Crud! My inverter won't power my e-bike charger!

[highdesertranger]

idling a gas engine to charge a battery is, hard on the engine, really hard on the alternator, and very inefficient. highdesertranger

 

[tx2sturgis]

You know, I've never run the numbers on solar vs battery use.  I always looked to Sternwake for that sort of thing.  

Sternwake is a wealth of knowledge, and still available on the other van dwelling forum.

The idea is to charge the e-bike battery while in-route between distant riding locations.  

That will work fine, assuming of course, your alternator is able to keep up and stay cool. Most automotive alternators can easily handle an added drain of 15-20 amps or so while cruising the highway, especially during the day, when your headlamps are off.

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[Seminole Wind]

Before long I'll look just like my avatar photo.

wait, that isn't you? i just thought you were from Louisiana... how will i ever recognize you if i see you while traveling... lol

 

[BigT]

Update...  It still isn't working..

I wired the inverter directly to the battery with 6 AWG stranded wire and a 30A fuse, but the bike battery charger still runs in spurts or surges.  
Exactly what it was doing before when I had it wired through the charge controller.  

No, I haven't checked the Volts from the battery to the inverter, but this isn't the first thing I've wired in the van, and I see no reason why the wires wouldn't be supplying 12V to the inverter.  

Is there any chance this Wagan "pure sine wave" inverter isn't really pure sine wave? (false advertising).  

If someone can recommend a high quality inverter, say in the 1,000 Watt range, I'll give it a try.  

I really want to be able to charge my e-bike battery while on the road or, someday, living out of the van.  

One question about running a higher power inverter...  Will I need to run larger wire or change anything from what I have now?
(6 gauge wire / 30A fuse).

 

[BigT]

I did a voltage-drop test today, and I don't think that's the problem.

With the engine running, no-load voltage was 14.23 at the inverter. When I plugged in the bike charger and turned on the inverter, the voltage only dropped to 14.20. Still, the charger ran in its usual surging condition.

With the engine turned off, the drop was a little more noticeable, going from 13.73 to around 12.80 Volts.
(I never run the inverter with the engine turned off).

Then I made a jumper about 12 inches long and connected the inverter directly to the battery, under the hood. I had to run slightly smaller wires, but at that length, I don't think it was an issue.
The results were the same: Surging waves of power from the battery charger.

I think it's time for a new inverter.

 

[tx2sturgis]

Have you charged the ebike with the charger plugged into shore power? Household power?

Assuming you have, and it works fine, maybe it is time for a new inverter.

I am using the GoPower 700 PSW, and I paid $299 for mine, they are now on Amazon for $199.

https://www.amazon.com/Go-Power-GP-...+inverter+700&qid=1550193265&s=gateway&sr=8-4

 

[BigT]

Yes, I've used shore power, in fact that's the only way I use it.  It works fine when plugged into a wall outlet.  
I guess maybe I just bought a defective unit.  

Thanks for the link.  How do you like the connectors the power and ground cables attach to?  I can't tell in the photo how they attach.

I've been looking at this 600W inverter too, but I've read a couple not so great reviews about how the power cables connect to it.

https://www.amazon.com/Xantrex-806-...GSTGX3N1JFZ&psc=1&refRID=5NCPBN44DGSTGX3N1JFZ

 

[LoveCareThinkDo]

This is a test. I've been getting a 404 error when I try to post.

 

[LoveCareThinkDo]

I think it's time for a new inverter.

Wagan is not known for their high quality components. 

At 400 watts, your inverter is just barely powerful enough. 3 Amps times 120 volts equals 360 watts.  Keep in mind that most things like chargers and tools use a bit more current when first starting up. So a 500 watt inverter, that is from a quality manufacturer would probably work for you. Though, that would then still only be able to handle your eBike charger, with nothing else plugged in to that inverter. There is nothing wrong with having multiple inverters, if your batteries, panels, and charge controller can handle it. 

Now, you said your eBike charger is 100-240 watts. Based on the current usage you listed, I'm guessing that means that is how much power it is able to put into the eBike battery. This makes sense. All these things are notoriously inefficient. So consuming 360 watts while only putting out 240 watts is about right. 

