Sterling "Alternator Lineariser"

[a64pilot]

Originally Posted by john61ct

Sorry do not follow, how it can be difficult?

I think he means voltage.
However float for a Lifeline battery is 13.3, what do you charge LFP at, isn’t it close to that?
If so then a Lifeline AGM may work

[rgleason]

Very interesting test.

Take any multimeter, set it to AC, and connect it to the alternator output. You should see no AC voltage if it is working properly. Now also reverse the multimeter leads and recheck--because some multimeters are built in a way that will show AC voltage one way, and not the other, even though in theory both should be the same..

Re charging LFP high voltage cutoff causing blown diodes on Alt, would a ZapStop protect the alt?

John, AFACIT as far as I can tell. Cant you at least spell it properly? I hate these things called acronyms, but they really are only used by texters.

[john61ct]

Originally Posted by a64pilot

I think he means voltage.
However float for a Lifeline battery is 13.3, what do you charge LFP at, isn’t it close to that?
If so then a Lifeline AGM may work

I'm talking about a little $20 throwaway SLA, no need to worry about its needs.

[john61ct]

Originally Posted by rgleason

John, AFACIT as far as I can tell. Cant you at least spell it properly?

That's funny. Look carefully at what you wrote.

Also think about our roles, relative relationship here. Maybe if I were getting paid, and you were my customer or editor. . .

[hellosailor]

rg-
The Zapstop is basically just a zener diode, designed to conduct and pass any SPIKES to ground. It would do nothing to filter out AC. The Zapstop has some merit, if you install one on the starter and one on the alternator, especially since normal startes will throw spikes up to 600 volts (for a few milliseconds, too fast for a meter to see) and on larger diesels that can be over 2000 volts. Eventually those can fry any electronics connected because they can slip past the battery "depending" on the overall wiring of the system. Normally, the battery is the defacto spike protection in a car or boat.

Funny thing, in all the vehemently disagreeing technical papers I've seen for all kinds of batteries, lithium-whatever or other types, I've NEVER seen a warning that alternators can or will produce enough AC to cause any damage to any battery. And that includes notes from GM, Delco, GE, East Penn DEKA, JCI...folks who usually are pretty good about saying "Here's how to kill our products".

Only the folks selling little magic boxes seem to think they are necessary. You know, like the guys selling magnetic fuel conditioners? Well, except of course those actually have passed milspec testing. (Of course, the spec says if you bolt it to the bulkhead, it won't fall off. Honest. But that's a valid military specification.)

[a64pilot]

Originally Posted by john61ct

I'm talking about a little $20 throwaway SLA, no need to worry about its needs.

Until it shorts and catches fire or similar.

[rgleason]

Excuse me, AFAICT. I just wanted to correct a guy who always seems to be right, and did not succeed at even that. Anyway thanks for the training.

[rgleason]

I am sorry but I am not understanding what the problem is that the small sla battery will solve.

[john61ct]

Originally Posted by a64pilot

Until it shorts and catches fire or similar.

You know very well that's specious. Are you saying preventing such a catastrophe would be difficult or onerous? Then buy this gadget!

Otherwise, I was responding to concern expressed about the LFP profile not properly caring for an expensive bank like Lifeline.

Obviously if that's what you want, then select one that is spec'd for low voltage.

Deka's GEL would last a very long time at around 14V, and their Float spec is 13.2V

But if you already have a Starter batt, all this is moot.

I'm not addressing your specific requirements here, that's for you to decide. I'm just engaging in a general discussion / debate trying to be constructive as possible.

[john61ct]

Originally Posted by rgleason

I am sorry but I am not understanding what the problem is that the small sla battery will solve.

As I stated above, both of the problems this expensive device is designed to solve.

Whatever your primary charge source is, no need to modify it. Keep it charging whatever lead batt you already have.

Or use any old cheap one, does not need to be large.

Then attach the input side of the Sterling BB to that circuit, and its output to your LFP. Adjust its output to your preferred profile and IMO you have no need for this gadget.

[Dockhead]

Originally Posted by john61ct

As I stated above, both of the problems this expensive device is designed to solve.

Whatever your primary charge source is, no need to modify it. Keep it charging whatever lead batt you already have.

