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pianotuna

Regina, SK, Canada

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Posted: 08/03/21 10:29am Link  |  Quote  |  Print  |  Notify Moderator

I have manual control over my charging solenoids.


Regards, Don
My ride is a 28 foot Class C, 256 watts solar, soon to have SiO2 batteries, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

eric1514

AZ ID

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Posted: 08/03/21 11:57am Link  |  Quote  |  Print  |  Notify Moderator

wnjj wrote:

...On second thought, why not just install a manual switch or switch the controls a relay?


pianotuna wrote:

I have manual control over my charging solenoids.


I would love to have a switch on my dash that turned off the solar to my chassis battery but again, that is all above my pay grade. Looking at this I wouldn't now where to begin.

[image]

When the weather gets more cooperative, I have some tests to run and it may turn out that this is nothing more than a light that needs to be ignored for a couple of hours a day.


2006 Isata Touring Sedan 250


pianotuna

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Posted: 08/03/21 12:54pm Link  |  Quote  |  Print  |  Notify Moderator

Hi,

Just look at the solenoid. There are two skinny wires. Put a switch in the positive lead.

eric1514

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Posted: 08/03/21 01:17pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

Hi,

Just look at the solenoid. There are two skinny wires. Put a switch in the positive lead.
Won’t that also keep the alternator from charging the house batteries?

pianotuna

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Posted: 08/03/21 03:51pm Link  |  Quote  |  Print  |  Notify Moderator

eric,

It gives you control over whether there will be charging or not. Personally I'd put a dc to DC charger in.

eric1514

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Posted: 08/03/21 05:03pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

eric,

It gives you control over whether there will be charging or not. Personally I'd put a dc to DC charger in.


I've got a bunch of testing to do before I get to that point but it is a very good option. The purpose of the solar was to augment the woefully low alternator output so maybe if the switch cuts off alt output to the house, it might not be a big deal.

But to drive home how little I know about the present system, is the solenoid the lower of the two canisters in my photo?

EDIT: Nevermind. That's the Auxiliary Battery Disconnect.

* This post was edited 08/03/21 05:12pm by eric1514 *

eric1514

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Posted: 08/03/21 05:48pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

eric,

It gives you control over whether there will be charging or not. Personally I'd put a dc to DC charger in.


I think what I am going to try and figure out how to build is a diode (if that's the right piece) with a remote manual bypass so that I can stop solar from going to the chassis battery but continue to receive alternator output to the house batteries while driving during the day. I think it could be inline with the cable that runs from the BIRD to the chassis battery. When I'm parked, I could bypass the "diode" and let shore, solar or generator juice flow wherever it's needed, like it does now. I would think I could build something like that for not a lot of money.

pianotuna

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Posted: 08/03/21 07:21pm Link  |  Quote  |  Print  |  Notify Moderator

eric,

That is exactly what a dc to DC charge controller does--it is a diode--but one that can pass a lot of amps.

Now you need to know the duty cycle and the amps output of the alternator

eric1514

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Posted: 08/03/21 08:08pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

eric,

That is exactly what a dc to DC charge controller does--it is a diode--but one that can pass a lot of amps.

Now you need to know the duty cycle and the amps output of the alternator


When I look at the simple wiring diagrams for installing a DC to DC charger, I see a set of cables from the starter battery to the charger and from the charger to the house batteries. Seems simple enough. Of course I'd be going through my shunt and I'd need a signal to turn it on. I get scared when I look at the 30 or so other wires in that photo I posted. Other than that...

Why would I need to know the duty cycle of the alt and how would I find out? And are you ever in ID?

pianotuna

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Posted: 08/03/21 08:46pm Link  |  Quote  |  Print  |  Notify Moderator

eric,

Alternators are rated in amps. Mine is 130 amps. However they are not made to run 'flat out'. The "usual" number (so I'm told by others) is about 1/3 continuous. So my 130 amp alternator can really only provide about 43 amps continuous. Of course, some amps are needed to keep the engine and other devices working.

There ARE continuous output alternators, but they may be a big chunk of change.

There are also external diodes that can be added on. But that is beyond my skill set.

That is why one needs to know the peak output of the alternator--and then not take it up to that for very long.

Generally with modern vehicles the computer (ecu) decides what alternator output needs to be to recharge the chassis battery after starting. That doesn't take very long, so house bank charging is often slow.

I do have a dc to DC charge controller--but it is not yet installed. I chose to use one that is limited to 20 amps output, because the input may well be 30 amps. The dc to DC boosts the voltage so that the house bank will charge faster. In other words, it over rides the ecu and draws more amps from the alternator. It does this by raising the output voltage--so more amps will flow.

Renogy makes one that is a 40 amp output--but which has a jumper that can be removed to limit it to 20 amps.

If you want a "top drawer" device Victron makes one, too.

BFl13 has a unit from Renogy and it works well for him.

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