Date
1 - 20 of 30
Another battery question
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Jerry Gaffke
Richard,
That Lossigy 20AH 12V LiFePO43 looks very interesting. Includes a BMS inside, should be as easy to use as a lead acid battery. Has 4x the Amp-hours of my Gooloo (though the Lossigy won't start my car!). Web hits on "Lossigy" seem mostly positive. A comparable Bioenno is nearly 4x the price. Jerry, KE7ER |
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AndyH
Yessir - the 10 Ah PSI cells are rated for 10C charge/discharge. One of the cell interconnects is a 100 A fuse, which can be seen in the photo. Radios had their own fuses as well. The battery started as a test pack and has a couple sets of balance leads for different BMS and LVC devices. The bench-top spaghetti monster. hihi
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 On Sat, Nov 26, 2022 at 12:32 PM, Jerry Gaffke wrote:
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Richard E Neese
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AndyH
Thanks Don. I'be only flown fixed wing RC, so am not familiar with how powered lift devices are managed. The ESCs I've used reduce or cut power to the motor when the battery gets low. Since servos are connected to the battery directly, they continue to function after the prop stops spinning. It makes it easy to glide back for a battery swap if one loses track of time.
Andy |
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Jerry Gaffke
Indeed, none of us have any argument with that. On Sat, Nov 26, 2022 at 05:38 PM, Don LeRoi wrote:
I don't object to anything that Andy is doing because he knows what he's doing. My concern is for people that don't know what they're doing. That's all. |
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Jerry,
I don't object to anything that Andy is doing because he knows what he's doing. My concern is for people that don't know what they're doing. That's all. Cheers, Don |
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Jerry Gaffke
Don,
Years ago, I occasionally used a small inverter type DC arc welder to charge a 24v offgrid lead acid battery bank. Could set the current to something appropriate, this was way faster than any other charger I had available. Worked great for me but I don't recommend this technique to others, they might try using their AC buzzbox or not guess right on which clamp is positive. If overcharged and/or poorly ventilated, the outgassing could have become quite dangerous. As Andy said: "Without automation, we become the management system - the battery is as dangerous as we are." Here's what Andy had to say about BMS's on RC aircraft batteries: "RC batteries aren't unsafe because they don't have an i ternal BMS. In RC use, management is split between the charger on the ground (charges, controls voltage and current, and balances). In the air, the speed controller monitors battery voltage and disconnects the load. The only weakness is cell level low voltage isn't monitored (though the low voltage disconnect is conservative for that reason)." So they keep the BMS as part of the charger, not part of the battery. This reduces the weight of what goes up in the air, which seems ideal. But anybody using one of those batteries (especially those charging at 25C!) should be using a BMS during charging. The operator (or aircraft firmware) needs to be smart enough to land the thing safely before the battery expires. Perhaps you object to this passage: "My bench battery for the past 12 or so years was a 'naked' 4S 10 Ah LiFePO4 pack made from PSI cells. I didn't worry about low voltage monitoring because I seldom discharged to 50%. I connected to an analogue BMS when charging with my bench PSU." So about the same as the RC battery, he charged with a BMS, and was careful not to discharge too far. Discharging to zero might ruin the battery, but would not be dangerous. Doesn't say if he fused it to limit the maximum current, but that's about the only additional safety measure I'd recommend. Jerry, KE7ER |
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ajparent1/kb1gmx
Never hand a hammer to someone that's never used one they will hurt
