Charging Ebike battery using an inverter from camper van battery

[IR772]

Was interested by this thread so did a bit of reading.

This link involves a laptop charger and is worth a scan considering the cost of Bosch battery chargers.

http://electronics.stackexchange.com/questions/128365/could-a-modified-sine-wave-inverter-destroy-damage-the-ac-adapter-for-a-laptop

 

[Danidl]

Was interested by this thread so did a bit of reading.

This link involves a laptop charger and is worth a scan considering the cost of Bosch battery chargers.

http://electronics.stackexchange.com/questions/128365/could-a-modified-sine-wave-inverter-destroy-damage-the-ac-adapter-for-a-laptop

That is an interesting link. The waveform shown is not what I would have understood as a modified sine wave . That is the ordinary square wave , there needs to be a dwell state at the end of each transition when all the driver transistors are in the off state in order to prevent a short of power to ground in case one of the transistors is tardy.
The reference to voltage overshoot may be a switching transient, but is just as likely to be an artifact due to unforeseen compensated probe.
A true modified sine wave generator will be use pulse width modulation using a very high speed switch in order to mimic the power output of a sine wave .. full voltage narrow pulses for the lower voltage and wider pulses of full voltage towards the peak.

 

[IR772]

Anything with "DrFriedParts" in is a must read in this household.

 

[Danidl]

Anything with "DrFriedParts" in is a must read in this household.

... I have been doing some more reading and remembering.
In the remember category, i once drove accross Ireland using a laptop computer in the car powered by one of those low cost inverters, and the laptops battery charger. The laptop was an adli purchased medion brand. I was using it as a GPS system . The only casualty was overheating in the cigarette lighter socket, both charger and inverter are still ok. This was a 6 to 7 hour charging event

What seems to be passing as" modified sine wave " Is a marketing term for square wave .

Reading again the article referred to , i suspect that the invertor was incapable of supply of sufficient power to the battery charger, it was therefore trying to engage the start up sequence with low voltage and driving excessive current into the switching transistor. The transistors was not getting into the high efficiency saturated state and consumes much more energy. Power engineers would call this a " brown out "

 

[Kendalian]

I'm a pretty careful guy at the best of times so I think a pure sine wave inverter is the way to go for safety. I'm thinking one of these 600w models which will enable me to charge 2 batteries at once.

http://www.armcoshop.co.uk/products/soft-start-pure-sine-wave-inverters-652-102uk.html?gclid=CNe4s5r72tICFQU8GwodYVUD4g

Cheers

Kendalian

 

[Danidl]

I'm a pretty careful guy at the best of times so I think a pure sine wave inverter is the way to go for safety. I'm thinking one of these 600w models which will enable me to charge 2 batteries at once.

http://www.armcoshop.co.uk/products/soft-start-pure-sine-wave-inverters-652-102uk.html?gclid=CNe4s5r72tICFQU8GwodYVUD4g

Cheers

Kendalian

... Good call, 600w one will allow you to use a power tool eg a drill or jigsaw as well as charging the battery. Note you would need to have either the van running or your solar panels assy charged , as the device will be drawing nearly 700w or nearly 70 amps at 12v ... very Thick cables at the low voltage input as well. Best of luck!

 

[IR772]

... 70 amps at 12v

!

 

[soundwave]

now thats a charger

 

[Danidl]

... Good call, 600w one will allow you to use a power tool eg a drill or jigsaw as well as charging the battery. Note you would need to have either the van running or your solar panels assy charged , as the device will be drawing nearly 700w or nearly 70 amps at 12v ... very Thick cables at the low voltage input as well. Best of luck!

.. I am not big into car parts, but I suspect that 600w of additional load on an alternator may be excessive. My reading suggests that normal ones are rated at 55 to 75amp, and only special vehicles ( jeeps, mountain rescue, military) have larger rated ones for winches etc. So charging a single battery would be more prudent. A power tool could be used as by its nature it is intermittent and the car battery can take up the slack.

 

[Kendalian]

Yes - I think you're right, though the Renault Master which the campervan is based on does have a 150 amp alternator. Again my carefullness suggests one battery at a time! I will probably get the 600w inverter and see what power it pulls when charging one battery (via the van's NASA BM1 battery monitor), then maybe consider charging 2 at a time.

Kendalian

 

[JohnnyGM7LSI]

Yes - I think you're right, though the Renault Master which the campervan is based on does have a 150 amp alternator. Again my carefullness suggests one battery at a time! I will probably get the 600w inverter and see what power it pulls when charging one battery (via the van's NASA BM1 battery monitor), then maybe consider charging 2 at a time.

