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thataway
Joined: 02 Nov 2003
Posts: 20812
City/Region: Pensacola
State or Province: FL
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
Photos: Thataway
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 Posted: Tue Dec 26, 2023 2:51 pm Post subject: |
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A specific answer to Marco Flaminco's question about belts and suspenders. This is a quote from a poster on Trawler Forum, which Marco also frequents.
| Quote: | | One test I saw, on on the 100A battery was the high current cut off of the BMS. Specs show 150A, but the battery went to 250A for 30 seconds before shutting down. In the test, the wire got very hot. So, I hope your fuses blows before the wires heats up too much. Not a big deal as long as the fuses are sizes right to each battery and the cables are over sized. |
One of the Major functions of the Battery Management System (BMS) is that it monitors temperatures in the battery (both hot and cold cutoffs). For many the low temp cutoff could be an issue, and a heated battery (which detracts from its full capacity) would be a good choice in AK, or even any latitudes where there is frequent freezing weather.
The below is quoted from Eco-worthy.com:
| Quote: | How does BMS work
(1) Monitor the battery
A BMS may monitor the state of the battery and it triggers a power module shutdown if the data is out of range.Monitoring the voltage of each cell is critical to the health of the battery, and lithium-ion battery BMS usually provides each cell with an operating voltage window in charging and discharging to avoid battery degradation.Because lithium battery cells are very sensitive to overcharging and over-discharging, and cells imbalance can lead to thermal runaway and cells degradation.It will decrease the efficiency and short the life span of the battery. Battery cells' operating voltage is between 2.5V and 4.2V depending on the lithium chemistry used. Running the battery beyond this range will result in a significant reduction in battery life and may even damage the battery.
(2) Protect the battery
A Battery Management System (BMS) can monitor and control the charging and discharging process to ensure that the battery stays within its safe operating range.
Overcharge Protection/Overdischarge Protection
BMS estimates the battery's SOC based on voltage and current measurements. This allows the BMS to predict when the battery has reached its current limit and once the battery voltage is above/below the safe limit, the BMS will limit the discharge current or terminate the discharge.
Overvoltage Protection/Undervoltage Protection:
BMS prevents overvoltage/undervoltage by limiting the charging current or stopping the charging process. When the battery's voltage is higher/lower than the safe voltage, the BMS will shut down the charging circuit to prevent damage to the battery.
Temperature Protection
Overcharge and overdischarge can cause the battery temperature to rise or even cause thermal runaway. BMS helps reduce this risk by monitoring battery temperature and taking action when the temperature exceeds its safe operating range.
(3) Short Circuit Protection
The battery management system (BMS) continuously monitors voltage, current and other parameters to prevent short circuit. Faulty wiring will cause short circuit which poses a significant risk to both the battery and the connected device. And BMS can protect the battery from short circuit.
(4) Balance the battery
Unlike lead-acid, the voltage of a fully charged lithium battery rises quickly. If not controlled in time, it may cause battery degradation. There will be a big perform difference between battery cells which may cause the malfunction within the safe voltage range.
TIPS: Battery Cells Consistency (SOC state of charge)
A good battery pack should look like a neat square in a parade, keeping the same rhythm as it moves forward. For example, during the charging process, the charging of other battery cells in the same battery pack must be stopped immediately once a battery cell is fully charged (reaches 100% capacity). Otherwise the battery will be overcharged and cause irreversible damage.
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When we had the Chinese "500 amp" rated switch blow up, the current draw was 300 amps. I was watching the Victron monitor. BMS didn't shut down the batteries, and the 500 amp fuse didn't blow. On the other hand 300 amps is a significant amount of current and other than starting the engine, it is rarely achieved. In this case I had both the microwave and induction burner on "Hi", as a test of the components, as well as preparing to fix dinner. I was using two different 120 volt outlets, each on a 15 amp breaker on the 120 V AC panel (under the aft dinette seat.). I have never done a high current analysis of the starter on the Honda 150 outboard, But the engine start battery was a group 24 FLA battery, My engine was a 2007 and should have the same specs as later Honda 150 battery requirements: 64Ah/5HR 80Ah/20HR. CCA 622. MCA 809. Generally the Honda 150s take somewhere in the 200 to 300 amps to start the 150 outboards. So that is not an unusual load. However if one monitor's the voltage on starting the FLA will often drop to 9 to 11 Volts during this high current draw period. There are some LiFePO4 batteries rated to start engines, but many that application is to be avoided. That is why good policy to have FLA as starting battery, and then the DC to DC charger is running off that FLA start battery.
_________________
Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018 to Oct. 2021
Thisaway 2006 22' CDory November 2011 to May 2018
Caracal 18 140 Suzuki 2007 to present
Thataway TomCat 255 150 Suzukis June 2006 thru August 2011
C Pelican; 1992, 22 Cruiser, 2002 thru 2006
Frequent Sea; 2003 C D 25, 2007 thru 2009
KA6PKB
Home port: Pensacola FL |
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Robert H. Wilkinson
Joined: 26 Jan 2011
Posts: 1234
City/Region: Port Ryerse
State or Province: ON
Vessel Name: Romakeme IV
Photos: Romakeme IV
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| Posted: Tue Dec 26, 2023 9:09 pm Post subject: |
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[quote="thataway"]
| Quote: | | One test I saw, on on the 100A battery was the high current cut off of the BMS. Specs show 150A, but the battery went to 250A for 30 seconds before shutting down. In the test, the wire got very hot. So, I hope your fuses blows before the wires heats up too much. Not a big deal as long as the fuses are sizes right to each battery and the cables are over sized. |
I suspect this is one of the reasons that a "Class T" - fast blow fuse is recommended for an inverter - especially on a 12v system where the amps are much higher than with a higher voltage - 24, 36, 48, etc. Most of the off grid systems that I am more familiar with use the higher voltage inverters and lower amps flowing in and out.