themselves, usually applied to many tools. Technology masks the hazards but can and often do make us safer. So to me the idea of low battery go home makes sense as it performs battery protection and reduces other hazards. Never said BMS/BMB were he only way just its common and most cases its the way to do it. As someone that flew electric models and real aircraft sudden fan stops make for much sweat. Allison ------------------ Please use the forum, offline and private will go to bit bucket. |
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Andy,
Thanks for your comments. I would suggest that RC battery packs without BMS are unsafe in the hands of people that don't understand the technology. For example, there's nothing to prevent someone from overcharging them by using the wrong kind of charger. Over-charging can cause thermal runaway and result in fire. Even on the right charger, if someone doesn't appreciate the need to balance the cells, one or more cells may eventually become seriously over-charged. I build multi-rotor RC helicopters for a living. I don't know of any that disconnect the load when the battery drops below a certain voltage. In my view, that would present another safety risk when the aircraft falls out of the sky. In my early days of flying electric aircraft, there weren't suitable Li-Po batteries and chargers available, so we used Milwaukee V28 tool batteries. However, we stripped out the BMS so that they couldn't shut off in-flight. Ultimately, we removed the 7 individual V28 cells to assemble our own 3S and 4S battery packs. Today, my flight controllers start the aircraft toward home at a certain low voltage threshold and land it if the voltage drops below the next threshold. Cheers, Don |
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Jerry Gaffke
Some addendums to my suggesting the use of a Gooloo 2000 for portable power. On Wed, Nov 23, 2022 at 06:08 PM, Jerry Gaffke wrote:
Speaking of fast discharging, it is amazing how well the new breed of auto jump start |
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Jerry Gaffke
Don,
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That Lumenier is a 10 Amp-hour battery, nominally 14.8 Volts. Rated for 25C, which means a maximum current of (10 Amp-hour) * 25C = 250 Amps, where the 25C has the rather odd units of Amps per Amp-Hour. So it can fully discharge that battery in (60 minutes)/25 = 2.4 minutes, with a power of 250 Amps * 14.8 Volts = 3700 Watts. A 3700 Watt appliance would blow fuses at 120 VAC, you would need a 240 VAC outlet. If you insist on moving that much power in and out of such a package weighing 0.845 kilo, that is inherently dangerous. But that's what the RC aircraft guys feel they need. When an aircraft is taking off it needs a burst of power, much more than when cruising along in even flight. The battery has to be as light as possible. And when they land with a depleted battery, they want to recharge it as quickly as possible (in this case around 2.4 minutes, assuming the max charge rate is the same as the discharge rate of 25C) That way they can get it back up in the air again for more fun. So they really are wanting to move 3700 Watts in and out of that battery. That's inherently unsafe, and why vendors also sell a "Lipo Safe Bag" to hold the somewhat expected explosion when charging at 3700 Watts. However, if you take that same product and charge/discharge at 10 Amps, and have an appropriate BMS hooked up when charging, there is very little danger of an explosion. Just make sure you don't short out those two roughly 1 cm diameter copper cables. Same applies to the starting battery in your car, not far from all that gasoline. Jerry, KE7ER On Fri, Nov 25, 2022 at 07:11 AM, Don LeRoi wrote: The common brick lithium battery packs are the least safe because they are very vulnerable to abuse. That is: over-charging, over-discharging, shorting, puncturing, and failure to balance the cells. These are the battery packs that have a main power lead and a balancing connector: |
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AndyH
Very cool, Jerry! It sounds lime you've a good handle on things there! I agree that commercial and most DIY BMS have wimpy shunts. I expect you already know that you likely don't need to shunt often, especially with your very conservative voltage settings. (For yet another tangent, the Smart ev and my current Outlander PHEV both have similar 250 mA-ish shunts. It takes a couple of cycles, or a day plugged in, but the battery will eventually balance. I seldom care, tho, as that extra 1/10 of a mile range isn't usually an issue hihi).
