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Post by gofast24 on Aug 30, 2020 11:34:45 GMT -5
Agree! A Li-FePO4 et al battery has a much different charge/float cycle voltage than AGM/Gel battery. Still not sure why a current (amp shunt) would tell you anything more than what your current (load) is at the time you are on DC power and looking at the amp draw? We have a analog ammeter in our breaker panel that indicated DC current draw, doesnt tell us any more than how much load is on the house battery. Still think the voltage of battery a better indicator of state of charge than what ammeter indicates? Again, have a Blu Seas OLED voltmeter on helm indicating the house battery voltage. When is shows below about 12.4 VDC time to shut down some DC loads or start gen set for a few hours to bring back to 13.3 or so. This regimen has worked for us 5 years now on the same group 8 D AGM battery installed in 2004. Yes, agree weight might be a factor but on our 22k pound 4160 a few pounds doesn't really mean much (like 1/2 more passenger on vessel)? You guys stay safe!! |
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Post by faverod on Aug 30, 2020 13:21:53 GMT -5
Here’s a handy chart for voltage versus battery capacity that I used for my solar install. At 12.4 volts you should still have 75% of your battery capacity. So call it 25% of useable capacity remaining. And remember that’s unloaded voltage, so with your house loads you could be seeing a lower voltage of ~12.2 volts with live draw on the battery.  |
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Post by lg260ss on Aug 30, 2020 18:21:55 GMT -5
Agree! A Li-FePO4 et al battery has a much different charge/float cycle voltage than AGM/Gel battery. Still not sure why a current (amp shunt) would tell you anything more than what your current (load) is at the time you are on DC power and looking at the amp draw? We have a analog ammeter in our breaker panel that indicated DC current draw, doesnt tell us any more than how much load is on the house battery. Still think the voltage of battery a better indicator of state of charge than what ammeter indicates? Again, have a Blu Seas OLED voltmeter on helm indicating the house battery voltage. When is shows below about 12.4 VDC time to shut down some DC loads or start gen set for a few hours to bring back to 13.3 or so. This regimen has worked for us 5 years now on the same group 8 D AGM battery installed in 2004. Yes, agree weight might be a factor but on our 22k pound 4160 a few pounds doesn't really mean much (like 1/2 more passenger on vessel)? You guys stay safe!! The shunt is used by my battery monitor to calculate number of amp hours used in real time. Monitor also gives voltage, percent of charge, battery run time based on current draw. The LiFePO4 batteries I bought for my boat are proven replacements for lead acid In marine, RV and solar applications. My charger is capable of charging and maintaining these batteries and the manufacturer of the batteries has verified the settings in profile 2 on my charger are more than sufficient. I’m glad you like the performance of your lead acid batteries, I could not get sufficient performance with lead acid for my demands. I’m now boating worry free with my new LiFePO4 batteries and every component performs bettter. |
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Post by faverod on Aug 30, 2020 20:14:24 GMT -5
I haven’t invested into the Lithium batteries yet but from what I’ve read your AGM battery setting may kill the life of those batteries. Lithium requires a consistent 14.2 volt charge profile, anything less actually discharges the battery. Both lead acid and agm have predefined charge profiles that utilize both voltage and time. Using your AGM profile will recharge the battery initially when the charger initialized bulk mode. That will provide the voltage you need with a fairly high current. However that will last for about four hours before the charger switches to absorption phase and idles voltage down to 13.8v but increases current. This would be at about 85% of charge on lead acid and the voltage reduction will reduce temperature. Final phase of charge being trickle will lower voltage even more to 13.2v and lower current to only 1-2 amps fluctuating. This is essentially maintaining mode. For a lithium you want a consistent 14.2 volts until it’s 100% full and then stop charging all together. So if you discharge your lithium down to 20% you will only recharge the battery through the bulk phase of the AGM bulk profile. Everything after that is discharging it. Meaning over time your individual cells will become out of balance and you will eventually destroy your $2,000 worth of batteries. You will find that eventually your batteries will just disconnect entirely. And those BMS need to be rebooted before you can just start them up again. Additionally you risk your alternators by not running a voltage regulator. If you are running underway and the BMS deems it’s fully charged they will shutoff current and you can guess what happens when you immediately shutoff the flow of current, you blow out your alternator diodes and smoke ensues. Two things you can do would be to every four hours, restart your battery charger and trick it back into bulk mode until your batteries are actually fully charged and then shut it off completely. The other would be to install a Sterling B2B charger to avoid the charging issue all together. The third would be to install a voltage regulator on your alternator or those will go at some point. These battery manufacturers will look at charge voltages on chargers and deem them ok but that’s not true. They may put out the required voltage but only for a short period of time. Remember they are in the business of selling batteries not chargers. I think it’s a fantastic idea that I will probably implement myself but not before I get a B2B charger and voltage regulator in place to protect my new batteries as well as all my wiring and engines.
