Best Inverter and Battery combination request

[SeanMG]

Hi All,

I really need assistance trying to figure out the best Inverter and battery combination.

My 83yr old mother-in-law is on oxygen 24/7 and our current set up is no longer viable.

Currently we have an ATP Hulk 3.5KVA 48V S.S.SUPS inverter with 6x 100ah Lead Acid batteries.
For load shedding all that is attached to the Inverter is her 300W oxygen machine and Hisense 55"' TV (I think its about 150W).
We replaced the 6 batteries last year Feb as load shedding killed the previous batteries.
When I tested the longevity of battery power after getting the new batteries last year we seemed to get around 7 hours back up time.
Obviously with the mad load shedding we have had last year and this year the batteries are now toast, not even lasting 1.5 hours with just the oxygen machine running.
Lucky to have a small 2KVa gennie as back up.
I tried to use all the different battery calculators I've seen on the forum, but I'm too dumb to understand how they work. :-(
I don't think the current inverter would work with Lithium-ion batteries, and cant find anything on the net about it.

Please could I ask for advise on a set-up, that would run the oxygen machine and a TV for my mother in law that could possibly run for at least 10-12 hours.

Any assistance would be greatly appreciated, before I buy another 6 LA batteries.

Thanks
Sean

 

[ld13]

You need lithium. Sure it is expensive, but you will not need to replace the batteries every year. What are you spending every time on lead acids, like R12k?

Load = 300+150 = 450W * 12 hours runtime = 5400Wh. Now adjust for 80% Depth of discharge (no battery likes being run flat to 0%), so 5400Wh becomes 6750Wh. Then you also need to factor in inefficiencies, as no inverter is 100% efficient. Lets say 85%? So 6750Wh becomes 7941, or ~8000Wh / 8kWh. Closest 48V that will surpass 8kWh is a 9.6-10kWh one, so 48V 200ah. They are quite pricey. You are looking at R40k - https://lifepower.za.com/product/preorder-lifepo₄wer-lithium-battery/

I run 24V, so am not too clued up with the 48V pricing. If someone could validate my math and correct me if there are any options cheaper than R40k?

Regarding compatibility, I could not find that inverter anywhere. I am also yet to see an inverter that is 'incompatible' with a BMS protected lithium battery. As long as it does not do like pulse charging, it should be fine.

Yes, the some of the mecer inverters don't "like" lithium, and can overheat if you set it on 20A charging, as the stupid idiots did not bother to couple the fans with a temperature sensor. Otherwise, lithium is quite forgiving. In some instances you will also simply land up leaving some capacity on the table as the charger might not be able to charge the battery to 100%, also not the end of the world.

Disclaimer: Lol, I am not a certified electrician/engineer or anything that even remotely resembles that. (in response to the request noted in another thread)

 

[leon.davibe]

Hi All,

I really need assistance trying to figure out the best Inverter and battery combination.

My 83yr old mother-in-law is on oxygen 24/7 and our current set up is no longer viable.

Currently we have an ATP Hulk 3.5KVA 48V S.S.SUPS inverter with 6x 100ah Lead Acid batteries.
For load shedding all that is attached to the Inverter is her 300W oxygen machine and Hisense 55"' TV (I think its about 150W).
We replaced the 6 batteries last year Feb as load shedding killed the previous batteries.
When I tested the longevity of battery power after getting the new batteries last year we seemed to get around 7 hours back up time.
Obviously with the mad load shedding we have had last year and this year the batteries are now toast, not even lasting 1.5 hours with just the oxygen machine running.
Lucky to have a small 2KVa gennie as back up.
I tried to use all the different battery calculators I've seen on the forum, but I'm too dumb to understand how they work. :-(
I don't think the current inverter would work with Lithium-ion batteries, and cant find anything on the net about it.

Please could I ask for advise on a set-up, that would run the oxygen machine and a TV for my mother in law that could possibly run for at least 10-12 hours.

Any assistance would be greatly appreciated, before I buy another 6 LA batteries.

