Good idea, now I understand. Wet cells don't hold their voltage if we tried to do that. I did it once running the engine and using the alternator to keep the voltage up for my inverter.
Lithium Battery Installation feedback requested
- Thread starter smokey73
- Start date
No, not really. About 65 Ah to go from cold to 135 F. Assuming the batteries are fully recharged by 1 or 2 pm daily (solar), might as well use the free excess energy for something? We also use the micro almost daily, blender for cocktails at 3pm and most importantly the coffee grinder
Running a water heating is nothing compared to folks who run air fryer, washer, air con, induction stoves off their batteries.
If you have 3-4 days of typical usage in storage, then add 300-600 W of solar, it either extends your stay or makes it almost unlimited (with the right sun and daylight hours). This was almost undoable 10 years ago in a sub 40 ft boat because of the space and weight of the batteries. I cut my battery space by half (gained a whole bench for food storage) and more than doubled my usable Ah. I took several hundred lbs out of the boat.
I know of a few boat explosions due to on demand propane water heater....
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You have like a 5 gallon hot water tank?No, not really. About 65 Ah to go from cold to 135 F. Assuming the batteries are fully recharged by 1 or 2 pm daily (solar), might as well use the free excess energy for something? We also use the micro almost daily, blender for cocktails at 3pm and most importantly the coffee grinder
Running a water heating is nothing compared to folks who run air fryer, washer, air con, induction stoves off their batteries.
If you have 3-4 days of typical usage in storage, then add 300-600 W of solar, it either extends your stay or makes it almost unlimited (with the right sun and daylight hours). This was almost undoable 10 years ago in a sub 40 ft boat because of the space and weight of the batteries. I cut my battery space by half (gained a whole bench for food storage) and more than doubled my usable Ah. I took several hundred lbs out of the boat.
I know of a few boat explosions due to on demand propane water heater....
I think mine is 15 gallons... I'd need closer to 200 Ah...
dj
Ventilation of LFP isn't as critical as for lead batteries because there is no off-gassing. As for temperature, LFP internal resistance is so low that they don't create much heat. I can charge ours at 0.4C (400A) while monitoring with a thermal camera and all that happens is the 4/0 wires going to the bus bars get slightly warmer. So if you have air space around the batteries, and this space has some connection to other air space (difficult not to have this), then you will be fine.
I've never heard of the allowance of 1" of movement in any direction. It is certainly not something I would allow for anything more than maybe a small start battery with loose flexible wires connected to it. Our Group 24 start batteries are strapped to a shelf and maybe they could move 1" if pushed around hard enough. I think anything more than 0.0 inches on a house bank made from multiple cells or batteries is asking for trouble.
Mark
We are the same. We have a 6gal heater and use ~50Ah to fully heat it to shutoff. It takes ~17Ah to get the water hot enough to make my wife happy showering in warm weather (I'm a pure cold water shower in the tropics).No, not really. About 65 Ah to go from cold to 135 F. Assuming the batteries are fully recharged by 1 or 2 pm daily (solar), might as well use the free excess energy for something? We also use the micro almost daily, blender for cocktails at 3pm and most importantly the coffee grinder
Of course, in the tropics the "cold" water in the tank is starting out at 85F...
We used to have a 12gal heater, and this would take over 2x as much Ah to heat water. However, we found we never needed that much hot water since it is only two of us. The 6gal heater is more than enough for 2. Could likely easily get by with a 3gal tank, but we are mostly in the tropics, so don't need steaming hot showers.
Mark
On my previous boat I installed a 300Ah EPOCH Essentials V2 with Victron Comms. On my current boat I am installing two EPOCH Essentials 460Ah. Originally the Victron Comms could not be daisy chained, so current boat batteries do not have comms. I believe they have changed that now so multiple batteries can be all talk to a Victron system.
Epoch batteries get a good review on Will Prowse's youTube channel, and they are made local to me. They have not let me down yet.
No issues.
Previous boat (1985 Catalina 30) I put in a 300Ah house bank and a 98Ah AGM start bank. I originally replaced the two FLA batteries with two AGM batteries for a mixed use bank. When they aged out, I replaced with LFP and kept one AGM for a start battery. Replacing two AGMs with a single LFP almost tripled my usable capacity.
Current boat(1995 Catalina 36 Mk II) will have a 920Ah capacity house bank and a 150 Ah AGM start bank. Originally it had two 198Ah AGMs as a house bank and the 150 AGM start bank. I am adding a Victron Multiplus 12|3000|120 inverter/charger and want a bank large enough to run all the DC & AC loads while not at the dock.
Lithium batteries REQUIRE a change to the charging systems unless those systems are already Lithium capable.
See the MarineHowTo, BoatHowTo and other articles on the web for more information.