Rob
_________________
Talk to me and I will listen-- but if its not about boats or fishing all I will hear is bla,bla,bla,yada,yada,zzzzzzzz |
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colbysmith
Joined: 02 Oct 2011
Posts: 4550
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
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| Posted: Fri Dec 29, 2023 7:33 pm Post subject: |
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Just about finished up with the install. Just have to finish hooking up the receptacles inside the cabin. But here are a few photos.
This first one shows the PVC board I used 4000 to glue it to the inside of the hull. You can see the machine screws I mounted from the back that the inverter will slide onto.
The next photo shows the inverter in position. Also shows the Victron Battery Monitor Shunt. I moved that over from the starboard side so it would be closer to the house batteries, and allow for a shorter inverter negative cable run.
This next photo is just a close up of my shunt
And the final photo is of most everything in the back completed.
The white triplex wire at the bottom right corner of that last photo, is the 12/3 that will carry the power into the cabin. I'll put a regular plug on the end (hanging down below the bilge hose) that triplex, to plug into any of the three inverter outlets. I'll get some photos later of the cabin receptacles later to upload. In the third photo, bottom right, you can just make out the 200 amp relay that turns the inverter on and off. The switching wire for that runs up the starboard side to my helm switch panel, where I'm using the old macerator switch. Colby |
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colbysmith
Joined: 02 Oct 2011
Posts: 4550
City/Region: Madison
State or Province: WI
C-Dory Year: 2009
C-Dory Model: 25 Cruiser
Vessel Name: C-Traveler
Photos: C-Traveler and Midnight-Flyer
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| Posted: Tue Jan 02, 2024 10:11 pm Post subject: |
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My inverter install project finished up.
The plug on the microwave shelf.
Inverter with cabin cable plugged in.
Galley plug
Helm switch panel.
Hey Harvey (Sleepy C), if you are reading this, see my new install just above the switch panel? 
Colby |
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T.R. Bauer
Joined: 17 Nov 2007
Posts: 1726
City/Region: Wasilla
State or Province: AK
C-Dory Year: 1993
C-Dory Model: 22 Cruiser
Vessel Name: C-Whisperer
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| Posted: Wed Jan 03, 2024 3:42 pm Post subject: |
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| Sometimes I wish had an inverter in the boat. Now you got me thinking! |
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Hunkydory
Joined: 28 Mar 2005
Posts: 2657
City/Region: Cokeville, Wyoming
State or Province: WY
C-Dory Year: 2000
C-Dory Model: 22 Cruiser
Vessel Name: Hunkydory
Photos: Hunkydory-Jay-and-Jolee
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| Posted: Wed Jan 03, 2024 5:05 pm Post subject: |
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Good job & documenting, Colby. I have used a 400 watt inverter from the start in our CD22 with the cigarette type plug in for 12 volt power & routinely switched the inverter from the pick up on the road to the boat on the water for operating or keeping batteries charged on all the miscellaneous battery powered electronics, then as iPhone & iPad came along to keep them charged. Several years ago, I hard wired it in the boat & keep a separate one in the pickup. I routinely need much less wattage than you, so it was a very simple job for me to install in the boat. For the short period of times, I need more ac power to top off boat batteries, use the ceramic heater or coffee pot ect I find just firing up my old Honda 2000 simpler, especially where I only have two size 24 AGM batteries for combined motor start & house use.
_________________
Jay and Jolee 2000 22 CD cruiser Hunkydory
I will not waste my days in trying to prolong them------Jack London
https://share.delorme.com/JuliusByers |
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ssobol
Joined: 27 Oct 2012
Posts: 3374
City/Region: SW Michigan
State or Province: MI
C-Dory Year: 2008
C-Dory Model: 22 Cruiser
Vessel Name: SoBELLE
Photos: SoBelle
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| Posted: Wed Jan 03, 2024 6:14 pm Post subject: |
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| Hunkydory wrote: | | Good job & documenting, Colby. I have used a 400 watt inverter from the start in our CD22 with the cigarette type plug in for 12 volt power & routinely switched the inverter from the pick up on the road to the boat on the water for operating or keeping batteries charged on all the miscellaneous battery powered electronics, then as iPhone & iPad came along to keep them charged. Several years ago, I hard wired it in the boat & keep a separate one in the pickup. I routinely need much less wattage than you, so it was a very simple job for me to install in the boat. For the short period of times, I need more ac power to top off boat batteries, use the ceramic heater or coffee pot ect I find just firing up my old Honda 2000 simpler, especially where I only have two size 24 AGM batteries for combined motor start & house use. |
I have the same setup and do the same thing, except I don't have a coffee pot and my gen is only a Honda 1000. I only need the plug-in inverter for is charging a laptop if I have one on a trip.
I run the boat off one battery and keep the other in reserve. |
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