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- #21
Non-traditional DC power system build (2 Viewers)
- Thread starter tincan45
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- Thread starter
- #23
Load testing and charging time!
I have had the fridge in for a couple days with the vehicle parked and 90+ temps and direct sun. Even in these conditions I'm averaging around 20ah per day consumption. I had to run across town to grab some supplies and in a 20 mile run I was almost fully charged again. These headway cells just suck up the power with over 300W input the entire time. I'm extremely satisfied with these numbers. I don't think I will ever need solar except for maybe a couple of very small panels for maintenance over long periods of sitting.
I have had the fridge in for a couple days with the vehicle parked and 90+ temps and direct sun. Even in these conditions I'm averaging around 20ah per day consumption. I had to run across town to grab some supplies and in a 20 mile run I was almost fully charged again. These headway cells just suck up the power with over 300W input the entire time. I'm extremely satisfied with these numbers. I don't think I will ever need solar except for maybe a couple of very small panels for maintenance over long periods of sitting.
Those batteries will suck up just about what ever you throw at them because of the low internal resistance. So you are managing the high and low voltage cutoffs through the charge controller and battery protect? What voltage do you have them set to?
When you say cheap Chinese BMS causing fires, which ones are you referring to? The $20 ones? I will most likely get the Overkill Solar BMS. Still Chinese and MOSFET based, but better quality and the guy does some additional testing and quality control.
When you say cheap Chinese BMS causing fires, which ones are you referring to? The $20 ones? I will most likely get the Overkill Solar BMS. Still Chinese and MOSFET based, but better quality and the guy does some additional testing and quality control.
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- #25
14.2 for charging. The victron will switch from CC to CV at about 13.9 volts. It's very configurable. Not to mention, the headway profile allows 5C (40A per cell) for charging so I could (in theory) throw 480 amps into this battery at once for a rapid charge. I'm fine with 25 amps!
12V (3.0 cell voltage) on the battery protect for low voltage (Option 8 in programming)
They settle down to 3.3-3.4 (13.2-13.4) pretty quickly. I've had these cells in some form of a build for a couple years so I'm pretty familiar with them now. I've run BMS (good and bad ones), but the BMS wastes a lot of energy trying to keep them within .1 volt of each other. These headway cells also seem to self balance if you let them do their thing, but they do bounce around +/- .2-.3 volts. If you look at the guys who run these on e-bikes in crazy 8S-16S configurations, most of them end up ditching the BMS as well.
I found a couple pics during the build...
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- #26
Hi Folks,
Because I no longer daily drive the LX, I finally drained my battery. It finally shut down after 9 days w/o driving and almost exactly one full year of continuous use. I figured this would be a good time for an update.
On paper my battery is 96ah. Full discharge showed 109ah. It's good to know I have a little extra in the tank if need be, but I think I'm going to raise my cut-off voltage a little because, for reasons I don't understand, it tripped my charging breaker when it got to cut-off voltage. I had to reset the charging breaker in order for the DC/DC to starting charging again. Perhaps someone here can help me understand why this happened. 60amp circuit on a 25amp charging circuit should be plenty of headroom unless the voltage disconnect shorts the load side when it turns off?
At any rate, it's nice to report an almost problem free experience with this setup. Here's a screenshot of the battery state when I got in to drive this AM (after resetting the breaker).
Because I no longer daily drive the LX, I finally drained my battery. It finally shut down after 9 days w/o driving and almost exactly one full year of continuous use. I figured this would be a good time for an update.
On paper my battery is 96ah. Full discharge showed 109ah. It's good to know I have a little extra in the tank if need be, but I think I'm going to raise my cut-off voltage a little because, for reasons I don't understand, it tripped my charging breaker when it got to cut-off voltage. I had to reset the charging breaker in order for the DC/DC to starting charging again. Perhaps someone here can help me understand why this happened. 60amp circuit on a 25amp charging circuit should be plenty of headroom unless the voltage disconnect shorts the load side when it turns off?
At any rate, it's nice to report an almost problem free experience with this setup. Here's a screenshot of the battery state when I got in to drive this AM (after resetting the breaker).