Thanks
Sean

the previous battery count on 48v system was part of the problem imo

your capacity usable would have been 3840 wh
but almost impossible to extract , 6 batteries on a 48v system would have meant silly layout (hope it was a typo)

the most you would be able to extract would have been 2560wh before damaging batteries

and thus 3150wh would have meant damaging batteries from day one
ie based on your 450w x 7hrs

you can use lifep04 on lead acid devices
the voltages match perfectly, you have to make sure to buy a 16s/51.2v battery or change settings on the inverter if buying a 48v pack

if you can change the settings you would want to maybe up the charge rate limitations of lead acid isn't there anymore so can get them full as quick as possible

ie you want the batteries always full to have to longest backup available

if you start with a 5.12kwh battery you would have about 10hrs backup with that load
and can later add more batteries if you need longer
working on an efficiency of 90% thumbsuck

i would buy a 51.2v pack instead of using 4x12v batteries to remove initial /subsequent balancing complications

Edit : on your existing device

 

[leon.davibe]

if using batteries in series

you want the following
ie always add in sets that match nominal voltage

ie in 12v system you can add 1 at a time if paralleling to add capacity

1-2-3-4 etc

in24v you have to have batteries in multiple of 2
2-4-6-8

and in 48v you want

4-8-12 etc

you may find that rearranging the batteries that you still have 4 good batteries and 2 bad batteries

if you remove the 2 bad ones and build a series pack with the 4 good ones you can then add extra batteries for more capacity

you can add a 51.2v lithium parallel ie
the lithium of 5.12kwh
and lead acid would give condition dependant up to 2.4kwh

for a combined 7.52kwh/7520wh
and 15hrs of backup
some will frown on this

as the lead acids degrade you can then later add another 5.12kwh/5120wh pack and sell the 4 for scrap should get about 1K for them

 

[leon.davibe]

If you are lucky and have 4 good batteries you could go back up to 5hrs of backup

Just by getting rid of the 2 bad batteries

And a proper balance

If you did not have a balancer the chances of 4 good batteries go up

Edit: a photo of the battery config will help to iron out any misunderstandings or incorrect assumptions

 

[leon.davibe]

You need lithium. Sure it is expensive, but you will not need to replace the batteries every year. What are you spending every time on lead acids, like R12k?

Load = 300+150 = 450W * 12 hours runtime = 5400Wh. Now adjust for 80% Depth of discharge (no battery likes being run flat to 0%), so 5400Wh becomes 6750Wh. Then you also need to factor in inefficiencies, as no inverter is 100% efficient. Lets say 85%? So 6750Wh becomes 7941, or ~8000Wh / 8kWh. Closest 48V that will surpass 8kWh is a 9.6-10kWh one, so 48V 200ah. They are quite pricey. You are looking at R40k - https://lifepower.za.com/product/preorder-lifepo₄wer-lithium-battery/

I run 24V, so am not too clued up with the 48V pricing. If someone could validate my math and correct me if there are any options cheaper than R40k?

Regarding compatibility, I could not find that inverter anywhere. I am also yet to see an inverter that is 'incompatible' with a BMS protected lithium battery. As long as it does not do like pulse charging, it should be fine.

Yes, the some of the mecer inverters don't "like" lithium, and can overheat if you set it on 20A charging, as the stupid idiots did not bother to couple the fans with a temperature sensor. Otherwise, lithium is quite forgiving. In some instances you will also simply land up leaving some capacity on the table as the charger might not be able to charge the battery to 100%, also not the end of the world.

Disclaimer: Lol, I am not a certified electrician/engineer or anything that even remotely resembles that. (in response to the request noted in another thread)

That is a really good price on almost 10kwh

If the inverter settings can't be changed

I would just double check the s count of the battery

ie 48v batteries tend to be used generically
For 48v or 51.2v batteries

ie a fancy ups that would shutdown the ups on the 12v ish 50% dod on a lead acid

would mean that it would shut down at a voltage that would leave a lot of capacity left in the battery if it is a 15s

ie it could shutdown with voltage drop anything between 20-50%soc
now yes if it shutdown at 100% dod you would not lose capacity

And would work perfect with a 16s 51.2v

 

[ld13]

@leon.davibe its 16s afaik, but would be best that you explain what you mean, or write it out, because I am guessing what you mean.

Secondly, do you know that there is an edit function on the forum and that paragraphs exist? It makes it so that one can read walls of texts, easier...

 

[leon.davibe]

@leon.davibe its 16s afaik, but would be best that you explain what you mean, or write it out, because I am guessing what you mean.

