Lifepo4 battery swap... Dropped 95 pounds off the back corner of the boat!

[gmtech16450yz]

Since I have Lifepo4 batteries in most everything else I own, I figured it was time to put them in our boat. One of my issues in the boat has been the voltage on regular lead acid (AGM) batteries is so low that I usually have to start one or both of the engines to use my electric anchor winch.

So I picked up a pair of NOCO NLP30's and I already had a NLP20 I wasn't using in anything. I'm using the two NLP30's as the house battery and the single NLP20 as the start battery. Any one of these batteries will start a V8 with no problem, the NLP20's have been working fine in our Yamaha SVHO skis. The reserve capacity of even the two NLP30's wouldn't work for those of you who use your stereo when sitting, which we don't. For us, running the Simrad Go9, the audio amp (for phone notifications through bluetooth), the marine radio and the occasional bilge pump running, we can sit for over 5 hours on those two house batteries. Not a big deal even if the house battery is run all the way down, the start battery will still be at 100%.

The benefits? The first is power. The two group 24 AGM's I had in there put out 1050cca when combined. The three Lifepo4's put out 1,900 cca. The cranking voltage of the AGM's was 10.9 volts. The cranking voltage of the Lifepo4's is 12.4 volts. That's a difference you can clearly tell when the engines are cranking up. So way more amperage and voltage.

The second is the weight. The two AGM's on a mounting pad was 115 pounds. The Lifepo4's on a mounting pad, with jumper cables on, weighs 15.5 pounds! That's a significant weight reduction. Again, this is something that the wake surfing guys won't want to do. We don't wake surf.

The only electrical system mod I had to do was to remove the dvsr. Lithium batteries sit at around 13.6 volts not being charged, that will turn the dvsr on all the time. I used a continuous use solenoid as a battery combiner. I ran ignition signal wires from each engine, through two diodes to trigger the solenoid. So whenever the engines get ignition power, the batteries are combined. That means they always use all three batteries for starting, that's a good thing.

(BTW, for those of you that have tapped off of the fuel pump or ignition circuit to control your dvsr, realize that you will only combine the batteries off that ONE engine. To combine the batteries with the dvsr or a solenoid like I did, you have to pull a fuel pump or ignition signal from BOTH engines. You also have to separate them with diodes so they don't backfeed each other. We often run on one engine for trolling so I needed to have either engine initiate battery charging.)

Pics of course...

 

[Neutron]

Since I have Lifepo4 batteries in most everything else I own, I figured it was time to put them in our boat. One of my issues in the boat has been the voltage on regular lead acid (AGM) batteries is so low that I usually have to start one or both of the engines to use my electric anchor winch.

So I picked up a pair of NOCO NLP30's and I already had a NLP20 I wasn't using in anything. I'm using the two NLP30's as the house battery and the single NLP20 as the start battery. Any one of these batteries will start a V8 with no problem, the NLP20's have been working fine in our Yamaha SVHO skis. The reserve capacity of even the two NLP30's wouldn't work for those of you who use your stereo when sitting, which we don't. For us, running the Simrad Go9, the audio amp (for phone notifications through bluetooth), the marine radio and the occasional bilge pump running, we can sit for over 5 hours on those two house batteries. Not a big deal even if the house battery is run all the way down, the start battery will still be at 100%.

The benefits? The first is power. The two group 24 AGM's I had in there put out 1050cca when combined. The three Lifepo4's put out 1,900 cca. The cranking voltage of the AGM's was 10.9 volts. The cranking voltage of the Lifepo4's is 12.4 volts. That's a difference you can clearly tell when the engines are cranking up. So way more amperage and voltage.

The second is the weight. The two AGM's on a mounting pad was 115 pounds. The Lifepo4's on a mounting pad, with jumper cables on, weighs 15.5 pounds! That's a significant weight reduction. Again, this is something that the wake surfing guys won't want to do. We don't wake surf.

