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understand 12v electrical

3K views 23 replies 8 participants last post by  Stu Jackson 
#1 ·
I am trying to setup our 1986 Catalina 30 TRBS with a good electrical system. But the more technology I throw at it the more I seem to get confused.

The first ting I did was get a clipper br-1 battery monitor. The then got 2 6volt 232 amp hour batteries. I spend 99% of my time on a mooring so solar is how I decided to keep them charged.

The first thing I noticed was my batteries were not getting above 85% charge or that is what the battery monitor told me. I have 2 30 watt solar panels conceited to a cheap charge regulator. After doing sum research I determined my charge regulator was a shunting one and the y take forever to charge to 100% if they ever do. So I now have a mppt charge controller on the way. A bit overkill for 60w panels but I may add more in the future.


Now here is where my question starts. I put my boat on the dock to charge it from shore power to se if I can get close to 100%. I changed the battery with Noco Genius g7200 smart battery charger that is rated for 230 amp hours.

When I went the next morning I reset by battery monitor and put a 5 amp load on the system. The battery monitor quickly went to 100% the dropped 1% every ten seconds until it steady off at 85% and 12.7 ish volts. So I charge the battery's again. When I get back same thing 100% on my battery monitor charger isn't charging any more. 5 amp load and it drops to 85%.


So my question is why cant I get my batteries closer to 100% or is my battery monitor or charger the problem. Could my 6 volts that are new not be holding a charge? Do I have a charger that just isn't very good and cant get it to 100%?
 
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#4 ·
sounds like you're doing the right stuff. If you're a sub sailor recall battery gravitates tell the story. Voltage is only an indicator. You can pull the batteries and have them checked out at a battery shop. Could be the voltage regulator on your solar panels. The mfgr ought to have the info you need on line.
 
#5 ·
I have the same battery monitor and it does the same thing on my installation.

I am "playing with" the settings (look in the little green manual that came with the system) to make sure I have them set right. I'll let you know if I have a breakthrough and please let me know if you have one.

I have 2-6V EGC2s in series as a house bank and a thirty watt solar panel hooked through a cheap shunt controller and it's more than enough to keep the system fully charged - it's always charged when I get to the boat - but after a half hour or so of running a couple of Caframo fans and charging my iphone through a small inverter the voltage is down to 12.7 from the 12.9V it was at my arrival on the boat and the capacity bar graph indicates 85 percent. The load on the bank is about 1.5 to 2.5A discharge depending on the solar panel output so I've only used about 1 A-H max out of the 100 that I have told the system that comprises 100 percent (50 percent discharged) of available by the time it indicates 85%.

I'm thinking that the Clipper BM-1 is perhaps too cheap/simple a system to give accurate indications.

I am going to load up the system at maximum discharge rate (everything on except A/P and transmitting on the VHF radio) and plotting a test discharge - voltage and current vs time (and taking sp. gr. periodically) as well as BM-1 voltage and discharge rate and capacity vs time and compare them.

Going to take a while since - using LEDs - I have got my total hotel load (excluding A/P and VHF-transmit) down to less than 10A with EVERYTHING on including nav and anchor and spreader and all cabin lights/Furuno GPS/sounder/fans/computer inverter so it's going to take 10-12 hours to do the discharge. Stereo/radio/weather instruments/backup electronics are all portable and dry cell powered.

I'll post the results later in the week.
 
#8 ·
I have the same battery monitor and it does the same thing on my installation.

I am "playing with" the settings (look in the little green manual that came with the system) to make sure I have them set right. I'll let you know if I have a breakthrough and please let me know if you have one.

I have 2-6V EGC2s in series as a house bank and a thirty watt solar panel hooked through a cheap shunt controller and it's more than enough to keep the system fully charged - it's always charged when I get to the boat - but after a half hour or so of running a couple of Caframo fans and charging my iphone through a small inverter the voltage is down to 12.7 from the 12.9V it was at my arrival on the boat and the capacity bar graph indicates 85 percent. The load on the bank is about 1.5 to 2.5A discharge depending on the solar panel output so I've only used about 1 A-H max out of the 100 that I have told the system that comprises 100 percent (50 percent discharged) of available by the time it indicates 85%.

I'm thinking that the Clipper BM-1 is perhaps too cheap/simple a system to give accurate indications.

I am going to load up the system at maximum discharge rate (everything on except A/P and transmitting on the VHF radio) and plotting a test discharge - voltage and current vs time (and taking sp. gr. periodically) as well as BM-1 voltage and discharge rate and capacity vs time and compare them.

Going to take a while since - using LEDs - I have got my total hotel load (excluding A/P and VHF-transmit) down to less than 10A with EVERYTHING on including nav and anchor and spreader and all cabin lights/Furuno GPS/sounder/fans/computer inverter so it's going to take 10-12 hours to do the discharge. Stereo/radio/weather instruments/backup electronics are all portable and dry cell powered.

I'll post the results later in the week.
Our setups sound very similar. Good to know I am not alone on this problem. I will report back with the results of my power down of my bm-1.
 
#6 ·
I'd suspect the monitor and it's set up. I'm assuming you set the capacity to 232ah.
After the initial install did you allow it to 'sit' and learn your batteries without a charge as the manual undoubtedly says you should?

