Sizing an inverter

[gerry mcg]

I’m looking at fitting a Pure sine wave inverter to charge eBike battery.
the question is what size? Space is a premium….so it needs to be compact.
ive two Bosch 230v chargers available ,
*one is a ‘standard‘ slow charge with a transformer with an input of 100-240v at 1.6A, output at 36V at 2A, and the other one is
Input of 100-240v at 2.15A, and an output of 36v at 6A.
I’m i correct in thinking the power requirement is 500W (230x2.15) plus an allowance for efficiency loss?
I don’t have any other 230v power requirements

I’m looking at Victron Energy Phoenix 12/800 or 12/1200 … (obvs the 800W inverter is cheaper and importantly, in a smaller case)
<Broken link removed>
<Broken link removed>

thanks

 

[Raul]

The one in first link is with ve direct port. On the second link is the old model without ve direct port. The old one is my preferred choice, it has a 6w no load draw, very economical and extremely efficient in its class. I have a 48v version for few years now and it’s a robust piece. The one with ve direct it has a increased consumption 11-12w on stand by.

 

[gerry mcg]

The one in first link is with ve direct port. On the second link is the old model without ve direct port. The old one is my preferred choice, it has a 6w no load draw, very economical and extremely efficient in its class. I have a 48v version for few years now and it’s a robust piece. The one with ve direct it has a increased consumption 11-12w on stand by.

Ah, ok i didn't realise that - so this is the newer 1200W one with VE Direct
<Broken link removed>
(same price i see)
and this is the older one
<Broken link removed>
(on either) if it is situates in a place where the rocker power switch is accessible, if I were to simply switch off the inverter at the rocker switch at the back, will that remove the no load draw issue?

 

[Raul]

Yes that’s correct. Switch it of, 0 load. Switch it to eco, will put it in search mode and consume a mare 2w until a load is detected. You can also add a remote switch at your convenience, without going in the cupboard.

 

[orridge]

If you can find one of these it would be an option instead of using an inverter https://www.e-bikeshop.co.uk/blog/post/bosch-ebike-12v-travel-battery-car-charger/

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

If you can find one of these it would be an option instead of using an inverter https://www.e-bikeshop.co.uk/blog/post/bosch-ebike-12v-travel-battery-car-charger/

Expensive for what they are and take twice as long to charge the batteries.

 

[gerry mcg]

Is 800W adequate, can i use a 500W? Or should i go for the 1200W one?

 

[autorouter]

Input of 100-240v at 2.15A, and an output of 36v at 6A.

Output is 36V 6A, so the output power is 36 x 6 = 216W.

Input is 100 to 240V, the 2.15A is likely to be the amps at 100V, ie a power of 100 x 2.15 = 215W. At higher voltage the power will be about the same, so the amps will be less. The upshot is, the power is likely to be nearer 250W than 500W.

 

[gerry mcg]

I might look at the 12/375 inverter then, as there is no point over spec’ing it

 

[Raul]

There is on eBay a 375va and a 800va for sale now. Not mine, just heads up, you could save some dosh on a used one.

^{_{Subscribers  do not see these advertisements}}

 

[Lenny HB]

I might look at the 12/375 inverter then, as there is no point over spec’ing it

I would go a bit bigger I have found if the charger has not been used for a while the startup current can trip the inverter if its not big enough.

 

[gerry mcg]

Ok, thank for the advice… Ive gone for a Victron phoenix 12/500 - just planning how best to fit it now

 

[gerry mcg]

I’ll be putting it close to the battery (0.5m) so the manual indicates 6mm2 cables are OK, with a 4mm2 ground - The installation instructions / wiring diagrams don’t appear to require a fuse between the battery and the inverter If the inverter is <1.5m from the battery, so I think i should be OK without one… I’m struggling to find a good chassis ground close to teh battery, but ive found the starter battery earth strap, so i should be able to ground to chassis if i run the ground to that?

 

[Lenny HB]

I’ll be putting it close to the battery (0.5m) so the manual indicates 6mm2 cables are OK, with a 4mm2 ground - The installation instructions / wiring diagrams don’t appear to require a fuse between the battery and the inverter If the inverter is <1.5m from the battery, so I think i should be OK without one… I’m struggling to find a good chassis ground close to teh battery, but ive found the starter battery earth strap, so i should be able to ground to chassis if i run the ground to that?

The 12/500 is 500VA approx 400 Watt allowing for inverter efficiency the voltage drop will be less than 1% with 6mm cable so all good.

 

[dunnah01]

Not sure why you need an inverter? Why not just plug the bike charger into the 240v supply or am I missing something.

Ding just understood that chargers are for bikes not to charge leisure batteries for inverter - off to get my coat

^{_{Subscribers  do not see these advertisements}}

 

[gerry mcg]

I‘ve successfully fitted the Victron phoenix 500W PSW inverter and all seems to work OK.
The positive is connected to the battery, and the negative to the negative terminal of the Vcitron shunt.
it seems to work well - drawing 17.5A (at 12v) (so 210W) to charge a 650W Bosch battery on a transformer with an input rating of 110-230v at 2.1A (231w) outputting at 36v at 6A (216A)

Out of interest, i plugged in a socket tester and i got errors - a intermittent buss and with the left LED illuminated green, the central unlit, and the right LED illuminated Red -
according to the socket tester - this is indicative of a L/N reverse… thoughts?

 

[Raul]

Your inverter does not have a true neutral. To make a true neutral, it needs to be bonded inside the inverter to a virtual PE, protective earth. On your model I’m not sure it is possible, the 1200va it is documented in the inverter manual under appendix.
It will work fine and is double insulated as it is, and safe. It will not work with sensitive neutral detection, like a boiler with flame detection trough the neutral. Other than that I would leave it as is and use it.

 

[gerry mcg]

Your inverter does not have a true neutral. To make a true neutral, it needs to be bonded inside the inverter to a virtual PE, protective earth. On your model I’m not sure it is possible, the 1200va it is documented in the inverter manual under appendix.
It will work fine and is double insulated as it is, and safe. It will not work with sensitive neutral detection, like a boiler with flame detection trough the neutral. Other than that I would leave it as is and use it.

Thanks