The only electrical system mod I had to do was to remove the dvsr. Lithium batteries sit at around 13.6 volts not being charged, that will turn the dvsr on all the time. I used a continuous use solenoid as a battery combiner. I ran ignition signal wires from each engine, through two diodes to trigger the solenoid. So whenever the engines get ignition power, the batteries are combined. That means they always use all three batteries for starting, that's a good thing.

(BTW, for those of you that have tapped off of the fuel pump or ignition circuit to control your dvsr, realize that you will only combine the batteries off that ONE engine. To combine the batteries with the dvsr or a solenoid like I did, you have to pull a fuel pump or ignition signal from BOTH engines. You also have to separate them with diodes so they don't backfeed each other. We often run on one engine for trolling so I needed to have either engine initiate battery charging.)

Pics of course...

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Wouldn't doing the ignition signal mod to the dvsr do the same thing? it will only combine the batteries to charge when the ignition is running. If the ignition is off they wont combine if the voltage is increased which the purpose for that was to have seperate battery charging banks with a plugged in charger

 

[gmtech16450yz]

Wouldn't doing the ignition signal mod to the dvsr do the same thing? it will only combine the batteries to charge when the ignition is running. If the ignition is off they wont combine if the voltage is increased which the purpose for that was to have seperate battery charging banks with a plugged in charger

Yeah I could have used the dvsr but I wanted the benefit of combining all 3 batteries for starting. The dvsr has a delay, and I'm also assuming it's a diode or transistor unit so it's doubtful it would pass battery amperage FROM the batteries for starting.

The advantage of the solenoid is it turns on quickly and it will pass amperage both directions. The solenoid approach works for what I wanted, it's perfectly fine to also use the dvsr if you don't care about combining batteries for starting.

Did you notice my comment about pulling an ignition signal from only one engine? Again, it's not a big deal for those that always run on both engines. Just wanted people to be aware of the possible issue.

 

[FSH 210 Sport]

I want to say up front that your battery set up looks clean and the weight drop is amazing, and I’m not trying to poo poo your set up. But, I do want to bring some things to your attention you may not be aware of.

One of the unsung advantages of using a dvsr with a dedicated start battery in OEM trim set up is that it isolates sensitive electronics from starting transients as the DVSR will open, if closed, when an engine starts due to the voltage dropping to 12.8 or lower. So your cranking voltage of 12.4 volts would have the DVSR open as well.

The DVSR as I understand it uses a solenoid operated movable contact to connect the batteries and not diodes, this contact, at least in the BEP Marine switch that comes in our boats, has continuous 140 amp capacity.

In the case of using the ignition hot or fuel pump hot to initialize the dvsr, this is an excellent way to keep the start battery isolated from any load except starting automatically when sitting with engines off regardless of buss voltage as the DVSR opens as soon as the engines shut off and do not wait until the buss voltage drops to 12.8 thereby preserving the highest voltage / capacity possible on the start battery. @lazergeek did the fuel pump hot mod on his 210 FSH and installed a simple relay set up so that when either engine is running voltage will be provided to the DVSR. The way I see it, you could have just run your two ignition wires and the diodes to the DVSR red wire and that would have worked just fine.

I am not familiar with the NOCO LFP batteries but will be investigating when I finish writing this post and will make any necessary edits. Having said that, one of the problems with using LFP batteries for starting batteries especially those that are not designed to be start batteries has to do with the BMS inside the LFP battery. Said BMS can turn off the start battery to protect the battery from what sees as excessive charge / voltage as most charging systems run at 14.4-14.5 volts, our boats included, while the engines are running, our boats included. If the BMS shuts the battery off while the engines are running the rec/regs have no where for the regulated minimum charge to go to and the rec/reg will be destroyed, this why most manufacturers initially would decline warranty coverage to charging systems if a LFP battery was used as a start battery. Mercury Marine has since provided a list of approved LFP start batteries for some of their product line. This is why having a dedicated lead acid (FLA or AGM) for a start battery is a good idea as that battery will always be connected to the charging system, then having that battery tie to the LFP battery after start up via the DVSR / ACR / Solenoid for charging is the safest bet for running LFP batteries and their high density storage capacity for house loads.