The Victron Inverter/Charger will charge both the house and the Start banks. I am installing 400W of solar to keep the house bank charged while away from the dock. The start bank will be charged by the engine alternator. I could add a DC-DC charger to charge the start bank from the house bank but do not see the need at this point. You could also use a DC-DC charger to charge the House bank from the Start bank while the engine is running.
I would likely keep things the way they are.
There is NO SUCH THING as a 'drop in replacement' LFP battery unless you are only talking physical size. Low power dumb alternators will eventually be killed by a lithium system. Charge sources that can not be programmed for Lithium banks will harm the batteries and possibly be damaged themselves. Most cabling is not up to the carrying the amps that a lithium bank can provide. Nearly ALL LFP batteries will need a Class T fuse to have the AIC (Amperage Interrupt Current) capacity to handle the Short Circuit Current (SCC) in case of a catastrophic failure that can produce 20,000+ amps. Most cheaper fuses only handle up to 10,000 amps. YOu still size the fuse for the cables ampacity.
Just because someone is on a forum does NOT make them an expert. If in doubt, ask a qualified person or research it web sites run by reputable people. (Not all websites have good information either.) One of the best things I've read was someone saying 'Experience s the WORST teacher'. People get away with ignoring the requirements and proper procedures and think it is all a waste of money and you don't have to follow them to be safe. They may get away with it for a long time and may even never have a problem. That doesn't mean YOU will be as fortunate.
Be aware that even if the battery has a high amp hour rating, that does not mean the BMS can supply that much on a continuous basis. Make sure your batteries can provide the amount of power you -may- need on a continuous basis or you will be disappointed in them.
BMSes are great, but they are not fool-proof. Don't skip the primary circuit protections thinking that having a BMS removes the need for it. They don't.
DC and AC electricity can be dangerous. If you do not fully understand what you are doing, PLEASE get someone qualified to help (and teach) you. A bad wiring job can cause your boat to burn and even kill someone (including YOU) either in the boat or in the water near your boat.
DO NOT CHEAP OUT. Buying cheap, undersized, untinned welding cable all in the same insulation color may seem like a deal, but when the connections corrode, the cables break internally and your systems start to fail you WILL regret the cheap economy. You can't run out into the front yard to await help if you have a fire while out on the water. Marine requirements are strict, but they are there to save your boat and your life.
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Thanks. I am going to just ignore that one. One of several ABYC recommendations I don't agree with, and can present reasonable arguments against.
Mark
That's a bit of a myth... Any charger with adjustable absorption and float voltage will do.
Any charger that will do absorption at 13.8-14.4V and float at 13.6V is fine for lifep4, as long as they don't have a recondition mode.... That means the majority of AGM chargers are fine for lifepo4.
I used to charge at 14.4 and float at 13.8V. I now charge at 13.8V and float at 13.55V. There is a very very small increase in charge duration (the last 1 %), compared to 14.4 but the batteries will last longer when exposed to lower voltages. There's also less chance of developing cell imbalance. Cell manufacturers usually specify <= 3.65V / cell. Note that they don't specify a specific voltage, just a max charging voltage. Less than 3.65V is fine. Too low and you won't get 100% SOC. 13.8V is the sweet spot for most packs. They can be charged with a simple constant voltage power supply, no need for fancy chargers. You need to now at what voltage your BMS starts balancing to calibrate your pack's charge voltage. If the manual doesn't stipulate this, don't buy that brand. That's why some pack builders specify 13.8V, 14.0, 14.4, 14.6V. If you can get full capacity at 13.8V and your balancer kicks in, then there's no real benefit to charge higher.
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Not true for lithium. (I think you were quoting E10?)
For lithium, ABYC E13 applies, they specify no visible movement. This is not difficult to do. A 3/4" x 1" strip of wood will prevent lateral movement. The battery must be able to be suspended upside down without movement as well (in case of a knock down, to avoid breaking electrical connections or causing shorts). Thus, many of the new / better quality batteries come with brackets to bolt them down. This greatly simplifies installation.
If doing a lifepo4 install, do yourself a favor and pay a few $$ to get temporary access to ABYC standards, it will be worth it (a drop in the bucket compared to the cost of refitting your electrical system). Keep in mind, ABYC specifies the MINIMUM recommended. You can always do better. Your surveyor (in NA) will likely quote ABYC standards if they find defects in your insurance survey.
Don't trust ABYC pdf you may find on the internet (not from ABYC website), they are likely old standards and there's been a lot of changes in the past 4 years. There's more than one chapter required when working on your electrical (E11, E13, A28, A 31)
No need for ventilation for Lifepo4. Unlike flooded cells, they don't off gas and they don't noticeably heat up during charge. This is also covered in ABYC E13. I have never installed a Lifepo4 batt where the manufacturer stipulated ventilation requirements. Yes, if you charge a cell to 100 V (400V for the pack), the valve will release some gases.