Secondly, do you know that there is an edit function on the forum and that paragraphs exist? It makes it so that one can read walls of texts, easier...

thanks for the constructive criticism , will try and keep it in mind


Yea according to the manual the nominal voltage is 51.2 which is the nominal voltage of 16s


yea verbalising my thoughts is often a thing for me, ie try and give too much logic vs too little
ie so others can get how i got to my opinion, but often the order in which i sometimes writes looks like a broken chatgpt response,

so they can get the gist and do their own research to confirm


so for original poster this would work perfect
ie he would not need to worry about compatibility


and save on extra cost of an new inverter
and can later change the device if charge rate isn't quick enough


though with the load of 450w it would mean after 4hrs 1800wh used

to recharge that the next 4hrs he is on Eskom a charge rate of 10a would do that without a problem
few devices have below a 10a charge rate , very unlikely on a 48v system


if the charge rate is lower then yes he might want to buy a new inverter
cause you want an inverter that can at least put back all you take out in a load shedding session the next 4 hrs your power is on

 

[RonSwanson]

Hi All,

I really need assistance trying to figure out the best Inverter and battery combination.

My 83yr old mother-in-law is on oxygen 24/7 and our current set up is no longer viable.

Currently we have an ATP Hulk 3.5KVA 48V S.S.SUPS inverter with 6x 100ah Lead Acid batteries.
For load shedding all that is attached to the Inverter is her 300W oxygen machine and Hisense 55"' TV (I think its about 150W).
We replaced the 6 batteries last year Feb as load shedding killed the previous batteries.
When I tested the longevity of battery power after getting the new batteries last year we seemed to get around 7 hours back up time.
Obviously with the mad load shedding we have had last year and this year the batteries are now toast, not even lasting 1.5 hours with just the oxygen machine running.
Lucky to have a small 2KVa gennie as back up.
I tried to use all the different battery calculators I've seen on the forum, but I'm too dumb to understand how they work. :-(
I don't think the current inverter would work with Lithium-ion batteries, and cant find anything on the net about it.

Please could I ask for advise on a set-up, that would run the oxygen machine and a TV for my mother in law that could possibly run for at least 10-12 hours.

Any assistance would be greatly appreciated, before I buy another 6 LA batteries.

Thanks
Sean

I was in a similar situation last year with a family member who had stage 4 cancer and was in palliative home care. She had an oxygen machine too, and a 3k inverter genny works great, but completely impractical for an 84 year old to wheel out, connect and fire up at 02H00 in the morning. I opted for a 5K Sunsynk, 3x Hubble batteries and an array of 14 panels. She passed away last Easter in hospital, but the setup still works great today. You should be able to get by with just the 5K Sunsynk and 2 Hubble AM2 batteries, panels are optional but strongly recommended due to losses associated with charging via Eskom.

 

[ld13]

yea verbalising my thoughts is often a thing for me, ie try and give too much logic vs too little
ie so others can get how i got to my opinion, but often the order in which i sometimes writes looks like a broken chatgpt response

I have a similar issue, just when I speak, with a somewhat broken verbal order. With the worst of it all being that I can hear that I am sometimes not making any sense.

By 16s you mean that there are 16 individual cells in series, instead of 15. Some manufacturers go as far as to over-volt those poor cells to reach the required voltage, or so I have heard.

 

[leon.davibe]

I have a similar issue, just when I speak, with a somewhat broken verbal order. With the worst of it all being that I can hear that I am sometimes not making any sense.

By 16s you mean that there are 16 individual cells in series, instead of 15. Some manufacturers go as far as to over-volt those poor cells to reach the required voltage, or so I have heard.

normally they give you the charge and float voltage to match their battery

which isn't a problem as most 48 systems can change the settings

if they can't you rely on the protection of the bms

edit and will keep the battery at higher voltage which isn't ideal but wont break it, maybe just reduce the life a bit
but we don't exactly have data to confirm this just , notions from the past

 

[SeanMG]

Thanks for all the feedback its greatly appreciated.

I'm really more confused now with all this :-(

This is what the Inverter looks like.
There are no buttons to check any data or change any settings.
I do think its set at 10A charging
I'm not able to get into the cabinet to check the battery configuration.

Would I be able to connect one of these batteries,

BATT 48V100A LI-ION PYL

Pylontech BATT 48V100A LI-ION PYL Batteries Pylontech Lithium Ion Rechargeable Battery UP5000 48V 100A 4.8KWH, Charge/Discharge Current 90-200A (Peak@15s), RS485/CAN, Discharge Voltage:44.5V, Charge/Voltage(V): 52.5~53.5, Cycle Life >4,500 (25℃) 95% DOD, (442x420x165mm), 41kgLithium Ion...

www.communica.co.za

BATT 48V115A LI-ION HBL

Hubble BATT 48V115A LI-ION HBL Batteries Hubble Lithium Ion Rechargeable Battery AM2-5500 48V 115A 5.5KWH, Charge/Discharge Current 105A,2xRS485 1xCAN BUS 1xRS232, Discharge Voltage:44.0V, Charge/Voltage(V): 53.8V,+/- 6000 cycles @ 50% DOD, Above 3000 Cycles @ 100% DOD,375x145x467mm, 42kgLithium...

www.communica.co.za

Without having to change any setting?
Just connect positive to positive negative to negative.

