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 > 12 v to 12 v trickle charger

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landyacht318

Near a large body of salty water

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Joined: 07/11/2007

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Posted: 01/17/20 02:54pm Link  |  Quote  |  Print  |  Notify Moderator

Definitely follow the agm manufacturer's float voltage recommendation. Do not think 12.8v is good enough. most spec 13.4 to 13.8v @77f.

If I hold either of my AGMs at 13.4, vs 13.6v while loads are running, the battery will discharge slightly. I can tell this as when i spin my voltage dial upto 14.7v it takes more than the 0.5% of c/20 amperage for a while, before amps again taper to that prescribed 'full' level.

Some of these Asian agms might not taper to that level 0.5% level at Vabs. So consider these full when amps stop tapering, and overfull when amps start rising at a constant absorption voltage. I've noticed mine do both, and depth of the discharge seems to play a part.

Temperature of course plays a part in the right float voltage as you know.

The current limiting potentiometer of boost or buck/boost converters can also limit amperage, if one wants to limit amperage to what the Chinese AGM battery claims to be them allowable.

My 18Ah agm says no more than 5.4 amps. I've exceeded this by a factor of 5, but would not do this regularly, or in hot ambient temperatures, or when the battery is nearing end of life.

The minimum current seems to be 0.5 amps on the voltage converters I've tested with the current limiting pot turned all the way down.

The crush stranded wire under screw terminals can be problematic and lack of an enclosure might be an issue. Drok sells some units with acrylic enclosures as well as voltmeters with a toggle buttons for toggling display from input to output voltage.
Not sure of if they have buck boost or just buck or boost.

I tend to solder instead of using the screw terminals, and all things which can be shorted or vibrate and break, like the wirewound toroid, get covered with Amazing goop after some rubbing alcohol degreases the flux and fingerprints.

Peeling off the cure 'amazing goop' is pretty easy, if required. It is Di-electric when cured. No issues with the evaporating solvents inside of AG damaging the circuit board. It does take days for the tolulene stink to go away completely, depending on the strength of your sniffer.

Mobilesport

Iowa

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Posted: 01/18/20 03:01am Link  |  Quote  |  Print  |  Notify Moderator

@Landyacht318
I've been trying to do people favors by turning them on to The Amazing Goop adhesive for years , no matter how hard I try people just shrug it off and don't listen .
There still stuck in the age of hot glue lol.

The amount of things you can do with that goop is absolutely astronomically amazing and that is a understatement.
You would think that there would be lines at the store of people buying goop.

Another cool thing about the goop is how you can adjust how strong a hold it has on something,,,,,, example,, lets say your planning to remove something in the future frequently, you just put a smaller amount on and then you can peel it off easier ,, if something is going to be more permanent you can put alot of goop on it , you would still be able to peel it off just more effort , one thing i do is mark the locations as where I put the goop with a white paint marker so I know where the goop is so I know where to aim to remove it ,,,

example, I glued my entire dash together on my old van , i didn't use any screws , if I ever wanted to remove a dash part I would look for a small white mark , take a flat head screwdriver and poke the goop to break it's seal , then simply peel the part off , then prepare the part for reinstall by peeling all the goop off the part very quickly and simply, come time to assemble the dash I would just put new goop on and Mark locations with the white paint marker in case I need to remove again in the future.

The goop makes nice grommets too.
Nice to hold wires in place or hold electrical components in project boxes.
I don't have time right now to talk about all the many uses but it would be cool to start a thread of just people showing what they used it for.

Lately I've been glueing metal brackets on components so I can mount the component with screws because I like to be able to remove components by just removing screws.
A sample of that would be my 110 volt power strip , I gooped on 2 brackets and then after the goop dries I mount the power strip to my wall with screws , and a mount to be able to mount my hall effect sensor for my ammeter,
Also a tool organizer made with cut up pieces of PVC conduit gooped together to hold my screw drivers , pliers , scizzors etc.
Its empty without tools in the picture .
Super cheap , like $3 for a long PVC tube , $4.80 goop , scrap plywood free.
pictures below
I use the extremely sticky chrome looking hvac tape to hold parts until the goop dries.

