Planning your own Solar Power System

I use ritar batteries from mantech.co.za

The 100aH sealed SLA is designed life of 10 years was R2k delivered.
 
7aH? That sounds low. A 50A charger will be about R2k.

When I first phoned mantech to place the inverter order I was going to buy a cotek inverter with a standalone charger.

They recommended I just get the UPS that has a built in 50A charger not to mention it worked out much cheaper.

What inverter do you use?
 
spiff said:
geesus ok so I've been quoted R1850 for a 7AH CTEK charger to charge a SMF101 12v 102amp battery - is this right?
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johnjm said:
7aH? That sounds low. A 50A charger will be about R2k.
When I first phoned mantech to place the inverter order I was going to buy a cotek inverter with a standalone charger.
They recommended I just get the UPS that has a built in 50A charger not to mention it worked out much cheaper.
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Slightly mixed messages there, I suspect.
At R1 850, you might have been quoted on something like a CTEK MXS 5.0, which has a maximum charging current of 5.0A; or possibly an XS7000, which can do 7.0A. The 5.0A or 7.0A has no direct relation to a 7Ah battery, it is simply the maximum current the unit can charge a battery at.

At the "rule of thumb" of charging a lead-acid battery at C/10, one would want to charge a 100Ah battery at no more than 10A (a lower amperage is fine, it will just take somewhat longer). Either the CTEK MXS5.0 or the XS7000 will happily charge various types of lead-acid battery of pretty much any size between 1 and 100Ah.

What makes the CTEKs pricier than a "plain" lead-acid charger is the additional intelligence for multiple battery types, multi-step charging and reconditioning.
For looking after a lead-acid battery with minimal fuss as close as possible to "connect and forget" mode, they're fine products. (I have both a "baby" XS 0.8 and an MXS 5.0).
 
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jcheek said:
Slightly mixed messages there, I suspect.
At R1 850, you might have been quoted on something like a CTEK MXS 5.0, which has a maximum charging current of 5.0A; or possibly an XS7000, which can do 7.0A. The 5.0A or 7.0A has no direct relation to a 7Ah battery, it is simply the maximum current the unit can charge a battery at.

At the "rule of thumb" of charging a lead-acid battery at C/10, one would want to charge a 100Ah battery at no more than 10A (a lower amperage is fine, it will just take somewhat longer). Either the CTEK MXS5.0 or the XS7000 will happily charge various types of lead-acid battery of pretty much any size between 1 and 100Ah.

What makes the CTEKs pricier than a "plain" lead-acid charger is the additional intelligence for multiple battery types, multi-step charging and reconditioning.
For looking after a lead-acid battery with minimal fuss as close as possible to "connect and forget" mode, they're fine products. (I have both a "baby" XS 0.8 and an MXS 5.0).
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ok thanks for clearing that up. so the 7ah CTEK charger will do the job.
 
OK am planning on going with the Axpert 5 KVA, just as a UPS for now. I have contact for well priced batteries so that is covered. PV will be stage two once the cash flow is there.
Q. Does any one know a good installer for this that will also give CoC.

EDIT: Cpt city bowl

thanks
 
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My batteries are fully charged and I even disconnect the Load, still there is a 400 to 500W drain... The specs says that stand-by should be around 20W or so...
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Currently I am running an experiment, I installed it in a system with a Pre-Paid meter, so I isolated the Axpert, removed it's load and also flipped the CBs to all other loads on my DB. So only thing pulling power will be Axpert. At the end of the day I will see if there was any actual power usage...
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Just for some feedback, experiment complete and it seems that one should not EVER trust an Engage Efergy V2 meter, made by Ellies. With the UPS it for some reason reports incorrectly. Looking at ACTUALS the unit draws less than 1kWh in 12hours, or about a 60 - 70 W continues draw.

Best to make provision for a continuous draw of 100W when designing for SOLAR component!

Draganchor: Any Electrician would be able to give you a CoC, but just remind them that you are installing an INLINE UPS. There is a specific method of install / signing off as dictated by Appendix S of the wiring code.
 
Rautenk said:
Just for some feedback, experiment complete and it seems that one should not EVER trust an Engage Efergy V2 meter, made by Ellies. With the UPS it for some reason reports incorrectly. Looking at ACTUALS the unit draws less than 1kWh in 12hours, or about a 60 - 70 W continues draw.

Best to make provision for a continuous draw of 100W when designing for SOLAR component!

