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Discussion Starter #61
read the voltage when you are trying to transmit on the radio at the battery and then at the radio maybe wiring that is going to the radio is high resistance. you may have a high voltage drop in the wiring. also try, put meter plus lead on the battery and the negative on the radio wire at the radio with the radio is transmitting that will tell you voltage drop. any thing over .2 volts and you have a wiring problem
Thanks, I'll take a look at this tomorrow when I get the new batteries in.
 

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Discussion Starter #62
Volts is volts, amps is amps.

A DMM and ammeter will tell the tale if you don't have a logger.

Start with a battery in decent condition, depleted down to around 12V.

Notate the V & A about every 20-30 min over 7-9 hours, stop when the current falls to around 0.010 or even 0.005.
Was about to start an 8 hour log and note the V and A...but then I saw my multimeter says 10 amp fuse. That means the 30amp charger is going to blow it out, doesn't it?
 

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And that DMM does not include an ammeter anyway does it?

If not what are you going to measure current with?

as opposed to voltage.
 

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Discussion Starter #65
And that DMM does not include an ammeter anyway does it?

If not what are you going to measure current with?

as opposed to voltage.
The battery is a Trojan T-105, 200 Ah.

I believe it measure Amps too. Says plug in red test lead for current measurements 400mA to 10 Amps. I guess I'm out of luck on a 30 amp charger.

**** this thing, I already took back two multimeters!
 

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An ammeter style you can use as an ongoing instrument would be good, Blue Sea's is maybe $70?

Even better an Ah counter, but good ones cost more. Here's a cheap chinese version


check it also shows amps real-time.

Best of all a proper BM, like Victron BMV-712 but of course pricey


Otherwise, a clamp-on style ammeter is more portable. make sure rated for DC amps not just AC.

Fluke is excellent but $

models 375 and 376.

Extech EX 830

Mastech, MS2115A
Cheap chinese ones include Unit-T UT203, UT207

Aneng AN8002 supposed to be OK

MaineSail here:

Also Recommendations for AC/DC voltmeter purchase - Cruisers & Sailing Forums
 

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Discussion Starter #67
Volts is volts, amps is amps.

A DMM and ammeter will tell the tale if you don't have a logger.

Start with a battery in decent condition, depleted down to around 12V.

Notate the V & A about every 20-30 min over 7-9 hours, stop when the current falls to around 0.010 or even 0.005.
As suggested, I recorded the V/A of my new batteries while charging over the course of 8+ hours (I went back in the morning to see if I could continue where I left off). Are you able to determine anything about the health of my 30 Amp Charles Charger based on this data? sorry about the formatting, it erased my spaces
HOUSE STARTER
Time Volts Amps Volts Amps
---- 12.29 0 12.34 0
10:00a 13.50 15.87 13.60 11.69
10:30 13.77 12.33 13.82 8.74
11:00 13.93 10.12 13.95 7.88
11:30 13.99 8.50 14.02 7.20
12:00 14.05 8.00 14.07 6.55
12:30 14.09 8.08 14.12 5.75
1:00 14.12 7.75 14.16 5.05
1:30 14.15 6.82 14.19 4.57
2:00 13.46 3.06 13.49 1.93
2:30 13.48 2.78 13.51 1.70
3:00 13.50 2.55 13.53 1.56
3:30 13.51 2.33 13.53 1.40
4:00 13.52 2.09 13.54 1.43
4:30 13.53 2.20 13.56 1.15
5:00 13.54 2.08 13.57 1.10
5:30 13.54 1.97 13.58 1.03
6:00 13.55 1.71 13.57 1.24
*BATTERY CHARGER OFF OVERNIGHT *
---- 12.82 0 12.82 0
11:30a 14.36 2.92 14.36 2.58
12:00 14.40 2.87 14.41 2.25
12:30 14.40 3.05 14.42 1.99
1:00 14.40 3.12 14.43 1.90
1:30 14.40 3.07 14.43 1.88
 

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Hard to say for sure, but it looks like it was trying to drive voltage up in Bulk mode, but never spent much time in Absorb, before a Float timer expired (3hrs). Lousy way to charge a battery, but not uncommon. What is the presumed amp hour capacity of the two batteries you detailed? Getting down to a couple of amps would be good, if the bank is large enough.
 

