LiFePO4 Install
- Thread starter dreadlocks
- Start date
shade
Well-known member
I figured as much, but I wondered if he'd seen a change in temperature between the old & new batteries. Iirc, the old one would get noticeably warm.
shade
Well-known member
I know this is getting OT, but how much heat is usually generated during resistance balancing of a 100Ah battery?
With Battle Born, I don't think there's access to the thermal data available to the BMS, or anything else, for that matter. I hope they have plans to change that aspect of their product. If they bundled a relatively inexpensive, but reliable external BMS with their batteries, they might still undercut the major brands on price and offer a more robust product. Maybe QC isn't good enough yet on cheap BMS modules to make that happen, or they're concerned that offering such a bundle would cast their "drop-in" claims in a bad light.
shade
Well-known member
That earned a chuckle. I think I just released more than that mounting winter tyres.
luthj
Engineer In Residence
It depends on balance and C rate. With a maintenance balance done every few charge cycles, a 100AH battery will probably only need about 20-60 minutes at 200mA or less (for a couple cells). So 200mA x 3.5V x 2 = 1.4W This assumes a charge rate less than 0.2C, and discharge less than 0.5C. EVs that charge at rates of 1C are going to need a lot more balance capacity, otherwise the charge can take a very long time, as the charger needs to throttle back to nearly nothing while the low cells come up.
The balance heat production is not significant in these cases. The real BMS heat produced in drop ins, is from the solid state relay FETs. These often have resistance greater than 20mOhm. When you run 50A+ through a resistor like that, its going produce significant localized heat.
The balance heat production is not significant in these cases. The real BMS heat produced in drop ins, is from the solid state relay FETs. These often have resistance greater than 20mOhm. When you run 50A+ through a resistor like that, its going produce significant localized heat.
dreadlocks
Well-known member
Got an Open Box TDK-Lambda SWS600L-48 PSU for $65, this will be the new charger that I'mna feed into the Solar Controller..
Still got some work to do, but redid alot of the wiring diagram for the next phase of buildout
Still got some work to do, but redid alot of the wiring diagram for the next phase of buildout
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dreadlocks
Well-known member
I'm going to run it into a SmartSolar 100/50, its going to be dual purposed for either the shore charger or the portable solar panel.. as neither will need to be used at the same time.. kill two birds w/one piece of hardware, and then the shore charger will sync charge status w/the fixed roof solar and I get all the nice monitoring, history and customization of charging profiles that victron offers.. I'm going to limit it at 40A output via configuration, which wont run the PSU at full tilt, although its capable of constant current at full duty.. should keep it working a long time running at 80% output where power efficiency is at its highest.
I cant adjust the voltage on my PD, its just 14.6 constant.. I been relying on the Solar mostly but when I run the genset I wanna fill it up faster than this dumb charger will let me, it struggles delivering full output.. and once everything is setup I'll be able to control the chargers on/off state remotely w/my Pi or an over-ride switch.. without the need for an external charge relay..
I got this PSU cuz it was high voltage, had PFC, took global voltage inputs without switches, had remote on/off IO, and most importantly was cheap.. much cheaper than a ProNautic 40A, and the price difference from a SmartSolar 30A to a 50A for the portable panel is still less all said and done.
This seemed like the best option to get me nice Victron Metrics for shore charging in the high current I need.. they dont have any 40A shore chargers.
I cant adjust the voltage on my PD, its just 14.6 constant.. I been relying on the Solar mostly but when I run the genset I wanna fill it up faster than this dumb charger will let me, it struggles delivering full output.. and once everything is setup I'll be able to control the chargers on/off state remotely w/my Pi or an over-ride switch.. without the need for an external charge relay..
I got this PSU cuz it was high voltage, had PFC, took global voltage inputs without switches, had remote on/off IO, and most importantly was cheap.. much cheaper than a ProNautic 40A, and the price difference from a SmartSolar 30A to a 50A for the portable panel is still less all said and done.
This seemed like the best option to get me nice Victron Metrics for shore charging in the high current I need.. they dont have any 40A shore chargers.
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Are you sure that nice MPPT SC will accept PSU input?
Lots don't, and some I hear can get damaged.
There's no harm using a dumb overvolted source for Bulk/CC-only charging, just cut off its upstream source with an adjustable HVC at say 13.9V (depends on the C-rate) and an appropriate relay / contactor switch.
Precision profiles going into CV/Absorb are only needed when benchmarking a SoC meter, testing capacity etc get a good adjustable shore-power PSU or DCDC for that, can be low amps just use after already at 95% with your big CC-only sources.
The key factor is effective current limiting otherwise the LFP will overload the source. I suppose a SC will maybe do the job but seems a bit redneck to me. .
Lots don't, and some I hear can get damaged.
