Freshening Charge

[outrigger999]

Hello. Can someone here post how exactly to do a freshening charge on the RE200 batteries? Would you use the EQ feature in the inverters to apply the float voltage to the battery string(s) for a 24 hour period? When would you feel it necessary to do this? The manual for the RE200 mention the freshening charge which I believe is designed to accomplish roughly the same thing that equalization would in flooded batteries. Normally you wouldn't use the EQ feature on AGM batteries but perhaps this is the best way to "equilize" the batteries without causing damage to them. Please outline if you could, the steps you'd take and the set of circumstances that would lead to doing a freshening charge.

Thanks!

[Kurt Lundquist]

The manual says run the freshening charge at 14.4-14.8 V for 16 hours with the battery temp sensor (RTS) in place. You should do this when the batteries are commissioned and anytime the batteries sit for more than 3 months without a charge. If the batteries are stored above 77┬░F it would be best to refresh more frequently. Heat is a killer so it would be even better if the batteries are not stored above 77┬░F.

For new systems I set the EQ voltage to the Freshening voltage and then set the EQ time for ~20 hours and enable the EQ cycle (16-24 hours is the acceptable range). If possible (grid tied) it doesn't hurt to run a Float charge for a few days afterwards. If you have OPTICSre setup you can easily go back into the inverter settings after a few days to shut off the float charge (reduce float timer below 24/7 or set to auto depending on your inverter model).

Other than storage of the battery you may want to consider a freshening charge if your system routinely operates at a partial state of charge. For example, if your system does not charge the battery bank to 100% at least once a week you will probably want to do the freshening charge at least once a month. On the other hand, if you charge the batts to 100% almost daily then I would not worry about it.

-Kurt

[outrigger999]

Thank you for the information. Very helpful.

[blackswan555]

Would it be better to use/set absorb voltage for this then reset to normal next day ? ( I am never confident which are and which are not temp compensated on EQ)

Tim

[outrigger999]

How do you execute a freshening charge for 24 hours with power coming from your solar array? I can of course cut off power to my batteries from my solar array power but I cannot really reach my solar array to cover it or somehow disable it from producing power during the day. If I run a freshening charge with my inverters and I use my backup power during this process, how do I prevent any damage from happening since the solar array is still producing power? Will that be an issue? Thanks.

[sodamo]

I have breakers in the combiner box and again before the CC, as long as turned off and no current would flow from the PV to bats would it matter?

[Kurt Lundquist]

How do you execute a freshening charge for 24 hours with power coming from your solar array? I can of course cut off power to my batteries from my solar array power but I cannot really reach my solar array to cover it or somehow disable it from producing power during the day. If I run a freshening charge with my inverters and I use my backup power during this process, how do I prevent any damage from happening since the solar array is still producing power?

The charge controllers will ensure the solar does not harm your batteries as long as you have the proper settings. If the battery voltage exceeds the charge controller target the controller will stop harvesting power from the array.

Regardless, as Sodamo says, it is important to have circuit breakers (or disconnects if you are using fuses) between the PV array and the charge controller input.

-Kurt

[outrigger999]

Sorry folks, perhaps I needed to be more clear. I do have the necessary breakers and disconnects for the solar array. I would disconnect my connection to the solar array, turn on my connection to the power company since they sit in the second position (where the generator would normally sit) and just run the freshening charge voltage on the batteries for 24 hours. I would do all this after they had reached the float stage, so they were known to be full. My question is even if I cut off the power from the array, where does the energy that the array is producing go? The array is installed on a tiled roof and it's delicate to walk on so I couldn't really cover the array while I did this. Do I run a risk of something burning out? My disconnects are below the charge controllers and before the batteries so would the charge controllers just dissipate the energy as heat?

Thanks for the insight in advance.

[Solar Jason]

If you look at a chart for a solar panel, as the voltage gets closer and closer to the open circuit voltage, the panels produce less and less current. So when you reach the open circuit voltage, there is no current flowing and thus no power to dissipate. If you disconnect the connection between the charge controller and the panels, the panels will happily sit at their open circuit voltage.

[outrigger999]

Sweet! Thanks Jason for the info, I did not know that. Just what I was looking for.