The quality of the BMS is what separates good LFP batteries from bad ones. The BMS protects the LFP battery from conditions that would damage it, excessive discharge / charge rates, excessive voltage, low voltage, high heat, charging at too low of a temperature, assures proper cell balancing etc.

I have a Minnkota Rip Tide Ulterra trolling motor on my boat, this trolling motor uses brushes on the commutator just like starter motors do. These motors were designed with Peukert (Peukert's law - Wikipedia) effect in mind. LFP batteries have a much better peukert effect meaning their voltage drop is much less when high discharge rates are applied to them. In a brush DC motor this will create higher temperatures as the power / watt (watts is equal to volts times amperage) increases beyond design criteria due to the sustained high voltage at designed high amperage. This is why Minnkota advises not running their brush type trolling motors above 85% or 8.5 prop speed as the heat rejection rate is too limited and will cause thermal run away and damage the trolling motor. How this will affect the starter motors in our boats I’m not sure of but I thought it was worth mentioning…. But, in the case of a hard start as some models of Yamaha boats experience, 19’ bow riders, 21’ FSH boats and others, extended cranking to get these engines started might affect the starters negatively, again I don’t know, and one could theorize the higher cranking speed might get the engine started sooner. This could be true for the 21’ FSH boats who’s hard start issues have been linked to excessively full water locks. I get it, we all like to hear our engines spin fast on start up and fire immediately. So yes, the advantages you mention are there in terms of available power, but the disadvantage as you elude to is decreased KWh storage due to the smaller battery size, skis don’t have the larger batteries like our boats do primarily because there isn’t room for them, secondly skis don’t have the house loads that our boats can have, and that works fine for your application since you run the engines a lot while engaged in your preferred activity.

Again, not crumbing on your work or post just wanted to make sure you and anyone else reading this thread were aware of all the facts.

Edit; At first glance it appears that the NOCO LFP batteries have a good BMS that will protect against parameters that could damage the battery. The batteries you have used https://no.co/nlp30 & https://no.co/nlp20 are start batteries with small Wh storage. NOCO also has dual purpose batteries with impressive cranking amps and a lot of storage capacity https://no.co/nlx24 & https://no.co/nlx27 I’m interested in their 9 series battery for a replacement of the YUASA YTZ 7 power sports battery for a friend of mines KTM 350 battery.

 

[gmtech16450yz]

Lol are you an engineer? I often tell my engineer buddy "Just stop thinking so much!" hahaha. Just like your well meaning and articulate post, please take my reply in the same friendly tone.

I didn't actually take a dvsr apart, although I'll probably never use the one I just took out so maybe I will dissect it so we all know for sure, but I doubt it has a mechanical relay. It literally say it's "Digital". That tells me it's diodes, or mosfets, not a mechanical switch. If you want to look at downsides to all of this, mechanical switches like the solenoid I'm using doesn't have any appreciable voltage loss. Diodes do. So what's the voltage drop through one of these dvsr's? I don't know but it has to be there if it's electronically switched. So even if it could pass starting amperage both ways, how much voltage drop would there be through it at cranking amperage? Those reasons are why I went with a solenoid instead of retaining the dvsr.

On the whole "the bms will shut off and the engine will die or the charging system will be destroyed" is internet bs. Mostly created in the beginning of lithium battery technology, those batteries either had no internal BMS, a poorly designed BMS or they just weren't meant for starter use. My entire life has basically been around automotive electronics. I spent 34 years as a GM World Class Technician, specializing in drivability and electrical systems as the lead tech in GM dealerships. I'm acutely aware of all the things you mentioned, like the effect the higher cranking voltage could have on the starters. LOW voltage kills motors, most motors can take much higher voltages than spec'd and be fine. It's the high amperage that comes with low voltage that burns up motors. Higher voltage/lower amperage is usually better for motors, not worse. Switching a dual voltage motor from running on 120 volts ac to 240 ac volts is a good example. Lower heat and better efficiency with higher voltage and less amperage. BTW you know what kills more car alternators than anything? Lead acid batteries that have shorted cells, which drops the voltage from 12 to under 10. The low voltage overloads the alternator and burns them up. Shorted cells in car batteries happens all the time, I could often tell just by the smell of the alternators.