Also, remember that 360 watts at 120 volts is still 360 watts at 12 volts. But, you would be drawing 360/12 or 30 amps out of your 12 volt system. And that doesn't account for the inefficiency of the inverter. So you will actually be drawing about 35 amps out of your 12 volt supply. So your 30 Amp fuse wouldn't really be enough to handle your current. It would be better to get a 50 Amp breaker. If you mount that breaker where you can easily get to it, you can use it as a switch for your inverter. 

Now, the next problem is: Can your 12 volt system provide a constant 35 amps for long enough to power the inverter that is powering the eBike charger. Just because you measure 14 volts on your 12 volt system with the inverter turned on, does not mean that your 12 volt system is providing enough current to run everything. If everything was just batteries and resistors, then the math would be easy. However, once you get electronic voltage controllers involved, things get too complicated to judge just by taking a voltage reading. Instead, you have to calculate based on what you know your components are capable of. 

First off is your battery: What battery are you using to power this whole thing? Or are you only powering it from your alternator while the engine is running? (Sorry, I did not read the entire thread. It gets tiresome reading through all the mythology that gets spread around here. I saw that your questions were still not answered, so I am jumping in to see if I can help.) If you are powering this off of a lead-acid based "house" battery, then you will likely need about 200 Amp hours worth of batteries. Keep in mind that you should not expect to charge your e-bike battery off of the house batteries. Given that one should only use about half of the Amp-hours in a lead-acid battery, and if you are using power quickly, as this eBike charger would do, then you can only get about half of that out of the battery before it is down to 50%. This would only give you about 50 Amp-hours of house battery that you could use for charging the eBike. That would last you less than two hours. No, I am guessing that you would need this 200 Amp hours to act as a decent buffer for the charge controller, which would be directly providing most of the power going into the eBike charger (unless you are using your alternator).

Second is your charge controller: It should be able to provide about 50 amps of power at 12-14.5 volts. If your charge controller can't provide 50 Amps, then all the additive inefficiencies will leave you with not enough power at the eBike charger. 

Third, are your solar panels: Can they really provide the 600 watts of power that this whole mess will need, once you account for the inefficiencies of the eBike charger, the inverter, the charge controller, and wire resistance? And do so on a continuous basis? I've got 610 watts of panels on my roof, but I don't expect them to ever put out 610 watts because they are laying flat on my roof. You would need maybe 900-1000 watts of panels to power this whole thing. And that's on a sunny day.

Yup. 30 amps is a hell of a lot to expect from a solar system. It can be done. Just ask JimInDenver. But it ain't cheap.

 

[LoveCareThinkDo]

I think it's time for a new inverter.

I had to post in two parts, for some reason. 

Here is an alternative: Look into finding a charger for your eBike that is designed to run off of 12 volts. I know the eBike batteries are 52 volts. But there is a device, called a voltage converter, that can convert 12 volts to 52 volts (or the likely 60 volt charging voltage). An eBike charger made to work on 12 volts would have one of these voltage converters in it. Now, why would this be better? A voltage converter would have less inefficiency than an inverter and charger strung together. It would also likely be able to charge at a lower current than your 120 volt, plug-in eBike charger. Those plug-in devices expect unlimited power to be available out of the house wall outlet. So they often don't work so great when there is not enough current available. But an eBike charger designed to plug into 12 volt systems would be designed to work with whatever current it could get. In this case, you would turn on (or plug in) the eBike charger only when the sun is shining and only after your house battery had been topped off. Your eBike battery would charge slowly over a few days. And that is better than nothing.

 

[LoveCareThinkDo]

One question about running a higher power inverter...  Will I need to run larger wire or change anything from what I have now?
(6 gauge wire / 30A fuse).

Yes, you should use a larger fuse. I suggest a 50 Amp breaker, as explained in my other post.

 

[BigT]

Wow, that's some really good information.  Thanks!

So here's what I've got...  A puny, 75 Amp/hr Northstar AGM battery, hooked to 190 Watts of solar and a SunSaver MPPT 15L CC.  
I never run the inverter/battery charger combo without the van's engine running, because I have no confidence in the system being able to keep up on its own.  

