Smart Alternator v Dumb

Ah yes, more load. Shall try in morning. But maybe draining the van battery first to partially flatten it, then to force alternator to work harder with or without lights might also be good tests.

I'm guessing that like I do , the OP only has portable solar panels.
Cheers
Jim

Yup , only portable panels. Powertech 110W which weigh a ton!

Alternately qld , The op could a attach a couple of semi flexible solar panels from an unnamed company & a DIY installation for well under $ 500 and be a lot more usable than the DC charger , would you think ??

160w solar panel

Only if the sun is shining while driving Nick.
Dcdc chargers are needed for when the solar charging system has already failed usually from poor weather conditions.
Edit that, alternator charging systems, even if only 60% efficient are needed.

Qld , totally agree with you there . I purchased a second hand Honda generator for the times when we are camped up at one location for this very reason .

The OKA is mostly electric and a tiny bit of gas (about 1kg/month on the road). HWS and heating is diesel.
99% of that electricity comes from fixed solar and 1% direct from the alternator on rare occasions.
We have not owned a generator for over 20 years.

The new build OKA will have over 2kW of solar, direct alternator charging for emergencies, no gas, induction cooking, diesel heating and HWS and everything else electric.
You cannot have too much solar.
Cheers,
Peter
OKA196 motorhome

Record the vans battery voltage before you start the car, then what it initially rises to when started and again after running for a recorded amount of time. With the LA battery you say you have you can tell a reasonable amount from voltage readings.
You should get a reasonably high flow rate to start with, it's the last 10 to 15% that it might struggle with.
What type of lead acid battery is it?

A Century Model C12 120XDA. It will be 3 years old at end of August. No problems with it but out of warranty by a year then.

You haven't expected the battery to be defective have you?

14.4 should be enough to fully charged it but even if you only get it to 80% while driving it's better than nothing. As long as you have the means to fully charge it soon as you can and before you store it

No defect expected but time has flown past. LOL

It does fly and you remember the expensive events a lot more vividly than others

Curious to know what engine your 30ah battery is cranking?
I can't see anything wrong with your charging theory in later vehicles. When deep cycle la batteries first become available in automotive sizes the charging systems in warmer climate countries maxed out at 14.2v which was too low to properly maintain deep cycle batteries but over the last two and a half decades it has krept up to 14.7 because of that but the myth still carries on, but now with temp compensated systems that can drop to very low 13s.
VD over long runs doesn't help but the only difference it makes is the time required for the distant battery to charge, the voltage will still equalise as the current demand diminishes.
From what I have read lithium batteries will charge provided the voltage does not exceed a certain level which varies from brand to brand from 14.4 to 14.6 but it is continuing to charge small currents after the battery state of charge is at 100% will cause irreversible damage over time. Weather this is true or not, who knows, it is just the theory of at least one chemical engineer.

"Curious to know what engine your 30ah battery is cranking?"
4 cyl, 4 L turbo charged Perkins diesel.
The Li replaced a 125Ah standard AGM. I have been using AGMs for cranking for about 15 years because wet cell LAs fall apart on the corrugations.
The Li crank has so far survived 25,000km including the Canning, so I am optimistic.
Cheers,
Peter
OKA196 motorhome

Yes corrugations are tough on batteries, I went to both start and acc batteries AGM but cooked them both prematurely under the bonnet, only lasted a couple of years so back to two flooded batteries under the bonnet.
Hopfully lithiums will hold up outside the engine bay but I think they will need passive cell balancing to cope with the constant charging. Time will tell.

There's that many differing opions on floating Lithiums so it is a try it and see yourself scenario.

My 200Ah of lithiums draw virtually zero current when fully charged yet I have seen upto 3% of capacity draw when floating cited by different sources. I just cant see how they come up with 3% unless there is a problem with the cells, or the batteries they are referring to have a BMS with integrated cell balancers.
I have been floating mine for 9 years now and no ill affects todate.

Both my solar charger and DCDC float charge Lithiums on the Lithium profile as do most if not all of the popular ones so float charging off the alternator is no different just the voltage may be a bit higher but then according to general information about there is no safe float voltage for Lithiums.

Interestingly the older version of my DCDC did stop charging the Lithium battery when the battery was fully charged, but it was a nuisance as the battery had to discharge to around 75% before the charger would enter charge mode again. I don't know of any charger that actually stops charging the Lithium once fully charged due to issue of deciding when to restart charging. It's not so bad if your measuring Ah in and out but most chargers don't do that and it gets a lot harder if your using voltage as the trigger point so it is easier to just go to a float charge.

Hi Leigh, I made an assumption re the 14.4 V on the 120 Series 2008 model. Just went and put meter on it at a cold start. It read 14.41 for a split second and then dropped to 13.80. Same with the second under bonnet battery, both being lead acid. So that is actually 0.15 V less than the 150 Series at a cold start. Tried it several times and same result, 14.4 volts at first contact then a drop to 13.8. A mystery to me.

Does the 120 have a VSR and a second battery, if so then the load of the second battery charging
is probably pulling it down. Usually the 120 will sit around 14.2V - 14.4V no load for around
10 - 20 minutes with the ambinet around 20C then drop down.

