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Old 02-05-2021, 17:53   #16
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Re: Ammeter/ parasitic draw reading

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Originally Posted by Apollo366 View Post
I ran a bunch of numbers, and my guess is it's a bad cell or 2 in the bank of Trojans, although it can still be a parasitic load some where.

Diminishing capacity over such a short time also indicates bad cells.

Hygrometer or volts by cell when at the 12.3V level should show any bad cells in the bank.

Happy hunting,

Apollo Wayne
When the batteries were new one of them was suspect. I bought them both at the same time from a Trojan distributor but the batteries dont have a date stamped anywhere on them (edit: i found it). There is some sort of code stamped on them but have no idea what it means. When they were new one of them was off-gassing pretty badly. Had a slight rotten egg smell. It went away gradually but I probably should have had them tested right away in hindsight.
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Old 02-05-2021, 18:00   #17
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Re: Ammeter/ parasitic draw reading

The presence of multiple ground connections at the engine block means that the SG200 shunt isn’t necessarily seeing all the power being drawn from the batteries. Maybe those circuits are dead - or one is an Vac ground - but this needs to be cleaned up.
Take your time, label wires. use old wiring for fishing new wires. explore how more modern wiring circuitry might be implemented with your re-wiring project. I had the power lines to a fridge and 12Vdc watermaker run through a switch panel to allow on-off control, with very long cable runs. I replaced this with relay control circuits. Basically, the panel switch turns the relay on and off (low current draw) and the power cables run directly to the device, thus reducing voltage drop. Be careful of using solid state relays (SSR). There are definitely places for their use, but the semi-conductor innards introduce their own voltage drop, possibly even worse than having the old power cables running to the panel switches.
Don’t ask me how I know this, but Amazon sells Chinese powerneters very similar to the SG200 or Victron BMV-712 in many functions for about $18. I’m beginning to add these to monitor energy use/efficiency for individual devices and am pleased what this fine level of detail can provide
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Old 02-05-2021, 18:05   #18
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Re: Ammeter/ parasitic draw reading

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Some draw is normal as said.
Sounds more like your losing capacity as you've mentioned.
I'm betting one or more of your T-105s are losing capacity.
I think your on the right path though.
Separate the units electrically, then test each cell with the hydrometer.
I think you'll find significant comparative differences.
Are your Batteries dated? Hopefully there all the same age.
SV Cloud Duster
They are both stamped A1 which should be January 2021 i believe. I bought them in February so that would correspond. Still checking but I think the T-105's should have a specific gravity of 1.28
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Old 02-05-2021, 18:18   #19
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Re: Ammeter/ parasitic draw reading

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so far, it seems as though the two t105 batts, connected in series, are being treated as one 12v batt. with a dvm, one can measure the terminal voltage of each batt while the two are installed in the usual way. the batts should have nearly identical terminal voltage, the sum of which should equal what is measured across the two in series. if the measured terminal voltage (taken with no significant load on the batts for at least 30 min. and measured on the batt terminal, not something connected) are not the same (within 0.05volts), then it is likely the batt with the lower terminal voltage reading has an issue. if the measured voltages are equal, then it is likely the problem is elsewhere in the form of a unknown current draw.
I forgot to do this. Im measuring them now. They have been disconnected for a few hours now. One measures 6.25 and the other 6.21. When they were brand new one of them was about 10% less SOC. I attempted to equalize them individually with a 6 volt charger before connecting them in series/parallel. I did measure them a few times when they were installed. One battery always seemed to be at a lower SOC.
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Old 02-05-2021, 18:27   #20
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Re: Ammeter/ parasitic draw reading

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Does absolutely everything go through your monitor shunt? Engine? Feel your alternator after the engine has been off overnight, if it is warm it is being energized even though the keys witch is off. Another possibility is a bad diode in the alternator.