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Discussion Starter #69
Hard to say for sure, but it looks like it was trying to drive voltage up in Bulk mode, but never spent much time in Absorb, before a Float timer expired (3hrs). Lousy way to charge a battery, but not uncommon. What is the presumed amp hour capacity of the two batteries you detailed? Getting down to a couple of amps would be good, if the bank is large enough.
These were two brand new 6V Trojans connected in series, 200 amp hours.

Is it possible it didn't spend much time in Float because it didn't need to? These were bought weeks before, I got 'em down to 12.29 before charging them up with the system for the first time.
 

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The timer I was referring doesn’t limit Float, it reverts to float after a specific amount of charge time. That’s somewhat common, but makes no sense, as the same time is applied to a deeply discharged battery as one that is lightly discharged.

I can‘t really say this is what’s happening. It’s just looks odd. What is measuring the amps? Getting down to 1amp of charge acceptance in float is pretty good for a 200Ahr bank.
 

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Float is lower voltage, and should only happen after charging is complete, truly 100% Full as per endAmps.

Which means, long after the transition from Bulk / CC stage to Absorb / CV stage, amps have dropped to a rate of say 0.05C

actual spec depends on the battery mfg/model.

Another way is, current rate has stopped falling, change slowed to less than 0.1A over an hour.

Depending on the initial C-rate made available by the charger (say 0.8C rather than 0.1C), and the CV setpoint used (say 14.2V rather than 14.8V)

the proportional time spent in CC stage vs CV stage can vary enormously.

But even with a high current charger, the overall time spent to get from say 50% SoC to genuine Full is usually well over five hours, can be 7+

99% of even to quality chargers by default terminate charging (drop to Float) far too early, very damaging to bank longevity.

It is up to the owner to lengthen the CV stage (AHT) for their unique situation, until true 100% Full is reached automatically most cycles, at least 2-3 times per week.

The purpose of Float is just for loads to be carried without cycling the bank unnecessarily, and to counteract self-discharge keeping the bank at 100% Full for as high a percentage of its lifespan as possible.
 

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amps have dropped to a rate of say 0.05
0.005C?

For the OP, who I suspect doesn’t understand these abbreviations, that 0.005 times the rated 20 amp hour capacity of the battery. 200 AH x 0.005 = 1

The voltage pattern does not appear to have been in Absorb for long, but still gets down to nearly a full indication. The voltages don‘t look right for AGM and why are there two sets of voltages and amps?

Others:

CV..... Constant voltage
CC....Constant current
SoC.. State of charge
 

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Yes 0.005C sorry

Translates to half an amp per 100Ah of capacity.


Another way is, current rate has stopped falling, change slowed to less than 0.1A over an hour.
Especially as a battery in poor health can take too long to get to the endAmps spec, can use both of these with an OR between them.

I can't grok those numbers, maybe a screenshot of the table properly formatted

or best would be a graph, V / A on the Y, time on the X is the standard

also maybe wiring is an issue, diagram the layout, everything properly crimped, checked for resistance?
 

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Sample chart, for illustration only, actual profile specs vary by model
VxMsRHKWfyoUgpbSs2d4Q5L346BRmGoaliBYc0YC_CY.jpg

and that " 80% SoC " transition point from CC to CV stage can vary greatly, does not matter so long as the bank is indeed getting to 100% Full eventually.
Especially with higher CAR chemistries (Charge Acceptance Rate)

Good article here from MaineSail

 

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Discussion Starter #75
The timer I was referring doesn’t limit Float, it reverts to float after a specific amount of charge time. That’s somewhat common, but makes no sense, as the same time is applied to a deeply discharged battery as one that is lightly discharged.

