Loadshedding solutions

[Hairy]

On 3/4/2023 at 11:26 AM, PhilipV said:

I'll take a stab. 

The 20a inverter can only charge at 20, wether it's into a lithium or a SLA battery. So in 4hrs of charging it will put back 80s, irrespective o wether it's into 100aH LiPo or 200aH SLA. 

Now here is where my knowledge gets shaky, but Lithium batteries charge at a different profile and higher volts than SLA, so an inverter originally specced for SLA won't be charging the Li optimally or even correctly, possibly damaging it? I think the salesman is talking porky pies. But you'll need to do some research on it. 

Methinks you are asking too much of your system. 

Left fuels idea:

Buy the 100aH battery, and add a solar panel and solar charger to it, that way when it's loadshedding the battery is charging and solar can even carry the load. 

Thanks

just got a quote for this solution

[-cK-]

Loving the zero Eskom import the last 3 days since my upgrade...

Also busy with intergrating the inveter sensors to HA now that I've found a solution to pulling in the sensor data so I can use it as parameters for my other smart devices like my geyser switch.  Ultimatly want to drop the geyser on essential supply and just set some parameters to ensure if it is loadshedding and there is enough SOC and PV the geyser can be turned on despite it being loadshedding and only if it is a 💩 day and the SOC and PV is to low wait for Eskom before turning it one...

[i24]

On 2/27/2023 at 6:45 PM, Hairy said:

 If one looks at going larger with the LA battery at 200Ah, you are at the same price as a 100Ah battery, with double the energy capacity where in theory after a long discharge would still leave a reasonable % of charge in the battery which hopefully will help with it’s life span. The Li though will charge up very quickly and more efficiently, and be ready for the next stage of load shedding.

 

1^st prize (Following alternative confirmation that it can charge Li) would be the 100Ah Li battery.

2^nd, the 200Ah LA battery … given the price, you may as well go Li 100Ah

3^rd , would be the 100Ah LA battery.

I have not checked if anybody else replied to this. But I have a 24V 3kVA, "non Li compatible" inverter at home. I have 4 100Ah lead acid batteries on it. It was sized for 2 100Ah batteries but I had 2 more used ones on hand so wired the 2nd pair in parallel. Our load is modest, just computers, TV and LED lights (120W to 250W). I have had no problems over about 5 months of heavy load shedding. Doubling the batteries in parallel allows, more capacity, lower depth of discharge and faster recharge. I have also set the cut off voltage to be about 40% of LA discharge to protect the batteries but we have never got it that low.

In the office we have UPS systems, also running on Lead Acid, These have been around for 10 years or more. We have got up to 7 years on a set of batteries - but we also have a diesel generator so the batteries do not have a hard life.

I looked at buying Lithium batteries for the last UPS replacements. But the 100Ah "LA Compatible" Lithium batteries were actually "2nd life" (ie 2nd hand) and more expensive than a new dedicated Li 48V unit.  The modern kit has smart comms between the battery and the inverter, this can optimise the charge cycle and battery protection. The old LA inverters and UPS's only measure the battery voltage and adjust charge behaviour to that. I suspect this does not allow full use of the available capacity of Li batteries. Also the LA charger's max voltage might not be enough to reach 100% charge in LI batteries. Maybe someone who has experience with "LA compatible Li" batteries on old generation inverters can comment.

As a rule of thumb, measure your load and estimate your required battery capacity. Then double the capacity. And if your using lead acid, double it again.

Get a gas stove for the kitchen and solar for the hot water. Use utility power for the rest of the kitchen and hot water. Also in the garage and for "hot" appliances like hair dryers. This allows 85% family convenience without spending many R100 000's.

I am not convinced that solar panels are cost effective verses a pure inverter setup (but this will change). My experience with solar geysers is that available solar energy drops off from the beginning of May to the end of August.

[Hairy]

35 minutes ago, i24 said:

I have not checked if anybody else replied to this. But I have a 24V 3kVA, "non Li compatible" inverter at home. I have 4 100Ah lead acid batteries on it. It was sized for 2 100Ah batteries but I had 2 more used ones on hand so wired the 2nd pair in parallel. Our load is modest, just computers, TV and LED lights (120W to 250W). I have had no problems over about 5 months of heavy load shedding. Doubling the batteries in parallel allows, more capacity, lower depth of discharge and faster recharge. I have also set the cut off voltage to be about 40% of LA discharge to protect the batteries but we have never got it that low.

In the office we have UPS systems, also running on Lead Acid, These have been around for 10 years or more. We have got up to 7 years on a set of batteries - but we also have a diesel generator so the batteries do not have a hard life.