My partner found these two possible ready solutions for her mothers Oxygen machine.

404 - Energy Independence

Sorry Not Found Go Back To Home

powerprovider.co.za

or

3Kva 2.75 Kwh Lithium Compact Power Station 3000W | Energy Independence

Efficient 3kVA 2.75kWh Lithium Compact Power Station for portable power solutions. South Africa's best back-up power and solar solutions.

powerprovider.co.za

Or if anyone knows of a company that they can recommend that I could contact or get to come out and chat to us about the options.
This is quiet urgent now :-(

Thanks, Appreciate

 

[ld13]

I'm really more confused now with all this :-(

Found your inverter, http://www.truepower.in/images/hulk.pdf
Specs are kinda useless. Only really confirms 10A, so 48V*10A = 480W, or ~500W charge? To charge up the 8000Wh battery capacity that you need, from 0% to 100%, will take 8000Wh/500W=~16h. But we are working with a lot of hypotheticals here.

The batteries and complete systems you linked will not have enough capacity to carry the load you mentioned.

If I were you, I would start off with getting a kill-a-watt/clamp meter to check exactly how much just the oxygen machine uses, power wise, because then one can do a few proper calculations.

 

[PsyWulf]

1st,get a Kill-awatt (borrow) measure properly,then proceed

 

[leon.davibe]

Thanks for all the feedback its greatly appreciated.

I'm really more confused now with all this :-(

This is what the Inverter looks like.
There are no buttons to check any data or change any settings.
I do think its set at 10A charging
I'm not able to get into the cabinet to check the battery configuration.

Would I be able to connect one of these batteries,

BATT 48V100A LI-ION PYL

Pylontech BATT 48V100A LI-ION PYL Batteries Pylontech Lithium Ion Rechargeable Battery UP5000 48V 100A 4.8KWH, Charge/Discharge Current 90-200A (Peak@15s), RS485/CAN, Discharge Voltage:44.5V, Charge/Voltage(V): 52.5~53.5, Cycle Life >4,500 (25℃) 95% DOD, (442x420x165mm), 41kgLithium Ion...

www.communica.co.za

BATT 48V115A LI-ION HBL

Hubble BATT 48V115A LI-ION HBL Batteries Hubble Lithium Ion Rechargeable Battery AM2-5500 48V 115A 5.5KWH, Charge/Discharge Current 105A,2xRS485 1xCAN BUS 1xRS232, Discharge Voltage:44.0V, Charge/Voltage(V): 53.8V,+/- 6000 cycles @ 50% DOD, Above 3000 Cycles @ 100% DOD,375x145x467mm, 42kgLithium...

www.communica.co.za

Without having to change any setting?
Just connect positive to positive negative to negative.

My partner found these two possible ready solutions for her mothers Oxygen machine.

404 - Energy Independence

Sorry Not Found Go Back To Home

powerprovider.co.za

or

3Kva 2.75 Kwh Lithium Compact Power Station 3000W | Energy Independence

Efficient 3kVA 2.75kWh Lithium Compact Power Station for portable power solutions. South Africa's best back-up power and solar solutions.

powerprovider.co.za

Or if anyone knows of a company that they can recommend that I could contact or get to come out and chat to us about the options.
This is quiet urgent now :-(

Thanks, Appreciate

I would not use either of those batteries on your inverter if you can't change the charge voltage

The first is a lifep04
But it is a 15s 48v battery

And the second is also a 48v battery but based on different chemistry it uses the 3.7v cells in a 13s config to get to 48.1v nominal voltage

Sure the bms will be a safety net , but i would prefer to have a 51.2v battery

Ie like the lifepo4wer battery that is a 16s config

If your usage is 450w then your current inverter will be able to charge back what you use in a 4hrs loadshedding stint ie you would use 1800wh approx and be able to charge back about 1920wh

If you have extra outages
And you use the extra capacity

it would take longer to inch back to 100 % full

Getting a meter to check is a good idea

That kit has a bit of a premium imo

For that amount of money

You could get more bang for buck

By first using your existing inverter and buy double the capacity

And if you see the inverter charge rate is a problem

You could address it with a R2k victron charge controller solution

Or some panels with a seperate mppt

 

[Ojcd45]

Thanks for all the feedback its greatly appreciated.