"At 400 watts, your inverter is just barely powerful enough. 3 Amps times 120 volts equals 360 watts."  

Your reply is the first time I've heard that my 400W inverter wouldn't be able to keep up.  Others are saying they're running bike chargers off less.

I'm very close to pulling the trigger on this $180, 600W inverter.  

https://www.amazon.com/Xantrex-806-...GSTGX3N1JFZ&psc=1&refRID=5NCPBN44DGSTGX3N1JFZ


.

 

[B and C]

I suggest you read the short page at the link provided. This will give you an idea of the amperage required for different size inverters. 6 Ga copper cable should be good for about 50 amps if the round trip length is less than 30 feet (15 one way) from what I am reading.

Parenthesis is for (24V system)

From: https://www.redarc.com.au/faq-tech-tips/inverter-current-draw

Question

How much current is drawn from the 12V (or 24V) battery when running a battery inverter?

Answer

The simple answer is- divide the load watts by 10 (20). E.g. For a load of 300 Watts, the current drawn from the battery would be:

300 ÷ 10 = 30 Amps (300 ÷ 20 = 15 Amps)

 

[Gr8ful]

I paid $100 for this 1000/2000 watt remote pure sne wave on Ebay eBay item number:232635463941
as I have a 500 watt elect li-ion elect bike also eBay item number:232635463941

 

[Weight]

A small investment in a Kill-A-Watt meter would go far in determining usage for any 120VAC appliance planed to use on an inverter. Before buying the inverter. https://www.amazon.com/P3-P4400-Ele...qid=1550239506&sr=8-3&keywords=kilowatt+meter
Harbor Freight also has them for a little less.
I am not a fan of DC circuit breakers on higher amp circuits, such as inverters. Give me a good old fuse any day.

Forum Rules.
DC = Direct Current, as from a battery.
120VAC = 120 voltage, Alternating Current as from an outlet in the house.

 

[BigT]

If I pull the trigger on this Xantrex 1000W inverter, will the 6 gauge wire and 50W maxi fuse still work, or will I need to run 2 AWG stranded cables and a breaker?
I'm going to have to relocate the inverter to under the driver's seat, and that will cut the cable length in half, to just about 5' or 6' from the battery.

I was told the 6 AWG and a 30A fuse would be OK for the 400W inverter, but I'm unsure if that will change with the more powerful model.   

I understand this setup won't be perfect, but will it work?    

https://www.amazon.com/Xantrex-806-...NM20QPFCDY4&psc=1&refRID=QF3YD81EWNM20QPFCDY4

.

 

[B and C]

I would use your existing 6 Ga wire (shortening it) with a 50 amp fuse. A 1000 watt inverter that is not running at capacity will not be drawing as much as it would if at full capacity. If you end up blowing the fuse, then is the time to get bigger cabling/fuse.

 

[tx2sturgis]

Thanks for the link.  How do you like the connectors the power and ground cables attach to?  I can't tell in the photo how they attach.

Robust screw terminals on the GoPower 700 PSW inverter.

 

[BigT]

Thanks to everyone who offered advise and ideas.  I just ordered the Xantrex 1000W model.  It should be here Monday and I should have it installed by the following weekend.  

Being an electrical moron, I really appreciate the helpful members of this site and their life-saving advise. 

 

[LoveCareThinkDo]

"At 400 watts, your inverter is just barely powerful enough. 3 Amps times 120 volts equals 360 watts."  

Your reply is the first time I've heard that my 400W inverter wouldn't be able to keep up.  Others are saying they're running bike chargers off less.

I'm just going off of the numbers you posted. It is very possible that either:

A) The numbers printed on your charger are not accurate. 
B) Your battery and charger are much more powerful than what those other people are using.
C) Their chargers are able to work with lower current for longer time while yours does not. 
D) Your first guess, that your inverter is crap, is accurate. 

There are just too many variables to troubleshoot this problem based on just a few messages. 

You should invest in a device called a Kill-A-Watt. It measures the actual wattage and current used by 120 volt appliances and devices. They cost about $20. You could plug that into the wall, plug your charger into that, then you would see exactly how many amps and watts your charger really uses. Be sure to check when the eBike battery is almost completely discharged and when it is almost full. They will be different.