You're right that there's no point to charging cells to 100% - especially the ones like LFP that carry most of their energy at a lower voltage. It'll definitely reduce the cycle life. (From Thundersky-Winston, for example - operational voltage is 3.8, though charge/discharge tests run to 4.0 V. I used to set shunts to 3.65 and charge to 3.6. Shunts didn't activate until a cell got weak. https://en.winston-battery.com/static/upload/image/20210516/1621135112165001.jpg Ok, the wind is back - time to sail. 73 all Andy |
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Jerry Gaffke
Andy,
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Sounds like you have made a career in offgrid power, something I have only dabbled with. The earthship must have been a major project and a big learning experience, I was looking hard at that before going with strawbale infill on our post-and-beam house, has a Faswall basement and is positioned for passive solar. Had 2.2 kW of PV till a couple years ago, now at 4.4 kW and will probably double that soon so we can get through dark NE Oregon December weeks without running a generator. Most winter heat is currently from windfall ponderosa pine, as I get older and less inclined to swing a chainsaw we may pivot to a large well insulated hot water reservoir in the basement heated by excess PV on occasional sunny winter days to keep the hydronic floors warm in bad weather. Wind and micro-hydro are vague possibilities here, but enough PV for cloudy weather at $0.50 per Watt is hard to beat. When we first bought, got by with a 20 foot yurt and 45W worth of PV from Harbor Freight and a couple used golf cart batteries. Most of that power went to a Sundanzer DCR225 fridge, cooling it off during the day and coasting through the night. Have power lines to the property, but was quoted $15k to get power to our building site if I dug the ditch. Was happy to hear that, as I was inclined to go offgrid anyway (we all need hobbies!). With 4.4 kW of PV and 29 kWh of LiFePO4, we pretty much never use the generator and my partner Liz need not think about my hobby when using the 26 cuft front loading fridge/freezer, 3 chest freezers, and dishwasher with superheater. I've given up complaining when and empty rooms are left with the very efficient LED lights left on. Being remote, power to the area occasionally goes out, and I rather enjoy telling the neighbors "no" when they ask if our power went out too. The JBD 200A BMS has a rather wimpy passive balancing scheme, discharging any cells with excessive voltage at maybe 250mA. This is proving adequate for the 2P16S pack of relatively well behaved LF280K cells from Docan, though I found it necessary to disable balancing at anything under about 3.41 Volts as the charge curve for the various cells differed enough below that value that the wrong cells were getting discharged. I'd guess this is because any cells with tighter specs were cherry picked for use in EV's. A minor nit of which I am sure you are aware, but seems worth pointing out to the forum: > "While the operational voltage per cell can vary between about 2.4 and 3.8, the family still has a max of 4.2 and a minimum of about 2V per cell." The LiFePO4 cells should never be charged much above 3.6 Volts, they would definitely be damaged if held at at 4.2 Volts. Pretty much all the other Lithium Ion chemisties are good to around 4.1 or 4.2 Volts as stated. I charge my battery to a max of 54.8 Volts (3.425 Volts per cell) and shut things down when it falls below 48.0 Volts (3.0 Volts per cell). This is using my Magnum PT100 charger, which was designed for lead acid and so is not aware of individual cell voltages. That range gives me something close to 99% of the available capacity and allows fast charging when only occasional sun is available, but avoids extreme highs and lows where top balancing (at the high end) and matched capacities (at the low end) become critical. As these cells diverge with age, I may need to program those high and low voltages to something more conservative. Ideally, I would instead figure out how to tell the PT100 to stop charging (without the possible voltage transients of letting the BMS take care of this) when any single cell exceeds 3.6 Volts. Letting the BMS relay cut out the battery when any single cell falls below 2.5 Volts is probably just fine. Looking forward to having an electric vehicle, especially if it can be cabled up to the house during a week of foul weather to make good use of that 70 kWh battery. Will check out Endless Sphere. When a difficult technical issue is raised on diysolar there can be ten different answers, and I might find eight of them to be misinformed. Jerry, KE7ER On Thu, Nov 24, 2022 at 01:06 PM, AndyH wrote:
I appreciate your comments about your off grid battery. While my battery business was tailored to ebikes, electric motorcycles, and the occasional plug-in Prius conversion, my personal goal was off-grid. I'm a huge fan of the passive solar Earthship and have a complete solar and wind package (minus battery) for a future building. While the energy demands for a passive solar building are about an order of magnitude lower than a conventional US single family house, my needs now that I'm living aboard a sailboat are down another order of magnitude. My PV needs dropped from 3KW for the Earthship to 100W. My current house battery is the battery I made for portable radio use - 2P4S 25 Ah LFP cells, a 100 A JBD BMS, and a 10A Genasun MPPT charge controller, all in a plastic 50 Cal ammo can. I would have preferred to use a Stewart Pittaway DIYBMS, but didn't get it integrated in time before I put my lab into storage before the move. If one is a DIY type, it's really hard to beat the DIYBMS, especially if they use Victron balance of systems equipment. |
