L/Battery - go large or go lithium?
- Thread starter Chris1983
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- dc - dc charger victron vsr
What is that a picture of?
Worktop
Ouch.
I guess maybe one of the resin repair kits for kitchen worktops maybe.
I won’t even ask how your seat base ended up on the worktop!
I guess maybe one of the resin repair kits for kitchen worktops maybe.
I won’t even ask how your seat base ended up on the worktop!
No, because 13.4v isn't 100% charge. Your shunt is reading incorrectly.
Did you set the correct settings on your shunt?
Did you set the correct settings on your shunt?
Yep that looks good, but set the "battery SOC on reset" to "Keep SOC". Now check the battery BMS SOC and manually set the shunt SOC to that. Then the next time it's actually fully charged (14.2v) it should sync to 100%.
Changed that, but this is what the fogstar has as info, 99%. But not 14.2v?
Tbh it's probably not far off, but remember the fogstar BMS doesn't read anything under 1a.
However, 13.4v is very close to fully charged, you'll see the voltage very quickly rise to 14.2v if you've got a charge coming in. 98% to 100% is 13.5v to 14.2v (roughly).
However, 13.4v is very close to fully charged, you'll see the voltage very quickly rise to 14.2v if you've got a charge coming in. 98% to 100% is 13.5v to 14.2v (roughly).
Where are you getting those voltages from? The recommended charging voltages for fogstar drift batteries are 14.2v in bulk and 13.6v in float - i.e the other way around from what you're quoting there. This is common with most multistage charging configurations, the voltage is higher in bulk charge and then backs off in float when the battery is essentially fully charged.
Yes, the voltage in bulk charge phase will rise slowly to about 13.5v at about 98% SOC then rapidly to 14.2v at 100%, then when the MPPT goes into float mode it'll drop down to 13.5v.
14.2v is the fully charged voltage.
The bulk charge is never 14.2v throughout the bulk stage, if that's what you mean? Although I don't think you do.
See here in my system:
Yes, no indication at all that you have a problem. Maybe just check tomorrow when it's had a day of sun to see if the charger is reporting making it into float.
It’s fine. Just use it and let it do its business and all settle down. You’ll then build up some data to analyse its performance.
Yep, so with the DC-DC and the MPPT they both get the battery voltage to 14.2v which is 100% charge, but the DC-DC as it's normally operating at a higher output which will be sending a higher voltage to the battery. So you might see higher voltage at the battery at the same state of change, depending what's charging the battery. But at the end of the day the only voltages that matter are 14.2v, which is fully charged, and 13.5v AFTER 14.2v which is the battery being kept at 100% charge.
Using voltages to determine the state of charge of LifePO4 is very hard as a charge or draw will alter it, and there's not much voltage difference between 30 and 80% charge - about 0.3v. That's why we have shunts that measure exactly the state of charge by counting in and out every single milliamp.
As the guys above have said, you're all good - and once you've had a full charge the shunt should then sync to 100% meaning it'll be accurate in it's SOC.
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