Today's Message Index:
----------------------
1. 09:49 AM - Re: Re: Brownout Step Up Converter (Charlie England)
2. 10:35 AM - Re: Re: Brownout Step Up Converter (Sebastien)
3. 12:36 PM - Re: Re: Brownout Step Up Converter (Charlie England)
4. 01:28 PM - Re: Re: Brownout Step Up Converter (Charlie England)
Message 1
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| Subject: | Re: Brownout Step Up Converter |
Hi Sebastian,
Thought I'd share some rough testing on a 4A rated booster, that seems to
use the same inverter IC as the one you're using. I bought these:
https://smile.amazon.com/gp/product/B07XG323G8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
I used an automotive brake light bulb that measures 2A draw at 14V and
~1.8A at 12.5V (about what a tired battery might be).
My results with the booster in the circuit, set for 11V output, which
should be adequate to keep an EFIS alive.
(list is: supply V/A booster V):
14/2.1 12.6
12/2.0 11.1
10/2.7 11.1
9/3.1 11.1
8.5/3.6 11.0
8.0/3.4 10.5
Supply V/A are read off my cheap Asian variable supply display, and rounded
to nearest tenth. Booster output V measured with Fluke meter, rounded to
nearest tenth.
After several minutes with the supply at 8V, the booster output starts
dropping a bit. I *suspect* that is because the inverter IC has no heat
sink and is beginning to thermal-limit to protect itself. In any case, the
booster should be loaded for only a few seconds during the start event.
Note: One thing I did was to insert a 'fat' diode in series with the supply
that goes directly to the lamp (also shown in the Z figure). The diode
output and the booster output both feed the lamp. When supply voltage drops
below booster output, the diode prevents the booster trying to feed back
into the supply at the booster's set voltage (obviously impossible).
Did you check your battery voltage at the battery terminals, or were you
using the EFIS to monitor battery voltage? My experience is that depending
on how the a/c is wired, the EFIS may see a lower than actual voltage, due
to diodes (or resistances) in the path to the EFIS input. Battery voltage
dropping to the 6V area when starting sounds like either high resistance in
the battery circuit, or a tired battery.
My GRT EFIS has multiple diode-isolated inputs, so the next step is to wire
the booster from my E-bus to a spare power input on the EFIS & try it out.
Charlie
On Sat, Sep 19, 2020 at 11:36 AM Sebastien <cluros@gmail.com> wrote:
> Now I'm getting confused. The converter Bob linked to has a minimum of 10
> volts input. Charlie's is 8.5 volts. The only time we want these units
> working is below 10 volts, and they need to work much lower than that. The
> last start on my aircraft recorded a 7.6 from a fully charged battery and
> that's just what the EFIS managed to capture at 1 sample per second.
>
> Looking again I have found a couple units that claim to work at very low
> voltages:
>
>
> https://www.ebay.ca/itm/DC-DC-10A-Buck-Boost-Converter-Step-Up-Down-regulator-Module-for-LED-Driver-US/254169431168
>
> https://www.ebay.ca/itm/DC-DC-Buck-Boost-Converter-Adjustable-CC-CV-Step-Up-Down-Power-Supply-Module/124260980594
>
> I'm considering ordering one for further testing.
>
> Bob best wishes for a quick recovery but take your time. Get yourself
> fully in fettle before worrying about anyone else!
>
> On Sat, Sep 19, 2020 at 8:17 AM Charlie England <ceengland7@gmail.com>
> wrote:
>
>> On 9/19/2020 9:26 AM, Robert L. Nuckolls, III wrote:
>>
>> At 11:02 PM 9/17/2020, you wrote:
>>
>> A couple weeks ago I ordered one of these off eBay:
>>
>> https://www.ebay.ca/itm/192243452240
>>
>> DC-DC Converter
>> 5 Amps
>> Input 3-35 V
>> Output 5-40 V
>>
>> I'm trying to support ~1 A EFIS during start so I thought 5 A would be
>> plenty but a closer look at the description says it's good for 3 A with a
>> maximum of 5 A. Turns out the 3 A is on the input side, not the output
>> side. With a voltage output set point of 10V and a ~1 A lamp connected, the
>> lamp browns out (literally) as soon as the input voltage sags below 9V. A
>> long way from the 7V minimum I was hoping for. I plugged it into a Battery
>> Analyzer at 1.0 and 0.5 A and momentarily dropped the input voltage to 8V.
