โMay-01-2021 07:44 PM
โMay-07-2021 07:01 AM
โMay-07-2021 05:51 AM
StirCrazy wrote:Most aftermarket BMS's have two sets of mosfets. One for charge, one for discharge. Each one is programmable independently. I would imagine this would be true for most sealed/prepackaged LifePo4/BMS units, too (no programmability though).
I dont think I would have a issue using a BMS to control the upper limit if it only shut down the charging but I dont know for sure if thats how the bigger ones work . . .
Steve
โMay-06-2021 07:13 AM
Itinerant1 wrote:
This has been covered already. BMS is there (or should be) as a last line of protection not the first.
"Float" if used in a daily cycling of the batteries won't hurt it but if your going to float them at storage for long periods of time then it could shorten the battery life.
โMay-05-2021 11:01 AM
โMay-05-2021 08:28 AM
BFL13 wrote:Yes, in an *typical* alternator application I agree there's very little to worry about. However, that's making an assumption on how the dc to dc charger will be used. It may or may not be turned off after a period of time depending on application. Bottom line, Renogy or PD did not qualify or restrict the use of the lithium mode in their dc to dc charger or converter in their user's manual.otrfun wrote:BB says you can leave it at 14.x for a week or two. Your DC-DC shuts off when you shut off the ignition, so no need for a float option. A converter stays on for as long as you are plugged in.
Finally got around to looking at the lithium charge options on our Renogy 40a dc to dc charger we have mounted in our truck camper. Bad news, the lithium mode is single-stage just like the PD, no float. However, the good news, in lithium mode you have 7 voltages to select from: 12.6v, 12.8v, 13.0v, 14.0v, 14.2v, 14.4v, and 14.6v. In lead acid/AGM/GEL mode it becomes a 2-stage charger (absorption and float). 3 absorptions choices: 14.1v, 14.4v or 14.7v. 3 float choices: 13.2v, 13.5v, and 13.8v.
Interesting that both Renogy and Progressive Dynamic (and no-doubt others) use single-stage lithium chargers. Got to wonder whether these manufacturers saw no harm in floating a LifePo4 indefinitely at higher voltages (let the BMS do the dirty work??), or they just assumed the end-user would simply disconnect/turn-off the charger for long-term storage (based on LifePo4's very low parasitics).
DC-DC is buck/boost so maintains 14.x whether alternator regulation has it above or below the chosen 14.x.
โMay-05-2021 07:39 AM
otrfun wrote:
Finally got around to looking at the lithium charge options on our Renogy 40a dc to dc charger we have mounted in our truck camper. Bad news, the lithium mode is single-stage just like the PD, no float. However, the good news, in lithium mode you have 7 voltages to select from: 12.6v, 12.8v, 13.0v, 14.0v, 14.2v, 14.4v, and 14.6v. In lead acid/AGM/GEL mode it becomes a 2-stage charger (absorption and float). 3 absorptions choices: 14.1v, 14.4v or 14.7v. 3 float choices: 13.2v, 13.5v, and 13.8v.
Interesting that both Renogy and Progressive Dynamic (and no-doubt others) use single-stage lithium chargers. Got to wonder whether these manufacturers saw no harm in floating a LifePo4 indefinitely at higher voltages (let the BMS do the dirty work??), or they just assumed the end-user would simply disconnect/turn-off the charger for long-term storage (based on LifePo4's very low parasitics).
โMay-05-2021 07:34 AM
โMay-05-2021 07:20 AM
โMay-05-2021 06:31 AM
โMay-05-2021 06:16 AM
โMay-03-2021 09:42 PM
otrfun wrote:3 tons wrote:The Progressive Dynamic EQ mode only applies 14.4v for 15 min every 21 hours before dropping back down to 13.2v or 13.6v. Battleborn only expressed concern about floating their LifePo4's at 14.6v 24/7, weeks/months at a time. Very significant difference.
The PD Lithium specific model is extremely flawed...Why??... Because it continues to charge the battery long after the battery is fully charged (eventually shortening battery life) and cannot be shut off without entirely disabling the 12v converter only function.....This is why their regular model is better, while itโll deliver the necessary 14.4v when using the Charge Wizard set to Boost, and the 13.6v Absorption will be of no consequence...However, Equalization mode will need to be defeated....
3 tons
IMO, anyone with a LifePo4 who has the need to leave their rig unattended for weeks, months at a time should simply disconnect them--ideally with a 40-50% SOC, regardless what kind of converter/charger they have. With a parasitic discharge rate of only 1-2% a month, they'll be fine for a very, very long time---at least a year or more. Even 13.6v will quickly float LifePo4's to 97-98% SOC. Unless I'm missing something here, what's the point? Is it possible this is the reason Progressive Dynamic designed a single-stage 14.6v converter to begin with? They saw no urgent need to float a LifePo4?
โMay-03-2021 09:14 PM
โMay-03-2021 08:16 PM
time2roll wrote:Great idea! 3-stage: 0/13.2v/14.2v. A totally programmable version (with a zero volt option) would be ideal. I would prefer a 14.6v bulk mode.
Yes looking for a PD lithium that charges to 14.2 and shuts off. When battery hits 13.2 PD should come back on until it holds 14.2 for short duration. No equalization. Or how about adjustable. I would buy one tomorrow.
โMay-03-2021 08:09 PM