DC power supply to power 12v DC panel instead of batteries

[Rugger]

Hi everyone,

Heres my situation. I have a 1 year old Trojan FLA 220ah battery bank and a slightly older interstate 220ah FLA bank. They both go from 100+% to 25% in 10 min with a 7 amp load.

Loads are: fridge draws 4-5 amps, laptop (12v charger) draws 2-3 amps, wifi draws 1/2 amp or less.

I've ruled out connection issues. Everything is pointing to the batteries being sulfated.

To desulfate i want to be able to use whats powered in my 12v panel, but that wouldn't be good for desulfication process.

So here's my possible solution that i'd like your opinions on.

While on shore power, how about replacing the battery power to the panel with a DC power supply that runs off the inverter? This is rated for 30amps, roughly 4x what i use.

https://www.amazon.com/MegaWatt-S-35.../dp/B00JZBE97U

It would be a permanent install with a switch to toggle between battery power and power supply power.

I would use this for about 8 hours a month.


Thoughts?

Thanks in advance everyone.

[smac999]

if your 220ah bank can't handle a 7a load for 10 mins. you need new ones. don't even waste your time on them. they should last 30 hours. if your problem was they only lasted 20 hours instead of 30. then maybe I'd spend time on them.

[Pete7]

Originally Posted by Rugger

I have a 1 year old Trojan FLA 220ah battery bank and a slightly older interstate 220ah FLA bank. They both go from 100+% to 25% in 10 min with a 7 amp load.

What exactly have you done to them to reach this point in a year?

[StuM]

Those batteries are stuffed. Almost certainly because of an inadequate charging system.



Replace them.
But before you do, tell us how you have been charging them. There are plenty of people here who can advise on an appropriate charging regime.

[djmarchand]

I agree that the batteries ae dead and all the equalization in the world won't revive them, so replace.


Also in my experience, if you charge your batteries fully at least every other day, there will be no need for equalization. Equalization is a technique to put moderate sulfates back into solution after standing discharged for significant time. Once the sulfates begin to reduce capacity significantly, the batteries are toast.


So replace the batteries and keep them fully charged and don't worry about equalization.



David

[Sailmonkey]

Beyond what everyone has already said about the batteries being complete toast.

How do you propose to run this power supply (that will be fine for your intended application) off of the inverter if the batteries are disconnected?

[OzePete]

Only a year or so old! Maybe they are sulphated due to erratic charging. Maybe they are finished but suggest removing them to a safe well ventilated area, connect each to a 3 to 4 Amp charger at say 14.5volts minimum for a day or so. (Check water levels first!)
I think you may be pleasantly surprised...

Here is an old but good article re batteries...
https://iceking.ca/icetechblog/Sulfated_Batteries.pdf

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[Rugger]

Originally Posted by Pete7

What exactly have you done to them to reach this point in a year?

They have been on the 20ish yer old Heart Interface charger the whole time. I've desulfated them once or twice.

topped off the water with distilled every 30 to 45 days.

[Cheechako]

FIRST: Charge the batteries long and well with a shore type charger. Near the end of that charge cycle feel each battery for heat. If one is very hot ... it's shorted inside and it's drawing the others down. I have had this occur twice on boats with relatively new batteries.

[Rugger]

Originally Posted by StuM

Those batteries are stuffed. Almost certainly because of an inadequate charging system.



Replace them.
But before you do, tell us how you have been charging them. There are plenty of people here who can advise on an appropriate charging regime.

The 20ish year old charger has supposedly been managing the charging. The setup should be fine. The default setup on the system is whats needed for these batteries so its fine.

Hooked up to shore power whole time with the exception of day sails and an overnight.

[john61ct]

Originally Posted by Rugger

The 20ish year old charger has supposedly been managing the charging. The setup should be fine. The default setup on the system is whats needed for these batteries so its fine.

Then what is your explanation for banks that should last at least 6 years, maybe 12+ when cared for meticulously, failing in less than a year?

You need a decent ammeter and a new battery, then use the knowledgeable people here, to find out what is wrong with your system(s).

IMO charging will indeed turn out to be the issue.

[Rugger]

Originally Posted by Sailmonkey

Beyond what everyone has already said about the batteries being complete toast.

How do you propose to run this power supply (that will be fine for your intended application) off of the inverter if the batteries are disconnected?

Thanks for pointing out an error in my post. I meant to say the DC power supply would run off of shore power rather than the inverter.

[john61ct]

Originally Posted by Rugger

So here's my possible solution that i'd like your opinions on.

While on shore power, how about replacing the battery power to the panel with a DC power supply that runs off the inverter? This is rated for 30amps, roughly 4x what i use.

An inverter produces AC power from DC usually batteries.

The power supply produces DC from AC.

Makes no sense to run the latter from the former, going in circles, huge inefficiency losses.

Just run the PS off your shore power.

But none of this is a "solution" to your fundamental problem of your batteries getting murdered.

Solve that first.

[Jammer]

Originally Posted by Rugger

So here's my possible solution that i'd like your opinions on.

While on shore power, how about replacing the battery power to the panel with a DC power supply that runs off the inverter? This is rated for 30amps, roughly 4x what i use.

https://www.amazon.com/MegaWatt-S-35.../dp/B00JZBE97U

Yes, you can do that. Yes, it will work.


But if your batteries have failed, there is no way to bring them back from the dead. No amount of Dr. McGellan's Snake Oil Liniment. No amount of Prof. Eggerston's magnetic resonance ultrasonic battery charger. You got a losing hand, read 'em and weep.


My batting average in diagnosing electrical problems over the internet is basically zero. Someone who knows what they're doing is going to have to get on your boat, test stuff, figure out what went wrong, and fix it, and then you're going to have to buy new batteries.

[Rugger]

Originally Posted by john61ct

Then what is your explanation for banks that should last at least 6 years, maybe 12+ when cared for meticulously, failing in less than a year?

You need a decent ammeter and a new battery, then use the knowledgeable people here, to find out what is wrong with your system(s).

IMO charging will indeed turn out to be the issue.

The reason for the post was to see if the power supply would work for powering the panel so i could still have my 12v devices working while i move on to troubleshooting the charging/battery system.

The previous owner indeed got 7 to 9 years out of batteries with this setup. I talk to him frequently. Everything in this system is (or was) super high quality when purchased. The ammeters included.

https://photos.app.goo.gl/nQJfvQfpiCNGMhXL6

The plan was to get the panel powered and disconnected from the batteries so I can do 3-4 desulfate cycles on one of the banks to see if i could breathe some life back into them.

When or if that doesnt work, tackle the issue of what is killing the batteries.