>> Even when voltage is restored it takes several seconds to recover back to
>> the set voltage with a 1 A load. A 0.5 A load is fine.
>>
>>
>> Good investigative work sir! You're
>> on the right track. The up-converter
>> you have is a bit on the light side.
>>
>> I'd go for beefy . . . and the up-converter
>> needs to be characterized in Watts. A converter
>> that would support a 5A load at 14V would be
>> rated at 70 W or more.
>>
>> The test articles I have on hand are, as I recall,
>> 150 W devices. I'm hoping to put power to them
>> to see if I can characterize their dynamic qualities
>> before I send you one.
>>
>> I'm a bit out of pocket right now. Getting ready for
>> some roto-rooter work on my back . . . got a leg
>> that occasionally says, "I quit". It would not be
>> a good thing to be loading a patient and suddenly
>> find yourself on the ground asking the patient
>> to help you up!
>>
>> Doc says it's a quick fix with excellent
>> prospects for success but in the interim,
>> my forays about the shop are limited. The
>> up converters I have are, I believe, this
>> one:
>>
>> https://tinyurl.com/yxndk24a
>>
>> Price is right, size is convenient . . .
>> and there is little risk for having
>> one that is too big. Thanks for sharing
>> your observations.
>>
>>
>> Bob . . .
>>
>> These:
>>
>> https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue
>> Claim to be good down to 8.5V input. Various wattage versions available.
>>
>> Charlie
>>
>>
>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon> Virus-free.
>> www.avast.com
>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=link>
>> <#m_4222304353412265700_m_4819214867954981025_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>
>
Message 2
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| Subject: | Re: Brownout Step Up Converter |
Very interesting Charlie. I was only using a 1A automotive bulb for load
and as you say my converter looks like it's using the same hardware as
yours so maybe the addition of the second power path makes enough of a
difference? I would not have thought so but it's worth a try, I'll wire it
up again and see.
Also when dropping the voltage down to 8V I'm doing it as quickly as
possible with the power supply fine adjustment. Were you slowly decreasing
the input voltage or doing so suddenly?
Mine was $10 CAD for one and those ones are $30 for 5 so the price is ok.
On Sat, Sep 26, 2020 at 9:55 AM Charlie England <ceengland7@gmail.com>
wrote:
> Hi Sebastian,
>
> Thought I'd share some rough testing on a 4A rated booster, that seems to
> use the same inverter IC as the one you're using. I bought these:
>
> https://smile.amazon.com/gp/product/B07XG323G8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
> I used an automotive brake light bulb that measures 2A draw at 14V and
> ~1.8A at 12.5V (about what a tired battery might be).
>
> My results with the booster in the circuit, set for 11V output, which
> should be adequate to keep an EFIS alive.
> (list is: supply V/A booster V):
>
> 14/2.1 12.6
> 12/2.0 11.1
> 10/2.7 11.1
> 9/3.1 11.1
> 8.5/3.6 11.0
> 8.0/3.4 10.5
> Supply V/A are read off my cheap Asian variable supply display, and
> rounded to nearest tenth. Booster output V measured with Fluke meter,
> rounded to nearest tenth.
> After several minutes with the supply at 8V, the booster output starts
> dropping a bit. I *suspect* that is because the inverter IC has no heat
> sink and is beginning to thermal-limit to protect itself. In any case, the
> booster should be loaded for only a few seconds during the start event.
>
> Note: One thing I did was to insert a 'fat' diode in series with the
> supply that goes directly to the lamp (also shown in the Z figure). The
> diode output and the booster output both feed the lamp. When supply voltage
> drops below booster output, the diode prevents the booster trying to feed
> back into the supply at the booster's set voltage (obviously impossible).