There's no harm using a dumb overvolted source for Bulk/CC-only charging, just cut off its upstream source with an adjustable HVC at say 13.9V (depends on the C-rate) and an appropriate relay / contactor switch.
Precision profiles going into CV/Absorb are only needed when benchmarking a SoC meter, testing capacity etc get a good adjustable shore-power PSU or DCDC for that, can be low amps just use after already at 95% with your big CC-only sources.
The key factor is effective current limiting otherwise the LFP will overload the source. I suppose a SC will maybe do the job but seems a bit redneck to me. .
dreadlocks
Well-known member
Plenty of people have done it just fine w/the Victron, as long as its bigger than the victron is configured for output it wont overload.. but this PSU has a constant current overload, it'll run full tilt if I wanted it too.. it'll do >42A at 14v, I'll have it capped at 40A in SC
Ive tested my existing smart solar, it does quite a good job at limiting current output.. it also has remote voltage sense and battery temp inputs (will stop charging when battery approaches freezing or gets too hot).. I wouldent do this with anything but the victron.. I'm building a custom monitoring/display solution so it'll make that part easier and there's not really much better suited high amp LFP chargers on market than the SmartSolar's.. Their AC chargers are low output, even the new Orion DC chargers are pretty low amps for a LFP setup.. with their 200A LFP now being the smallest they offer, you could chain up 3 of those 30A units in parallel.. thats some money.. would it be better to get a 24v alternator and wire it up to a 100A smart solar at that point? shrug.. seems like it if you could do a dual alt setup
I was always going to use separate SC for the fixed and portables, and now instead of having a dumb CCV @ 14.6v fixed that I have very little control over.. I'll have a completely customizable charger, I can script to behave however I want.. Right now if I want to balance all the cells I have to hold it at 14.6v all day and I dont like that.. I only need to get to 14.2v to start balancing.. I'm not wanting to charge at any voltage higher than 14.2v w/these new set of cells.. and I'll have float voltage ~90% SOC.
Ive tested my existing smart solar, it does quite a good job at limiting current output.. it also has remote voltage sense and battery temp inputs (will stop charging when battery approaches freezing or gets too hot).. I wouldent do this with anything but the victron.. I'm building a custom monitoring/display solution so it'll make that part easier and there's not really much better suited high amp LFP chargers on market than the SmartSolar's.. Their AC chargers are low output, even the new Orion DC chargers are pretty low amps for a LFP setup.. with their 200A LFP now being the smallest they offer, you could chain up 3 of those 30A units in parallel.. thats some money.. would it be better to get a 24v alternator and wire it up to a 100A smart solar at that point? shrug.. seems like it if you could do a dual alt setup
I was always going to use separate SC for the fixed and portables, and now instead of having a dumb CCV @ 14.6v fixed that I have very little control over.. I'll have a completely customizable charger, I can script to behave however I want.. Right now if I want to balance all the cells I have to hold it at 14.6v all day and I dont like that.. I only need to get to 14.2v to start balancing.. I'm not wanting to charge at any voltage higher than 14.2v w/these new set of cells.. and I'll have float voltage ~90% SOC.
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Alrighty then!
If you have time write up a detailed "all charge sources through SmartSolar" thread
perhaps with links to other threads, reference sources etc
and I'll send a bunch of doubting thomas people from other forums to it,
and for sure try it myself when I get a Round Tuit.
If you have time write up a detailed "all charge sources through SmartSolar" thread
perhaps with links to other threads, reference sources etc
and I'll send a bunch of doubting thomas people from other forums to it,
and for sure try it myself when I get a Round Tuit.
shade
Well-known member
I didn't realize Victron was getting out of the sub-200A game.
An alternative to multiple Orion-Tr chargers would be a 50A or 100A buck-boost model. Roughly the same amount of money, though.
I hope your PSU-SC design works.
luthj
Engineer In Residence
Battleborn teardown. The narrator is a bit effusive (he is an affiliate marketer). He seems really surprised that BB under rates the battery to avoid the top and bottom 2% for longevity.
That BMS looks suspiciously similar to a couple Chinese BMS you can buy direct today. Which means, you can probably connect to the UART com port, and change settings (or monitor) if you are willing to cut a rectangle out of the top of the case for access.
Note there is only 1 temp sensor, and its pretty close to the outside of the case, and not the core of the pack.
Vibration resistance is probably not particularly high based on the floating cell groups.
That BMS looks suspiciously similar to a couple Chinese BMS you can buy direct today. Which means, you can probably connect to the UART com port, and change settings (or monitor) if you are willing to cut a rectangle out of the top of the case for access.
Note there is only 1 temp sensor, and its pretty close to the outside of the case, and not the core of the pack.
Vibration resistance is probably not particularly high based on the floating cell groups.
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