Battery - longer standby time

[Analog Revenant]

Hi!

A quesiton for the power experts.

I have a 600w SPS600 inverter trolley which have been my life saver. It runs a few lights, internet, alarm, work station and TV. My deep cycle GEL battery is coming to an end after quite a few years of service.

With the pending worsening of load shedding I'm looking to double my standby time for longer power cuts. I also ordered 400w worth of 12V solar panels that will charge the batteries during the day (inverter has built in 12V solar charger)

So my thinking was to order 2 x deep cycle GEL batteries and connect them in parallel, which should give me almost double the standby time. This would cost me R6500 for the two GEL batteries (12V 100Ah).

The other option is to go with a drop-in Lithium (LiFePo4 12V 100Ah) , but I would only be able to afford 1 @ R8000.

I do understand that the GEL batteries have a shorter time span, and less cycles. But looking at how my previous battery lasted since 2019, the GEL batteries does not seem to be that bad. Especially looking at the cost.

So giving my need for longer standby time, does it make more sense to go with the 2 x GELs? Any thoughts on this?

Thanks in advance

 

[derp90]

By standby time, do you mean time you use the battery for to get you through loadshedding? Won't it just be annoying to get GEL batteries and then they deplete in capacity faster?

As a side note, how loud is the fan on your unit? Does the fan start up regulary when it's fully charged and on Eskom supply?

 

[leon.davibe]

I would always go lithium

Can get lithiums cheaper ask @wingnut771 to hook you up if they have stock

ie you get more bang for buck as no peukert losses on lithium

My 2c

Edit
And you won't need to buy again in a few years

 

[Analog Revenant]

By standby time, do you mean time you use the battery for to get you through loadshedding? Won't it just be annoying to get GEL batteries and then they deplete in capacity faster?

As a side note, how loud is the fan on your unit? Does the fan start up regulary when it's fully charged and on Eskom supply?

yes, sorry - I meant battery usage time. I've been surprised at my previous GEL battery - it really was a workhorse. Looking at the costs, lithium is k@k expensive though, so yeah. Depends on what the single Lithium can get, but I assume not much more usage time vs the GEL both being 100Ah. But I'm no expert - so hence asking here..

Fan on the SPS600 is loud hey! My unit is installed in the garage, and I have dedicated wiring from the unit to dedicated UPS plugs in the house. I could not stand that noise in the house

 

[Tomtomtom]

Lead acid can last a long time if depth of discharge is low. Typically you see max recommended DoD of 50% but if you have successfully run yours for 3+ years then your DoD is/was probably < 30% or so in practice. That said most of the damage was probably done in the last 6 months.

LiFePO4 is much less sensitive to DoD so even at 80% cycles it outlasts lead at say 30%.

So 2x 12V 100 Ah lead acid = 2400 Wh, but at 30% "safe" DoD => 960 Wh effective.
This is maybe just about equivalent to 1200 Wh lithium (at 80% DoD).

I would probably pay the extra R 1 500 for LiFePO4 and this whole forum would agree I think - but it's also not completely unreasonable to go with oversized lead acid.

Especially since you survived 3+ years on the last one. It's the devil you know. Just don't substantially increase the load.

 

[Analog Revenant]

Lead acid can last a long time if depth of discharge is low. Typically you see max recommended DoD of 50% but if you have successfully run yours for 3+ years then your DoD is/was probably < 30% or so in practice. That said most of the damage was probably done in the last 6 months.

LiFePO4 is much less sensitive to DoD so even at 80% cycles it outlasts lead at say 30%.

So 2x 12V 100 Ah lead acid = 2400 Wh, but at 30% "safe" DoD => 960 Wh effective.
This is maybe just about equivalent to 1200 Wh lithium (at 80% DoD).

I would probably pay the extra R 1 500 for LiFePO4 and this whole forum would agree I think - but it's also not completely unreasonable to go with oversized lead acid.

Especially since you survived 3+ years on the last one. It's the devil you know. Just don't substantially increase the load.

thanks tripple-T, valuable info!

 

[derp90]

Was it expensive to wire the unit from the garage to dedicated plugs? I'm running an MPSG 1000 next to the TV, and it is supposed to be quiet, but the fan is on 24/7 and gets on my nerves. Sounds like a moderately noisy PC. I'm looking to either replace the fan with something quieter or make another plan.

 

[Pineapple Smurf]

If you look after those gel batteries you can get many years life out of them, especially when you are now going to double up on capacity
I had 2 old 2nd hand truck batteries (105aH) donated to me long time ago
I ran them for 6 years and they were always on 12.6 volts when loadshedding ended

I only ran bare basics on them to get the most life

So yeah lithium is the way to go but if you are not going to punish your load then go with the gels

 

[wingnut771]

Hi!