>
> Did you check your battery voltage at the battery terminals, or were you
> using the EFIS to monitor battery voltage? My experience is that depending
> on how the a/c is wired, the EFIS may see a lower than actual voltage, due
> to diodes (or resistances) in the path to the EFIS input. Battery voltage
> dropping to the 6V area when starting sounds like either high resistance in
> the battery circuit, or a tired battery.
>
> My GRT EFIS has multiple diode-isolated inputs, so the next step is to
> wire the booster from my E-bus to a spare power input on the EFIS & try it
> out.
>
> Charlie
>
> On Sat, Sep 19, 2020 at 11:36 AM Sebastien <cluros@gmail.com> wrote:
>
>> Now I'm getting confused. The converter Bob linked to has a minimum of 10
>> volts input. Charlie's is 8.5 volts. The only time we want these units
>> working is below 10 volts, and they need to work much lower than that. The
>> last start on my aircraft recorded a 7.6 from a fully charged battery and
>> that's just what the EFIS managed to capture at 1 sample per second.
>>
>> Looking again I have found a couple units that claim to work at very low
>> voltages:
>>
>>
>> https://www.ebay.ca/itm/DC-DC-10A-Buck-Boost-Converter-Step-Up-Down-regulator-Module-for-LED-Driver-US/254169431168
>>
>> https://www.ebay.ca/itm/DC-DC-Buck-Boost-Converter-Adjustable-CC-CV-Step-Up-Down-Power-Supply-Module/124260980594
>>
>> I'm considering ordering one for further testing.
>>
>> Bob best wishes for a quick recovery but take your time. Get yourself
>> fully in fettle before worrying about anyone else!
>>
>> On Sat, Sep 19, 2020 at 8:17 AM Charlie England <ceengland7@gmail.com>
>> wrote:
>>
>>> On 9/19/2020 9:26 AM, Robert L. Nuckolls, III wrote:
>>>
>>> At 11:02 PM 9/17/2020, you wrote:
>>>
>>> A couple weeks ago I ordered one of these off eBay:
>>>
>>> https://www.ebay.ca/itm/192243452240
>>>
>>> DC-DC Converter
>>> 5 Amps
>>> Input 3-35 V
>>> Output 5-40 V
>>>
>>> I'm trying to support ~1 A EFIS during start so I thought 5 A would be
>>> plenty but a closer look at the description says it's good for 3 A with a
>>> maximum of 5 A. Turns out the 3 A is on the input side, not the output
>>> side. With a voltage output set point of 10V and a ~1 A lamp connected, the
>>> lamp browns out (literally) as soon as the input voltage sags below 9V. A
>>> long way from the 7V minimum I was hoping for. I plugged it into a Battery
>>> Analyzer at 1.0 and 0.5 A and momentarily dropped the input voltage to 8V.
>>> Even when voltage is restored it takes several seconds to recover back to
>>> the set voltage with a 1 A load. A 0.5 A load is fine.
>>>
>>>
>>> Good investigative work sir! You're
>>> on the right track. The up-converter
>>> you have is a bit on the light side.
>>>
>>> I'd go for beefy . . . and the up-converter
>>> needs to be characterized in Watts. A converter
>>> that would support a 5A load at 14V would be
>>> rated at 70 W or more.
>>>
>>> The test articles I have on hand are, as I recall,
>>> 150 W devices. I'm hoping to put power to them
>>> to see if I can characterize their dynamic qualities
>>> before I send you one.
>>>
>>> I'm a bit out of pocket right now. Getting ready for
>>> some roto-rooter work on my back . . . got a leg
>>> that occasionally says, "I quit". It would not be
>>> a good thing to be loading a patient and suddenly
>>> find yourself on the ground asking the patient
>>> to help you up!
>>>
>>> Doc says it's a quick fix with excellent
>>> prospects for success but in the interim,
>>> my forays about the shop are limited. The
>>> up converters I have are, I believe, this
>>> one:
>>>
>>> https://tinyurl.com/yxndk24a
>>>
>>> Price is right, size is convenient . . .
>>> and there is little risk for having
>>> one that is too big. Thanks for sharing
>>> your observations.
