I need someone with an electrical or engineering background

[rpcrowe]

I have just purchased a Schumacher XP2260 Power Source (Jump Starter) so that I can always start my motorhome. I try to run the motorhome regularly in order to keep the battery charged but, I often forget to do this. The jump starter will allow me to jump start the motor home or any other vehicle I need it for.

However, this unit has an inverter with two A/C outputs. I wonder if I could use this to power a studio strobe such as my White Ligtning WL5000 outdoors. The problem is that I cannot figure out the power requirements for the strobe.

Here is the electrical info for the WL5000

Powering: 120VAC, 50/60HZ, 2A
Maximum Power: 250 wattseconds in the WL 10,000 units, and 130 wattseconds in the WL
5,000 units
Controls: Full Power, 2/3 Power, 1/3 Power, and Test/Discharge
Modeling Lamp: 100w household max. (indicates recycle status)
I don't plan to use the modeling light)
Recycle Time: 3/2/1 seconds in the WL 10,000 units, and 1.5/1/0.5 seconds in the WL 5,000
units

Here is some information from various sources regarding the inverters' capability

Built-in 400 Watt power inverter for 120V AC household power •
This unit has an 18 amp hour internal battery. It can power a device drawing 110 watts for about 1.5 hours,
The Instant Power™ must be used with devices drawing 200 watts or less. Ifthe wattage is not marked on the device, use only devices that draw less than 1.7 Ampsof AC current.
It is recommended that you don't use this to power
1.
Switch Mode Power Supplies
2.
Linear Power Supplies
3.
Class 2 Transformers
4.
Line Filter Capacitors
5.
Shaded Pole Motors
6.
Fan Motors
7.
Microwave Ovens
8.
Fluorescent and High Intensity Lamps (with a ballast)
9.
Transformerless Battery Charger

I realize that in talking watts and watt seconds, we are talking apples and oranges...

I don't want to hurt either the new power supply or my old WL5000 units. Otherwise, I'd just plug one or two units in and try it...

[Saorsa]

Your specs show that the strobe draws 2 amps and the inverter says not to use it for devices drawing more than 1.7.

For safety purposes I would suspect that the strobe requirements are overstated and the inverter load understated.

What would concern me is that it appears that the inverter is not putting out a true sine wave by the list of precluded devices. These include a couple of different forms of power supplies and storage via capacitor.

I wouldn't chance it without more detailed knowledge of the stobes design.

[xpatUSA]

I have just purchased a Schumacher XP2260 Power Source (Jump Starter) so that I can always start my motorhome.

However, this unit has an inverter with two A/C outputs.

These two outlets are described in the manual as "modified sine wave" unlike your household outlets which are pure sine wave. Most stuff should work OK when powered with "modified sine wave" - audio equipment might buzz a bit.

I wonder if I could use this to power a studio strobe such as my White Ligtning WL5000 outdoors. The problem is that I cannot figure out the power requirements for the strobe.

Here is the electrical info for the WL5000

Powering: 120VAC, 50/60HZ, 2A

That's all you need to know, the rest is to do with the flash output expressed in units of energy.

The WL5000 consumes 120VAC X 2A = 250 Watts from the Schumacher 120VAC outlet.

Here is some information from various sources regarding the inverters' capability

Built-in 400 Watt power inverter for 120V AC household power •
This unit has an 18 amp hour internal battery. It can power a device drawing 110 watts for about 1.5 hours,
The Instant Power™ must be used with devices drawing 200 watts or less. If the wattage is not marked on the device, use only devices that draw less than 1.7 Ampsof AC current.

Almost as bad as photography for obfuscation, eh? I think the problem here lies in the "modified sine-wave" bit because the above paragraph makes no sense.

In theory 400W at 120V is 3.33 Amps. And one strobe only takes 2 Amps which theoretically makes the Schumacher AC outlet more than adequate. However, this simple arithmetic is based on a) pure sinewave and b) RMS Watts not "peak". In view of the much smaller limit of 1.7 Amps, I'm going to say that their "modified sine-wave" bears little resemblance to a real sine-wave and is most likely a stepped square waveform - horrible but quite common with cheap inverters.

My opinion is that a load of one strobe (no modeling light) might work but the risk of lower performance is high and the risk of damage is significant.

[xpatUSA]

Your specs show that the strobe draws 2 amps and the inverter says not to use it for devices drawing more than 1.7.

For safety purposes I would suspect that the strobe requirements are overstated and the inverter load understated.

What would concern me is that it appears that the inverter is not putting out a true sine wave by the list of precluded devices. These include a couple of different forms of power supplies and storage via capacitor.

I wouldn't chance it without more detailed knowledge of the stobes design.

We were typing at the same time, Brian, and looks like we agree. Not often that I agree with anybody

Richard,

Unless you like buying new batteries may I strongly suggest that you permanently trickle charge the motor home battery with the type of low-current charger that switches on and off as needed. Lead-acid batteries that are allowed to discharge below 12V suffer a permanent reduction in capacity and, if allowed to go fully flat, can actually die.

