It sounds like you need to do a complete re-fit – batteries, charger, alternator – and not simply swap batteries.
From: Bill Coleman via CnC-List <[email protected]> Sent: Wednesday, June 01, 2022 9:38 AM To: 'Stus-List' <[email protected]> Cc: Bill Coleman <[email protected]> Subject: Stus-List Re: Batteries again Thank you for outing the hack, sometimes it is hard to know who to believe when something (like this) is not your area of expertise. I just found this on my Balmar regulator instructions, which gives me pause . .. LFP LiFeP04 Recommendations Our LFP program is a generalized version of the recommendations provided by the top LFP battery manufacturers. For best performance and compatibility, please consult your battery manufacturer and use the regulator’s advanced programming features to adjust the LFP program as needed. LFP batteries are more sensitive to abuse than a traditional chemistry battery and can fail catastrophically. It is HIGHLY recommended that the charging system as a whole be installed or inspected by a qualified marine electrical installer that has experience with Balmar charging system products and LFP batteries. The LFP profile is intended to work with the battery manufacturer’s battery management systems (BMS). The LFP profile IS NOT a replacement for a BMS. *Many LiFePo4 batteries have a Battery Management System (BMS) that may disconnect the battery from the alternator as a protective action or when charging is complete. The regulator must be shut down before the battery is disconnected .Running an alternator without a battery will damage the alternator and may damage any attached system. This is doubly true if the battery can be disconnected during high current charging, causing a load dump. The load dump can easily cause a high voltage spike which will destroy the alternator’s rectifier, at minimum. This is not a warrantable failure. To reiterate: THE ALTERNATOR MUST BE SHUT DOWN BEFORE DISCONNECTING THE BATTERY. THE ONLY SAFE WAY TO SHUT DOWN THE ALTERNATOR IS TO TURN OFF THE REGULATOR. The preferred method of turning off the regulator is disconnecting the regulator’s ignition (brown) wire, but if used as an EMERGENCY ONLY shutdown, disconnecting the regulator’s power input (red) wire in addition to the ignition wire has a very low chance of damaging the regulator. *LFP batteries will readily accept a damaging amount of current. Applying too much charge current to a LFP battery will, at the very least, permanently damage the battery’s capacity. It is CRITICAL to ensure that the alternator is not capable of exceeding the maximum continuous charge current rating of your battery (or batteries). As always, check with your battery manufacturer for specifics. Your battery manufacturer may supply you with a “C-rate” for charging and discharging. The maximum amount of charging current your battery can safely handle is determined by multiplying the “C-Rate” by the capacity of the bank. i.e. 4x 100Ah 12V batteries rated at 0.5C charge = 400 Ah * 0.5C = 200amps MAX. If your alternator is capable of outputting more current, at any time or condition, than the battery (or batteries) can handle, you may use the Amp Manager feature on the MC-624 to lower the maximum field drive output, and thereby lower the maximum alternator output current. See page 10 of your regulator manual for details and instructions. Be aware that it is not an exact 1:1 correlation between field output and alternator output, so start with more reduction (lower output) than you think you need and adjust accordingly. *It is strongly recommended that an alternator temperature sensor (MC-TS-A) be used when charging LFP batteries. Given the extremely high charge acceptance rate of LFP batteries, the alternator will be driven to full output for almost all of the charge cycle. This can cause overheating in automotive style alternators resulting in a significantly shortened lifespan. When equipped with the MC-TS-A temperature sensor, the MC-624 will help you protect your investment by reducing the field voltage to your alternator by 50% when over the “AL1” temperature threshold. If you cannot use an MC-TS-A in your application, you should monitor the alternator’s temperature (measure as close to the loop ends of the stator as possible) and discontinue charging if the alternator temperature rises above the maximum recommended level. You may also use the Amp Manager feature on your MC-624 to reduce maximum output until a tolerable alternator temperature is maintained under all conditions. *Most LFP battery manufacturers specify minimum and maximum charging temperatures to be from freezing (32°F, 0°C) to around 111°F (44°C). Again, consult with your battery manufacturer for specifics. When equipped with a MC-TS-B, the MC-624 can disable charging if the battery temperature exceeds the “B1L” temperature threshold and re-enable charging when the temperature drops below the threshold. This feature is meant to supplement, not replace, your BMS’s temperature protection features. “B1L” should be adjusted to be slightly less than BMS’s temperature threshold. Note that the regulator does not have the capability to prevent