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AndyH
Don,
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RC batteries aren't unsafe because they don't have an i ternal BMS. In RC use, management is split between the charger on the ground (charges, controls voltage and current, and balances). In the air, the speed controller monitors battery voltage and disconnects the load. The only weakness is cell level low voltage isn't monitored (though the low voltage disconnect is conservative for that reason). (An example, not a recommendation) https://www.amazon.com/gp/aw/d/B0B5LLVSRK My bench battery for the past 12 or so years was a 'naked' 4S 10 Ah LiFePO4 pack made from PSI cells. I didn't worry about low voltage monitoring because I seldom discharged to 50%. I connected to an analogue BMS when charging with my bench PSU. I use LiCo pouches the same way. Without automation, we become the management system - the battery is as dangerous as we are. https://endless-sphere.com/forums/viewtopic.php?t=26554 If their bulk works for the mission, tool packs do make things easy, tho - and using them definitely reduces the need to not touch batteries until after coffee! Best, Andy On Fri, Nov 25, 2022 at 09:11 AM, Don LeRoi wrote: The common brick lithium battery packs are the least safe because they are very vulnerable to abuse. That is: over-charging, over-discharging, shorting, puncturing, and failure to balance the cells. |
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ajparent1/kb1gmx
What needs to be respected is written on the label...
Lithium tech allow a significantly greater amount of energy to be in a far smaller and lighter package. And if not managed they can deliver it all in short order, such as short circuits. 25C and 50C that means the nominal discharge current times either as a maximum. So we are talking in excess of 50A and as high as 500A, things melt if not adequately fused or otherwise protected. That can include the battery itself. That means for a lot of uses its safe if not abused, that includes both mechanical and electrical abuses. Specifically do not bend, fold, spindle, mutilate, peirce, overheat, charge while too hot or too cold. All kidding aside how many of those abuses are perpetrated by the average Ebiike or Hoverboard user? That's a 148WH battery, if pushed to the limit easily delivers 7400wh for maybe a minute. That is a lot of energy. For that level of power we are talking the equivilent of a 10Hp engine!! Its also enough power to run a 100W radio (about 240W DC input) for maybe hours depending on TX and RX time. While being able to supply the needed 18-20A on 100W TX. This is why power tools and other safe batteries are max current protected for discharge. Most all have a matching charge system. For example I have a built up 18650 11AH 3S4P pack with BMB selected for a current cutoff of 8A. Since its only running a FT817 that is more than needed but enough to protect the battery from a short. If I were to attempt to charge with more than 13.1V the board cuts off the battery and rendered it safe. If any cell in the pack goes under 2V or over 4.2 it also cuts off. It uses a specific charger I made for it. That is basic protection. Another pack with BMS does both that and has a charging port that has the needed current and voltage control for charging with uncontrolled voltage source, again for safety. It also does charge leveling plus all the BMB safety functions. But the BMS value is it allows for a simple wall wart charger with enough output voltage as all the management is on the board. So if I were to use that pouch pack battery it would be placed in a heavy wall plastic case with BMS added and suitable connectors for field and other uses. Or I'd just buy a battery with all that is in a nice hard plastic case with standard tab or wire connectors. FYI most of the 7-9ah Lithium tech (usually Lipo or Lifepo4 families) replacement for gell cell 12V batteries do all that as well. However if you buy a quality battery with protection it will outlast most other alkaline (NiCd, Nimh) and lead acid tech but a wide margin making their cost actually economical. Allison ------------------ Please use the forum, offline and private will go to bit bucket. |
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The common brick lithium battery packs are the least safe because they are very vulnerable to abuse. That is: over-charging, over-discharging, shorting, puncturing, and failure to balance the cells. These are the battery packs that have a main power lead and a balancing connector:
 They have no built-in protection. Cordless power tool lithium battery packs are among the safest because they are encased in hard plastic and have built-in short circuit, over charging, and over discharging protection. Also, you can't forget to balance the cells because balancing is also internal. Cheers, Don |
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Jerry Gaffke
Also, note that when clicking on "Battery" in the upper left of http://www.powerwholesale.net/,
you are presented with the following choice: Category Battery Li-ion battery
LiFePo4 Battery
Ni-MH Battery
Ni-cd battery
They wouldn't sell as many if they made it too complicated. ;-) Jerry, KE7ER On Thu, Nov 24, 2022 at 05:00 PM, Jerry Gaffke wrote: Curious, we wound up at the same vendor. |
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Jerry Gaffke
Curious, we wound up at the same vendor.
