So after todays crash of the forum i was able to retrieve some information that got lost from the google cache concerning this thread:
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ozz93666 Online
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#5 1 hour ago (This post was last modified: 1 hour ago by ozz93666.)
There is also the question of efficiency of charging .... the quicker you charge the more will be wasted in heat ...
It all depends on the internal resistance of the pack ... at a rough guess charging at 1C that's 1hr for a complete recharge 10% of input might be lost in heat ...
charging at 1/10th C ... that's 10 hrs for a complete recharge perhaps about 1% is lost
This is due to I squared R loss inside the cell , in the example above the current is one tenth ... square that and you get one hundredth ...so the rate of power loss is one hundredth at 1/10C compared to C ... but since you charge ten times longer at 1/10C the overall reduction in energy loss is ten times
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Robert Baumer Online
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#6 58 minutes ago
(1 hour ago)ozz93666 Wrote:
There is also the question of efficiency of charging .... the quicker you charge the more will be wasted in heat ...
It all depends on the internal resistance of the pack ... at a rough guess charging at 1C that's 1hr for a complete recharge 10% of input might be lost in heat ...
charging at 1/10th C ... that's 10 hrs for a complete recharge perhaps about 1% is lost
Very good point.... and I am not sure that much heat would be a enemy to your packs. I noticed that my charge backs off on the charge when the batteries get too warm which extends charging time. I would say that while the 1000 setting would be the preferred, 200 would be the safest and easier on your cells.
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ozz93666 Online
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#7 49 minutes ago
(58 minutes ago)Robert Baumer Wrote:
(1 hour ago)ozz93666 Wrote:
There is also the question of efficiency of charging .... the quicker you charge the more will be wasted in heat ...
It all depends on the internal resistance of the pack ... at a rough guess charging at 1C that's 1hr for a complete recharge 10% of input might be lost in heat ...
charging at 1/10th C ... that's 10 hrs for a complete recharge perhaps about 1% is lost
Very good point.... and I am not sure that much heat would be a enemy to your packs. I noticed that my charge backs off on the charge when the batteries get too warm which extends charging time. I would say that while the 1000 setting would be the preferred, 200 would be the safest and easier on your cells.
I think that backing off (on your opus?) is due to getting near the end of charge ...the opus has no temperature censor.... it goes into trickle mode ... in normal circumstances temperature should not be an issue , cells can handle up to 60*c with no problem .. that's too hot to touch!!! ... being warm to the touch if not an issue.
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daromer Online
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#8 48 minutes ago (This post was last modified: 45 minutes ago by daromer.)
ozz93666: The Opus have 1 sensor per cell just under the cell. If or how its used i cannot tell though but the sensors are there Smile
I put in 150A easily currently and when rest of panels is up a bit above 200A. BUT... I have a huge bank so per cell this is nothing.
With my curent solar panel setup (17kw) it would take 1 FULL day of sunlight to charge it.. but more realistic is 2 days of charge. Currently my nightly useage takes 3-4 hours to charge back up again. (Will go faster when the added panels are there)
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Current: 10kW Mpp Hybrid | 4kW PIP4048 | 57kWh LiFePo4 | 40*260W Poly
Upcomming: PCM60X Charger | 28*260w | 14S 18650~30kWh | LiFeP04 18kWh Smile
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ozz93666 Online
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#9 15 minutes ago
(48 minutes ago)daromer Wrote:
ozz93666: The Opus have 1 sensor per cell just under the cell. If or how its used i cannot tell though but the sensors are there Smile
Ooooppps I stand corrected ...consulting the manual I see it says it cuts out at 60*c this would never be used in normal usage ...
@ 60*C you cannot put your finger on the cell without pulling away .. it feels very hot ,and 60*C is still within the manufacturers working limit ...
I think you agree the backing off of charge current is when opus goes into trickle mode near the end of charge ...nothing to do with warm cell (about 40*C)
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continues with Comment now at #5 (Korishan)