the roof are not departing anytime soon.
The single Victron 50A controller is still in one piece in its enclosed stairwell location.
The domestic 32" permanently wall and swivel mounted TV is still in one piece without a daily hide under the pillows.
The motorhome has not been connected to mains power for at least 3 years.
We do not need or own a generator.

The list goes on.
No advice given, just facts.

Which is why I asked here from curiosity and to see if the answers were relevant, then discussed with an auto electrician...

I thought answering the original question was against the vibe of internet forums?

:) :)

Cheers,
Mark

Variety is the spice of life

Thanks Lee, as stated earlier, checked with auto electrician doing work on my van and he has confirmed my current settings (no pun intended) are all good...

Though I think your post would have more impact if you suggested others and myself are idiots and used lots of capitals...

Cheers,

Mark

.
Bob, wives are so often unsympathetic about the extraordinary efforts we men go to in order for them to be able to charge their phones, hey?

So true, Allan!

Bob