I looked at buying Lithium batteries for the last UPS replacements. But the 100Ah "LA Compatible" Lithium batteries were actually "2nd life" (ie 2nd hand) and more expensive than a new dedicated Li 48V unit.  The modern kit has smart comms between the battery and the inverter, this can optimise the charge cycle and battery protection. The old LA inverters and UPS's only measure the battery voltage and adjust charge behaviour to that. I suspect this does not allow full use of the available capacity of Li batteries. Also the LA charger's max voltage might not be enough to reach 100% charge in LI batteries. Maybe someone who has experience with "LA compatible Li" batteries on old generation inverters can comment.

As a rule of thumb, measure your load and estimate your required battery capacity. Then double the capacity. And if your using lead acid, double it again.

Get a gas stove for the kitchen and solar for the hot water. Use utility power for the rest of the kitchen and hot water. Also in the garage and for "hot" appliances like hair dryers. This allows 85% family convenience without spending many R100 000's.

I am not convinced that solar panels are cost effective verses a pure inverter setup (but this will change). My experience with solar geysers is that available solar energy drops off from the beginning of May to the end of August.

Thank you for the detailed response.

 

As it currently stands I have an option from ACDC on a 200ah Li battery with a compatible 1000W inverter for around the 16K mark inc VAT, and then the co. that I got the LA solution from before, are looking to swap out our 600W LA inverter for a 1000W Li inverter and then couple this to a 200ah Li battery ... final pricing expected today for this solution.

[fanievb]

On 3/12/2023 at 9:44 PM, -cK- said:

Loving the zero Eskom import the last 3 days since my upgrade...

Also busy with intergrating the inveter sensors to HA now that I've found a solution to pulling in the sensor data so I can use it as parameters for my other smart devices like my geyser switch.  Ultimatly want to drop the geyser on essential supply and just set some parameters to ensure if it is loadshedding and there is enough SOC and PV the geyser can be turned on despite it being loadshedding and only if it is a 💩 day and the SOC and PV is to low wait for Eskom before turning it one...

 

What's your grid trickle feed setting? Installer told me to keep it at 30, so I'll never have zero import, unless there's loadshedding/outage

[i24]

3 minutes ago, Hairy said:

200ah Li battery with a compatible 1000W inverter for around the 16K mark inc VAT,

That sounds like very good value for your spend. This should keep a home office, TV and some LED lights going.

Next gotcha's

• Do you plan on wiring it into your DB board? Very convenient, but requires careful planning as to which circuits run off the inverter and what gets plugged into them. Budget up to ~R10 000.
• Check the noise specs for the inverter fans. Ours can get noisy, but fortunately it is quite far away from our bedroom.

[Hairy]

6 minutes ago, i24 said:

That sounds like very good value for your spend. This should keep a home office, TV and some LED lights going.

Next gotcha's

• Do you plan on wiring it into your DB board? Very convenient, but requires careful planning as to which circuits run off the inverter and what gets plugged into them. Budget up to ~R10 000.
• Check the noise specs for the inverter fans. Ours can get noisy, but fortunately it is quite far away from our bedroom.

This will just be to run my work station, internet and a desk lamp with no need to tie it into the house wiring.

Fan noise ... certainly not even a boeing 747 can be noisier than our current 600W inverter.....We are on the other side of the house, and just close our bedroom door now.

[i24]

On 3/4/2023 at 11:26 AM, PhilipV said:

I'll take a stab. 

The 20a inverter can only charge at 20, wether it's into a lithium or a SLA battery. So in 4hrs of charging it will put back 80s, irrespective o wether it's into 100aH LiPo or 200aH SLA.

It is not that simple. Our Lead Acid compatible inverter has 3 cycle of charging:

• Initially max current (Ie the nominal 20A).
• Then at "bulk" charge, constant voltage (14.1V) until the charge current drops to about 20%.
• Then "float" charge, constant voltage (13.5V).

So if you double your Ah capacity the charger will spend longer in the 1st and 2nd cycles. Net result you get more Ah into your system in less time.

The real problem with LA is that the max current charge time is limited and the actual time to fully charge them is much longer.

A dedicated Li charger will charge at constant current with 14.5V, or higher voltage, until the battery is 80% full, then back off to a float charge.