These lithium and lifepo4 batteries are used in tons of vehicles these days, and with very little issues. They're an awesome upgrade for motorcycles, I have them in both of mine. I have 700ah of lifepo4's in our motorhome on a full Victron system. Those particular NOCO batteries are meant for starting, did you see the cold cranking amperage comparison between them and the AGM's I replaced? They are stout batteries that guys are using in cars starting V8's. Yeah the reserve capacities are less than the AGM's I replaced, but again you have to keep voltage in mind. The voltage of a lifepo4 at with only 5% capacity left is higher than a fully charged lead acid battery. The other factor is that itself, you can run these batteries down to 5 or 10 percent. Lead acid batteries can only be run down to about HALF of their capacity, and at that, the voltages are well below 12 volts. So you end up with slow accessories like anchor winches and stereo amps running at dangerously low voltages. Again, for a lot of electric devices, it's low voltage that's worse than high.

The bottom line on this battery subject is lead acid batteries are inferior to Lithium (Lifepo4 specifically) and need to go away. Lead acid batteries only have ONE advantage, that's price. That's changing though, especially with restrictions on lead in products. Oh, you mentioned our skis... When the lead acid battery that was only a year old failed in my wife's ski, we used ONE of the Lipo's from my RC car to start her supercharged 1.8 engine. A battery I carried in my pocket started that engine with no problem. And that lead acid battery failure? We were halfway through a week at the lake, the ski was starting fine. One afternoon when we were about 2 miles from the dock she went to start her ski and it was totally dead. Nothing. We ended up towing her ski with mine all the way back. The battery must have broken a plate or the terminal connection inside, it was an open circuit. So did the engine die or was the charging system destroyed when the battery went open circuit? Nope. The only way we knew it failed was when she went to restart it after swimming around for awhile. Yeah lead acid batteries fail all the time. We drove to the nearest Walmart and bought a NOCO NLP20 and enjoyed the rest of our week with a ski that started way faster. BTW, tell your buddy to definitely buy a Lifepo4 battery for his KTM. Here's what he needs... Antigravity battery

Thanks for the reply though, you did bring up good points. I hope I cleared some of them up in a way that didn't sound snotty? lol.

 

[Beachbummer]

That is pretty cool!!!

You made me look... Verty interesting batteries, but there is not much Amp/Hour capacity for aux loads. I have a 10amp compressor for the SUP that runs for a while sometimes , I'd be concerned with capacity, the big heavy cheap batteries I have are 70Ah each or higher reserve, , maybe 10-30 which I use from time to time with music and the compressor.

How are you handling your accessory power use?

Best of Luck!

 

[gmtech16450yz]

That is pretty cool!!!

You made me look... Verty interesting batteries, but there is not much Amp/Hour capacity for aux loads. I have a 10amp compressor for the SUP that runs for a while sometimes , I'd be concerned with capacity, the big heavy cheap batteries I have are 70Ah each or higher reserve, , maybe 10-30 which I use from time to time with music and the compressor.

How are you handling your accessory power use?

Best of Luck!

Keep in mind that lead acid batteries can only really be run down to 50% or so. So that 70ah reserve is comparable to 35 or 40ah lithium. Again, the lithium voltage is going to be considerably higher after using 3/4 of that capacity. So your air compressor will run faster and your SUB will blow up quicker.