>>>
>>>
>>> Bob . . .
>>>
>>> These:
>>>
>>> https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue
>>> Claim to be good down to 8.5V input. Various wattage versions available.
>>>
>>> Charlie
>>>
>>>
>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon> Virus-free.
>>> www.avast.com
>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=link>
>>> <#m_-413585332925668195_m_4222304353412265700_m_4819214867954981025_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>>
>>
Message 3
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| Subject: | Re: Brownout Step Up Converter |
I re-ran the test, dialing back to as low as 7V as quickly as possible
while using the pot on the power supply. No difference in characteristics.
I then tried it with the lamp fed only by the booster; same result. At 7V
supply, current demand is a few tenths over the 4A rating of the booster,
and output voltage dropped to right at 10V. Below 7V the booster seems to
shut down (light slowly goes out) and if V is brought back up to ~12V, it
recovers within a second or two. Remember, I'm recording data with Mk1
eyeball & pencil. I'll report again when I get it 'breadboarded' in the
plane.
What's the exchange rate & border penalty in Canada these days? I paid less
than US$8 for the pack of 5, shipped. (Sincere apologies if you're getting
Trumped.)
Charlie
On Sat, Sep 26, 2020 at 12:44 PM Sebastien <cluros@gmail.com> wrote:
> Very interesting Charlie. I was only using a 1A automotive bulb for load
> and as you say my converter looks like it's using the same hardware as
> yours so maybe the addition of the second power path makes enough of a
> difference? I would not have thought so but it's worth a try, I'll wire it
> up again and see.
>
> Also when dropping the voltage down to 8V I'm doing it as quickly as
> possible with the power supply fine adjustment. Were you slowly decreasing
> the input voltage or doing so suddenly?
>
> Mine was $10 CAD for one and those ones are $30 for 5 so the price is ok.
>
> On Sat, Sep 26, 2020 at 9:55 AM Charlie England <ceengland7@gmail.com>
> wrote:
>
>> Hi Sebastian,
>>
>> Thought I'd share some rough testing on a 4A rated booster, that seems to
>> use the same inverter IC as the one you're using. I bought these:
>>
>> https://smile.amazon.com/gp/product/B07XG323G8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
>> I used an automotive brake light bulb that measures 2A draw at 14V and
>> ~1.8A at 12.5V (about what a tired battery might be).
>>
>> My results with the booster in the circuit, set for 11V output, which
>> should be adequate to keep an EFIS alive.
>> (list is: supply V/A booster V):
>>
>> 14/2.1 12.6
>> 12/2.0 11.1
>> 10/2.7 11.1
>> 9/3.1 11.1
>> 8.5/3.6 11.0
>> 8.0/3.4 10.5
>> Supply V/A are read off my cheap Asian variable supply display, and
>> rounded to nearest tenth. Booster output V measured with Fluke meter,
>> rounded to nearest tenth.
>> After several minutes with the supply at 8V, the booster output starts
>> dropping a bit. I *suspect* that is because the inverter IC has no heat
>> sink and is beginning to thermal-limit to protect itself. In any case, the
>> booster should be loaded for only a few seconds during the start event.
>>
>> Note: One thing I did was to insert a 'fat' diode in series with the
>> supply that goes directly to the lamp (also shown in the Z figure). The
>> diode output and the booster output both feed the lamp. When supply voltage
>> drops below booster output, the diode prevents the booster trying to feed
>> back into the supply at the booster's set voltage (obviously impossible).
>>
>> Did you check your battery voltage at the battery terminals, or were you
>> using the EFIS to monitor battery voltage? My experience is that depending
>> on how the a/c is wired, the EFIS may see a lower than actual voltage, due
>> to diodes (or resistances) in the path to the EFIS input. Battery voltage
>> dropping to the 6V area when starting sounds like either high resistance in
>> the battery circuit, or a tired battery.
>>
>> My GRT EFIS has multiple diode-isolated inputs, so the next step is to
>> wire the booster from my E-bus to a spare power input on the EFIS & try it
>> out.
