MorganCarey
New Member
- Joined
- Jul 19, 2020
- Messages
- 49
OK, so I don't have a HUGE amount of experience building battery banks but this is a pretty basic question as it relates to SLA batteries.
For context, I have built a DIY LiFePO4 24V battery. I top balanced all cells in parallel as per all diy writeups. The concept makes sense to me. I can see the difference in my BMS stats for each cell if any get out of balance.
The simple question is... is this balancing required for SLA batteries that are to be wired in series?
If you're interested in the debate keep reading:
I have a new position at work in the telecom sector. I was previously a line-man of sorts, but I've moved into a new role that finds me responsible for switching equipment maintenance in the telecom network. Part of this is testing and maintenance of battery strings. We use SLA batteries on our terminals. They are 48V strings made up of 12V SLA batteries wired in series.
These batteries are charged and topped up by rectifiers that run off mains. There is NO battery balancing mechanism in play, nor any conditioning cycles. These are straight 48V rectifiers. Target voltage is approximately 52V.
The batteries will on occasion be discharged to below 50% during power outages. I believe critical equipment shutdown happens around 42 volts. They absolutely do hit this depth of discharge easily a few times a year as these machine are located in rural areas where the hydro grid is susceptible to storm damage with extended outages.
OK, if you're still with me, thanks for sticking around...
The debate:
Recently I identified an issue with a battery in an existing string. It had shorted itself. Policy now as the budgets shrink is to replace the single battery in the string.
Again, I'm new to the position, but basically I was going to bring all the batteries back to the office and balance charge them along with the new cell over night. My mentor said I'm crazy and that's not required. I asked, well should we at least charge the replacement battery first before adding it back to the string in production (it had been sitting on a shelf for who knows how long at our supplier). His reply was basically no, and that the batteries will self balance while they are wired in series and hooked up to the rectifier.
This doesn't sound right to me. If they were Lithium batteries this would definitely be wrong, but these are SLA and I don't have a ton of experience here with SLAs wired in series.
What say you guys?
For context, I have built a DIY LiFePO4 24V battery. I top balanced all cells in parallel as per all diy writeups. The concept makes sense to me. I can see the difference in my BMS stats for each cell if any get out of balance.
The simple question is... is this balancing required for SLA batteries that are to be wired in series?
If you're interested in the debate keep reading:
I have a new position at work in the telecom sector. I was previously a line-man of sorts, but I've moved into a new role that finds me responsible for switching equipment maintenance in the telecom network. Part of this is testing and maintenance of battery strings. We use SLA batteries on our terminals. They are 48V strings made up of 12V SLA batteries wired in series.
These batteries are charged and topped up by rectifiers that run off mains. There is NO battery balancing mechanism in play, nor any conditioning cycles. These are straight 48V rectifiers. Target voltage is approximately 52V.
The batteries will on occasion be discharged to below 50% during power outages. I believe critical equipment shutdown happens around 42 volts. They absolutely do hit this depth of discharge easily a few times a year as these machine are located in rural areas where the hydro grid is susceptible to storm damage with extended outages.
OK, if you're still with me, thanks for sticking around...
The debate:
Recently I identified an issue with a battery in an existing string. It had shorted itself. Policy now as the budgets shrink is to replace the single battery in the string.
Again, I'm new to the position, but basically I was going to bring all the batteries back to the office and balance charge them along with the new cell over night. My mentor said I'm crazy and that's not required. I asked, well should we at least charge the replacement battery first before adding it back to the string in production (it had been sitting on a shelf for who knows how long at our supplier). His reply was basically no, and that the batteries will self balance while they are wired in series and hooked up to the rectifier.
This doesn't sound right to me. If they were Lithium batteries this would definitely be wrong, but these are SLA and I don't have a ton of experience here with SLAs wired in series.
What say you guys?