Battery Charging with Ham Radio Power Supply

[John61CT]

> I have never had my house batteries below 65% and that only once.

Well that's easily done, no harm at all.

Report the results back here, V and A logged every 20 minutes.

A 20-hour load test goes down to 10.5V, of course only on shore power, well controlled conditions.

And the resulting data radically improves your Trimetric's SoC accuracy.

IMO should be done at least annually, more often once SoH falls below 85%.

 

[John61CT]

> Before I equalize I check specific gravity; all cells have always been 1.27+, with the Trimetric reporting 100%. I am using S.G. as my figure of merit for 'full'.

Not nearly as accurate as endAmps unless after 48+ hours isolated.

 

[tx2sturgis]

And an ACR is required rather than a mnual switch for those of us with less than perfect checklist memories.

Too easy to forget, leave it in the combined position when engine's off and loads deplete Starter, if you're out in the boonies no fun.

An ACR is best, and as long as you don't need it for cranking currents, not even expensive.

I'm taking the entire thread into consideration:

Cost is a factor.

A genset is out of the question.

Spiff was willing to, and stated that he would be checking hourly on the inverter-powered power supply if he went that route, so I assumed flipping a manual switch once every now and then is just as easy to do.

And,

An ACR is a great option, but again, cost for large capacity units is fairly high.

 

[John61CT]

> If the GC batteries DO get deeply depleted, then when they are paralleled with the starter battery, they will see a HUGE influx of current from your healthy starter battery

It is a myth to think it is that "huge", or that this is in any way a problem

> more or less rapidly equalizing the level of both sets of batteries

Voltage "level" will by definition settle at a median point set by the batteries (size, SoC/resistance) but the Alt's contribution striving for Absorb is likely the biggest factor.

If you mean by "level" SoC, that cannot with a lead House bank, happen for another 4-6 hours no matter hoe large the charge source.


> alternator output will be divided between 3 partially depleted batteries.

This I don't understand, House bank is one "battery" even if composed of four strings of 2V cells.

All (99.9%) of the Alt output is accepted by House in this case. But even if both batts are at 50%, 20% might go to Starter (smaller size, maybe higher resistance) and 80% to House.

There is again, no problem there.

 

[John61CT]

> An ACR is a great option, but again, cost for large capacity units is fairly high.

Best is to put Alt output direct to House.

Then even a low-amp Echo Charger is fine to keep Starter maintained.

I pick them and similar up on eBay for under $20.


Brand new Blue Sea units rated with current limiting to 60A continuous for $35, no rewiring the alt required.

We're talking the cost of a few fast food meals for infrastructure that lasts decades.

BTW for that sort of duty cycle, the sort of high-amp switch I'd trust (Blue Sea, Marinco, BEP) costs new as much or more than the ACRs I'm talking about.

But yes, if OP is certain he'll never ever forget to isolate the banks when shutting down the engine, a manual switch is fine.

 

[tx2sturgis]

> If the GC batteries DO get deeply depleted, then when they are paralleled with the starter battery, they will see a HUGE influx of current from your healthy starter battery

It is a myth to think it is that "huge", or that this is in any way a problem

Read all the words in the sentence you quoted: I specifically said 'deeply depleted'...meaning the fully charged battery will toss a lot of current in the direction of the deeply depleted ones. Haven't you ever jump started a dead battery in a car with the good battery from another car? Sparks, sometimes a LOT of them, heated clamps,  and a loaded alternator and reduced RPM of the running engine are a couple of clues. It is NOT a myth, John.

And I never said it was a problem....it works well, thats why I suggested doing it...I was simply telling Spiff it will happen. In this case, its a GOOD thing. But allowances need to be made in the form of fat cables, connectors, and switches.

 

[tx2sturgis]

> alternator output will be divided between 3 partially depleted batteries.

This I don't understand, House bank is one "battery" even if composed of four strings of 2V cells.

I was referring to the three batteries in this system: Two golf cart batteries and one engine starting battery.

The GC batteries are always referred to in this forum and elsewhere as batteries. Two of them in series is technically a battery bank.

 

[Spaceman Spiff]

But yes, if OP is certain he'll never ever forget to isolate the banks when shutting down the engine, a manual switch is fine.

Me, forget???  I never forget anything . . . . . What were we talking about?

 

[tx2sturgis]

Something like a "Remove Before Flight" tag might be handy!

 

[John61CT]

wrt functionality, performance, a bank is a battery and a battery is a bank.

Only makes a difference as to how many trips you have to make when you carry them.

 

[John61CT]

wrt the "surge connecting a depleted to a full bank"

I was just making sure everyone understands it isn't a problem.

http://www.smartgauge.co.uk/nosurge2.html

And depleted meaning down to 50%, not shorted or otherwise damaged.

And yes of course with all such mods, nice fat cables, proper wiring, crimping and connections are important, not to mention refraining from creating lots of sparks

 

[Spaceman Spiff]

Something like a "Remove Before Flight" tag might be handy!

I actually do have flags I attach to my steering wheel to remind me to latch the refrigerator and pick up the leveling blocks before I drive away.  :s

I do have a great memory and I hope someday I stumble across it again.