Your description, although cute, says nothing about your boat so we cannot even guess at what engine you have.
i have an 1980 Universal 5432 engine. The wiring harness from the engine to the start panel is the worse wiring on the entire boat. It all in very bad shape. There is no on/off switch just a push button start. It VERY badly corroded and has the old Ammeter installed. This is a known issue as are the trailer terminals connecting some heavy amperage wires. It starts perfectly though. As bad as it all looks it works. I have been avoiding it all because it plan to install a new engine next year and have been hoping i can squeak by with whats there. I'm just a weekend bay sailor right now so never that far from shore/ a tow. The alternator is another questionable item. I beleive it to be the original alternator and MAY have blown diodes. Its a hot mess. We havn't been using the boat most of this last year so i havn't confirmed the alternators health. I am currently replacing the wet exhaust system so cant start it.
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Old 02-05-2021, 18:34   #21
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Re: Ammeter/ parasitic draw reading

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The usual suspects for parasitic draw, are damaged chafed insulation on cables, that are causing leakages, current to ground, not enough

to blow a fuse but battery sapping 24/7.

Have you checked the wiring to your bilge pump switch, which may have a problem while sitting in a wet bilge,

Does your bilge pump cycle on/off while you are away from boat.

Do you have any systems on standby, or sleep mode,

Check YouTube for "parasitic draw on car battery"

where you can find out how to find and isolate parasitic draw.


https://www.youtube.com/results?sear...on+car+battery


Thanks kish. I have a dry bilge (dripless). I literally have cob webs and spiders living in my bilge, no joke.

The bilge pump is brand new UL listed Rule pump. The switch is also new. Water Witch sensor switch which is potted in epoxy. Obviously none of the wiring gets wet. All of the wiring to and from the pump and switch back to the panel switch and battery is brand new. The panel switch is a bit old but works perfectly and has an inline fuse which is also new. The only time the pump ever goes on is a couple of times a year when i drag the hose in and test it.
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Old 02-05-2021, 18:42   #22
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Re: Ammeter/ parasitic draw reading

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i have an 1980 Universal 5432 engine. The wiring harness from the engine to the start panel is the worse wiring on the entire boat. It all in very bad shape. There is no on/off switch just a push button start. It VERY badly corroded and has the old Ammeter installed. This is a known issue as are the trailer terminals connecting some heavy amperage wires. It starts perfectly though. As bad as it all looks it works. I have been avoiding it all because it plan to install a new engine next year and have been hoping i can squeak by with whats there. I'm just a weekend bay sailor right now so never that far from shore/ a tow. The alternator is another questionable item. I beleive it to be the original alternator and MAY have blown diodes. Its a hot mess. We havn't been using the boat most of this last year so i havn't confirmed the alternators health. I am currently replacing the wet exhaust system so cant start it.
That sounds like a nightmare. If there is just a start button either there is an oil pressure switch to power the alternator or it is continuously powered. Is there a way to disconnect the engine from the battery and still power everything else? If yes, disconnect the engine and check your power draw. If you don't understand your wiring disconnect it from power except when you are aboard.

PS. Your automatic bilge pump should be powered 24/7.
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Old 03-05-2021, 02:36   #23
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Re: Ammeter/ parasitic draw reading

How did you "fully" charge them? With shore power and a CC that does proper bulk and absorption? Because they show 12.7V at rest doesn't necessarily mean they're fully charged.
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Old 03-05-2021, 06:30   #24
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Re: Ammeter/ parasitic draw reading

Chris from Balmar here. When you are seeing that 20% very early in the discharge cycle, what does the SG200 show as the State of Health?

If you batteries are compromised, but the SG200 has not yet learned your batteries and is showing a SoH of 100%, then what you are seeing is plausible. Essentially, your SoH should be lower, and the monitor recognizes the decreased capacity as the voltage is going much lower than it should for the removed AHs. THis is still better than a typical AH meter, which would simply count down from 100%, damn the actual capacity. Once you get a good SOH, then the SoC should be more linear.

