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Post by faverod on Mar 7, 2021 19:48:16 GMT -5
Hah, yes good to know that the alternators are cheap. I did think about putting in a current restrictor or a current buck but apparently the B2B Victron charger has a buck built into it so it’ll protect the battery as well as the alternators. Also it can step up voltage as well so I don’t see a downside yet. The price is only about $270 for a 30 amp. I believe the Mercruiser alternators are 70 amp max output so I think 30 amp should be fairly reasonable even at lower rpm’s. I could scale that down to 20 amp too. Based on my this past summer the alternators were usually putting out about 22 amps at low rpms.
You are correct on the two fridges cycling between 7-9 amps during the hour. They probably average 5-6 over the course of an hour combined.
AliExpress is advertising a site wide sale starting tomorrow so fingers crossed they mark some percentage off and I can get an order in. Should be here by June which works fine for Vermont boating.
Looking forward to hear how your install goes.
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Post by gofast24 on Mar 8, 2021 11:46:06 GMT -5
Good luck, I bought my Fly Power 200 AH from Amazon, didnt want to take a chance on direct from China and at the time 3-4 months delivery, and if problem, what would China do to correct it? At least with Amazon I was paying for peace of mind, cost $200 more than Aliexpress but? Hopefully will have new LiFePo4 in this weekend, forecast is 77 on Sunday. Need both sons to pull out old 120# Group 8 D agm battery and easily put new 44# one in. Will advise result when new battery down to 50/75% SOC and see what engine alternators will push into battery. The new, to be installed at the same time battery monitor/gage will tell all  |
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Post by gofast24 on Mar 17, 2021 10:18:34 GMT -5
Good luck, I bought my Fly Power 200 AH from Amazon, didnt want to take a chance on direct from China and at the time 3-4 months delivery, and if problem, what would China do to correct it? At least with Amazon I was paying for peace of mind, cost $200 more than Aliexpress but? Hopefully will have new LiFePo4 in this weekend, forecast is 77 on Sunday. Need both sons to pull out old 120# Group 8 D agm battery and easily put new 44# one in. Will advise result when new battery down to 50/75% SOC and see what engine alternators will push into battery. The new, to be installed at the same time battery monitor/gage will tell all New battery in, great ! As it held 13.9 volts after not being used/charged for two weeks, when starting engines the alternators said "this battery is full, dont need to push any current into it" . Really nice battery monitor gauge verified no charge going into battery. Also interesting , with house charger off could turn on every DC load on boat and monitor indicated current out, in amps, then turn on house charge and it indicated current in (charging) battery. I take back everything I said about how great or 8 D AGM battery did (over 6 years of usage) , the LiFePO4 is great, so far:) Picture as installed attached! EDIT 3/20/2021 = Excuse the sloppy wire layout, just to test all connections, then went back and re routed cables, some tie wraps , etc. Those two big 20 year old 2/0 cables were like trying to bend/route solid 1/2" copper pipes and didnt want to put a side load on either battery post, especially the shunt negative post as load would be transferred thru the shunt itself! Attachments:
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Post by lg260ss on Mar 18, 2021 6:58:35 GMT -5
Good luck, I bought my Fly Power 200 AH from Amazon, didnt want to take a chance on direct from China and at the time 3-4 months delivery, and if problem, what would China do to correct it? At least with Amazon I was paying for peace of mind, cost $200 more than Aliexpress but? Hopefully will have new LiFePo4 in this weekend, forecast is 77 on Sunday. Need both sons to pull out old 120# Group 8 D agm battery and easily put new 44# one in. Will advise result when new battery down to 50/75% SOC and see what engine alternators will push into battery. The new, to be installed at the same time battery monitor/gage will tell all New battery in, great ! As it held 13.9 volts after not being used/charged for two weeks, when starting engines the alternators said "this battery is full, dont need to push any current into it" . Really nice battery monitor gauge verified no charge going into battery. Also interesting , with house charger off could turn on every DC load on boat and monitor indicated current out, in amps, then turn on house charge and it indicated current in (charging) battery. I take back everything I said about how great or 8 D AGM battery did (over 6 years of usage) , the LiFePO4 is great, so far:) Picture as installed attached? You will see the real benefits when you start using it! All of your DC components will work better, you may even have to turn your fridge down a bit. |
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Post by faverod on Mar 18, 2021 9:23:19 GMT -5
I’m assuming the BMS in the battery itself shutdown charging for the battery since it was already at capacity? I’ll be curious to see how it reacts with a drawdown of 20-30% and how the alternators kick in. It sounds like worst case scenario would be slow cruise back to dock with a battery accepting full charge but the rpms of the engine not being sufficient for the alternators fans to cool enough. On plane it’s probably going to be alright, so if in doubt while watching the charging occur, speed up to aid in cooling. With your battery monitor live you should be able to see current spiking. Would be great to see alternators temperatures with IR thermometer pre and post too if you have one handy.