charging during low temperatures. www.balmar.net <http://www.balmar.net> / Customer Service: +1 (360) 435-6100 x1 / Technical Support: +1 (360) 435-6100 x3 Tech Service is available Monday - Friday (8:30am - 7:30pm EST) I guess you have to do your homework! Bill Coleman Entrada, Erie, PA From: Riley Anderson via CnC-List [mailto:[email protected]] Sent: Wednesday, June 01, 2022 7:16 AM To: Stus-List Cc: Riley Anderson Subject: Stus-List Re: Batteries again Paul makes some good points but I want to remind everyone that there is no such thing as a drop in replacement lithium battery for boats. Accommodations must be made on the charge side. Charge profiles need to be 3 stage and specific to lithium chemistries. Also, you can do serious damage to your alternator if you try hooking up a large lithium bank to a small alternator. The internal resistance of lithium cells is so low, the alternator will quickly burn out trying to supply the load. Additionally, the drop in replacement type batteries pose an additional hazard in that a high voltage disconnect would also destroy your alternator if precautions are not taken. One last gripe, the YouTuber, Will Prowse, is a hack. He is not an engineer, nor an expert on lithium batteries. He is an expert in online marketing. His business model is to promote the cheapest of products with affiliate links so he gets a kickback of anything he mentions. People always want cheap, and are fooled into believing they're getting cheap and great when someone on the internet purports to be an expert. On Thu, May 26, 2022, 3:24 PM Dreuge via CnC-List <[email protected] <mailto:[email protected]> > wrote: Dave, As I mentioned in previously replies to the list, it no longer makes any sense to buy lead acid batteries(i.e. flooded, gel, or AGM) for a house bank. For lead acid, the AH capacity is highly dependent on the current load due to the Peukert Effect. Deep cycle lead acid batteries are rated at C/20. For a 100AH rated battery, this is 100AH/20H = 5A. This is often called the 20H rate, i.e. 5A * 20H = 100AH. If the actual load is 20A, then the same 100AH rated lead acid battery would only provide 60AH (or 10AH at 100A). And worse, one should only use 50% of a lead acid battery’s capacity as going below 50% substantially degrades the battery lifetime. This means that a 100AH lead acid battery has an effective 50AH @ 5A (or 30AH @ 20A). Let’s assume a 100AH lead acid battery price of $264 (the average of the Amazon prices), then 2 batteries would cost one $528 and one would get an effective 100AH (50%*200AH) at 5A loads. Now, the price of LiFePO4 batteries have come way down in the last few years and their performance and lifetimes are a magnitude better. A 100AH LiFePO4 battery is typically rated at 1C. That is they can deliver 100AH at 100A for 1H(or 5A at 20H or 20A at 5H). They can also charge at amps up to 100A which is impossible for a lead acid battery. And LiFePO4 batteries live 5 times longer. That is, one would expect to replace 5 sets of lead acid batteries before replacing a LiFePO4 battery. Yes, LiFePO4 batteries are more complex as they require a battery management system (i.e. BMS), but there are companies which provide 12V drop in replacements with the BMS built internal to the battery. Top companies like Battle Born sell a 100AH LiFePO4 for $874 and provide a 10yr warranty. Renogy sells a 100AH LiFePO4 for $765. A company, CurrentConnected.com <http://CurrentConnected.com> , sells a SOK 100AH LiFePO4 battery for $569 and it has a 10 yr warranty! YouTuber Will Prowse rates the SOK as the best value LiFePO4 12V drop in replacement (see https://www.mobile-solarpower.com/lithium-batteries.html). There are a plethora of cheaper 100AH LiFePO4 batteries that can be found on Amazon, Ebay, AliExpres, …, but one gets little service and limited warrantees, so I would recommend avoiding these. Rather than buying 2 100AH lead acid batteries for $528 at a total weight of 140lbs(70lbs each) , one could just buy 1 100AH LiFePO4 for $569 weighing only 28lbs and get a better performing battery. That is basically the same price. If one takes into account the increased lifetime, the saving is HUGE! If one builds their own DIY LiFePO4 battery, the savings is much much greater. Last year I replaced 2 100AH lead acid batteries with one DIY 560AH LiFePO4 battery for a little over $900 (see my blog link below). The DIY LiFePO4 battery occupies the same location and physical space as the previous 2 lead acid batteries, it weighs much less (95 lbs vs 125 lbs), but has 5 TIMES the capacity. I recently gave a talk on off-grid solar systems a local amateur radio society meeting. The discuss the battery as the heart of the system and make the case for LiFePO4 batteries. My slides from the talk are available on my blog: https://svjohannarose.blogspot.com/2021/10/solar-off-grid-system.html Also, the details of my DIY 560AH LiFePO4 are posted at the link below which includes details about alternator charging. https://svjohannarose.blogspot.com/2021/06/adding-new-lifepo4-to-house-battery.html - Paul E. 1981 C&C Landfall 38 S/V Johanna Rose Fort Walton Beach, FL http://svjohannarose.blogspot.com/