There is still a lot of misinformation out there when it comes to Lifepo4 (even in this forum, and this thread...). Get your data from the source . OEM install manual, ABYC, RCD, CE, etc... If you are doing a self-install, get educated from the source, not just from the forums before crimping your first wire !
Bad electrical is the #1 source for recreational boat fires.... do it perfect the 1st time, or don't do it all.
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It only states the maximum movement, which if anything seems a bit liberal. I think it may date back to FLA batteries contained in a box and movement within that box. We have about an ⅛" gap around the bottom of the battery and 0" vertical as they are strapped down to the base.
No need to spend any money. ABYC offers a short term "Recreational Membership" for free which gives read only access to the Standards. With a little computer savvy the individual standards can be downloaded as PDFs.
We also charge to 13.8V. Many times after the battery has reached 13.8V and the charge source turned off, I have re-engaged the charge and brought them to 14.5V. This usually only takes a minute, and represents an additional 0.1% of battery capacity (which is a whopping 1Ah of our 1000Ah bank). So unless charging >0.5C, specifying higher charge voltage is just stressing the chemistry for no reason.
Higher charge rates do need higher voltages, and in the same vein lower charge rates can get by with lower voltages. We are usually charging at ~0.2C with solar. On days when the solar is low and charging 0.05C or less, the batteries get completely full at ~13.6V.
I guess the charge voltage is based on the BMS balancing for the companies recommending higher voltages, but a good battery should not need much balancing, or very often. We have an external balancer that can be turned on if needed, but we haven't had any of our cells go out of balance more than 15mV at the top of the charge in a couple of years. If the battery is good, one should only need to occasionally bring it to higher voltages to check and maintain balance.
Mark
I think that's a very good example of when we say - the standards are a minimum requirement.
I have never tolerated that much movement for my batteries. They are not allowed to move. I can't imagine being in a serious storm where being in your boat is like being in a washing machine for several days with batteries thrashing around like that.
dj
The Wattcycle 314Ah mini is a killer value. Some of the best physical internal construction I have seen other than Epoch.
This article shows how easy it is..
Affordable & Well Built- Wattcycle 314Ah Mini - Marine How To
The Epitome of Value! In our never ending search to find readers products for their boats that are both safe and affordable, the Wattcycle 314Ah BT Mini fits the bill. LFP cell prices will remain low for a bit longer (ignoring tariff's) and
marinehowto.com
This article shows how easy it is..
Easy LiFePo4 Conversion - Marine How To
Easy LiFePo4 Conversion Before reading this article please read the 101 article on Drop-In's: Drop-In Batteries Be An Educated Consumer Hardly a day goes by where we don't see or hear
marinehowto.com
As you know the battery I built for my own boat back in 2009, way before drop-ins even existed, was only ever charged to 13.8V. It will be 17 years old in May and still delivers 100% of rated capacity. Contrast that to Battleborn that recommends 14.6V and many of them are barely capable of delivering 60%..
@Maine Sail A rather fortuitous post. I listened to your video but I have some questions - mainly I didn't understand well how to get the discount on the batteries you are recommending. Do I have to send you a note somehow to get the discount? Or is that button on your website all that's needed. Also, will that discount work on any of thier batteries or just that 314Ah battery?The Wattcycle 314Ah mini is a killer value. Some of the best physical internal construction I have seen other than Epoch.
Affordable & Well Built- Wattcycle 314Ah Mini - Marine How To
The Epitome of Value! In our never ending search to find readers products for their boats that are both safe and affordable, the Wattcycle 314Ah BT Mini fits the bill. LFP cell prices will remain low for a bit longer (ignoring tariff's) andmarinehowto.com
I will buy through you if that helps you. Plus, the prices are excellent!
dj
Thanks Rod, Curious to see the Victron IP65 "plug in" charger in the circuit. I would think you'd want to charge from the alternator (if correctly sized) or from Shore Power/Generator through a Sterling programmable charger. Why the plug in charger. I'll read the LiFePo 101 and maybe it will be answered there. Tried to do some funding on the MHT page but it rejected it. I'll try again tomorrow.
By the way, everybody out there. If you haven't put some funding in to keep the MHT site alive consider all the advice that has appeared on there and ask yourself what you would have done without it. Some of you might not have needed it, but for me, it was my go to site for everything from how to set up floats on my mooring line to considerations like this for installing Lithium Batteries..
By the way, everybody out there. If you haven't put some funding in to keep the MHT site alive consider all the advice that has appeared on there and ask yourself what you would have done without it. Some of you might not have needed it, but for me, it was my go to site for everything from how to set up floats on my mooring line to considerations like this for installing Lithium Batteries..
Click the link on my web site or the video description, put what you want in the cart when you hit check out it will give you a spot for the discount code: MHT8
Link here: WattCycle Deep Cycle LiFePO4 Battery | RV, Boat & Off-Grid Batteries
Link here: WattCycle Deep Cycle LiFePO4 Battery | RV, Boat & Off-Grid Batteries