>>
>> Charlie
>>
>> On Sat, Sep 19, 2020 at 11:36 AM Sebastien <cluros@gmail.com> wrote:
>>
>>> Now I'm getting confused. The converter Bob linked to has a minimum of
>>> 10 volts input. Charlie's is 8.5 volts. The only time we want these units
>>> working is below 10 volts, and they need to work much lower than that. The
>>> last start on my aircraft recorded a 7.6 from a fully charged battery and
>>> that's just what the EFIS managed to capture at 1 sample per second.
>>>
>>> Looking again I have found a couple units that claim to work at very low
>>> voltages:
>>>
>>>
>>> https://www.ebay.ca/itm/DC-DC-10A-Buck-Boost-Converter-Step-Up-Down-regulator-Module-for-LED-Driver-US/254169431168
>>>
>>> https://www.ebay.ca/itm/DC-DC-Buck-Boost-Converter-Adjustable-CC-CV-Step-Up-Down-Power-Supply-Module/124260980594
>>>
>>> I'm considering ordering one for further testing.
>>>
>>> Bob best wishes for a quick recovery but take your time. Get yourself
>>> fully in fettle before worrying about anyone else!
>>>
>>> On Sat, Sep 19, 2020 at 8:17 AM Charlie England <ceengland7@gmail.com>
>>> wrote:
>>>
>>>> On 9/19/2020 9:26 AM, Robert L. Nuckolls, III wrote:
>>>>
>>>> At 11:02 PM 9/17/2020, you wrote:
>>>>
>>>> A couple weeks ago I ordered one of these off eBay:
>>>>
>>>> https://www.ebay.ca/itm/192243452240
>>>>
>>>> DC-DC Converter
>>>> 5 Amps
>>>> Input 3-35 V
>>>> Output 5-40 V
>>>>
>>>> I'm trying to support ~1 A EFIS during start so I thought 5 A would be
>>>> plenty but a closer look at the description says it's good for 3 A with a
>>>> maximum of 5 A. Turns out the 3 A is on the input side, not the output
>>>> side. With a voltage output set point of 10V and a ~1 A lamp connected, the
>>>> lamp browns out (literally) as soon as the input voltage sags below 9V. A
>>>> long way from the 7V minimum I was hoping for. I plugged it into a Battery
>>>> Analyzer at 1.0 and 0.5 A and momentarily dropped the input voltage to 8V.
>>>> Even when voltage is restored it takes several seconds to recover back to
>>>> the set voltage with a 1 A load. A 0.5 A load is fine.
>>>>
>>>>
>>>> Good investigative work sir! You're
>>>> on the right track. The up-converter
>>>> you have is a bit on the light side.
>>>>
>>>> I'd go for beefy . . . and the up-converter
>>>> needs to be characterized in Watts. A converter
>>>> that would support a 5A load at 14V would be
>>>> rated at 70 W or more.
>>>>
>>>> The test articles I have on hand are, as I recall,
>>>> 150 W devices. I'm hoping to put power to them
>>>> to see if I can characterize their dynamic qualities
>>>> before I send you one.
>>>>
>>>> I'm a bit out of pocket right now. Getting ready for
>>>> some roto-rooter work on my back . . . got a leg
>>>> that occasionally says, "I quit". It would not be
>>>> a good thing to be loading a patient and suddenly
>>>> find yourself on the ground asking the patient
>>>> to help you up!
>>>>
>>>> Doc says it's a quick fix with excellent
>>>> prospects for success but in the interim,
>>>> my forays about the shop are limited. The
>>>> up converters I have are, I believe, this
>>>> one:
>>>>
>>>> https://tinyurl.com/yxndk24a
>>>>
>>>> Price is right, size is convenient . . .
>>>> and there is little risk for having
>>>> one that is too big. Thanks for sharing
>>>> your observations.
>>>>
>>>>
>>>> Bob . . .
>>>>
>>>> These:
>>>>
>>>> https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue
>>>> Claim to be good down to 8.5V input. Various wattage versions available.
>>>>
>>>> Charlie
>>>>
>>>>
>>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon> Virus-free.