Or use any old cheap one, does not need to be large.

Then attach the input side of the Sterling BB to that circuit, and its output to your LFP. Adjust its output to your preferred profile and IMO you have no need for this gadget.

Sure, but even if you can get a lead battery into the picture, how do you make this work?


If you connect the alternator to the lead and regulate the alternator to provide the correct charge profile for the lead, then you can charge the lithium with a B2B charger. But these are too small to put the full output of a heavy duty alternator into a large lithium bank.


So if you regulate the alternator for lithium, and connect it to the lithium bank, in order to get the full alternator output into the lithium, what then?


The B2B chargers are not supposed to be used without the first "B" -- but are they really? I thought they had an override for use with regenerative braking.



In any case, perhaps an easier solution to this would be to use one of Sterling's Alternator-to-Battery chargers, instead of the B2B charger. That would seem to neatly solve every problem, at the expense only of losing the ability to charge from battery to battery. If you don't plan to do that much, you could simply run the regular charger (separate for lead since the charging profile is different) via the inverter.


This would eliminate any issue with protecting the alternator, and would provide a way to keep charging the lead batteries from the alternator in case the lithium is taken offline by HVC or otherwise.

[Dockhead]

Originally Posted by john61ct

As I stated above, both of the problems this expensive device is designed to solve.

Whatever your primary charge source is, no need to modify it. Keep it charging whatever lead batt you already have.

Or use any old cheap one, does not need to be large.

Then attach the input side of the Sterling BB to that circuit, and its output to your LFP. Adjust its output to your preferred profile and IMO you have no need for this gadget.

Keep in mind that you will be limited to the size of the Sterling chargers. Perhaps you could gang them, but that gets expensive and complex.



Some people have very large alternators up to 200 amps @ 24v or more. Mine is 110 amps @ 24v, and even that is far beyond the capability of any of the Sterling B2B's. The largest one for 24v to 24v is 35 amps.


Having a 110 amp alternator (or 200) and being being able to charge the lithium, which can accept 1C or more, at only 35 amps, would defeat one whole big advantage of lithium.

[senormechanico]

If this "AC" is really just DC voltage ripple at the alternator terminal, in effect, it's only going to be a "current" ripple at the battery until they're 99% full.
At that point, any measurable voltage ripple ought to be flattened by a much smaller electrolytic value than the Sterling Lineariser's.


One of these days, I'll try it just for fun.
I will start with something like 10,000 microfarads from my parts stash and my portable oscilloscope.
Cost to buy one? Around ten bucks.


https://www.ebay.com/itm/Capacitor-1...4AAOSwgQ9VhjHY

[a64pilot]

The idea of a lead battery in line with the LFP is I thought to protect the alternator in the event of an LFP disconnect.
It was my understanding that you would set the voltage of the alternator to the LFP charge voltage and it would just flow through the lead battery.
If this is the case, then it would make sense to choose a quality lead battery, just one, no bank needed that ideally has a float voltage very close to the LFP charge voltage, if possible.
Some have said there is no charge at float, that is incorrect, anyone with Solar has seen good charge at float voltage, it’s not usually until later in the day that bank voltage climbs into absorption level, if at all.
How much charge at float voltage depends on battery SOC.
Absorption gets the job done much, much faster is all.
However continuous voltage at float level will do no harm to a battery, so ideally a lead acid battery inline with an LFP bank if the charge voltage corresponded to the lead float voltage, would likely last a very, very long time.
However go get a small cheap battery, if you hold it above float voltage, something bad may eventually happen, don’t you think? Or even hold it well below float isn’t good either.
Then there is why in the World after spending thousands of dollars on your LFP system, would you cheap out on one component?

[john61ct]

Yes stacking the BB chargers is required

**if** the usual ICE runtime - apart from charging purposes - is not sufficient

Until Charles gets the bigger ones out, his plan is up to 240A so far.

But that issue has little to do with the pro's / con's of this gadget.

That said, remember, the whole BB requirement is only for those unable (or unwilling) to fit an MC-614 to get full alt output direct into the bank.

Where again a cheap little lead batt will protect the alt diodes from the failsafe cutoff after tge VR / field current cutoff failing.