Oddly enough I took it to Batt World yesterday to test 2nd battery. It failed as I knew it would as it is 7 years old. Of course his readout said replace battery. It was wired thru a switch to an Engel socket in left rear wall but I had cut wires etc to hook it onto our Waeco which has since died. In 7 years the 2nd batt was active for about 4 months in 4 years and not at all for the last three. So I will not get one for the 150 as it has a 220V outlet to run our newer Waeco - still a 2008 model but 2nd hand. A test of 10 mins for the fridge off the piddly 100W Toyota inverter - engine running - will have the purists rolling their eyes for being too short. I will go out now and disconnect 2nd batt and check voltmeter. Fingers crossed.

Something odd going on there, the charge rate of the 120 is higher than the 150. you need to disconnect any add on system and check the voltage at the cranking battery.

Disconnected 2nd batt and no change to above readings. It is a REDARC VSR system which was in the car when purchased in 2018.

Just realised what I wrote above is wrong, should have been:

They also lowered the charge rate of the alternator compared to the 120.

Your 120 should be giving you a higher reading than your getting if it still has the OEM alternator and its working ok. The 14.1V your see when it first starts is ok, the 13.8 is on the low side for a cold engine bay.

The thing you need to look at is the voltage will drop when the engine bay warms up and when the load on the alternator gets high. You need to measure what voltage are you seeing across the cranking battery when the cars have been driven for around 40 minutes?

One important thing you need to test, when you plug the van in and get a bit over 12 .7volts what is the voltage at the crank battery whilst charging the van?
It's definitely getting some amps, will just take time and the line voltage drop will diminishes as the battery in the van nears full charge. As long as the voltage at the start battery is higher than the vans current will be flowing.

It has thick wire from crank batt to Anderson plug, say 5 mm true Cu diameter. 3 m length. The volts are the same off batt terminals as the And plug. The old 120 series only has 3 mm thick wire as is the 2m long van wiring from plug to batt. But no voltage drop between batt terminals and plug.
Based on todays experiment. the van battery was recharged in 10 minutes. After 1.5 hours it fell back to 12.34V and held that when I checked another 3.5 hours later. Maybe I should run the Waeco for a few hours to really draw the van batt down and redo the experiment.

If you have no voltage drop you have no current flow unless you have 0 resistance in the cabling
which is not going to be the case?

There will be no voltage drop if there is no current flowing so just checking the voltage at the battery and the Anderson plug is pointless if there is nothing plugged in to the plug drawing power.
Run the van battery down to about 60% then plug it in to the car and get it charging and measure the volts of the start battery and the van battery while it is charging. Go for a drive and repeat in half an hour.

The previous owner ran a 42 L fridge without problems. My Waeco manual says models CF-35 thru to my CF 60 all use 0.7A at 240V. So by P=VI that is 168W yet the inverter is rated at 100W and the fridge ran OK. Perhaps I should tap into the Anderson plugs thick cable and run leads into the rear cabin and run it on DC. Then take it for a drive for a longer test.

Warrie.
you have just reinforced what I meant. A larger Waeco running 6amps on 12 is 72 Watts but through the inverter you figures indicate 165. So around 90 w MORE is being used on those figures if the 12v -240v inverter is used. Probably not that much but still a hefty loss. Taking it for a test drive isn't going to change that situation. The alternator can be relieved of a significant load.
Using the Anderson plug 12v power is wise in my view.

Yes, it is only live with the engine running, so when I stop it would have to be plugged into a DC supply. The old 120 series had this wired in off the 2nd batt. So I could put a 2nd batt in the new 150 series using an auto sparky. But the one I have talked with says no to 2nd batt and wants to add a BC DC Redarc 40 amp new fangled contraption, rewire what seeems to be perfectly thick cable etc, all at over $150/hour. Do I sound like a Luddite? LOL . The whole problem here is with the smart/temp regulated alternator. My van is too small to put the fridge inside and run off the van batt and portable solar panels. This is all still a work in progress. I have a month to sort it before heading from Sydney to Lake Eyre via Flinders and to canoe on the Cooper.

Warrie, i think you need to speak to a different auto sparky,

I rang a few and they said they don't do 2nd batts and BCDC's. So I guess I will have to go further afield.

A lot don't do it anymore because everyone is an expert these days.
If they try so sacrifice a little efficiency to save you a lot of money and the first camp site you pull into someone looks at it and tells you the sparky had no idea because it wasn't 100% perfect you would be straight on the phone jumping up and down.
The sparky won't supply cheap components, if one fails a week's drive away he is liable for the cost of another sparky supplying and fitting another part so they don't sell cheap gear.
All you want is for your stuff to work like it did in the other wagon and as you have found there are several ways to do it but the professional won't do it less than perfect so it's a $700 redarc unit not a $200 kings one and so on. They will have a set, tried and proven design that they know works and will be very reluctant to vary too much from it, that is the wall your up against.
They need to install fool proof systems that require little to no user input.
Your posts are a little confusing as you refer to both cars comparing them.
How much management are you prepaired to do or do you need a hook up the van and go set up?