How to regulate Voltage supply to the Inverter?

[Eleceng1979]

Keep the cc to the trojan spec to not kill batteries...  Now the really bad idea... i am not responsible for this but it is an idea, is frowned upon, but since your already stuck with a crap inverter, try this...

Use length of wire to add voltage drop.  You will lose efficiency and lose some power in this but a small wire feeding the inverter will cause drop, heat up and also lower the inverter voltage progressively with more current flow.

What is your wire size now?  A piece of 10awg, with 55 amps flowing (2000w) will drop 2.2 volts and make your inverter happy.  I think this is a horrible idea, will run hotter and sustained max 2000w loads will eventually harm the wire.

A more scientific approach is to build a dc choke to drop some voltage...same concept but proper wire size and substantial lengths, coiled tightly.

You need 6/8 awg depending on type...so 10 isn't so bad.

You need a better inverter, an aims 5k model comes to mind but is like $600.  Not much in the 36v area as 48V is the standard above a couple kw.

For giggles...add a stupid amount of wire length you have for a test

[Westbranch]

to be clear about that cheap inverter powered by a 36V FLA battery...

Yes, you can create a 'state' wherein you can use the Inverter by keeping the maximum charge voltage low enough to avoid inverter shutdown.  This   WILL    undercharge your batteries, AND by doing so, they will die an EARLY DEATH... the life span of which is usually measured in ~ 5 to 10 years for good , well charged FLA's, or maybe longer, and you are willing to accept the costs of early replacement...

But what you cannot do is properly charge those batteries and run that Inverter simultaneously..

You could also just run the inverter after you were in float, or after the sun goes down and shut it off when the sun comes up... but this requires you  to watch daily for those 2 times... a PITA

So go ahead and reject all the information put before you and continue  be prepared to replace the batteries within a year or possibly less, but remember that you compared the replacement cost of those batteries against the cost of that cheap inverter, and thought that it was the cheapest way to go....

[mat]

Hi,
After a early failure of my Cotek inverter, i now have the same crappy inverter, but with 48v input (i hope to be able to upgrade soon, it's oversized to handle fridge surge and guzzling amps... Well...)

Mine is ok up to 61,5v, which is for me an equalizing charge.

Yours shuts down at 45v, for 36v bank. That's 15v for a 12v battery, also what i understand to be an equalizing voltage.

So, my question : are trojan batts really designed to have such a high absorb voltage ? If so, at how much do they equalize ?

[sigp2101]

Hi,
After a early failure of my Cotek inverter, i now have the same crappy inverter, but with 48v input (i hope to be able to upgrade soon, it's oversized to handle fridge surge and guzzling amps... Well...)

Mine is ok up to 61,5v, which is for me an equalizing charge.

Yours shuts down at 45v, for 36v bank. That's 15v for a 12v battery, also what i understand to be an equalizing voltage.

So, my question : are trojan batts really designed to have such a high absorb voltage ? If so, at how much do they equalize ?

Trojans 105s equalize at 48V. My inverter starts to indicate overvoltage at 41.5V but fridge still works, light works TV works only vacuum shuts it off. If voltage is below 41.5 everything works fine. Go figure.

[mat]

Ok, so as your fridge seems quite effecient, i would guess your problem isn't related to charge voltage, but to the too high surge of your vaccum.
Mine has zero surge capabilities...


Edit :
Apparently you say it's only when charging that your vaccum won't start ? If so, i'm maybe wrong... But still i think something surge related as eveeything else works ok...
Still, maybe you could use your vaccum when not charging ? Doesn't seems a big issue to me...

Mat

[mat]

Or you could also have a lees high voltage absorb  dor the 2 to 5 days you're at your cabin, and program again the good parameters before you leave, that should help...

Mat

[sigp2101]

Or you could also have a lees high voltage absorb  dor the 2 to 5 days you're at your cabin, and program again the good parameters before you leave, that should help...

Mat

I can turn solar array off while I am there and that would solve the problem too.

[mat]

In the end, your system : your choices...

Mine is far from perfect due to local availability/budget...

You had here lots of good advices (not talking about mine !!!) from people doing solar for years...

Stop charging your batts to use a vaccum... Well, why not...

Have fun !

Mat