Kendalian

My camper van is also a Renault Master, and has the 150amp alternator, the problem with them is, when the alternator sees the engine battery reach 12.8 to13v, the regulator drops the charge back to a trickle 5 to 10 amps, and takes forever to charge them, the setup is designed to power everthing on a journey between campsites where you can hookup to mains, I seldom use campsites, so I have fitted a Sterling 120amp Batter to Battery charger, it draws power from the alternator and boosts it to 120amps, which charges my 550Amh batteries very quickly and the batteries run my 2KW pure sine wave inverter, the inverter also runs tv, sky box, toaster, microwave, laptop ect, solar power charging is fine when its sunny, but the Battery to Battery charger is a good backup and reliable, a 45 min drive will re-charge my batteries.

 

[Kendalian]

Your campervan must be set up different to mine. When the split charge kicks in the alternator 'sees' 300 amps of battery and continues to charge at a high level until al batteries are fully charged.

cheers

Kendalian

 

[GLJoe]

I want to charge a Bosch 400 battery from the batteries in the camper van
....
My question is, do I need to use a Pure Sine Wave inverter

Just giving this question a bump, as it doesn't seem there ever was a definitive answer.
I'm also interested whether the same also applies for the standard 4A Yamaha chargers as well.

 

[Deleted member 4366]

Get yourself a lightweight generator. They're always useful. these ones are only about 9kg and they're very quiet:

http://www.ebay.co.uk/itm/Ex-Demo-Wolf-Power-Genie-WPG950-800w-2-6HP-Petrol-Inverter-Camping-Generator-/282593415907?hash=item41cbe152e3:g:12IAAOSw-FZXj3~x

 

[Kendalian]

I went for a 300w pure sine wave inverter in the end for £70 https://www.amazon.co.uk/dp/B00J68QL0K/ref=pe_385721_37986871_TE_item
When charging the battery it is taking 8.9 amps, with the leisure batteries sitting at 12.5v.

Cheers

Kendalian

 

[Deleted member 4366]

I went for a 300w pure sine wave inverter in the end for £70 https://www.amazon.co.uk/dp/B00J68QL0K/ref=pe_385721_37986871_TE_item
When charging the battery it is taking 8.9 amps, with the leisure batteries sitting at 12.5v.

Cheers

Kendalian

That's 45Ah to charge your battery from flat (5 hours), which puts you on the limit of discharge for a 90Ah battery that's in good condition. You would then need to charge that leisure battery back up to full again before you could charge your bike. You can do it, but a deep discharge like that is not good for a leisure battery. It's no problem if you have your motor running while you do it, but then you might as well get a portable generator, which will probably use less fuel , and it has loads of other uses, like rescuing your motor-home when you run the cranking battery flat.

 

[GLJoe]

Get yourself a lightweight generator. They're always useful. these ones are only about 9kg and they're very quiet:

http://www.ebay.co.uk/itm/Ex-Demo-Wolf-Power-Genie-WPG950-800w-2-6HP-Petrol-Inverter-Camping-Generator-/282593415907?hash=item41cbe152e3:g:12IAAOSw-FZXj3~x

Yes, I can see a small generator like that could be a sensible option in many scenarios.
However I already have a couple of (non sine) inverters, and if I could use those to charge a Bosch/Yamaha battery using the existing 4A chargers while I'm driving from place to place, that would be ideal. And I don't particularly fancy the idea of having a petrol generator running in the back of the RV on a long drive .....

 

[Kendalian]

Well, I have 220 ah of leisure battery capacity; 200 w of solar panels on the roof (charges at over 10ah on a reasonable day); I tend to tour around quite a bit and the alternator is 150 amp; worst case I will pay for electric hook up - in summary, I'm not worried about depleting batteries.

I wouldn't entertain a generator, anti-social monsters - you are hated if you use them on sites!

Cheers

Kendalian

 

[PeterCo]

It's not quite answering the question but many of us living on narrowboats also have e bikes, often folding ones. My charging is always done with the boat engine running usually as we travel along. My set up is fairly typical. There are four 110 a/h leisure batteries charged by the 70amp alternator. In addition there are two 100w solar panels feeding into the batteries via a mppt solar inverter. This often shows 10amps in the sun but they do little more than trickle charge the batteries in winter.
The boat has a Vetus 1000w inverter to provide 240v power which we use for charging the Volt 12ah bike battery, my wife's hair straighteners, an electric drill occaisionaly, small vacuum etc but not the tv, lights or fridge. We are a low use 12v system on the whole.
We have no problems keeping the bikes battery charged up. Mind you it's only used two or three times a week. I get normally a comfortable thirty mile or so range.

 

[Deleted member 4366]

I thought we were talking about a camper van parked up off site somewhere. Surely, if you're on site, you can charge from the mains. why would you want to use an inverter?