Yeah the BMUs in the merit sun ones are handling equalization of the cells inside and enforcing limit on over-current etc. It also determines how many series/parallel ones you can have too.
The chargers are pretty basic – they are just a single-stage power supply with a fixed current. They do typically shut off after the batteries are charged. The problem with a lead acid charger is that they are doing constant current until a certain voltage is hit and then switches to constant voltage for how long it took to finish the first stage and then switch to float. The BMU would have to do a bit of trickery to make that work and pretend to be a lead acid battery. For reference, the charger for the 48V LiFePO4 system is a single stage, 57.6V/20A power supply. From: AF <[email protected]> Date: Thursday, October 29, 2020 at 10:18 AM To: [email protected] <[email protected]> Subject: Re: [AFMUG] Lithium lead acid replacement batteries I don't really know Adam. I know that multi-cell LiFePo batteries need (and usually include) a BMU to manage the states/flow between cells, and I know that LiFePo batteries don't want (or need) a bulk or equalization. Beyond that, I think they just need a different charger, but I don't know how sophisticated it needs to be. bp <part15sbs{at}gmail{dot}com> On 10/28/2020 3:12 PM, SmarterBroadband wrote: Hi Bill I thought with the drop in replacements the BMU handled the charging? From: AF [mailto:[email protected]] On Behalf Of Bill Prince Sent: Wednesday, October 28, 2020 12:37 PM To: [email protected]<mailto:[email protected]> Subject: Re: [AFMUG] Lithium lead acid replacement batteries LiFePo (Lithium Iron Phosphate) is considered very safe. Completely different charge profile vs lead acid though. bp <part15sbs{at}gmail{dot}com> On 10/28/2020 12:32 PM, Steve Jones wrote: my biggest concern with lithium is im a dolt and dont know for sure which variants arent prone to explode On Wed, Oct 28, 2020 at 2:11 PM TJ Trout <[email protected]<mailto:[email protected]>> wrote: https://batteryhookup.com/<https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbatteryhookup.com%2F&data=04%7C01%7C%7C2a594395149c49c6172e08d87c1ddaf0%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637395814946292325%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=5jvqBPBDQDH%2FVIputDcthcpkZwjxjD2hE81zdaouM9w%3D&reserved=0> On Wed, Oct 28, 2020 at 10:11 AM Harold Bledsoe <[email protected]<mailto:[email protected]>> wrote: I’ve used the Merit Sun batteries for other applications. They work well and have a BMS. That said, they cannot be used with a lead-acid charging profile. Another option would be to disable the charger on the UPS (if possible?) and use a separate LiFePO4 charger for the batteries. That will give you more options. From: AF <[email protected]<mailto:[email protected]>> Date: Wednesday, October 28, 2020 at 11:44 AM To: 'AnimalFarm Microwave Users Group' <[email protected]<mailto:[email protected]>> Subject: [AFMUG] Lithium lead acid replacement batteries Is anyone using Lithium replacements for lead acid it there UPS setups. Our standard setup is 4 12v 100 amp hour external batteries on APC or Alpha UPSs. I read that some of the LiFePO4 12v Lithium batteries are drop in replacements for lead acid. Are all with built in BMUs considered drop in? Any one doing this? What make and model have you used. Price? Also interested to hear if anyone has purchased though Alibaba? Prices look good, but are they too good to be true? -- AF mailing list [email protected]<mailto:[email protected]> http://af.afmug.com/mailman/listinfo/af_af.afmug.com<https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Faf.afmug.com%2Fmailman%2Flistinfo%2Faf_af.afmug.com&data=04%7C01%7C%7C2a594395149c49c6172e08d87c1ddaf0%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637395814946302321%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=KYc7%2FBIDO%2BvA2QW5MqZgYIdE3NkJGEJfQcb7wszRn1Q%3D&reserved=0> -- AF mailing list [email protected]<mailto:[email protected]> http://af.afmug.com/mailman/listinfo/af_af.afmug.com<https://nam10.safelinks.protection.outlook.com/?url=http%3A%2F%2Faf.afmug.com%2Fmailman%2Flistinfo%2Faf_af.afmug.com&data=04%7C01%7C%7C2a594395149c49c6172e08d87c1ddaf0%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637395814946302321%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=KYc7%2FBIDO%2BvA2QW5MqZgYIdE3NkJGEJfQcb7wszRn1Q%3D&reserved=0>
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