 

[-cK-]

23 minutes ago, fanievb said:

 

What's your grid trickle feed setting? Installer told me to keep it at 30, so I'll never have zero import, unless there's loadshedding/outage

I set mine to 0 as it was at 20w.  I asked the installer why and the reason was primarily if you have a Pre Paid meter it helps prevent the thing going into tamper mode so they tend to just set it at 20w by default.  Seeing as I don't have one we just set it to 0 as a test and well it works for me. I have not had an issue with it set to 0.  No trickle feed nor feedback to grid as it set to Zero Export.

As you stated if that is set to anything more than 0 you will never have Zero Export.  20w would mean 14units per month minimum on my account. 

I'm at that point that if Eskom can't provide constant power why should I pay them anything for nothing 🤷‍♂️

 

Oh and I also made sure with our Municipality I won't get nailed with some silly charge if my usage is 0units in a month.

Edited March 14, 2023 by -cK-

[Bomberman]

Finally have my units installed. Just waiting for my panels, should be here in a week. 

Must say, waking up this morning with electricity really made a difference. One could say it brightened up my day hahaha

[fanievb]

1 hour ago, -cK- said:

I set mine to 0 as it was at 20w.  I asked the installer why and the reason was primarily if you have a Pre Paid meter it helps prevent the thing going into tamper mode so they tend to just set it at 20w by default.  Seeing as I don't have one we just set it to 0 as a test and well it works for me. I have not had an issue with it set to 0.  No trickle feed nor feedback to grid as it set to Zero Export.

As you stated if that is set to anything more than 0 you will never have Zero Export.  20w would mean 14units per month minimum on my account. 

I'm at that point that if Eskom can't provide constant power why should I pay them anything for nothing 🤷‍♂️

 

Oh and I also made sure with our Municipality I won't get nailed with some silly charge if my usage is 0units in a month.

I have a "normal meter" with zero export selected, but installer reckons he doesn't trust the settings so we err on the side of caution. But I'm going to lower my trickle to 20 to see what happens.

Our municipality charges me a connection fee irrespective of my usage, but in any case still use some eksdom, as I run a higher SOC at night just in case and my aircon goes through units like its free, but it's summer and its hot and I like sleep.

[-cK-]

1 hour ago, fanievb said:

I have a "normal meter" with zero export selected, but installer reckons he doesn't trust the settings so we err on the side of caution. But I'm going to lower my trickle to 20 to see what happens.

Our municipality charges me a connection fee irrespective of my usage, but in any case still use some eksdom, as I run a higher SOC at night just in case and my aircon goes through units like its free, but it's summer and its hot and I like sleep.

Yes that last little piece of pie crumb one can't get rid off.  A connection fee to a broken network...😔

You can try 10 as well think that is the lowest you can set it via the touch screen or test it for a day at 0 perhaps.  Only saw one little blimp of a feedback 0.06 in the last 4 days (had those random feedback's even with trickle feed set at 20 🤷‍♂️)

Side note I'm now running Priority load 99% of the time.  When in Priority load the inverter seems to run off solar and battery at night if on Battery Priority the inverter runs on "solar" in the day if there is excess available and AC power at night.  My personal observation and deduction.

Edited March 14, 2023 by -cK-

[fanievb]

 

 

[Frosty]

4 hours ago, fanievb said:

What's your grid trickle feed setting? Installer told me to keep it at 30, so I'll never have zero import, unless there's loadshedding/outage

Mine is set to 10W

[Jehosefat]

2 hours ago, -cK- said:

Side note I'm now running Priority load 99% of the time.  When in Priority load the inverter seems to run off solar and battery at night if on Battery Priority the inverter runs on "solar" in the day if there is excess available and AC power at night.  My personal observation and deduction.

That setting shouldn't make a difference to what it runs on at night. Mine is set on Priority Battery and runs on solar during the day and the battery at night until I get down to the specified SOC. My guess is that you have the SOC settings too high overnight or you are not using the timer.

[-cK-]

5 hours ago, Jehosefat said:

That setting shouldn't make a difference to what it runs on at night. Mine is set on Priority Battery and runs on solar during the day and the battery at night until I get down to the specified SOC. My guess is that you have the SOC settings too high overnight or you are not using the timer.

Yes you you are correct in my SOC was high.  This was when I was still "locking out" my battery during peak time to save max capacity for evening loadshedding and running on battery from 02:00-sunrise. 

What I basicaly noticed was if I was at 100% SOC and in battery priority mode everything ran of AC but if I was in Priority load and the SOC was 100% the inverter would drain at about 1% per hour so at 2:00 I would end up at like 92% eventhough the SOC was set at 100% which led me to make the assumption that the inverter is powered from the battery if in priority load mode vs if it is in battery priority as the SOC will not drop untill I started using it during loadshedding 🤷‍♂️.