My 212 Limited S uses about .7 amps for the audio and rear audio display. With the Simrad, audio amp and marine radio all on when sitting my boat draws about 2.5 amps. The two NLP30's are rated at 7.8ah, so they're good for at least 14ah. 14ah capacity at a 2.5 amp draw is 5 and a half hours! How often do you sit in your boat for that long? And if we did, turning off the marine radio and Simrad would bump that capacity up to 20 hours.

The math proves out, I put a 4 amp draw on this system on the house side for almost 4 hours and the voltage of those two little lifepo4's was 12.7 volts. The starter battery was still at 100% and the engines started right up.

Yes, of course MY battery setup wouldn't work for those who blast their stereos when out on the lake. But honestly I'd like those batteries to die in those boats. lol.

 

[FSH 210 Sport]

Lol are you an engineer? I often tell my engineer buddy "Just stop thinking so much!" hahaha. Just like your well meaning and articulate post, please take my reply in the same friendly tone.

I didn't actually take a dvsr apart, although I'll probably never use the one I just took out so maybe I will dissect it so we all know for sure, but I doubt it has a mechanical relay. It literally say it's "Digital". That tells me it's diodes, or mosfets, not a mechanical switch. If you want to look at downsides to all of this, mechanical switches like the solenoid I'm using doesn't have any appreciable voltage loss. Diodes do. So what's the voltage drop through one of these dvsr's? I don't know but it has to be there if it's electronically switched. So even if it could pass starting amperage both ways, how much voltage drop would there be through it at cranking amperage? Those reasons are why I went with a solenoid instead of retaining the dvsr.

On the whole "the bms will shut off and the engine will die or the charging system will be destroyed" is internet bs. Mostly created in the beginning of lithium battery technology, those batteries either had no internal BMS, a poorly designed BMS or they just weren't meant for starter use. My entire life has basically been around automotive electronics. I spent 34 years as a GM World Class Technician, specializing in drivability and electrical systems as the lead tech in GM dealerships. I'm acutely aware of all the things you mentioned, like the effect the higher cranking voltage could have on the starters. LOW voltage kills motors, most motors can take much higher voltages than spec'd and be fine. It's the high amperage that comes with low voltage that burns up motors. Higher voltage/lower amperage is usually better for motors, not worse. Switching a dual voltage motor from running on 120 volts ac to 240 ac volts is a good example. Lower heat and better efficiency with higher voltage and less amperage. BTW you know what kills more car alternators than anything? Lead acid batteries that have shorted cells, which drops the voltage from 12 to under 10. The low voltage overloads the alternator and burns them up. Shorted cells in car batteries happens all the time, I could often tell just by the smell of the alternators.

These lithium and lifepo4 batteries are used in tons of vehicles these days, and with very little issues. They're an awesome upgrade for motorcycles, I have them in both of mine. I have 700ah of lifepo4's in our motorhome on a full Victron system. Those particular NOCO batteries are meant for starting, did you see the cold cranking amperage comparison between them and the AGM's I replaced? They are stout batteries that guys are using in cars starting V8's. Yeah the reserve capacities are less than the AGM's I replaced, but again you have to keep voltage in mind. The voltage of a lifepo4 at with only 5% capacity left is higher than a fully charged lead acid battery. The other factor is that itself, you can run these batteries down to 5 or 10 percent. Lead acid batteries can only be run down to about HALF of their capacity, and at that, the voltages are well below 12 volts. So you end up with slow accessories like anchor winches and stereo amps running at dangerously low voltages. Again, for a lot of electric devices, it's low voltage that's worse than high.

