Any multi-voltage DC->AC inverters?

[pwbset]

Forgive my ignorance, but I'm not finding what I'm looking for. I'm building a new ebike battery for the season soon and it's likely going to be in the 60-75v range. What I'd like to be able to do is put it in my camper at night and hook it into an inverter that will output 120v AC for laptops/TVs etc. etc. (and ideally use said inverter with a solar panel to charge the ebike battery ?!? ) Is there an "any DC voltage" inverter out there that will do this? Am I over thinking the whole thing?? Any tips? Thanks!

 

[dumbass]

Forgive my ignorance, but I'm not finding what I'm looking for. I'm building a new ebike battery for the season soon and it's likely going to be in the 60-75v range. What I'd like to be able to do is put it in my camper at night and hook it into an inverter that will output 120v AC for laptops/TVs etc. etc. (and ideally use said inverter with a solar panel to charge the ebike battery ?!? ) Is there an "any DC voltage" inverter out there that will do this? Am I over thinking the whole thing?? Any tips? Thanks!

Power inverters are for the most part low effecency and therefore, rob your capasity for bike riding the following day. Of course the standard inverters are going to be 12v so you would need to lower your voltage while using the inverter. Solar charging is possible but slow and expensive. personally I would consider an SLA battery for the camper with solar charger for it.

 

[will_newton]

Is there an "any DC voltage" inverter out there that will do this? Am I over thinking the whole thing??

yes, you need a DC-DC converter.

these are not in your 60+voltage range, but I'd ask Justin anyway, he may know how to get you going, you may be able to find others. http://www.ebike.ca/store/store_accessories.php

you may be better off to re-title your thread, a DC inverter changes AC to DC and they are very common. I only checked here because I thought you were crazy and had never heard of one. :lol:

 

[pwbset]

yes, you need a DC-DC converter.

:lol: Wait.. no... I need AC out of the inverter... not DC. I don't know my inverters obviously. My camper is already rigged for 120VAC "shore power" and I want to mimic that with my ebike battery so DC->AC. I know there are plenty of 12v DC->AC inverters, but I want one that will input 60-75VDC and output (preferably pure sine wave) 120VAC. I'm sure you already knew that, but I feel like I'm confusing people (and myself). Clearly. :wink: :lol:

I'll re-title my thread to "Any multi-voltage DC->AC inverters?"

 

[TylerDurden]

My casual use of the term inverter is in line with the following:
"An inverter is an electrical device that converts direct current (DC) to alternating current (AC); the converted AC can be at any required voltage and frequency with the use of appropriate transformers, switching, and control circuits."
http://en.wikipedia.org/wiki/Inverter_(electrical)

That said, DC-DC should be more efficient, if available . Many of the electronic AC-DC supplies for gadgets can run on the 60V DC already.

Solar intended inverters that accept high-voltage DC can be pricey. Pure sine will be very pricey.

 

[pwbset]

An inverter is an electrical device that converts direct current (DC) to alternating current (AC)

Yes.. clearly this is what I need... but...

Many of the electronic AC-DC supplies for gadgets can run on the 60V DC already.

...the opposite of this. Right? I need DC->AC. Obviously. Are you saying I can buy any old plain jane inverter and be able to just plugin my ebike battery even if it's like 16s LiMn @ 67.2VDC and get 120VAC output? What am I missing here? It seems like every inverter I've run across only accepts 12v DC input.. like from a car battery of course. Why is this so difficult for me to understand? :lol: Everyone says I need DC-DC, but I want to use the existing 120VAC system in my van. If I wasn't already bald I'd be pulling out my hair. :lol: :wink:

 

[BLUESTREAK]

HEY PWBSET: Go to (AIMES POWER INVERTORS) thay have on that uses 42volts----67volts and is a pure sine wave. AIMES is one of the best ,I have a 5000 watt continous 10000watt surge hooked to 9 105amphr gel cell battries to run most of my home lights and refrig. for about 3 days if i am carefull in its use before i have to run my 7000watt propane generator (FLORIDA WEATHER YOU KNOW).

 

[Canis Lupus]

Why would you want 120 volt for laptops which mostly run off 18 or 19 volt? A simple step up transformer from 12 to 19 volt would do that job better instead of converting to 120 volt which then has to be converted again to 19 volt. That's extremely wasteful as the heat being produced by the transformers will tell you.