>>>> www.avast.com
>>>> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=link>
>>>> <#m_-2951286493721026940_m_-413585332925668195_m_4222304353412265700_m_4819214867954981025_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>>>>
>>>
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| Subject: | Re: Brownout Step Up Converter |
Additional thought. Did you ensure that your bench power supply was
supplying the additional current needed when the voltage drops? Mine has
a current limit knob in addition to the voltage control; I have to be
sure I've dialed in enough current that the supply doesn't hit the limit.
Charlie
On 9/26/2020 2:29 PM, Charlie England wrote:
> I re-ran the test, dialing back to as low as 7V as quicklyas possible
> while using the pot on the powersupply. No difference in
> characteristics.
>
> I then tried it with the lamp fed only by the booster; same result. At
> 7V supply, current demand is a few tenths over the 4A rating of the
> booster, and output voltage dropped to right at 10V. Below 7V the
> booster seems to shut down (light slowly goes out) and if V is brought
> back up to ~12V, it recovers within a second or two. Remember, I'm
> recording data with Mk1 eyeball & pencil. I'll report again when I get
> it 'breadboarded' in the plane.
>
> What's the exchange rate & border penalty in Canada these days? I paid
> less than US$8 for the pack of 5, shipped. (Sincere apologies if
> you're getting Trumped.)
>
> Charlie
>
> On Sat, Sep 26, 2020 at 12:44 PM Sebastien <cluros@gmail.com
> <mailto:cluros@gmail.com>> wrote:
>
> Very interesting Charlie. I was only using a 1A automotive bulb
> for load and as you say my converter looks like it's using the
> same hardware as yours so maybe the addition of the second power
> path makes enough of a difference? I would not have thought so but
> it's worth a try, I'll wire it up again and see.
>
> Also when dropping the voltage down to 8V I'm doing it as quickly
> as possible with the power supply fine adjustment. Were you slowly
> decreasing the input voltage or doing so suddenly?
>
> Mine was $10 CAD for one and those ones are $30 for 5 so the price
> is ok.
>
> On Sat, Sep 26, 2020 at 9:55 AM Charlie England
> <ceengland7@gmail.com <mailto:ceengland7@gmail.com>> wrote:
>
> Hi Sebastian,
>
> Thought I'd share some rough testing on a 4A rated booster,
> that seems to use the same inverter IC as the one you're
> using. I bought these:
> https://smile.amazon.com/gp/product/B07XG323G8/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
> I used an automotive brake light bulb that measures 2A draw at
> 14V and ~1.8A at 12.5V (about what a tired battery might be).
>
> My results with the booster in the circuit, set for 11V
> output, which should be adequate to keep an EFIS alive.
> (list is: supply V/A booster V):
>
> 14/2.1 12.6
> 12/2.0 11.1
> 10/2.7 11.1
> 9/3.1 11.1
> 8.5/3.6 11.0
> 8.0/3.4 10.5
> Supply V/A are read off my cheap Asian variable supply
> display, and rounded to nearest tenth. Booster output V
> measured with Fluke meter, rounded to nearest tenth.
> After several minutes with the supply at 8V, the booster
> output starts dropping a bit. I /suspect/ that is because the
> inverter IC has no heat sink and is beginning tothermal-limit
> to protect itself. In any case, the booster should be loaded
> for only a few seconds during the start event.
>
> Note: One thing I did was to insert a 'fat' diode in series
> with the supply that goes directly to the lamp (also shown in
> the Z figure). The diode output and the booster output both
> feed the lamp. When supply voltage drops below booster output,
> the diode prevents the booster trying to feed back into the
> supply at the booster's set voltage (obviously impossible).
>
> Did you check your battery voltage at the battery terminals,
> or were you using the EFIS to monitor battery voltage? My
> experience is that depending on how the a/c is wired, the EFIS
> may see a lower than actual voltage, due to diodes (or
> resistances) in the path to the EFIS input. Battery voltage
> dropping to the 6V area when starting sounds like either high
> resistance in the battery circuit, or a tired battery.
>
> My GRT EFIS has multiple diode-isolated inputs, so the next
> step is to wire the booster from my E-bus to a spare power
> input on the EFIS & try it out.