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From http://www.powerwholesale.net/about_us.html "About Us Docan Technology (Shenzhen) Co., Limited is a famous OEM battery factory with providing battery solution for customers, located in Shenzhen, Guangdong Province of China." Was no longer in a hurry when getting the second set of 16, so had those shipped from China, those took about a month before being dropped off by UPS and the price was significantly less. All cells were pristine, extremely well packaged, and worked well. Both buys were made through the same Docan rep, and payment for both was made through alibaba, paypal, and my credit card company. A bit scary to buy that way, but I read enough favorable reviews of Docan to buy with confidence. Jerry, KE7ER On Thu, Nov 24, 2022 at 01:06 PM, AndyH wrote:
I've not used powerwholesale. .... I have had good results from Docan Power and their Houston, TX warehouse. |
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Andy, I looked at your bio on QRZ.COM... Very impressive and thought inspiring and it encourages imagination. Thanks. Bob KK5R
On Thursday, November 24, 2022 at 04:06:46 PM EST, AndyH <awhecker@...> wrote:
Lost a reply on the phone...let's try this again on the laptop... With respect, Jerry, "common usage" depends on the group being surveyed. For the general public, I agree that "lithium ion", "Lithium polymer", and LiCoO are used interchangeably. It's like saying all capacitors are electrolytic. In the marine world, lithium ion specifically means LFP/LiFePO4. In research and transportation, lithium Ion means the family and one has to identify the chemistry being discussed. Even within specific chemistries, there can be 'power cells' or 'energy cells', and some LFP are doped with yttrium or other elements. While the operational voltage per cell can vary between about 2.4 and 3.8, the family still has a max of 4.2 and a minimum of about 2V per cell. https://marinehowto.com/lifepo4-batteries-on-boats/ https://www.researchgate.net/publication/277963083_Effects_of_yttrium_ion_doping_on_electrochemical_performance_of_LiFePO4C_cathodes_for_lithium-ion_battery I've not used powerwholesale. I used to import 10 Ah cylindrical cells from PSI in Taiwan. I've used A123 cylindricals; Headway, PSI, Thundersky (thundersag...), CALB, and other prismatic LFPs. I've also used plenty of LCO pouches from Hobby King, both for RC and portable radios. NiCd and NiMH before that. My 5KW electric scooter/motorcycle was my primary vehicle and BMS test bed when I was building batteries. It had a 21S pack of 60 Ah Thundersky LiFeYPO4 cells. I have had good results from Docan Power and their Houston, TX warehouse. They stock grade A and B cells from CALB, CATL (supplies VW), and EVE. DIYSolar and DIYElectricCar both have too much bad info. I prefer the signal to noise ratio of the Endless Sphere forum - more engineers and fewer "youtube influencers". I appreciate your comments about your off grid battery. While my battery business was tailored to ebikes, electric motorcycles, and the occasional plug-in Prius conversion, my personal goal was off-grid. I'm a huge fan of the passive solar Earthship and have a complete solar and wind package (minus battery) for a future building. While the energy demands for a passive solar building are about an order of magnitude lower than a conventional US single family house, my needs now that I'm living aboard a sailboat are down another order of magnitude. My PV needs dropped from 3KW for the Earthship to 100W. My current house battery is the battery I made for portable radio use - 2P4S 25 Ah LFP cells, a 100 A JBD BMS, and a 10A Genasun MPPT charge controller, all in a plastic 50 Cal ammo can. I would have preferred to use a Stewart Pittaway DIYBMS, but didn't get it integrated in time before I put my lab into storage before the move. If one is a DIY type, it's really hard to beat the DIYBMS, especially if they use Victron balance of systems equipment. https://www.youtube.com/@StuartPittaway/videos https://github.com/stuartpittaway/diyBMSv4 Best, Andy KG5RKP/MM On Thu, Nov 24, 2022 at 09:05 AM, Jerry Gaffke wrote:
Andy, |
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AndyH
Lost a reply on the phone...let's try this again on the laptop...
