New batteries but low voltage

[kmacdonald]

Originally Posted by sailorboy1

Use partial posts to take whatever you want out of context. I did the right thing and like I wrote if you would have chosen not to replace 6 year old 6v wet cell batteries given the same conditions you're an idiot!

You got good use out of them. I hope your next set last as long.

[thomm225]

Originally Posted by leftbrainstuff

Its not unusual to see 12.2V on house batts under load. Its resting voltage that is important.

If you remove all load, ie isolate the batts, you should see the voltage quickly recover to 12.4+ V. Ideally 12.6V.

We have 10 year old T105s that are still going strong. They are thirsty at this age.

Have you checked electrolyte levels. While you're at it check specific gravity which is a more consistent measure of charge.

Sent from my SM-N900T using Cruisers Sailing Forum mobile app

This seems about right.........

I had 12.72 tonight on my old battery/new battery in parallel with an uncalibrated dvm no load for a couple days now. (and no charge since yesterday)

Solar panel float voltage was 19.75

[mitiempo]

Originally Posted by thomm225

Solar panel float voltage was 19.75

Could you explain this float voltage please?

[senormechanico]

That's gotta be open circuit voltage on the panel.

[mitiempo]

Originally Posted by senormechanico

That's gotta be open circuit voltage on the panel.

My thought as well. Why no controller? That voltage is a battery killer.

[pcmm]

Originally Posted by sailorboy1

I had been getting up in the morning with battery voltage of 12.2 with 60-90AH out. So since the batteries were 6 years old and I had abused them I replaced them yesterday with 4 new Trojan T105s that I charged till they accepted 9A at 14.4V. To test them I turned off shore power and went to bed. This morning they were reading 12.25V at -6.3A and -67 AH. This seems way too low based on the AH and is the same as the old batteries.

Why did you take them off the charger if they were still taking 9amps of current. that to me would indicate that you haven't reached full charge yet. When you took them off the charger did you reset the AH to zero?

[thomm225]

Originally Posted by mitiempo

Could you explain this float voltage please?

I have a simple system not like most of you.

I have a 100 watt solar panel charging two 12 volt batteries in parallel through one of those really cheap CMPT02 Chinese Controllers. (and yes I've heard how bad they are) I paid $12.00 each for them and bought two. (3 years ago)

After my batteries charge up to the controllers allowed voltage of 14.4 volts for a few days, I will at times unhook the batteries from the controller. (and subsequently the panel sometimes for a few days to a week)

I have alligator clips on those leads from the controller to the batteries

When you unhook the batteries the solar panel is basically floating. Mine on a cloudy day will read 19 volts or so. I've seen it as high as 22 volts

On the day I read 19, when I plugged the batteries back in it read 13.4 or so on the panel side and 12.8 or so on the battery side of the controller immediately after reconnect. It had been disconnected over night and this was after work also

I'm doing a few more checks these days because I replaced a battery recently and because this thread has perked my interest a bit.

Also this came up on a CF thread a while back. A guy was reading 22 volts out of his solar panel or maybe on his system monitor..........I believe it ended up he had some kind of disconnect problem between it and the load. At the time, I tested that out on mine and sure enough it was correct


https://www.google.com/search?q=cmpt...9Xzu4kQZYvM%3A

[sailorboy1]

Originally Posted by pcmm

Why did you take them off the charger if they were still taking 9amps of current.

because I wanted to cycle them at least once and only had limited time to have shore power

[Bleemus]

Not sure if I am following correctly but it is normal to get those voltages from solar panels. My two Kyocera 140 watt panels in parallel will put out about 18 volts and my MPPT controller will convert the extra volts to more amps unlike a PWM which shuts down when voltage hits the set level. Do you think you have a fault seeing 22volts?

[masonc]

Originally Posted by Bleemus

These work fine for start batteries but are useless for deep cycle.

If you want to properly test Lead Acid flooded storage batteries, you need a refractometer. I know that sounds expensive, but it actually isn't. This is mine.
Cost is about $20.
ATC Glycol Refractometer Car Antifreeze Battery Acid Engine Coolant Tester Tool | eBay

The other way to test a battery in a string is to charge well, until the electrolyte bubbles for at least an hour. The voltage on each 12V battery should be over 15V. After the batteries cool, load with significant load and measure the voltage on each battery. There should be little difference. If one is about 2V lower, it has a dead cell and must be replaced.

[thomm225]

Originally Posted by Bleemus

Not sure if I am following correctly but it is normal to get those voltages from solar panels. My two Kyocera 140 watt panels in parallel will put out about 18 volts and my MPPT controller will convert the extra volts to more amps unlike a PWM which shuts down when voltage hits the set level. Do you think you have a fault seeing 22volts?

You must remember I'm talking floating voltage. (I was an electronics tech back in the day, computer/electronics later) We called it floating voltage when the load was removed from the power supply, or ahead of the full wave rectifier, half wave rectifier, multivibrator, etc. The circuit was open so to speak

If you unhook your solar panel from the load and check the voltage at the leads on a bright sunny day you will read probably 22 volts with the sun high.