I can‘t really say this is what’s happening. It’s just looks odd. What is measuring the amps? Getting down to 1amp of charge acceptance in float is pretty good for a 200Ahr bank.
A clamp-on meter was measuring the amps.

I'm not sure I understand what's being said regarding the Charles charger... are you guys saying the low amp readings near the end, which I guess is the Float charge portion, didn't last long enough? Or should have gone lower, to well below 1 amp...but maybe I just didn't keep charging long enough? I assumed the measurements would continually drop as it had been doing so steadily.

Also, I wondered...is it weird that the two banks were being charged at different amp rates right off the bat (one was 15, the other closer to 10)? Perhaps more resistance in the run to the starting bank. Also...it's a 30 amp charger, so should it not be pushing 30 amps during the Bulk portion?
 

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are you guys saying the low amp readings near the end, which I guess is the Float charge portion, didn't last long enough?
I really suggest you read up on charging and how it works. It will help you understand the answers to your questions better. Float is perpetual and shouldn’t even start, until the bank is near full (ie accepting very low amps in Absorb phase)

Your table shows voltage dropping whne accepting between 3 and 6 amps, which is high for your bank size. That’s why I thought it may be on a timer. However, I see no Absorb level (constant voltage).
 

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Discussion Starter #77
I really suggest you read up on charging and how it works. It will help you understand the answers to your questions better. Float is perpetual and shouldn’t even start, until the bank is near full (ie accepting very low amps in Absorb phase)

Your table shows voltage dropping whne accepting between 3 and 6 amps, which is high for your bank size. That’s why I thought it may be on a timer. However, I see no Absorb level (constant voltage).
I’ve read a fair bit (and continue to study) but this went a step beyond.

Are you sure you guys arent being a little too textbook when in fact this Charles 30 amp 3-stage charger is charging pretty much as it should? I mean, as long as this charger isn’t out right murdering these batteries, I’m probably happy… I’d love it if these lasted 10+ years but if they lasted 7 or so, I’d be fine with that. It’s definitely not a smart charger, that’s for sure.

Down the line, I’m definitely getting one though (when I upgrade to AGM batteries).
 

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The phenomena of the CC-CV transition, and the amps trailing down as 100% is approached

are not the result of any "smart" charge regulation.

The factors involved in those events are:

starting SoC
battery size and chemistry
temperature
amps made available (CC), and
voltage setpoint (CV)

The only actual regulation involved in the charge cycle, is delivering the maximum current possible (pulled / requested by the battery) and holding a maximum voltage as per the V setpoint.

All that happens the same way, even with the dumbest PSU!

The only "extra" functionality that makes it "a charger" is some algorithm that determines "battery full" and automatically stops the charging cycle, usually by dropping to a lower Float V setpoint.

Adjustability of those setpoints, also ideally of the AHT and current rate, is the only other "intelligence" that makes for a more useful unit.

See above for the usual situation, most chargers drop to float way to early, never reaching true 100% Full.

_
I still have not seen data, but the "experiment" really should only involve

one known-good unit at a nominal 12V configuration e.g. one pair of Trojans, wired properly

starting at around 50% SoC

with no loads connected at all.
 

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Are you sure you guys arent being a little too textbook when in fact this Charles 30 amp 3-stage charger is charging pretty much as it should?
If you were convinced that was true, why ask more textbook questions? Do you see three stages of charging in your tables? I’m just trying to tell you I don’t. I’ve also said I’m not so sure about your measurement system, so feel free to take it all with a grain of salt.

You may get your desired 7 years, which is also a factor of your discharge usage . No way to know.
 
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Get to the point where your system at least can be configured to reach the ideal behaviour.

Then when circumstances or convenience dictate compromises, at least you are consciously doing so.

I still think the bank infrastructure may not be properly wired up!
 
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