Draganchor: Any Electrician would be able to give you a CoC, but just remind them that you are installing an INLINE UPS. There is a specific method of install / signing off as dictated by Appendix S of the wiring code.
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Well, yes the efergy only measures the current and multiplies that with the voltage ypu set. It does not compensate for power factor, so it really only measures apparent power, and not real power. But in a home woth multiple devices connected, it gives a good indication of consumption, but being more prone to errors when consumption is low. (Transformers with a small load and chargers without a load usually have poor power factors same goes for CFL lamps and LEDs).

The plug top efergy is much more accurate for single devices, as it measures real power (and also calculates power factor)
 
Rautenk said:
... it seems that one should not EVER trust an Engage Efergy V2 meter, made by Ellies. With the UPS it for some reason reports incorrectly. Looking at ACTUALS the unit draws less than 1kWh in 12hours, or about a 60 - 70 W continues draw.
Click to expand...

To measure power (and therefore energy) accurately, an energy meter/monitor needs to sense :
  1. Voltage being applied to the appliance (or system)
  2. Current being drawn by the appliance / system
  3. Time relationship (phase) between the voltage and current
It also needs to be able to deal with complex voltage and current waveforms that aren't the nice, clean sinusoidal shapes in the textbooks.

Most of these "wireless energy monitors", like the Owl and the Efergy system, use a clip-on current sensor at the appliance or DB board to get a current signal (2), and rely on a single-point voltage measurement (usually at the "hub") to get a voltage signal (1) and some idea of the time relationship (3). Some devices don't bother with a voltage measurement at all (ie they just assume 230V, or some other pre-set value).
At best this is an approximation that might work reasonably well for "simple" appliances like stoves, kettles and heaters. The approximation would fail where there is three-phase power, or where the supply voltage is not sinusoidal (such as on the output of an entry-level UPS or inverter device). It could also be inaccurate where the device itself draws large, complex currents from the supply. Typically this would be true for for anything that contains electronics of significant size/rating - like an inverter. Under "perfectly wrong" conditions the results could be wildly inaccurate.
That is why you will almost never see any definitive statement about measurement accuracy on these wireless monitoring devices.

A prepayment meter, or indeed any kind of energy billing meter, is generally a much more accurate device that needs to comply with strict metrological accuracy standards. Provided the meter is from a reputable supplier, you will usually get accurate results. Hence your "prepayment meter" experiment was well-founded!


P924 said:
Well, yes the efergy only measures the current and multiplies that with the voltage you set. It does not compensate for power factor, so it really only measures apparent power, and not real power.

<snip>

The plug-top efergy is much more accurate for single devices, as it measures real power (and also calculates power factor)
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+1 !
 
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Ok so just an update.

new battery and pure sine wave inverter worked perfectly last night, outlived escum's 2.5hr load shedding. plugged in the CTEK charger and the battery was fully charged this morning.

Now I need a proper change over switch - any advice on a manual / automatic or a DIY relay type?
 
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Maybe a bit off topic but just thought I would ask, got a small 600va ups that I want to run an lcd off, lcd max power draw is 120W but will be running it in eco mode so probably half that.

Looking for a cheap 24/30ah 12v battery in Durbanville/Sunningdale area Cape Town. Alternatively 6v12ah x 2

Only need it to last for the next two months.

Anyone know a place I can just pop in and pick one up?
 
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spiff said:
not to complex - just want to be 100% sure the mains is off.

manual seems a better way to go for me as I don't want my battery been used during the day when I'm not there.
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Then those Hager units will work nicely - the output side can only ever be connected to one of the two input sides at any given time.

As a further safeguard you can go for the "centre off" type, where the centre switch position disconnects the output completely. I have just such a scheme (Hager SFT125 changeover switch) on a UPS setup of mine:

UPS output panel.jpg
 
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jcheek said:
Then those Hager units will work nicely - the output side can only ever be connected to one of the two input sides at any given time.

As a further safeguard you can go for the "centre off" type, where the centre switch position disconnects the output completely. I have just such a scheme (Hager SFT125 changeover switch) on a UPS setup of mine:

View attachment 208522
Click to expand...

great thanks for info. will look into it.
 
jcheek said:
Then those Hager units will work nicely - the output side can only ever be connected to one of the two input sides at any given time.

As a further safeguard you can go for the "centre off" type, where the centre switch position disconnects the output completely. I have just such a scheme (Hager SFT125 changeover switch) on a UPS setup of mine:

<snip/>
Click to expand...

That looks very neat! Well done!
 
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