nice summary Riley; thanks Wade Oh Boy 33-2
On Wed, Sep 15, 2021 at 10:39 AM Riley Anderson via CnC-List < cnc-list@cnc-list.com> wrote: > Hi Joe and any others interested in this topic. > > I install lithium batteries as my side job and after installing lithium on > our 38-ii and other large boats and consulting on another half dozen boats, > I can speak with some authority on this topic. > > *The risk of serious electrical or fire damage can be entirely mitigated > by properly installing the right equipment and following a strict circuit > topology. Most people who have installed lithium do not do this and this is > precisely why we hear about "lithium fires" so commonly.* > > Before diving into the details, you should be aware that in order to > safely install lithium batteries on a boat, you need to buy top-quality > gear that is compatible with the exact lithium chemistry of your batteries. > Can you use an AGM charge profile from the old charger you have lying > around? Sure, you may be willing to take more risks than others but this is > not acceptable in a professional install and it also reduces the efficiency > of your expensive batteries that you bought for their high efficiency in > the first place! It is these "indirect" costs of making the lithium safe > aboard that will dramatically increase the investment cost. Also, in order > to take full advantage of the perks of lithium you need to be able to > efficiently charge the system. This means a substantial solar array or very > high output alternator (often requiring serpentine belts and larger > pulleys). *For the weekend sailor or anyone tied to a dock most of their > season, these costs cannot be justified over conventional lead-acid or AGM > technology.* > > My wife and I live aboard and spend our entire season on anchor or > mooring. This is where lithium shines. We have 720 watts of solar and 320 > Ah of lithium. *We run a fridge, separate freezer, fans, computers, > microwave, electric kettle, with enough excess power each day to either > make 6 gallons of hot water through the inverter or run a 5000 BTU air > conditioner on high for 5 hours through the night.* We have all the > luxuries of home and are never concerned about running out of power. > > *The details:* > > The Battleborn, Dakota, and Renogy batteries that advertise *a "drop-in" > replacement for lead-acid should never be used on a boat*. These were > designed for van-lifers who can pull over and escape if something goes > horribly wrong. > > The key with lithium is that you need to protect both your boat and > its electronics and your substantial investment in batteries. Lithium > batteries will not tolerate overcharging, this is where the fire risk comes > in. On the other hand, over-discharging will not cause a fire risk but will > destroy your battery. The "drop-in" replacement batteries "solve" this by > disconnecting their terminals in the case of either overcharge or > over-discharge. This is unacceptable on a boat for two reasons: 1) most > obviously, if you lose all DC power underway, you no longer have VHF, > depth, chartplotter, bilge pumps, radar, etc. 2) if the alternator is > spinning but there is no battery to accept the charge, it will send > unregulated voltage through the entire electrical system. > > The proper way to install lithium involves implementing a dual-DC bus > topology where all of the charge sources come into a single "charge bus" > and all of the loads run on a separate "load bus". Victron Energy is the > only company with off-the-shelf batteries and related components to > implement such a system. Of course, the savy DIYer can build their own > lithium banks and program a compatible battery management system to achieve > a similar end result but this involves a serious appreciation for the > nuances of lithium and circuitry design. Essentially, a battery management > system (BMS) will both balance the individual cells in a battery and > measure the voltage of each cell. If any single cell reaches its upper > voltage threshold value, the BMS triggers a relay to disconnect the charge > bus and prevent overcharging (keep in mind, there are other steps necessary > to protect alternators, I'll come back to this later). If any cell reaches > its lower voltage threshold, the BMS similarly triggers a relay > disconnecting the load bus to prevent over-discharge. The separation of > charge and load busses is critical as it allows the system to recover on > its own. In the event of a low-voltage disconnect, the charge bus remains > connected and the battery can recharge. In a high-voltage disconnect, the > loads are still connected and can bring the battery back down to a safer > voltage. > > To charge lithium from an alternator, you need a lead-acid or AGM in > between to act as a buffer (most commonly, this can be your starter > battery). The alternator charges the lead battery. Connected to the lead > battery is a DC-DC charger that is capable of three-stage charging with > LiFePO4 charge profiles. This charger then runs into the charge bus > mentioned above. The Victron Energy Orion Smart charger > <https://amzn.to/3kaCbG8> is a great choice here (Bluetooth programmable > and automatically detects when the engine is running so that you cannot > drain the start battery). > > The buffer battery protects both your boat's electronics from unregulated > voltage in the event of a high-voltage disconnect and keeps your alternator > from overheating. If you connect a 60 amp alternator to a 100 amp/hour > lithium, the low internal resistance of the lithium will allow it to pull > more amps than your alternator can keep up with. This will quickly burn out > the alternator. Not to say that direct alternator charging of lithium can't > be done, but it is usually cost prohibitive as the alternator needs to be > extremely high output and have a sophisticated regulator designed for > lithium. > > *The price:* > > Our lithium batteries, BMS, charge and load relays, shunt, wiring, bus > bars, and monitoring computers and displays all in came to about $5000. > This does not include the cost of solar charge controllers or panels, > inverters, or alternator charging via DC-DC chargers. A 200 Amp-hour system > could be done in the manner I outlined above with off-the-shelf parts and > slightly less sophistication for around $3000. I hope this gives you and > everyone else a good overview of what is involved in both the cost and > installation. > > After writing this all up I feel like I can justify a self-plug. As I > said, I do installs and consults part-time. If you're interested in > pursuing lithium and just want some guidance I'm happy to answer questions > with no strings attached. If you want a more in-depth consultation or are > in the southern New England area and want help with the install, my work is > high quality and my rates are very reasonable! > > Feel free to get in touch, > > Riley > (860) 538 8446 > > > > > > > > > On Tue, Sep 14, 2021 at 9:27 AM Della Barba, Joe via CnC-List < > cnc-list@cnc-list.com> wrote: > >> My batteries are about shot and I am thinking of going to lithium >> batteries. I have to say I thought I knew this stuff and it seems massively >> confusing with a ton of directly contradictory information. One big issue >> seems that if the BMS disconnects for any reason, that will do a lot of >> damage to your alternator and perhaps other equipment too. Add to that my >> regulator does not have a specific lithium setting, I would need to get >> into the custom menus and try and make one. >> >> What seems to be the best bet is just to connect the alternator to the >> start battery and use a DC-DC charger to charge the lithium bank. Some of >> them also take solar input, so that saves me buying a solar controller with >> lithium settings, which is something else I don’t currently have. >> >> >> >> Joe >> >> Coquina >> Thanks to all of the subscribers that contributed to the list to help >> with the costs involved. If you want to show your support to the list - >> use PayPal to send contribution -- https://www.paypal.me/stumurray >> Thanks - Stu > > > > -- > Fair winds and following seas, > > Charlotte Freeland & Riley Anderson > SV Freight Train > Middletown, CT USA > Thanks to all of the subscribers that contributed to the list to help with > the costs involved. If you want to show your support to the list - use > PayPal to send contribution -- https://www.paypal.me/stumurray Thanks > - Stu
Thanks to all of the subscribers that contributed to the list to help with the costs involved. If you want to show your support to the list - use PayPal to send contribution -- https://www.paypal.me/stumurray Thanks - Stu