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wjh
Full Member
Posts: 51
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Post by wjh on Mar 19, 2021 13:38:58 GMT -5
Interested to see how it holds up over the next 6+ years. Would be nice to loose half the weight and it last longer and perform better
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Post by gofast24 on Mar 20, 2021 4:14:16 GMT -5
New battery in, great ! As it held 13.9 volts after not being used/charged for two weeks, when starting engines the alternators said "this battery is full, dont need to push any current into it" . Really nice battery monitor gauge verified no charge going into battery. Also interesting , with house charger off could turn on every DC load on boat and monitor indicated current out, in amps, then turn on house charge and it indicated current in (charging) battery. I take back everything I said about how great or 8 D AGM battery did (over 6 years of usage) , the LiFePO4 is great, so far:) Picture as installed attached? You will see the real benefits when you start using it! All of your DC components will work better, you may even have to turn your fridge down a bit. Put a at the end of your sentence? Dont think I will have to turn down fridge The thermostat will just love that the inside (beer) gets cooler quicker |
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Post by gofast24 on Mar 20, 2021 4:34:27 GMT -5
I’m assuming the BMS in the battery itself shutdown charging for the battery since it was already at capacity? I’ll be curious to see how it reacts with a drawdown of 20-30% and how the alternators kick in. It sounds like worst case scenario would be slow cruise back to dock with a battery accepting full charge but the rpms of the engine not being sufficient for the alternators fans to cool enough. On plane it’s probably going to be alright, so if in doubt while watching the charging occur, speed up to aid in cooling. With your battery monitor live you should be able to see current spiking. Would be great to see alternators temperatures with IR thermometer pre and post too if you have one handy. BMS did not shut down charge, when charging at home the supplied LiFePO4 10 amp charger brought the battery up to 14.6 VDC and then auto stopped charging itself. After letting battery set disconnected for a couple of days the voltage stabilized at 14.1 and stayed there for two weeks before installing it last Sunday. Update = At boat yesterday , battery has been connected for one week but no DC loads) = (All info from new great battery monitor meter at helm) = Voltage down to 13.6, after some unknown 0.5 amp parasitic load on battery for 1 week (think it is one of the audio amps that the turn on wire connected full time vs. being switched via the DC "Stereo" breaker in the salon panel). House battery charger on all week but not putting any charge into battery (again, think house charger sees 13.6 volts and says "dont need to send any charge to that battery, it's full")? Then after a few minutes with stereo playing loud and some cabin lighting to get battery down to 13.4/13.5 volts, house charger kicked in, charging at 20 amps, great. Turned off house charger immediately, waited a few minutes, started engines, they apparently charged the starting batteries first (I cant monitor the charge going to starting batteries) , then after a few minutes, engines alternators started to put about 3-4 amps into house battery! Didnt wait around any longer, went home. Will see what battery voltage and SOC is when I go back to boat tomorrow to check. Note, with battery isolator between starting batteries and house battery the house battery can get a charge from alternators but not feed back to starting batteries? |
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Post by gofast24 on Mar 22, 2021 10:10:39 GMT -5
Thanks, great idea! Only question is if I install this (where?)the info on this unit indicates= "measures two voltage inputs (up to 75V) and one current shunt (up to 60A using the internal shunt), then "external shunt capable (up to 1000A) and can control external relay / SSR". So where did you install yours as the 60 amp max. built in shunt will not be anywhere what will be drawn from the battery ? If just going to and from the Charles 60 amps would work, but then what am I getting, just either alternator or house charger + charge levels. Got this, $42, smile.amazon.com/gp/product/B0824X5MKM/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc= It works great, dont need Bluetooth, just mounted gauge to helm. Results of final install in boat and testing when house battery charger starts to charge and at what % SOD / voltage = Went to boat yesterday = Battery and house charger doing great! When I got here, no DC loads for 24 hours, house charger left off yesterday, this AM battery at 13.47 VDC, 99.6% fully charged, and the mysterious 0.5 amp load not showing up! Turned on fresh water pump, toilets, stereo on low (kind of) and voltage went down to 13.34 but house charger not kicking in. Then, turned on engine room blowers (take 14 amps !) and in 1 minute house charger came on pushing 24.5 amps into battery, great again. So, story is that house charger wont kick in until it sees house battery at or below 13.25 volts, then it will come alive In about one hour house charger brought battery back to 13.98 VDC, 99.8% full charge (199.5 AH), also great. Now, last thing is get battery discharged to about 50% and see what engine alternators will do? Things looking good so far! |
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Post by gofast24 on Mar 22, 2021 10:19:59 GMT -5
Interested to see how it holds up over the next 6+ years. Would be nice to loose half the weight and it last longer and perform better Will let you know in 6 years |
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Post by gofast24 on Mar 23, 2021 11:41:28 GMT -5
At boat this AM, battery at 13.45 VDC, no charge shown on battery monitor, and no DC loads on, so great! Moral of story, house battery charger wont push charge into battery until it is below 13.34 VDC, then comes on like gangbusters,25 amps+, in 1 hour battery back up to full charge, 13.86 VDC. Like what it is doing, think everything will be fine!!
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Post by gofast24 on Mar 25, 2021 5:36:28 GMT -5
At boat this AM, battery at 13.45 VDC, no charge shown on battery monitor, and no DC loads on, so great! Moral of story, house battery charger wont push charge into battery until it is below 13.34 VDC, then comes on like gangbusters,25 amps+, in 1 hour battery back up to full charge, 13.86 VDC. Like what it is doing, think everything will be fine!! battery monitor installed at helm. It is nice that it displays everything going in and out of battery including voltage, amps (+ / -) , AH remaining, % of full charge (you have to tell monitor what AH your battery is when you first connect it, in my case, 200 AH), and back light will pulse when battery receiving a charge and stay lit when discharging (pressing left and right buttons at the same time will turn off this feature). Can you imagine a bright blue flashing light on all night when battery accepting a charge? Will get picture this weekend. Attached poor quality pictures   of the installed battery monitor gauge just below the old blue Seas OLED voltmeter. Voltmeter will just stay there to plug hole it is in PS: The battery monitor is showing (dont think you can read it in pic?) 0.017 amps discharging from battery! When testing this at home it is showing the current draw of the back light |
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