[image]

[image]

[image]

* This post was edited 01/18/20 03:43am by Mobilesport *


Big high roof van , 2000 watt Custom on board Honda genset , custom Meanwell 40 amp battery charger , 100 ah Battleborn lifepo4 , kisae battery capacity monitor , Planner 44d diesal heater, 6 gal red Bass pro diesal fuel tank. At&t hot spot router

Tom_M

New Hope, MN

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Posted: 01/18/20 04:57am Link  |  Quote  |  Print  |  Notify Moderator

landyacht318 wrote:

Your 2.0 volt differential claim, is simply absurd, and shows you have Zero experience with such a product. Perhaps long ago with older less efficient transistors a 2 volt drop could be expected, but certainly nothing like offered in Mr wizard's link.
I'm a retired electronic tech and have worked with many types of power supplies. Granted, my experience may be a bit dated, but the simple fact is you will not be able to charge a 12 volt battery using a 12 volt source. The charge voltage has to be higher than the battery voltage. Even if the voltage differential was zero volts you will never get more than 12 volts out of the buck converter. The specs for the buck converter that MrWizard mentioned are:

Input Voltage: 6V to 40V DC(10V to 40V is suggested)
Output Voltage: 1.2V to 36V DC

The output voltage will never be higher than the input. At the high end the voltage differential is 4 volts. At the low end it's 4.8 volts. At mid range the differential probably is much less but will always be greater than zero. The simplest solution is to use a boost converter.


Tom
2005 Born Free 24RB
Towing 1978 VW Bug convertible
Minneapolis, MN


MrWizard

Traveling

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Posted: 01/18/20 09:10am Link  |  Quote  |  Print  |  Notify Moderator

The one i posted was simply an example
Posted because it showed the size dimensions
And i assume his system DC is more than a Flat 12v which is only 50% SOC
Between solar and alternator power when driving or shore power when parked, there should be no problem with a proper input voltage that is high enough, being available to drive the DC converter


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Mobilesport

Iowa

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Posted: 01/18/20 11:19pm Link  |  Quote  |  Print  |  Notify Moderator

pianotuna wrote:

Any suggestions?

Looking to keep a 10 amp-hour AGM charged while running the Pinella Remote. I think a trik-l-start is on the large side.


What about briefly charging from the alternator?
I believe that's how most RV generators batteries are wired.

DrewE

Vermont

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Posted: 01/19/20 01:45pm Link  |  Quote  |  Print  |  Notify Moderator

Mobilesport wrote:

pianotuna wrote:

Any suggestions?

Looking to keep a 10 amp-hour AGM charged while running the Pinella Remote. I think a trik-l-start is on the large side.


What about briefly charging from the alternator?
I believe that's how most RV generators batteries are wired.


My RV generator just uses the house battery for its starting battery, and relies on the converter to recharge it (from the generated AC power) when it's running. There's no dedicated battery charging circuit in the generator at all, nor indeed a dedicated generator battery. I think that's quite a common setup, though I gather sometimes the generator is wired to use the chassis battery rather than the house battery on some motorhomes. It's also worth noting that most built-in RV generators need 12V power not just for starting but also to power the field of the generator so it will generate power; they just plain don't operate at all without 12V power.

I do have a battery combiner circuit so that the house battery is connected to and recharged by the main engine alternator when driving my motorhome, which is also standard; that is entirely separate from the generator.





Mobilesport

Iowa

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Posted: 01/19/20 05:21pm Link  |  Quote  |  Print  |  Notify Moderator

DrewE wrote:

Mobilesport wrote:

pianotuna wrote:

Any suggestions?

Looking to keep a 10 amp-hour AGM charged while running the Pinella Remote. I think a trik-l-start is on the large side.


What about briefly charging from the alternator?
I believe that's how most RV generators batteries are wired.


My RV generator just uses the house battery for its starting battery, and relies on the converter to recharge it (from the generated AC power) when it's running. There's no dedicated battery charging circuit in the generator at all, nor indeed a dedicated generator battery. I think that's quite a common setup, though I gather sometimes the generator is wired to use the chassis battery rather than the house battery on some motorhomes. It's also worth noting that most built-in RV generators need 12V power not just for starting but also to power the field of the generator so it will generate power; they just plain don't operate at all without 12V power.

I do have a battery combiner circuit so that the house battery is connected to and recharged by the main engine alternator when driving my motorhome, which is also standard; that is entirely separate from the generator.

Or just start it from the RV battery then no charging is needed , the RV alternator would charge the RV battery back up

* This post was edited 01/20/20 07:01am by Mobilesport *

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