I actually checked mine again today after the post I made earlier and the floating voltage with the sun low here at 36.55 lat N, 5 pm and it read 19.1 or so. After hooking the alligator clips to the batteries it was 13 volts panel side, 12.8 battery side with the batt selector in the off position down below

[Bleemus]

Originally Posted by thomm225

You must remember I'm talking floating voltage. (I was an electronics tech back in the day, computer/electronics later) We called it floating voltage when the load was removed from the power supply, or ahead of the full wave rectifier, half wave rectifier, multivibrator, etc. The circuit was open so to speak

If you unhook your solar panel from the load and check the voltage at the leads on a bright sunny day you will read probably 22 volts with the sun high.

I actually checked mine again today after the post I made earlier and the floating voltage with the sun low here at 36.55 lat N, 5 pm and it read 19.1 or so. After hooking the alligator clips to the batteries it was 13 volts panel side, 12.8 battery side with the batt selector in the off position down below

Then it would appear your batteries are not fully charged or you have a bad controller.

[senormechanico]

Originally Posted by thomm225

You must remember I'm talking floating voltage. (I was an electronics tech back in the day, computer/electronics later) We called it floating voltage when the load was removed from the power supply, or ahead of the full wave rectifier, half wave rectifier, multivibrator, etc. The circuit was open so to speak

If you unhook your solar panel from the load and check the voltage at the leads on a bright sunny day you will read probably 22 volts with the sun high.

I actually checked mine again today after the post I made earlier and the floating voltage with the sun low here at 36.55 lat N, 5 pm and it read 19.1 or so. After hooking the alligator clips to the batteries it was 13 volts panel side, 12.8 battery side with the batt selector in the off position down below

So it's NOT a "float voltage" or as you now call it a 'floating voltage', it's an OPEN CIRCUIT voltage.
Take a look at any solar panel sticker.
They list open circuit voltage as Vsc
They list voltage at max power as Vmp
They list current at max power as Imp
They list current at short circuit as Isc
That's what matters.
Nowhere do they list "float" voltage or current.

When I started my professional electronic career, I repaired car radios in the car (all tubes with vibrator power supplies) for $1.50 +parts IN THE CAR. If it couldn't be fixed in the car, we pulled the radio repaired it on the bench with customer waiting, and replaced it. $1.50 removal, $1.50 replacement, and $1.50 + parts. And we made money doing it.
That was back in 1965.

As a professional electronic tech for 30 + years, I would expect more of an electronics tech these days but then again, maybe not...Went cruising and returned to "civilization" if you can call it that.
I'm now over 70, officially an old fart. so flame away !

[thomm225]

Originally Posted by Bleemus

Then it would appear your batteries are not fully charged or you have a bad controller.

HaHa! Good one!

The internet is great as long as you know who to listen to.

The batteries are fine.

[thomm225]

Originally Posted by senormechanico

So it's NOT a "float voltage" or as you now call it a 'floating voltage', it's an OPEN CIRCUIT voltage.
Take a look at any solar panel sticker.
They list open circuit voltage as Vsc
They list voltage at max power as Vmp
They list current at max power as Imp
They list current at short circuit as Isc
That's what matters.
Nowhere do they list "float" voltage or current.

When I started my professional electronic career, I repaired car radios in the car (all tubes with vibrator power supplies) for $1.50 +parts IN THE CAR. If it couldn't be fixed in the car, we pulled the radio repaired it on the bench with customer waiting, and replaced it. $1.50 removal, $1.50 replacement, and $1.50 + parts. And we made money doing it.
That was back in 1965.

As a professional electronic tech for 30 + years, I would expect more of an electronics tech these days but then again, maybe not...Went cruising and returned to "civilization" if you can call it that.
I'm now over 70, officially an old fart. so flame away !

I was a tech for 21 years then a manager (and tech still when needed if a system goes down) of humans (techs) for 21 years and still rolling.

We don't really have straightup electronics techs these days. You'd get lost to quickly without at least some computer skills. Our O'scopes all have dust on them

I started with tubes, this on deployable Air Traffic Control PAR/ASR Radar Systems (plus IFF) and it went from there. I'm not really a fix it guy though but I was good at it so I did it plus there was a bonus to go that route. There was also a bonus to go infantry 0300 Grunt but I was thinking job after I reckon.

Anyway, now we have Ethernet from "box" to "box" and Raid Arrays with software techs going in every few days to "update" stuff! Rarely is there fun troubleshooting involved usually failed circuit boards are sent out for repair are simply thrown in the trash and replaced. (We don't even get to align the heads on our washing machine size disk drives anymore!)

As I remembered it, we called it floating/open circuit samie same in my head when there was no current flow, but if you want to freak out over the wording and send nastygrams I get it. I just hope it makes you feel better.............I was going to add old man but we have software techs older than you at work on our systems that still use mainframe computers! (Encore)

My system works great and cost maybe $100.00 for the solar panel and controller. The batteries were maybe $84.00 each

My solar panel is in float mode now. Batteries will read around 12.7 volts this morning when I stop by. One new battery and one 5 year old battery in parallel