<ads> wrote in message
> On Sun, 3 Jun 2018 15:37:55 -0400, "Jim Wilkins"
>
>>...
>>Changing the subject slightly, I was considering a Li-ion battery
>>bank
>>and 900W solar but having contacted 4 Companies not one was
>>interested! and because its rather a lot of money I wasn't convinced
>>I
>>knew enough to DIY. I do have the generator changeover switch so a
>>battery bank may well work with the generator plus add solar at
>>anytime. Run the generator to charge up the batteries and run
>>quietly
>>in the evenings.
>>----------------------------
>>
>>The problem I encountered with my solar battery system was the high
>>idle power of pure-sine inverters suited to 120VAC refrigerators.
>>The
>>inverter I have runs continuously and consumes as much overall from
>>the battery as my small fridge. It needs to be sized for the
>>starting
>>surge, which is 12A on mine.
>>
>>I'm testing a Chinese Alpicool DC-powered fridge/freezer which can
>>operate directly on 12V or 24V. It has its own set of quirks to deal
>>with but so far it doubles the battery run time when it's the only
>>load, and may permit a smaller and more efficient modified sine
>>inverter for non-motor loads in the daytime.
>>
>>-jsw
>>
>
> Most commercial suppliers are not interested in relatively small
> installations because the pricing they can give on big systems falls
> apart below a couple of kw. There's similar setup time and labor
> for
> a few solar panels as for 4 times that many as well as the wiring so
> the costs for small solar don't work out.
>
> I'm handy at finding good used and recycled gear, as well as finding
> bargains in electronic equipoment. I put together a 12 volt, 540AH
> (6480WH) battery bank with two 2000 watt pure sine wave (PSW)
> inverters, a 500 watt PSW inverter, two 30 amp MPPT charge
> controllers, 900 watts of solar panels and all the interconnect
> wiring, fuses, circuit breakers and monitoring equipment for
> $100US.
> The electronics were shipped but the batteries and solar panels were
> sourced locally (no shipping, just gas for my truck). The solar
> panels are not yet permanently mounted (still working out which of 3
> possible mounting locations is the best location).
>
> I do have 25 amps of precisely controlled battery charging equipment
> that can be powered by a gasoline generator (NOT the $0 cheapie
> charger from the auto parts store). An hour of that charging
> provides
> 1 to 4 hours of runtime from the battery bank, depending on the
> season
> (more heat and light needed in winter and less sun available for
> solar
> charging).
>
> My design goal was "Wait until daylight" power so I would not be
> setting up the gas gen in the dark or during a thunderstorm because
> most of our outages are less than 16 hours. Depending on the
> season,
> the system provides 10 to 20 hours of limited power. The design
> meets
> my goal and I learned a great deal about solar power.
My system is similarly assembled from whatever I could find
second-hand or build, a little smaller because my property is mostly
shaded. I made V-shaped fold-out legs for my Grape panels from 1/2"
EMT conduit and move them around to dodge shadows when I need several
hundred Watts for discharged batteries, otherwise 1-2A from panels in
fixed locations keeps the backup batteries topped off.
The parts I designed and built because they aren't commecially
available are a 25A fast charger and a float charger for battery
maintenance composed of an LM350 adjustable linear voltage regulator
and this voltage and current meter for feedback:
https://www.amazon.com/DROK-Digital-0-33-00V-0-3-000A-Measurement/dp/B00IZU4D4Q/ref=sr_1_173?s=industrial&srs19938011&ie=UTF8&qid 96089483&sr=1-173
Th voltmeter helps find the lead-acid gassing threshold and then stay
just below it, and the ammeter indicates when the battery is coming
up, fully charged, or degrading from age. The numbers to look for are
in the battery manufacturer's data sheets.
The 25A fast charger is a Variac driving a "50A" (at 20% duty cycle)
arc welder transformer, rectifier and capacitor etc. I designed it
more for experimenting and component testing but it can charge any
battery between 1.5V and 48V and the Variac adapts it to a poorly
regulated generator. If you already have the parts or find them cheap
it's a good use for them, although the welder voltage/current
characteristic is constant current and the voltage can rise too high
if left unattended or unregulated. This DPS5015 switching regulator
works really well and is controllable enough to charge bare Lithiums
or NiCads. I bought it before the 20A model became available.
https://www.amazon.com/uniquegoods-Step-down-Programmable-Adjustable-Regulator/dp/B01N3YSE6S/ref=sr_1_1?s=industrial&ie=UTF8&qid 28198322&sr=1-1&keywords=dps5015
I learned how to charge sample batteries with lab power supplies when
I became the battery tech at Segway.
http://batteryuniversity.com/learn/article/charging_with_a_power_supply
I add a series diode to keep battery voltage from feeding back into
the power supply if it's switched off.. The DC desulfation technique
they mention does work, sometimes. If you are serious about salvaging
old 12V batteries the Harbor Freight Carbon Pile tester is very
useful.
