Electrical gurus: help!

[BCO]

I'm in the process of building myself a solar charging station for my electric bicycle, and so far it's coming on well except for one issue.

I've connected an 80W solar panel to its little controller unit which in turn runs to a 45Ah battery. The battery is then connected to a 400W inverter which needs to power my e-bike's battery charger. The bike's charger is designed to run off mains power, hence the need to put an inverter between it and the battery.

The problem is this:

The inverter only has 2 x 2 prong outlets, while my bike's charger has a normal 3 prong kettle/PC power supply plug input. That means the charger needs to be earthed, right? What do I do about this if the inverter only outputs the live/neutral and has no earth? Does direct current from the battery that's been converted to AC even need to be earthed?

 

[Piepalook]

I'm in the process of building myself a solar charging station for my electric bicycle, and so far it's coming on well except for one issue.

I've connected an 80W solar panel to its little controller unit which in turn runs to a 45Ah battery. The battery is then connected to a 400W inverter which needs to power my e-bike's battery charger. The bike's charger is designed to run off mains power, hence the need to put an inverter between it and the battery.

The problem is this:

The inverter only has 2 x 2 prong outlets, while my bike's charger has a normal 3 prong kettle/PC power supply plug input. That means the charger needs to be earthed, right? What do I do about this if the inverter only outputs the live/neutral and has no earth? Does direct current from the battery that's been converted to AC even need to be earthed?

No , no need to earth it, it will work fine.

 

[zamicro]

It will work without being earthed, BUT if your charger is enclosed in a metal case, I would be wise to treat it as if you might be shocked by it.

 

[BCO]

Thanks guys. So I'll need to remove the three pronged plug at the inverter end of the kettle plug and put on a 2 prong plug. But what do I do with the earth wire then?

 

[Piepalook]

Thanks guys. So I'll need to remove the three pronged plug at the inverter end of the kettle plug and put on a 2 prong plug. But what do I do with the earth wire then?

Isolate that.You do not need it.
If you do not isolate that, it might touch on a metal part and your trip switch will trip.
No more power!

 

[BiteMe]

what has been said about the earth wire is true,

regarding your project, i am sure you have the best intention, but i have to say there is going to be a huge loss when using the invertor, they arent very efficient at all. something inside me says it may be better in the long run to investigate the charger for the bicycle itself, and see if you cant change it to work directly off dc..instead of going from dc--->ac--->ac--->dc

 

[BCO]

what has been said about the earth wire is true,

regarding your project, i am sure you have the best intention, but i have to say there is going to be a huge loss when using the invertor, they arent very efficient at all. something inside me says it may be better in the long run to investigate the charger for the bicycle itself, and see if you cant change it to work directly off dc..instead of going from dc--->ac--->ac--->dc

I realise it's inefficient, but I don't want to void the warranty on my bike's very expensive Li-Ion battery (or damage the battery for that matter), so I'm not going to modify the charger in any way or use any charger besides the one that came with the bike. Besides, on most days, an 80W panel should make more than enough power, even with the inefficiencies involved.

 

[Piepalook]

I realise it's inefficient, but I don't want to void the warranty on my bike's very expensive Li-Ion battery (or damage the battery for that matter), so I'm not going to modify the charger in any way or use any charger besides the one that came with the bike. Besides, on most days, an 80W panel should make more than enough power, even with the inefficiencies involved.

I also worked out the amps drawn,you will be ok,the solar panel will recharge the battery.

You must admit ,you have a very elaborate, very expensive way of recharging a 12 volt battery! LOL!

 

[BCO]

I also worked out the amps drawn,you will be ok,the solar panel will recharge the battery.

You must admit ,you have a very elaborate, very expensive way of recharging a 12 volt battery! LOL!

Yes, but it's carbon free. Now my bike is powered by the sun and not burning coal.

 

[Paulr]

Nice going there BlueCollar!

BTW - even when your bike comes out of guarantee, be careful about changing the charger. Lithium based batteries are finnicky things, and a decent Li-Ion charger will check the condition of each cell individually, balancing the charge to each one to max their lifespan. The process of charging these babies are a LOT more involved than charging a lead acid, NiMH etc etc.

Enjoy your non-polluting commute!