althemusicwizard
New Member
- Joined
- Jun 10, 2021
- Messages
- 63
Hi guys,
As we head into winter in the UK, I've decided to replace the huge lead-acid battery bank I installed nine months ago for a MASON 280L 15kWh battery bank containing Grade B Envision 304Ah prismatic cells. Fogstar, in the UK are offering the 'build your own battery' for £1999, which is about the best price I've ever seen. The two main reasons for changing the bank are size (the new bank will be tiny in comparison) and the ability of lithium to sit at charge rates of 80-30% without suffering sulphation. I'm currently charging all of the batteries individually (they are 230Ah 12V Varta sealed batteries) and having charged two of them and then discharged them (at a C rating of about C15) have found that before charging them, the batteries were probably around 70% full. It seems the settings of my Iconica solar inverters (each able to handle 6000W at Voltages between 150-450V - my arrays are around 375V on average) have probably been set too low on the absorption time side of things. The result was, as we head into winter and the sun is no longer around for very long, the voltage on the bank was heading lower and lower. First impressions after charging a few batteries individually seem promising.
I based the size of the lead-acid bank around the calculation that we probably use around 15kWh per day. A 92kWh bank therefore could provide two days energy at about a 70% depletion rate, and then be charged back up by solar or the grid. The difficulty is of course, knowing where the actual bank is at any one time. A battery monitor helps, but is only a rough guide to the state of the bank. As the bank depletes and refills, any lack of refilling (due to the absorption rate not being long enough, or the fluctuating temperature of the batteries) means that after nine months of use, the balancing between batteries is going to be off. I'm not sure how successful buying separate balancers for each battery would have been, but I think they were about £40. I only paid £100 for each battery so that seemed too expensive to me. As it is, each battery as scrap is worth £20, and possibly as much as almost £70 if I strip them down myself (and if the scrap-yard then takes the lead). It would seem a shame to do this, because in a smaller bank, say 8-16 batteries per bank, they would probably be easier to maintain.
At the initial outset, I had a 9.5kW electric shower (consuming around 200A) but this summer this has been replaced with a 200L unvented cylinder, removing the need for such a large power draw. This can be heated via solar (it's worked great between April and September) and now heading into winter can be set to come on at night for cheap electricity.
So my question (sorry for the long preamble) is:
1. My Iconica inverters (3 running in parallel) don't seem to offer any setting for LiFePO4 batteries. They have settings for USER that list charge rates for onset voltage from grid, absorption rate of charge and length, float charge rate. Here's the manual with the settings starting at Pg13
Will the Mason BMS handle all of this out by itself?
Thanks for any help offered.
As we head into winter in the UK, I've decided to replace the huge lead-acid battery bank I installed nine months ago for a MASON 280L 15kWh battery bank containing Grade B Envision 304Ah prismatic cells. Fogstar, in the UK are offering the 'build your own battery' for £1999, which is about the best price I've ever seen. The two main reasons for changing the bank are size (the new bank will be tiny in comparison) and the ability of lithium to sit at charge rates of 80-30% without suffering sulphation. I'm currently charging all of the batteries individually (they are 230Ah 12V Varta sealed batteries) and having charged two of them and then discharged them (at a C rating of about C15) have found that before charging them, the batteries were probably around 70% full. It seems the settings of my Iconica solar inverters (each able to handle 6000W at Voltages between 150-450V - my arrays are around 375V on average) have probably been set too low on the absorption time side of things. The result was, as we head into winter and the sun is no longer around for very long, the voltage on the bank was heading lower and lower. First impressions after charging a few batteries individually seem promising.
I based the size of the lead-acid bank around the calculation that we probably use around 15kWh per day. A 92kWh bank therefore could provide two days energy at about a 70% depletion rate, and then be charged back up by solar or the grid. The difficulty is of course, knowing where the actual bank is at any one time. A battery monitor helps, but is only a rough guide to the state of the bank. As the bank depletes and refills, any lack of refilling (due to the absorption rate not being long enough, or the fluctuating temperature of the batteries) means that after nine months of use, the balancing between batteries is going to be off. I'm not sure how successful buying separate balancers for each battery would have been, but I think they were about £40. I only paid £100 for each battery so that seemed too expensive to me. As it is, each battery as scrap is worth £20, and possibly as much as almost £70 if I strip them down myself (and if the scrap-yard then takes the lead). It would seem a shame to do this, because in a smaller bank, say 8-16 batteries per bank, they would probably be easier to maintain.
At the initial outset, I had a 9.5kW electric shower (consuming around 200A) but this summer this has been replaced with a 200L unvented cylinder, removing the need for such a large power draw. This can be heated via solar (it's worked great between April and September) and now heading into winter can be set to come on at night for cheap electricity.
So my question (sorry for the long preamble) is:
1. My Iconica inverters (3 running in parallel) don't seem to offer any setting for LiFePO4 batteries. They have settings for USER that list charge rates for onset voltage from grid, absorption rate of charge and length, float charge rate. Here's the manual with the settings starting at Pg13
Will the Mason BMS handle all of this out by itself?
Thanks for any help offered.
