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i never did replace it. a new 3s lithium pouch pack cost more than a new boost pack from a different company.

my best guess is that it was a low oil alarm. if your oil dipstick is in good condition, check it and note the oil level. my dipstick was damaged and i couldnt reliably tell the oil level. so i drained the oil, put a new oil filter on, and added new oil to spec. can't remember exactly how much. that stopped the alarm.

yeah, mine are most definitely li-nmc. the spec sheets says so, the operating voltage max is 4.2v (so clearly not LFP), and the pack is 7s (almost all 24v LFP packs are 8s -- 7s would be very unusual, with a pack voltage of 3.2*7=22.4v.)

@@AJTarnas yes I think you got very lucky with these packs, hope they prove useful over time, I've had a few cell failures over the years, my cells from 2005, but in general very good quality.

this pack is definitely a 7s li-nmc chemistry. but i see you figured that out in another comment. that's crazy that yours are dated 2005. that's so early for LFP. my packs were supposedly manufactured in 2017. i don't use them much these days because my main house battery is now a 14.4kwh 16s EVE LFP bank.

@@AJTarnas the a123 cells go way back, initially they were only lipo4 type, I have some older cells but different format, they were used in dewault tools at one stage. Many folks were scrambling to find lipo4 and one early source was battery tools. These days no problems can get what you want easily.

@@namenotshown9277 "lipo4" is not a chemistry. do you mean lithium-polymer (lipo) or lithium iron phosphate (lifepo4 / LFP) ? i bet the very old ones were lipo. LFP was rare in the early 2000s and would probably not have been used in power tools. ...looking into this more, i'm seeing where the confusion is. early a123 batteries were lithium-polymer chemistry with a unique proprietary chemistry including a "nanophosphate"-doped cathode. so a123 would sometimes call this "Li-PO4". it's not closely related to LFP, it's a modified li-polymer chemistry. it appears that li-nmc eventually matured to be higher performance than the early proprietary li-nanophosphate. i think you are wrong that this chemistry is "safer". it is less safe than modern li-nmc. li-nanophosphate may have been safer than li-polymer in 2005, but that's not really relevant anymore. LFP is much safer than li-polymer, li-nanophosphate, and li-nmc. lithium titanate would be the next step up of safety beyond LFP.

excellent! glad to be helpful.

i THINK it's a "low oil" alarm. it stopped beeping after i did an oil change. (this was complicated for me because my oil dipstick is inaccurate. but i just added the volume of oil specified for this engine and hoped for the best.)

ha! true. no one should copy me. i have since upgraded to 14kwh 16s lithium iron phosphate EVE cells. my cable management is only slightly better.

in the central valley and elsewhere they are usually for legal agriculture. here they are almost exclusively for weed.

i don't think that's much of a concern. these packs will degrade over time even if they just sit unused. so just use them. you really can't discharge them too low because your inverter will stop working around 23v -- the battery is empty down around 21v. you shouldnt overcharge it, that would be dangerous. but most BMS's actually won't balance charge these cells until they reach 4.15v or so. which is really closeto "full". i don't like going to "absolutely full" but i get close at 28.6v (4.09v * 7 cells). in case that's not clear, these packs contain 7 groups of 3 pouch cells that have a voltage range of roughly 2.9v to 4.2v. but it's dangerous to go over or under those limits, unless you have really good electronics monitoring these (like victron equipment), so i try not to get close. most ofthe power is between around 27v down to 24v. there's a plateau around 25.7v -- the charge-discharge curve isnt linear, it's a bit unusual. so once the battery is charged up to 27.5v or so, it isn't storing many more watt-hours at 28.0v or 28.5v.

yep! hard to believe it was only a year ago. have been using one pack to run my house (i live off grid in the mojave desert), one for the music studio, one as a mobile power bank, and two packs are sitting unused currently. i learned a bit more about them through use. the bms i have on two of them doesnt seem to work, but they remain very well balanced anyway.

@@AJTarnas Do you have other videos related to this pack? I just came upon 4 of them. No clue how and where to get started. Any tips?

@@johnle231 sure! i just made an overview of my main system. also look up ben mcfeeters, he's usedthese packs. ruclips.net/video/IpkalaWpeOs/видео.html

@@AJTarnas Thank you imma check it out

@@AJTarnas Ben mcfeeters? I didn’t see any videos on it

noted -- maybe some day i'll have better internet and upload a higher res version of the video.

@@AJTarnas I understand. I just got Starlink after suffering with super slow internet for the last 15 years. Great video regardless. Thanks