-jsw
On Sunday, June 3, 2018 at 8:37:48 PM UTC+1, Jim Wilkins wrote:
> The problem I encountered with my solar battery system was the high
> idle power of pure-sine inverters suited to 120VAC refrigerators. The
> inverter I have runs continuously and consumes as much overall from
> the battery as my small fridge. It needs to be sized for the starting
> surge, which is 12A on mine.
>
> I'm testing a Chinese Alpicool DC-powered fridge/freezer which can
> operate directly on 12V or 24V. It has its own set of quirks to deal
> with but so far it doubles the battery run time when it's the only
> load, and may permit a smaller and more efficient modified sine
> inverter for non-motor loads in the daytime.
>
> -jsw
Thanks Jim like I say I've no knowledge on how to build it myself so gathering info in the hope I can get enough to perhaps DIY
Interesting re the Alpicool I've looked at a few DC powered units and thought they were mostly shy of having enough insulation so haven't bought one yet.
> On Sunday, June 3, 2018 at 8:37:48 PM UTC+1, Jim Wilkins wrote:
>
>> The problem I encountered with my solar battery system was the high
>> idle power of pure-sine inverters suited to 120VAC refrigerators.
>> The
>> inverter I have runs continuously and consumes as much overall from
>> the battery as my small fridge. It needs to be sized for the
>> starting
>> surge, which is 12A on mine.
>>
>> I'm testing a Chinese Alpicool DC-powered fridge/freezer which can
>> operate directly on 12V or 24V. It has its own set of quirks to
>> deal
>> with but so far it doubles the battery run time when it's the only
>> load, and may permit a smaller and more efficient modified sine
>> inverter for non-motor loads in the daytime.
>>
>> -jsw
>
> Thanks Jim like I say I've no knowledge on how to build it myself so
> gathering info in the hope I can get enough to perhaps DIY
> Interesting re the Alpicool I've looked at a few DC powered units
> and thought they were mostly shy of having enough insulation so
> haven't bought one yet.
In cool weather the Alpi C20 works well enough as an indoor freezer
set at -18C. Right now my kitchen is at 17C and in midwinter I let the
house drop to 13C. When I put the Alpi in the back of my white SUV on
a sunny 28C day it ran continuously at -12 to -15C until I covered the
cold compartment with a winter parka, leaving the vents clear.
Here in the Northeast USA we suffer summer hurricane and winter ice
storm power outages, sometimes for a week or more. In that case I'd
reset it to -4C which keeps frozen food lightly frosted for a while
but doesn't freeze drinks solid, and greatly increases the battery run
time.
-jsw
On Sun, 03 Jun 2018 03:08:23 -0700, dolmen wrote:
> On Saturday, May 26, 2018 at 4:24:17 PM UTC+1, Johnny B Good wrote
>
>> Given enough time between now and Armageddon, I've no doubt we'll see
>> water cooled fuel injected engine modules being used in the later more
>> compact, quieter and even more fuel efficient portable inverter gensets
>> with built in Li-ion battery backup and automatic electric start. :-)
>>
>> --
>> Johnny B Good
>
> Thanks for the detailed reply, I'm in no way educated in the workings of
> these, but rely on kind folks like you on the web sharing their
> experience and knowledge to inform me, then I makes my choice. I do have
> a larger petrol open frame chinese type generator, it works but not so
> refined. At least I'm not stuck when the power does go off, and it
> drives everything freezers, oil burner, pumps and lights etc However the
> inverter one caught my eye but never managed to get one and the much
> higher prices quoted for the red ones leave a bad taste for something
> that is going to sit for months on end!
I know where you're coming from. Sheesh! An extra 800 quid just to
upgrade that 99 quid Parkside inverter genset I'd bought back in April to
a quieter version. If you're going to use it for emergency home power,
there are much cheaper ways to deal with the noise pollution[1]. Even the
A1 version that went on sale in UK Lidl stores last Thursday are still
one hell of a bargain at 129 quid versus the 280 quid 1200/1500W Impaq
models available from local Screwfix stores in the UK.
> Changing the subject slightly, I was considering a Li-ion battery bank
> and 900W solar but having contacted 4 Companies not one was interested!
> and because its rather a lot of money I wasn't convinced I knew enough
> to DIY. I do have the generator changeover switch so a battery bank may
> well work with the generator plus add solar at anytime. Run the
> generator to charge up the batteries and run quietly in the evenings.
I'm afraid I can't offer any practical advice regarding Li-ion battery
banks and chargers. My experience is more to do with good old fashioned
lead acid battery setups, mainly to do with various UPSes I've used over
the past 20 years or so.
What I can say, if you're thinking of using lead acid batteries with a
1KW or higher output inverter, is not to make the mistake I've seen in
many a youtube vid of using 12v inverters with a bank or two's worth of
forklift truck batteries.
If you're going to buy a 1 or 2 KW inverter choose a 24v or, better yet,
a 48v inverter setup which will save a small fortune in heavy duty
battery cables as well as reduce I squared R losses. Instead of circa
100A per KW of grid voltage output from a 12v battery (which is starter
cranking amps territory), a 48v battery will reduce this to just under 25
amps per KW of grid voltage power.
