Power Inverter For Dummies (in a 100 series)

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thegoodword

thegoodword

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Please be simple and reply in layman’s terms as I am not a very educated electric user. I have searched and read this forum’s threads on power inverters and alternators for a (2005) 100 series. I even wandered over to the great Google and I am just not finding dumbed down data.

Here what I am after: I want to purchase a power inverter to plug into the rear cargo area cigarette lighter. I want to charge a 400 watt battery. I want the capability to charge a 650 watt battery in the future. The battery is for a La Pierre 900FS BOSCH e-drive bicycle: http://www.lapierrebicycles.com/bikes-mountain-ebike-race-overvolt-fs-900

Is attaining what I want as simple as purchasing a 650 watt power inverter and plugging it into the rear cargo area cigarette lighter and charging the battery while the vehicle is running? Will I fry my alternator or drain the battery? Can I get away with not installing a second battery and still achieve charging this battery? What is the largest watt inverter I can safely use?
 
What are the requirements of the charger? There should be a sticker on it somewhere - post it up.

You likely won't be able to run through the cigarette outlet, as I think they're good for 3A max (or close to that amount).
 
If you want to charge your electric bike off your 4.7 V8 using an inverter you may be better off with a motorcycle.

You're going to need a big inverter and a lot of hours to charge a large battery like that. As stated above, you need to find the input rating of the charger first and then work your way back to get inverter size and wire size required and then see if your source is up to it.

Most inverters over 400W must be hardwired as the current draw is too great for the cig plug.

My guess is multiple pre-charged batteries are going to be a more useful solution than charging while driving would be.
 
No, there is no connection between the "wattage" of a battery (whatever that means really, odd spec) and the wattage of the inverter. It's not like if you have a battery capable of delivering 400 W (is that a max figure?) then you need a 400W inverter.

as stated, you have to figure out the numbers backward.
The alternator and battery should handle a reasonable charger just fine.
I would say figure out how fast (how long) you want the charging to take for the specific battery, that would tell you what kind of charger you will need, that will tell you what kind of inverter you will need, that will tell you what kind of plug and wiring you will need, that will tell you if what you have now in the truck is adequate or not.

Might as well bite the bullet and read a bit about the basics of electrical power and 12V wiring, it will serve you well forever.
 
Seems these bikes use 36v LI battery's rated at 400Wh. So... your cargo area cig outlet, stock, is rated at 12v and 10A which means you can safely draw up to 120W at 10 A into a load without frying your trucks wiring or blowing the fuse. I guess the bike comes with a charger to plug into your wall outlet, it's obviously an ac input with 36v dc output at some current level. Now to get the correctly sized inverter we need to know the load and this will be on the charger, something like 120V ac and 1A nominal for, say, 120W input (ac) and maybe you have something like 36v and 2A (72W) dc output. But here's the thing, low cost inverters are not efficient, maybe 75% max, and the cheaper ones don't have a good clean sinusoidal output which also impacts their output power quality. Now a trap for players is when they read the specs for a cheapy inverter and it says 100W output therefore that'll work on my 120W rated cig outlet. Unlikely because inverters consume power (heat) to convert power and to get 100W ac out of an inverter you'd likely need to put in 130 or 140W dc which exceeds the standard cig lighter capacity. I suspect that the input power requirements of the 36v charger combined with the losses of an inverter will exceed the 120W/10A capacity of the cig lighter, but let us know what the charger specs are anyway. If it's output is 36v and only 1A you might be able to make it work.
 
So here's the initial scoop. The factory outlet in the cargo area is rated for 120 watts. The largest inverter you should try to use there is a 150. I recommend the Samlex 150 PST sine wave inverter. However, in looking at the specs for your bike, I'm certain the charger for that 400 watt-hour battery will draw a lot more than 120 watts. (That's only 1 amp at 120 volts). Look on the charger and see what the power draw is. The lighter plug is rated for slightly more, but still likely won't work. So, to run that battery charger, you'll most likely need to hardware a larger inverter directly to the main vehicle battery and charge the bike battery while your going to the next place to bike. You won't hurt the battery or alternator doing that so long as the engine is running. And: volts X amps = watts. Many others have hard wired inverter so a search will turn up info on that. Samlex makes larger sine wave inverters too.
 
One more bit of info, it's the input draw of the charger that matters, so look for the amp draw at 120 volts and multiply amps by volts to get watts.
 
Sandroad said:
So here's the initial scoop. The factory outlet in the cargo area is rated for 120 watts. The largest inverter you should try to use there is a 150. I recommend the Samlex 150 PST sine wave inverter. However, in looking at the specs for your bike, I'm certain the charger for that 400 watt-hour battery will draw a lot more than 120 watts. (That's only 1 amp at 120 volts). Look on the charger and see what the power draw is. The lighter plug is rated for slightly more, but still likely won't work. So, to run that battery charger, you'll most likely need to hardware a larger inverter directly to the main vehicle battery and charge the bike battery while your going to the next place to bike. You won't hurt the battery or alternator doing that so long as the engine is running. And: volts X amps = watts. Many others have hard wired inverter so a search will turn up info on that. Samlex makes larger sine wave inverters too.
Click to expand...

I do not believe it is true that you can only put on a xyzW max rated inverter on a xyzW max rated plug. The inverter can certainly be larger nominally. It's the power drawn by the charger + the inverter losses that should not exceed the xyz W rating of the plug. Now, a 1000W inverter will probably have higher absolute losses than a 120W inverter but in principle I think it's perfectly fine to put a bigger inverter on a smaller plug if you use a small enough charger. (Well, as long as you will remember not to plug a 1000W load later on simply cuz it says 1000W on the inverter, that is...)
 
Thanks for the education everyone. Any more information you can provide in helping me not only understand 100 series electric (specifically for the cargo area plug) and acquiring an inverter that will do the job is appreciated. Here is what the charger says:
Input: 100V - 230V ~ 50-60Hz 2.2A
Output: 36V --- 4A
 
Good info. That means the power requirements of the charger are 264 watts. That's about double what the cargo area plug is rated for, so that likely won't work and likely neither would the 150 watt inverter I mentioned earlier. You could try it, but you'll probably blow the fuse to the cargo area outlet with that much draw. That means to charge the bike battery, you'll need to go to plan B or C. If it was mine, I would buy a Group 34 deep cycle Duracell AGM battery along with a Samlex 300 sine wave inverter. I would keep both in a large battery box in the cargo area and anytime I needed to charge the bike battery, I would attach the inverter to the AGM battery and plug the charger into the inverter Then, when I got home, I would put the AGM battery on a home charger and get ready for the next trip. I would go AGM (expensive) because they are non-spillable and don't vent hydrogen. I would go with a sine wave inverter (also more expensive) because they supply clean power and tend to be much higher quality than modified sine wave inverters. Plan C would be to wire a larger inverter into the main vehicle battery, but I've not done that so you'll need to read about it from other posts on the forum.
 
Yes, agree, Sandroads on the money. Your charger coupled with an inverter will draw about twice what the 10A outlet is designed to provide. An AGM + 300W (continuous) quality inverter like the Samlex in a portable battery box would solve your problem, particularly if you're looking at occasional use. If you ride/charged daily you'd probably want to go for a permanent, hard wired solution. There are inexpensive, simple little 120Vac power meters like the kill-a-watt meter that can be had for $25 and they will tell you exactly how much power your charger (or any other 120Vac domestic device) is actually drawing. Out of interest roughly how much are spare batteries for the bike?
 
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