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Monday, February 25, 2013

LiFePO4 DIY ESS - CALB Battery Pack First Charge after Bottom Balancing

Friday night, after checking that all the cells were at 2.75V (same as the morning), I started the charge process, screwing the leads of my 300W 24V LiFePO4 charger directly onto the battery pack terminals.

Here are some pictures of the charge steps at different hours: Note the voltage changes and the time on the clock in the back 


I cheked the cells voltages every once in a while and they remained perfectly together all the way 


I stopped the charging during the night for security reasons, and restarted it int he morning


Then I decided to test one of the three small low cost chargers I received this week, clamping the leads onto the battery pack terminals

and AC power, it just starts, with a red led and the small fan cranks up slowly, but remains pretty quiet





and it pushes roughly 100W into the pack




I then tried the two other chargers 

got rid of the US AC plugs and leads connectors

clamped them on the pack terminals in parallel with the 300W charger leads

and hook together the AC side wires and plugged them in using a French AC plug (no earth/ground on these chargers because they are all plastic) 

286W are used when all 3 small chargers are switched on


Now I switched the 300W back on, we are at 605W used and pushed intot the battery pack

Volatge is going up 0.1V






And the target pack voltage is reached at 28V, equals 3.5V per cell, as Jack Rickard recommands in his charging advices and I do not want to stress the new CALB cells for this first charge

Here, the chargers have been switched off, and I started the Grid Tie Mode, and the voltage immediatly drops ... 


This is the amount of energy used to almost fully charged the 8 CALB CA180FI cells

Control Board with all GTI relays closed/on


And this is the generation graph for this first fully charged day

Focus/Zoom on the generation part of the graph

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