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With respect, Jerry, "common usage" depends on the group being surveyed. For the general public, I agree that "lithium ion", "Lithium polymer", and LiCoO are used interchangeably. It's like saying all capacitors are electrolytic. In the marine world, lithium ion specifically means LFP/LiFePO4. In research and transportation, lithium Ion means the family and one has to identify the chemistry being discussed. Even within specific chemistries, there can be 'power cells' or 'energy cells', and some LFP are doped with yttrium or other elements. While the operational voltage per cell can vary between about 2.4 and 3.8, the family still has a max of 4.2 and a minimum of about 2V per cell. https://marinehowto.com/lifepo4-batteries-on-boats/ https://www.researchgate.net/publication/277963083_Effects_of_yttrium_ion_doping_on_electrochemical_performance_of_LiFePO4C_cathodes_for_lithium-ion_battery I've not used powerwholesale. I used to import 10 Ah cylindrical cells from PSI in Taiwan. I've used A123 cylindricals; Headway, PSI, Thundersky (thundersag...), CALB, and other prismatic LFPs. I've also used plenty of LCO pouches from Hobby King, both for RC and portable radios. NiCd and NiMH before that. My 5KW electric scooter/motorcycle was my primary vehicle and BMS test bed when I was building batteries. It had a 21S pack of 60 Ah Thundersky LiFeYPO4 cells. I have had good results from Docan Power and their Houston, TX warehouse. They stock grade A and B cells from CALB, CATL (supplies VW), and EVE. DIYSolar and DIYElectricCar both have too much bad info. I prefer the signal to noise ratio of the Endless Sphere forum - more engineers and fewer "youtube influencers". I appreciate your comments about your off grid battery. While my battery business was tailored to ebikes, electric motorcycles, and the occasional plug-in Prius conversion, my personal goal was off-grid. I'm a huge fan of the passive solar Earthship and have a complete solar and wind package (minus battery) for a future building. While the energy demands for a passive solar building are about an order of magnitude lower than a conventional US single family house, my needs now that I'm living aboard a sailboat are down another order of magnitude. My PV needs dropped from 3KW for the Earthship to 100W. My current house battery is the battery I made for portable radio use - 2P4S 25 Ah LFP cells, a 100 A JBD BMS, and a 10A Genasun MPPT charge controller, all in a plastic 50 Cal ammo can. I would have preferred to use a Stewart Pittaway DIYBMS, but didn't get it integrated in time before I put my lab into storage before the move. If one is a DIY type, it's really hard to beat the DIYBMS, especially if they use Victron balance of systems equipment. https://www.youtube.com/@StuartPittaway/videos https://github.com/stuartpittaway/diyBMSv4 Best, Andy KG5RKP/MM On Thu, Nov 24, 2022 at 09:05 AM, Jerry Gaffke wrote:
Andy, |
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