A quesiton for the power experts.

I have a 600w SPS600 inverter trolley which have been my life saver. It runs a few lights, internet, alarm, work station and TV. My deep cycle GEL battery is coming to an end after quite a few years of service.

With the pending worsening of load shedding I'm looking to double my standby time for longer power cuts. I also ordered 400w worth of 12V solar panels that will charge the batteries during the day (inverter has built in 12V solar charger)

So my thinking was to order 2 x deep cycle GEL batteries and connect them in parallel, which should give me almost double the standby time. This would cost me R6500 for the two GEL batteries (12V 100Ah).

The other option is to go with a drop-in Lithium (LiFePo4 12V 100Ah) , but I would only be able to afford 1 @ R8000.

I do understand that the GEL batteries have a shorter time span, and less cycles. But looking at how my previous battery lasted since 2019, the GEL batteries does not seem to be that bad. Especially looking at the cost.

So giving my need for longer standby time, does it make more sense to go with the 2 x GELs? Any thoughts on this?

Thanks in advance

1 x LFP is like having 2 to 3 times gel depending on load (peukert (gel capacity is measured over 10 hours)).
LFP will last 10+ years, gel (LA) is a lucky packet.

My 2c.

 

[Analog Revenant]

Was it expensive to wire the unit from the garage to dedicated plugs? I'm running an MPSG 1000 next to the TV, and it is supposed to be quiet, but the fan is on 24/7 and gets on my nerves. Sounds like a moderately noisy PC. I'm looking to either replace the fan with something quieter or make another plan.

The electrical cable itself was the most expensive - I think I paid around R1500 in total. But it solved my issue, and relatively straight forward - it's not going through the house DB, it's a small UPS network by itself.

 

[Analog Revenant]

1 x LFP is like having 2 to 3 times gel depending on load (peukert (gel capacity is measured over 10 hours)).
LFP will last 10+ years, gel (LA) is a lucky packet.

My 2c.

awesome, thanks for the info

 

[Analog Revenant]

If you look after those gel batteries you can get many years life out of them, especially when you are now going to double up on capacity
I had 2 old 2nd hand truck batteries (105aH) donated to me long time ago
I ran them for 6 years and they were always on 12.6 volts when loadshedding ended

I only ran bare basics on them to get the most life

So yeah lithium is the way to go but if you are not going to punish your load then go with the gels

shot thanks, and yeah that's true hey - difficult to make the decision though

 

[derp90]

The electrical cable itself was the most expensive - I think I paid around R1500 in total. But it solved my issue, and relatively straight forward - it's not going through the house DB, it's a small UPS network by itself.

So it's a physical cable that goes into your house with a plug on the end, not one of your house wall plugs?

 

[Pineapple Smurf]

shot thanks, and yeah that's true hey - difficult to make the decision though

Yup
I was cruising on around 80 watts to 130 watts depending on the load
6 years for 2nd hand batteries that were free
No complaints

 

[wingnut771]

Yup
I was cruising on around 80 watts to 130 watts depending on the load
6 years for 2nd hand batteries that were free
No complaints

No stage 6 (8) LS either back then and had plenty of time to recharge.

 

[Pineapple Smurf]

No stage 6 (8) LS either back then and had plenty of time to recharge.

True
But then again charging was quick as each battery never ever once dipped below 12.6 volts at any time

 

[wingnut771]

True
But then again charging was quick as each battery never ever once dipped below 12.6 volts at any time

So you were cycling them to 10% DOD. Of course they would last. These days it’s a lucky packet if the power even comes back after LS. Then those LA take a real beating and need 2 days to recover if ever.

 

[Pineapple Smurf]

So you were cycling them to 10% DOD. Of course they would last. These days it’s a lucky packet if the power even comes back after LS. Then those LA take a real beating and need 2 days to recover if ever.

Yup, I nurtured those lead acids very nicely

 

[Pineapple Smurf]

Happy Battery Happy Life
Kinda like you married people
Happy Wife Happy Life

 

[Analog Revenant]

So it's a physical cable that goes into your house with a plug on the end, not one of your house wall plugs?

yes, basically a glorified extension cable. The cable runs in PVC pipes from the inverter through the roof until a new installed socket on the wall. Basically it's a wall socket mounted on an external box on the wall. I have two such wall plugs.

The cable daisy chains back through the PVC from the first to the second plug. And then they are clearly marked as UPS.
It's the same concept as installing the old red wall plugs in big offices that was connected to UPSs. I've done quite a few installs when I was still a systems admin.