If you do have a bad cell, then the SoC may drop to 0% perhaps 20-30% before the bottom. I have seen this where the SOC is in the 50s, and then boom it is 0%. This is because the voltage and calculated impedance are soo out of range that goes to 0%. Especially if you hit termination voltage way before you should.

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Old 03-05-2021, 07:04   #25
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Re: Ammeter/ parasitic draw reading

I didn't see any mention of type of battery charger. Is the charger maybe not fully charging the batteries?
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Old 03-05-2021, 10:00   #26
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Re: Ammeter/ parasitic draw reading

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I didn't see any mention of type of battery charger. Is the charger maybe not fully charging the batteries?
Sterling Pro Charge Ultra on shore power. I have the remote display for the charger which shows bulk and absorption voltages as its charging. I do loose .1 volts at the batteries due to the length of run and wire gauge i would guess. I havn't tried to correct for the drop so the batteries do see roughly .1-.2 volts less that what i should be charging them at.
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Old 03-05-2021, 10:25   #27
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Re: Ammeter/ parasitic draw reading

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Chris from Balmar here. When you are seeing that 20% very early in the discharge cycle, what does the SG200 show as the State of Health?

If you batteries are compromised, but the SG200 has not yet learned your batteries and is showing a SoH of 100%, then what you are seeing is plausible. Essentially, your SoH should be lower, and the monitor recognizes the decreased capacity as the voltage is going much lower than it should for the removed AHs. THis is still better than a typical AH meter, which would simply count down from 100%, damn the actual capacity. Once you get a good SOH, then the SoC should be more linear.

If you do have a bad cell, then the SoC may drop to 0% perhaps 20-30% before the bottom. I have seen this where the SOC is in the 50s, and then boom it is 0%. This is because the voltage and calculated impedance are soo out of range that goes to 0%. Especially if you hit termination voltage way before you should.

Chris
Hi Chris, thanks for chiming in. I've had the SG-200 connected since i installed the batteries (about 3 months) and it still showed 100% SOH when I pulled the batteries yesterday. My hydrometer and load tester should arrive tomorrow so i'll be able to confirm the batteries health then.
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Old 04-05-2021, 17:21   #28
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Re: Ammeter/ parasitic draw reading

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Hi Chris, thanks for chiming in. I've had the SG-200 connected since i installed the batteries (about 3 months) and it still showed 100% SOH when I pulled the batteries yesterday. My hydrometer and load tester should arrive tomorrow so i'll be able to confirm the batteries health then.
I am curious to know what load tester you have ordered?

Is it just a simple 'load' tester or more of a full blown 'capacity' tester?
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Old 04-05-2021, 17:39   #29
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Re: Ammeter/ parasitic draw reading

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I am curious to know what load tester you have ordered?

Is it just a simple 'load' tester or more of a full blown 'capacity' tester?
Schumacher bt-100 6v/12v load tester volt meter.

definately not a full blown capacity tester. i was in a hurry to get something so didnt have time to do much research on them.

received it this afternoon and tested both batteries with it. it showed both as weak. i confirmed both batteries are bad with a hydrometer so it seems to work and be reasonably accurate.

learning how to do capacity testing is probably next on my list.
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Old 04-05-2021, 20:55   #30
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Re: Ammeter/ parasitic draw reading

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That sounds like a nightmare. If there is just a start button either there is an oil pressure switch to power the alternator or it is continuously powered. Is there a way to disconnect the engine from the battery and still power everything else? If yes, disconnect the engine and check your power draw. If you don't understand your wiring disconnect it from power except when you are aboard.

PS. Your automatic bilge pump should be powered 24/7.
sorry i missed this. my bilge pump is directly wired to a single charge bus so its powered 24/7.

i do turn the selector switch and the AC main breaker off every time i leave the boat. I dont trust my old wiring to leave it unattended.

hmm...i dont think there is any way to isolate the engine panel. the starter and alternator wire go to the common post on the 1,2,B switch at the distribution panel. the alternator output i plan on moving to the main charge bus, its something i just havnt gotten to yet. when the battery selector switch is on, the engine (starter) is powered.
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