I use two kinds of trickle charger out here: an AC-powered one for the 12V toilet system (country life, eh?) and a solar-powered one in my barn for a 12V powered Roberts radio and a couple of bench lamps.

PM me if you would like more details.

[CP140]

Yeah... a lot of things don't like the "dirty" power coming off a generator or the modified sine-wave inverters... I ran into a few issues powering computers and radios during the big windstorm (500,000 households in the dark) last month.

There are solutions out there than can provide nice clean power... but they tend to be more expensive.

As others have said, a dedicated trickle charger for the motorhome is the way to go...and for the studio strobe... the portable jump starter may work... depends on how grumpy the strobe power supply becomes when it sees dirty power.

As an example... I have three big 12V AGM batteries that I use to power radios (Amateur Radio guy with a strong interest in emergency preparedness). I discovered during last month's storm that the battery charger I have for those batteries doesn't like the dirty power coming off the generator. The charger runs hot and shuts down before the battery is charged...

[Dave Humphries]

Lots of good info above Richard, especially on keeping your motorhome battery alive by other means. Not that I have tried solar, but it worked when monthly top up charging (by long utility/mains extension lead) with a decent quality mains charger under the bonnet/hood.

++++++++++++++++++

As a general rule, but not wise to apply to this specific case due to the amps limits applying...

If the modelling light is tungsten, its stable, mostly resisitive load, might actually 'encourage' the inverter to produce a higher quality 'modified sine wave', in doing so, it may also discourage undesirable interactions between the voltage/current/power control circuits in the strobe and the inverter, which otherwise might actually 'fight' each other to try to stabilise things - and in process, cause damage to themselves.

++++++++++++++++++

I succumbed to buying one of these jump starter devices with an 18 A/h battery inside (no inverter in mine).

What I found was that keeping the jump starter's battery topped up was even more of a problem, whether I left it on trickle charging in house, or charged it weekly, it frequently showed 'flat' with the built in test button. Not very confidence inspiring.


Also, consider that; at only 18 A/h (compared to a vehicle battery of 70 A/h, often more), it contributed negligible amount of amps to turn over a vehicle when the starter might draw hundreds of amps (for a few seconds).

So what do I use mine for?
I used it a couple of times to keep alive the 'security memory' in a car radio 'live' while changing out a knackered car battery, since I wasn't supplied with code to reactivate and didn't want to be faced with needing a new radio too.

++++++++++++++++++

My view is the only thing that's gonna help start a vehicle is another battery of similar capacity to the vehicle's own (well charged).

There are (no doubt expensive) motor trade wheeled cart jump starters which hold such batteries (which work), or use another vehicle, but the little 'off the shelf' jump starters sold to the public are a complete waste of money.

HTH, Dave

[xpatUSA]

++++++++++++++++++

As a general rule, but not wise to apply to this specific case due to the amps limits applying...

If the modelling light is tungsten, its stable, mostly resisitive load, might actually 'encourage' the inverter to produce a higher quality 'modified sine wave', in doing so, it may also discourage undesirable interactions between the voltage/current/power control circuits in the strobe and the inverter, which otherwise might actually 'fight' each other to try to stabilise things - and in process, cause damage to themselves.

Sorry, Dave, I'm going to disagree with this speculation because it might encourage Richard to give it a try. The output waveform is created by switching devices that are either 'on' or 'off'. This inverter has two switch circuits involved - one for half voltage, one for full voltage. Such devices are virtually immune to "encouragement", sad to say. The "modified sine" waveform is absolutely horrible and, as I said earlier, bears little resemblance to a proper sine wave, as can be seen below:



A waveform like that killed a power tool battery charger of mine some years back and I've only used a true sine wave inverter ever since. If Richard's strobe has chips and stuff inside, I personally would not connect it to Schumaker - too high a risk, IMHO.

Another type uses a technique called Pulse Width Modulation (PWM) which gives more 'samples' per wave but the waveform is still horrible:

++++++++++++++++++

Also, consider that; at only 18 A/h (compared to a vehicle battery of 70 A/h, often more), it contributed negligible amount of amps to turn over a vehicle when the starter might draw hundreds of amps (for a few seconds).

The instantaneous current available from a battery is not directly related to it's capacity. That current is dependent on the battery's internal resistance which, in turn, is dependent on the battery technology and electrode design.

There are (no doubt expensive) motor trade wheeled cart jump starters which hold such batteries (which work), or use another vehicle, but the little 'off the shelf' jump starters sold to the public are a complete waste of money.

HTH, Dave

I have to agree with that. I had one (made in a far-off land of course) . . . lasted only a few months. I destroyed it with a lump hammer in a fit of pique

[Dave Humphries]

I hear what you're saying Ted and I wouldn't try it, so neither should Richard.

I still believe that some circuits will generate a more predictable waveform with a significant steady state load than if they didn't have it and their generation regulation was playing 'follow me' with an electronic switched mode PSU.

I agree with your technical reasoning on the small battery too, but in practice, I bet I'm right

Now, I hadn't considered that 'alternate' method of disposal, I think mine went to the community WEEE disposal site (in one piece) for recycling.