When it was showing a state of charge of 85 % what was it showing as AH remaining?

You may need to just unplug it and start from scratch, but be assured your 60w of panels and a mppt will and should bring it up to full charge and keep it there if the boat is used as a weekend cruiser and you don't moor the boat with under 60%.
 
#7 ·
One thing I didn't find was how to reset it. So you may be corect as when it was first bulged in the batteries were new and not fulley charged. I don't recall how long untill I started charging. My mppt charger arrived and has been running for 5 or so days. I will unplug the bm-1 and recaliberate that way.
 
#9 ·
Odds are it is just an issue with setting up the batteyr monitor, but you might also want to look for the manufacutring date on the batteries. If there is no date code embossed or stamped someplace (usually on a side, near the top. sometimes on the top, and often intentionally hidden under the edge of a label) to see how long the batteries were sitting at the dealer. If they were more than 90 days old, it is also possible they lost some capacity due to sulphating while sitting around. One never knows without taking a look.
 
#11 ·
I have went through the manual a few times didn't say anything about six cycles. The info is very limited.

1:Go into eng settings. adjust the capacity adjust the temperature. Press illum to finish engineering settings.
2: Do not put the battery on charge immediately.
3: apply a load to the battery by switching on lights or instruments and wait for a few min for the BM! to learn the battery's characteristics and to show a steady reading before stating charging.
Didn't get time to unplug it yesterday as the family was not interested in me messing with things on our last day off but did watch it closer. We had a 12v color connected and it was drawing 1.5 to 3 amps depending on solar input. Battery went from 100% to 85 in the first 5 min. The next 10 it went to 75% Then over the next two plus hours went from 75% to 74%. When I shut things down for the day it when up to 80% in 5 min or so.

But this is just for information I still have to reset it.
 
#15 ·
So I reduce the amp hours entered in the battery monitor from 232 to 209. This cause the charged to jump 10% from 75% to 85%. So it is looking like my new 6 volts may not be putting out the amp hours the monitor thinks they should. I assume if I dropped the amp hours to 185 or so I would count down from 100% properly.

I have contacted the battery manufacture first and will look into returning the batteries.

I am going to do one more charge from shore with the setting at 209 and se what happens. 10% off listed amp hours is normal but 20 to 25% seem to be to much in my mind.
 
#16 ·
So far you've only confirmed that the batteries an dbattery monitor have different points of view. There's no reason to think the batteries would need to go back, although any battery dealer should have a load tester available to cycle and test the batteries and confirm their actual capacity. (Thousand-dollar plus computerized internal resistance testers, not just the old carbon pile load tests.)

I'd suggest you have two ways to go: Take the batteries in for testing, heavy grunt work and the risk of acid spilling and eating your cloths or something in the car (truck?).

Or, get a couple of old automobile high beams or a similar simple resistive load, and do your own real-time load tests on the batteries. With a typical 55W auto highbeam headlight (often free from the dumpster since folks tend to burn out the low beam first in dual-beam bulbs) you consume roughly (55/14.4) 3.8 amps per hour, so one of those bulbs should burn for about 26 hours to consume a real 100 amps from a battery bank. With a couple of multimeters you can confirm the amperage it is pulling and the voltage left in the battery, and you are close neough to the "nominal" 20-hour rate so thosefigures should still apply. This also gives your battery monitor a reality check versus the meters.

If the date code on the batteries (usually embossed or stamped near the top but hidden under the edge of the big label) in within the last 90 days, the odds are there's noting wrong with the batteries unless one is grossly defective.
 
#17 · (Edited)
You make sum good points. The test you suggest is basically what the battery monitor is doing from my understanding. But I se how what you suggest would be more accurate as it is not estimating. I did contact the manufacture first as I really don't what to take them out. I will se what they say before going back to the shop where I got them.

I need a proper full charge after taking 10% off the amp hours before I do anything. I have a mppt solar charger and it was still charging when I was last on so the batteries were not full. Not much sun the last few weeks. So I will go a charge of the land charger again and test.
 
#20 ·
My understanding is it should only be 5% to 10% off new. But I suppose if you take off 10% for new and another 10% because you never get the full rating that could be the 20 or so present I am missing.

It makes me a bit nervous discharging to 10.5 like they suggest 11.9 is empty 10.5 is dead isn't it?
 
#19 ·
Changing the AH capacity of the bank from the 232 'manufacture' capacity to 209 AH changed your state of charge by 10% because you dropped your capacity 10%.

Put it back to 232 AH, run a equalization process via your charger (overcharge them on purpose)... and above all else do some reading on how batteries work.

If I can learn it, so can you.
 
#23 ·
Put it back to 232 AH, run a equalization process via your charger (overcharge them on purpose)... and above all else do some reading on how batteries work.

If I can learn it, so can you.
That is what the reseller of the batteries suggested after talking to them. I have been doing a lot of reading on how batteries work but thanks for that sugestion also.
 
#22 ·
True, but a 20 hour test brings the battery down to 10.5 volts. The load should be 5% of battery or bank size for accuracy. If you can't get it exact don't bother trying - you already have an inaccurate AH estimation and don't need another one.

I don't expect the issue to be the batteries, but the monitor.
 
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