Better still you can get laptops like the Aus eee which run off 12 volt, which is the type I took on an extended bike tour around Greece. Low voltage TV's are also available although I have never cared for TV so much as to want to lug one around with me on a bike tour.

I also had several other smaller low voltage electrical appliances with me on tour. I took a variable voltage Lith Ion battery (5-19 volt) with multi connectors and USB charging outlet which took care of my laptop and other devices when I was deprived of a power point.

 

[pwbset]

Why would you want 120 volt for a laptops which mostly run off 18 or 19 volt?

Admittedly that was a piss-poor example of the need for standard 120VAC. My whole point was that I wanted to piggyback on the existing wiring setup in my van. I realize the waste of all the conversions and that DC appliances etc. are badass, but I'm just trying to work with what I've got is all.

 

[pwbset]

HEY PWBSET: Go to (AIMES POWER INVERTORS) thay have on that uses 42volts----67volts and is a pure sine wave.

BINGO! That's exactly what I was talking about! Thank you so much for the link!!!!!

http://www.aimscorp.net/PWRI150048S.htm

"dc input / operating voltage: 41.6-67 Vdc"

 

[TylerDurden]

My whole point was that I wanted to piggyback on the existing wiring setup in my van. I realize the waste of all the conversions and that DC appliances etc. are badass, but I'm just trying to work with what I've got is all.

Ja, that was not clear. My westy has the AC wiring, but the only uses are the fridge and one wall outlet. So I'd rather save the 600 bucks and use DC-DC.

 

[will_newton]

OK, I get you now. You could run a DC-DC converter to get your 12VDC output from the batteries, then run that output into an AC inverter to get 120 VAC.

here's a little thing on DC-DC converters. http://endless-sphere.com/forums/viewtopic.php?f=16&t=2264

 

[amberwolf]

Most likely your laptop's AC adapter will run right off the battery pack's DC voltage. Several of the ones I have here will run down to 40-50 VDC, or even lower. One I am using to power my CFL headlight and taillight runs down to 30-ish VDC.

Many AC-powered items will also run on DC if they use AC adapters (or internal power supplies) that are listed as 110-220VAC 50/60Hz input.

 

[pwbset]

My westy has the AC wiring

Yes... this is an old '72 bay campmobile as well. I'm going to have things like TV/AppleTV/laptop etc. in there so... I dunno... I'll think about it. You're right it's a lotta dough when there are inexpensive workarounds and a 12VDC makes much more sense as well. I just like the idea of hitting a remote camp site, bombing around on the ebike up the mountains for awhile and then using the same pack to "entertain" me at night and then charging it all up with a solar panel in the morning. Hmm.

 

[pwbset]

here's a little thing on DC-DC converters. http://endless-sphere.com/forums/viewtopic.php?f=16&t=2264

Sounds like a real viable option there... thanks for the link.. I'll edumacate mahself on it.

 

[Canis Lupus]

My westy has the AC wiring

Yes... this is an old '72 bay campmobile as well. I'm going to have things like TV/AppleTV/laptop etc. in there so... I dunno... I'll think about it. You're right it's a lotta dough when there are inexpensive workarounds and a 12VDC makes much more sense as well. I just like the idea of hitting a remote camp site, bombing around on the ebike up the mountains for awhile and then using the same pack to "entertain" me at night and then charging it all up with a solar panel in the morning. Hmm.

I still don't understand: you've got a 36 or 48 volt ebike battery, let's say, and you want to convert it to 12 volt, then back to a higher voltage via an inverter, which will then be converted back to a lower voltage for individual appliances.

It's puzzling.

Then you've got the problem of recharging from a 12 or 24 volt solar panel to what voltage - 36 or 48 volt?

Don't get me wrong, I'm interested in what you are doing, having thought about much the same type of situation. I don't mean any disrespect by my comments.

 

[pm_dawn]

Hi !

An idea is to look at a UPS that takes this kind of voltage in the Pack.

Regards
/Per

 

[Canis Lupus]

Another way of tackling this is to chat to a marine electrician. They deal with this type of situation all the time. Well set up boats resemble self-contained houses and are capable of powering themselves for months without the need for shore power.