>
> Charlie
>
> On Sat, Sep 19, 2020 at 11:36 AM Sebastien <cluros@gmail.com
> <mailto:cluros@gmail.com>> wrote:
>
> Now I'm getting confused. The converter Bob linked to has
> a minimum of 10 volts input. Charlie's is 8.5 volts. The
> only time we want these units working is below 10 volts,
> and they need to work much lower than that. The last start
> on my aircraft recorded a 7.6 from a fully charged battery
> and that's just what the EFIS managed to capture at 1
> sample per second.
>
> Looking again I have found a couple units that claim to
> work at very low voltages:
>
> https://www.ebay.ca/itm/DC-DC-10A-Buck-Boost-Converter-Step-Up-Down-regulator-Module-for-LED-Driver-US/254169431168
> https://www.ebay.ca/itm/DC-DC-Buck-Boost-Converter-Adjustable-CC-CV-Step-Up-Down-Power-Supply-Module/124260980594
>
> I'm considering ordering one for further testing.
>
> Bob best wishes for a quick recovery but take your time.
> Get yourself fully in fettle before worrying about anyone
> else!
>
> On Sat, Sep 19, 2020 at 8:17 AM Charlie England
> <ceengland7@gmail.com <mailto:ceengland7@gmail.com>> wrote:
>
> On 9/19/2020 9:26 AM, Robert L. Nuckolls, III wrote:
>> At 11:02 PM 9/17/2020, you wrote:
>>> A couple weeks ago I ordered one of these off eBay:
>>>
>>> https://www.ebay.ca/itm/192243452240
>>> <https://www.ebay.ca/itm/192243452240>
>>>
>>> DC-DC Converter
>>> 5 Amps
>>> Input 3-35 V
>>> Output 5-40 V
>>>
>>> I'm trying to support ~1 A EFIS during start so I
>>> thought 5 A would be plenty but a closer look at the
>>> description says it's good for 3 A with a maximum of
>>> 5 A. Turns out the 3 A is on the input side, not the
>>> output side. With a voltage output set point of 10V
>>> and a ~1 A lamp connected, the lamp browns out
>>> (literally) as soon as the input voltage sags below
>>> 9V. A long way from the 7V minimum I was hoping for.
>>> I plugged it into a Battery Analyzer at 1.0 and 0.5
>>> A and momentarily dropped the input voltage to 8V.
>>> Even when voltage is restored it takes several
>>> seconds to recover back to the set voltage with a 1
>>> A load. A 0.5 A load is fine.
>>
>> Good investigative work sir! You're
>> on the right track. The up-converter
>> you have is a bit on the light side.
>>
>> I'd go for beefy . . . and the up-converter
>> needs to be characterized in Watts. A converter
>> that would support a 5A load at 14V would be
>> rated at 70 W or more.
>>
>> The test articles I have on hand are, as I recall,
>> 150 W devices. I'm hoping to put power to them
>> to see if I can characterize their dynamic qualities
>> before I send you one.
>>
>> I'm a bit out of pocket right now. Getting ready for
>> some roto-rooter work on my back . . . got a leg
>> that occasionally says, "I quit". It would not be
>> a good thing to be loading a patient and suddenly
>> find yourself on the ground asking the patient
>> to help you up!
>>
>> Doc says it's a quick fix with excellent
>> prospects for success but in the interim,
>> my forays about the shop are limited. The
>> up converters I have are, I believe, this
>> one:
>>
>> https://tinyurl.com/yxndk24a
>> <https://tinyurl.com/yxndk24a>
>>
>> Price is right, size is convenient . . .
>> and there is little risk for having
>> one that is too big. Thanks for sharing
>> your observations.
>>
>>
>> Bob . . .
>>
> These:
> https://www.ebay.com/itm/DC-DC-Converter-10-12-15-20A-150-250-300-400-1200W-Step-up-Step-down-Buck-Boost/382219150784?hash=item58fe0965c0:g:6OwAAOSwisVZrgue
> Claim to be good down to 8.5V input. Various wattage
> versions available.
>
> Charlie
>
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