I'm really more confused now with all this :-(

This is what the Inverter looks like.
There are no buttons to check any data or change any settings.
I do think its set at 10A charging
I'm not able to get into the cabinet to check the battery configuration.

Would I be able to connect one of these batteries,

BATT 48V100A LI-ION PYL

Pylontech BATT 48V100A LI-ION PYL Batteries Pylontech Lithium Ion Rechargeable Battery UP5000 48V 100A 4.8KWH, Charge/Discharge Current 90-200A (Peak@15s), RS485/CAN, Discharge Voltage:44.5V, Charge/Voltage(V): 52.5~53.5, Cycle Life >4,500 (25℃) 95% DOD, (442x420x165mm), 41kgLithium Ion...

www.communica.co.za

BATT 48V115A LI-ION HBL

Hubble BATT 48V115A LI-ION HBL Batteries Hubble Lithium Ion Rechargeable Battery AM2-5500 48V 115A 5.5KWH, Charge/Discharge Current 105A,2xRS485 1xCAN BUS 1xRS232, Discharge Voltage:44.0V, Charge/Voltage(V): 53.8V,+/- 6000 cycles @ 50% DOD, Above 3000 Cycles @ 100% DOD,375x145x467mm, 42kgLithium...

www.communica.co.za

Without having to change any setting?
Just connect positive to positive negative to negative.

My partner found these two possible ready solutions for her mothers Oxygen machine.

404 - Energy Independence

Sorry Not Found Go Back To Home

powerprovider.co.za

or

3Kva 2.75 Kwh Lithium Compact Power Station 3000W | Energy Independence

Efficient 3kVA 2.75kWh Lithium Compact Power Station for portable power solutions. South Africa's best back-up power and solar solutions.

powerprovider.co.za

Or if anyone knows of a company that they can recommend that I could contact or get to come out and chat to us about the options.
This is quiet urgent now :-(

Thanks, Appreciate

Where are you located, if in jhb and surrounding areas talk to Steve at loadfed solar, he'll sort you out

LoadFed Solar - R and D Energy (Pty) Ltd
064 044 2640

https://g.co/kgs/C8BRm4

 

[leon.davibe]

If you can set/change the charge voltages you could use either of the 2 batteries you posted about on your existing inverter

If not you have to get a 51.2v nominal battery

BSL Battery 51.2V - 100Ah CANBUS (5.12kWh)

BSL Battery 51.2V - 100Ah CANBUS (5.12kWh)

re-volt.co.za

The term 48v gets used way to generic imo

48v nominal is 15s battery
And 16s 51.2v nominal voltage

Yet many listings refer to them both as 48v batteries sometimes , some sites do state the nominal 51.2v

Ie a 12.8v (4s) lifep04 matches 12v lead acid default charge settings 100%

And hence 4*12.8 = 51.2v matches 4x12v battery default charge settings

And thus why you want a 51.2v 16s battery if you can't change settings

Like i said the bms will be a safety net. And can prevent even the 48v batteries from overcharging but may keep them at a higher voltage that some say may affect life expectancy (salt based on opinions on the internet)

But prefer to get the batteries closely matched to existing for device standard charge settings + default overcharge protection

 

[morbill]

It might be practical to have a oxygen cylinder around as back up. My father had a 20m long tube, just need to be careful of tripping

 

[leon.davibe]

Another 51.2v example

That should be able to carry the load for more than the 12hrs if need arrises
And if you find that you have more outages that exceed inverter charge rate you can decide the way forward

ie can buy another inverter later or add panels or additional charging

Fivestar 7.68kwh 51.2v 150ah LiFePo4 Wall Mount Lithium Battery

Fivestar 7.68kwh 51.2v 150ah LiFePo4 Wall Mount Lithium Battery (10005949) Package Contents: 1x 7.68kwh 51.2v 150ah LiFePo4 Battery

www.electromannsa.com

 

[leon.davibe]

Naturally budget matters

ie hence why i am making suggestions based on existing inverter

The batteries will work on other inverters too

Assuming that the inverter met the need in the past

ie could charge back whatever got used back in the past

Normally if they cant even with good batteries you will find that stage 6 highlights that rather quickly ie 2-3 days would leave you in the dark at some point if charge rate is too low vs usage