 

[liveforphysics]

My westy has the AC wiring

Yes... this is an old '72 bay campmobile as well. I'm going to have things like TV/AppleTV/laptop etc.

Assuming the TV is an LCD, then everything you mentioned there ultimately runs on low voltage DC. Also, none of those things are using a transformer that does go from AC to AC without first turning it to DC, then switching it at high frequency. In other words, none of the devices you mentioned could care less if they get AC, DC, and would only run worse on a pure-sine wave.

The apple TV DC converter, and the laptop DC converter would work simply by connecting them to your E-bike pack directly. If the LCD TV is one of the super thin ones that has an external DC brick, it would connect directly to the E-bike pack as well. If not, with some very minor work inside the TV, you could solder the leads on internally in the TV and have it run directly as well.

-Luke

 

[pwbset]

Hmm... duh... never thought of all that.. thanks for the tips! It would be ideal to have a "DC" only camper.. I'd like to get one of those uber-efficient DC fridges as well. Those things are cool! Doh. :wink:

Assuming the TV is an LCD, then everything you mentioned there ultimately runs on low voltage DC. Also, none of those things are using a transformer that does go from AC to AC without first turning it to DC, then switching it at high frequency. In other words, none of the devices you mentioned could care less if they get AC, DC, and would only run worse on a pure-sine wave.

The apple TV DC converter, and the laptop DC converter would work simply by connecting them to your E-bike pack directly. If the LCD TV is one of the super thin ones that has an external DC brick, it would connect directly to the E-bike pack as well. If not, with some very minor work inside the TV, you could solder the leads on internally in the TV and have it run directly as well.

-Luke

 

[pwbset]

I still don't understand: you've got a 36 or 48 volt ebike battery, let's say, and you want to convert it to 12 volt, then back to a higher voltage via an inverter, which will then be converted back to a lower voltage for individual appliances.

Well... having run ebike batteries from 18v-87v so far I wanted solution that would work with any DC voltage. Since my van is AC and everything I wanna run is AC at the input I was just trying to figure a way to convert it all. As Luke points out all that stuff is just converted to DC anyway.. doh! Might as well keep it simple and just convert the whole van to low voltage DC anyway. That'll be better for fridges/solar panels options etc.

As I said in my original post... I'm overthinking it all. Still not sure how I'm gonna actually accomplish this all, but it's still winter so I got time to learn it all.

 

[amberwolf]

The apple TV DC converter, and the laptop DC converter would work simply by connecting them to your E-bike pack directly.

That's basically what I said.

 

[pwbset]

That's basically what I said.

:lol: I see that now. I wasn't making the connection sorry. It usually takes 2-3 of the same thing before I clue in. Never claimed to be the brightest bulb. :wink: Thanks for the info!

 

[pwbset]

So wait... can someone explain to me how an AppleTV or MacMini that's rated to receive 120-240VAC/50-60Hz can be directly connected to say a 16s/67.2VDC LiMn battery? Is it because the "brick" and it's guts convert whatever it gets to.. in the case of the Mini.. 18.5VDC @ 6A anyway? I mean... essentially I take like a 6 in 1 power strip, hack the ends with andersons, plug all my appliances into that and I'm good to go? Is it really that easy?

 

[amberwolf]

It might be.

Basically, all most of these bricks are is a DC-DC converter with a bridge rectifier and big capacitors on the front end to convert AC to DC.

So as long as it's startup voltage is low enough that it'll begin operating on lower voltages, which is usually the case, then it will probably work.

Now, keep in mind that power out must still equal power in, so it will draw more current at that lower input voltage than it does at the higher wall-AC voltage.

Also, since it will only be running thru two of the four bridge rectifier diodes, they will heat up more than usual, if they are separate and not part of a rectifier module that dissipates all the heat as one object. If you don't mind opening up the bricks to bypass that bridge for the DC connections, then even that won't matter.

My old Toshiba laptop runs off my battery pack at 48V, but it wouldn't run off the 36V pack. It would only charge itself up. So even at the lower input voltage it did still work, just not enough power output to run the laptop as a whole.

It should not hurt anything to at least try the idea, so try out that power strip with andersons, and see what happens. I didn't blow any of the stuff I've tried so far up, so even though some things don't work that way, many do, and none have so far been harmed by doing it (although it is theoretically possible to do so).