I’ll just add that the reason most of these batteries work so well in solar applications is because of MPPT solar chargers which have a lithium charge profile and know to maintain voltage at the constant rate and then shut off. Moving these in a RV/Marine application and adding in two other forms of charging not customized to the battery type is not going to make for longevity.
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Post by lg260ss on Aug 30, 2020 20:44:51 GMT -5
I haven’t invested into the Lithium batteries yet but from what I’ve read your AGM battery setting may kill the life of those batteries. Lithium requires a consistent 14.2 volt charge profile, anything less actually discharges the battery. Both lead acid and agm have predefined charge profiles that utilize both voltage and time. Using your AGM profile will recharge the battery initially when the charger initialized bulk mode. That will provide the voltage you need with a fairly high current. However that will last for about four hours before the charger switches to absorption phase and idles voltage down to 13.8v but increases current. This would be at about 85% of charge on lead acid and the voltage reduction will reduce temperature. Final phase of charge being trickle will lower voltage even more to 13.2v and lower current to only 1-2 amps fluctuating. This is essentially maintaining mode. For a lithium you want a consistent 14.2 volts until it’s 100% full and then stop charging all together. So if you discharge your lithium down to 20% you will only recharge the battery through the bulk phase of the AGM bulk profile. Everything after that is discharging it. Meaning over time your individual cells will become out of balance and you will eventually destroy your $2,000 worth of batteries. You will find that eventually your batteries will just disconnect entirely. And those BMS need to be rebooted before you can just start them up again. Additionally you risk your alternators by not running a voltage regulator. If you are running underway and the BMS deems it’s fully charged they will shutoff current and you can guess what happens when you immediately shutoff the flow of current, you blow out your alternator diodes and smoke ensues. Two things you can do would be to every four hours, restart your battery charger and trick it back into bulk mode until your batteries are actually fully charged and then shut it off completely. The other would be to install a Sterling B2B charger to avoid the charging issue all together. The third would be to install a voltage regulator on your alternator or those will go at some point. These battery manufacturers will look at charge voltages on chargers and deem them ok but that’s not true. They may put out the required voltage but only for a short period of time. Remember they are in the business of selling batteries not chargers. I think it’s a fantastic idea that I will probably implement myself but not before I get a B2B charger and voltage regulator in place to protect my new batteries as well as all my wiring and engines. I’ll just add that the reason most of these batteries work so well in solar applications is because of MPPT solar chargers which have a lithium charge profile and know to maintain voltage at the constant rate and then shut off. Moving these in a RV/Marine application and adding in two other forms of charging not customized to the battery type is not going to make for longevity. I’m using the gel setting, not agm. My starting batteries will not shut the current off from the alternator. My charger has a lithium setting but the ranges are higher than the battery manufacturer recommends. The BMS will balance out of balance cells. The batteries have a 10 year replacement warranty and are assembled in the USA. You should call Battleborn, they are very knowledgeable and love to answer questions regarding their batteries and different applications for them. |
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Post by faverod on Aug 30, 2020 21:15:08 GMT -5
Great, good luck with it.