[1] There are plenty of youtube vids demonstrating the many ways of how
*not* to create quiet generator enclosures by folk who have totally
underestimated the problems of containing the noise pollution in a
plastic or wooden box breached by the relatively large holes required to
vent the enclosure to prevent the generator from cooking itself with (and
choking on) its own exhaust fumes.
A suitcase styled inverter generator out of necessity, provides its own
forced air ventilation to both cool the inverter module and the engine
and, in particular, the exhaust muffler to prevent it melting the plastic
casing.
Installed into a properly designed brick enclosure, it shouldn't need
any additional fan cooling if the sound absorbent lined ventilation tunnel
[2] for the exhaust is sized a little larger in CSA to that of the
exhaust vent that typically encloses the muffler's exhaust pipe. A few
inches of separation between the rear of the generator and the mouth of
the exhaust vent needs to be provided to utilise the venturi effect to
draw additional air past the sides of the generator to prevent heat build
up within the enclosure.
Obviously a similarly sized intake vent will be needed at the opposite
end, with a suitably labyrinthine pathway to the intake end of the
generator with blocks of sound absorbent material strategically placed so
as not to choke down the intake path.
Also, just like the exhaust end there needs to be clearance for the
extra air drawn in by the exhaust venturi effect to work its magic of
removing any residual heat build up from conducted and radiated heat that
would otherwise normally escape direct to the atmosphere. I doesn't need
much of an airflow to achieve this goal in the case of suitcase styled
inverter gensets compared to a typical open framed generator.
In any case, it would only be prudent to monitor the interior air
temperature to be verify that there's no overheating risk to the petrol/
gas tank contents or the generator itself. This should be done as part of
the commissioning tests at the very least.
Depending on the results of those tests, you can decide whether or not
there's any need to permanently monitor the enclosure temperature to
provide an overheat alarm which could be used to start a timer to shut
the generator off automatically for your own peace of mind.
[2] Most of which can consist of a vertical brick chimney (say 6 foot or
so tall) to take advantage of the exhaust heat energy to generate an
additional draw assist to the ventilation airflow and to direct the
residual noise skywards and away from neighbouring properties.
Any weatherproofing measures against rain ingress should ideally be
effectively sonically transparent to avoid deflecting residual exhaust
noise back towards your immediate neighbours. This trick of simply
deflecting the noise skywards can account for a 6dB reduction in the
horizontal plane so it's worth trying to avoid spoiling this effect with
a standard rain proofing cowl if you can.
--
Johnny B Good
>
>>...
>>Changing the subject slightly, I was considering a Li-ion battery
>>bank
>>and 900W solar but having contacted 4 Companies not one was
>>interested! and because its rather a lot of money I wasn't convinced
>>I
>>knew enough to DIY. I do have the generator changeover switch so a
>>battery bank may well work with the generator plus add solar at
>>anytime. Run the generator to charge up the batteries and run
>>quietly
>>in the evenings.
>>----------------------------
>>
>>The problem I encountered with my solar battery system was the high
>>idle power of pure-sine inverters suited to 120VAC refrigerators.
>>The
>>inverter I have runs continuously and consumes as much overall from
>>the battery as my small fridge. It needs to be sized for the
>>starting
>>surge, which is 12A on mine.
>>
>>I'm testing a Chinese Alpicool DC-powered fridge/freezer which can
>>operate directly on 12V or 24V. It has its own set of quirks to deal
>>with but so far it doubles the battery run time when it's the only
>>load, and may permit a smaller and more efficient modified sine
>>inverter for non-motor loads in the daytime.
>>
>>-jsw
>>
>
> Most commercial suppliers are not interested in relatively small
> installations because the pricing they can give on big systems falls
> apart below a couple of kw. There's similar setup time and labor
> for
> a few solar panels as for 4 times that many as well as the wiring so
> the costs for small solar don't work out.
>
> I'm handy at finding good used and recycled gear, as well as finding
> bargains in electronic equipoment. I put together a 12 volt, 540AH
> (6480WH) battery bank with two 2000 watt pure sine wave (PSW)
> inverters, a 500 watt PSW inverter, two 30 amp MPPT charge
> controllers, 900 watts of solar panels and all the interconnect
> wiring, fuses, circuit breakers and monitoring equipment for
> $100US.
> The electronics were shipped but the batteries and solar panels were
> sourced locally (no shipping, just gas for my truck). The solar
> panels are not yet permanently mounted (still working out which of 3
> possible mounting locations is the best location).
>
> I do have 25 amps of precisely controlled battery charging equipment
> that can be powered by a gasoline generator (NOT the $0 cheapie
> charger from the auto parts store). An hour of that charging
> provides
> 1 to 4 hours of runtime from the battery bank, depending on the
> season
> (more heat and light needed in winter and less sun available for
> solar
> charging).
>
> My design goal was "Wait until daylight" power so I would not be
> setting up the gas gen in the dark or during a thunderstorm because
> most of our outages are less than 16 hours. Depending on the
> season,
> the system provides 10 to 20 hours of limited power. The design
> meets
> my goal and I learned a great deal about solar power.