The bottom line on this battery subject is lead acid batteries are inferior to Lithium (Lifepo4 specifically) and need to go away. Lead acid batteries only have ONE advantage, that's price. That's changing though, especially with restrictions on lead in products. Oh, you mentioned our skis... When the lead acid battery that was only a year old failed in my wife's ski, we used ONE of the Lipo's from my RC car to start her supercharged 1.8 engine. A battery I carried in my pocket started that engine with no problem. And that lead acid battery failure? We were halfway through a week at the lake, the ski was starting fine. One afternoon when we were about 2 miles from the dock she went to start her ski and it was totally dead. Nothing. We ended up towing her ski with mine all the way back. The battery must have broken a plate or the terminal connection inside, it was an open circuit. So did the engine die or was the charging system destroyed when the battery went open circuit? Nope. The only way we knew it failed was when she went to restart it after swimming around for awhile. Yeah lead acid batteries fail all the time. We drove to the nearest Walmart and bought a NOCO NLP20 and enjoyed the rest of our week with a ski that started way faster. BTW, tell your buddy to definitely buy a Lifepo4 battery for his KTM. Here's what he needs... Antigravity battery

Thanks for the reply though, you did bring up good points. I hope I cleared some of them up in a way that didn't sound snotty? lol.

Right on… I appreciates the knowledge you bring to the table.

If you look at my battery upgrade thread you will see I had quite the serendipitous journey converting to LFP batteries and learning a lot about them. I agree with you on the capacities of lead acid batteries being 50% of the rated Ah, great video by Mortons on the Move in my battery thread.. I will differ with you on this, lead acids are good at starting, and next to LFP batteries are the cheapest per kWh, but not in the long term of lifespan.. the noco site had a great stat, batteries that are discharged 100% have roughly 1000 cycles, 80% DOD=5000 cycles and 50% DOD in excess of 10,000 cycles.. as I think I said in my battery thread, if and when I upgrade to a different boat, all of my LFP equipment will come out of my boat and a new set of FLA batteries will go in with the Minnkota chargers for the new owner, the LFP equipment will go into the new or new to me boat and keep right on trucking for who knows how long.. I only discharge my BB batteries to 80% on really long days, and less than that on days where I troll fast and use the engines to provide most of the thrust and the troller acts as an autopilot and cruise control.

Back in the day when the lithium batteries first became available there were a lot of failures in dirt bikes, most of them involved fire whilst a person was riding, and or the charging system being wiped out. This was not too much of an issue if your bike was still using a fly wheel fired ignition, but when the systems became reliant on the battery voltage to fire the ignition that is when it became a bigger problem.

It took the local aftermarket store years to get me to try a LFP battery in my 570 Husaberg..an Anti Gravity, then I wished I had done it sooner, especially with dead engine starts. I bought those batteries back in 2012? And they are still working great, but, those were the ones made in Chatsworth CA. The ones they have now have the ReStart feature on them and are made in china and are having issues.

Again, I appreciate the back and forth, you didn’t come off snotty, just confident. Nice to see we can have a back and forth without anyone getting butt hurt.

 

[Beachbummer]

Keep in mind that lead acid batteries can only really be run down to 50% or so. So that 70ah reserve is comparable to 35 or 40ah lithium. Again, the lithium voltage is going to be considerably higher after using 3/4 of that capacity. So your air compressor will run faster and your SUB will blow up quicker.

My 212 Limited S uses about .7 amps for the audio and rear audio display. With the Simrad, audio amp and marine radio all on when sitting my boat draws about 2.5 amps. The two NLP30's are rated at 7.8ah, so they're good for at least 14ah. 14ah capacity at a 2.5 amp draw is 5 and a half hours! How often do you sit in your boat for that long? And if we did, turning off the marine radio and Simrad would bump that capacity up to 20 hours.

The math proves out, I put a 4 amp draw on this system on the house side for almost 4 hours and the voltage of those two little lifepo4's was 12.7 volts. The starter battery was still at 100% and the engines started right up.

Yes, of course MY battery setup wouldn't work for those who blast their stereos when out on the lake. But honestly I'd like those batteries to die in those boats. lol.

I can provide evidence of the voltage drop you point out. I actually installed a volt booster to keep the air compressor running at 14v, otherwise with the load the battery drops below 12v and the compressor stops to prevent the 12v from draining too much. So, fair point.

Maybe in a year or two as prices come down or capacity goes up I'll be game, but glad for you and your trailblazing enhancements.