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Post by omarf4 on Aug 30, 2020 23:06:06 GMT -5
The issue with alternators is true if the 33 express didn’t have the digital voltage sense relays that come pre-installed on this model boat. The DVSR charges the standard lead acid starting batteries, then when it sense voltage over 13.4 volts on those SLA’s, it closes, which sends current to the house batteries (LiFePO’s) and SLA batteries.
When the house battery is full, the BMS cuts current, which the DVSR handles as fully charged, maintaining current back to the SLA starting batteries. The alternators are perfectly safe with those relays in place.
The battleborn and ionic batteries used in this thread, both do not need a float charge (also correct), but if one existed at 13.2-13.8 vdc, it’s perfectly handled by the BMS.
I am a converted believer in the lithium batteries for house battery usage, but yes, a proper voltage regulator/relay is needed and an advanced BMS that can handle a float charge.
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Post by gofast24 on Sept 2, 2020 10:24:36 GMT -5
Quote = "You will find that eventually your batteries will just disconnect entirely. And those BMS need to be rebooted before you can just start them up again" ? My thoughts= Dont believe the BMS will totally disconnect you from your DC boat loads, just stop charging? Same as AGM/Gel etc.? Also, a BMS (separate from battery pack or integrated into battery) absolutely required to keep individual cells balanced. From what I have read the LiFE PO4 etc. nominal 12 VDC automotive replacement batteries take care of everything internally but not sure about engine alternator voltage regulator settings (or house battery charger) ? Still happy with our $465 5 year old AGM using the digital OLED Blue Seas volt meter at help to determine when to lower DC loads or start gen set for a few hours (or run propulsion engines to do the recharge under way)
Also, when your running propulsion engines the alternators are still providing the current to run the engines / fuel pumps/ignition systems, and other DC loads etc? So, they wont may stop charging the batteries but will continue to provide somewhere around 13.2 VDC for loads? Thinking a LI battery would be happy with 13.2 VDC?
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Post by gofast24 on Sept 2, 2020 10:27:49 GMT -5
Here’s a handy chart for voltage versus battery capacity that I used for my solar install. At 12.4 volts you should still have 75% of your battery capacity. So call it 25% of useable capacity remaining. And remember that’s unloaded voltage, so with your house loads you could be seeing a lower voltage of ~12.2 volts with live draw on the battery. If you are down to 75% of full charge why do you only have 25% amp hours capacity remaining? Yes, dont want to totally discharge battery, especially bad for battery life/charge cycles left. |
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Post by faverod on Sept 2, 2020 19:59:00 GMT -5
Primarily because you don’t want to drag down a lead acid or agm below 50% of capacity. Secondarily, because some 12v appliances like certain refrigerators will have a low voltage cutoff and turn themselves off once the voltage drops too low.
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Post by gofast24 on Sept 5, 2020 12:18:58 GMT -5
Primarily because you don’t want to drag down a lead acid or agm below 50% of capacity. Secondarily, because some 12v appliances like certain refrigerators will have a low voltage cutoff and turn themselves off once the voltage drops too low. We never let our 8 D AGM get below 12.4 VDC. Dont think our fridges/freezer will cut off below a certain voltage (maybe just stop running the compressor?)? If so, we never experienced that? Fridge/Freezer is both AC/DC powered. If loosing dock power it will use the house battery 12 VDC and keep running but also never had that happen in 6 years, even with a day or so of lost shore power? Fridge/Freezer uses about 3-4 amps of 12 VDC house battery when running, but as is typical, cycles on and off so never has been a problem loosing everything in fridge/freezer. |
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Post by gofast24 on Sept 6, 2020 10:50:25 GMT -5
OK, you guys have me convinced a Li-FePO4 is the way to go but with current engine alternators and Charles house charger not capable of properly charging/maintaining a Li-FePO4 will just stick with the AGM until next new Regal:) You guys have a safe and Happy Labor day!
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