Charging an electric bike when off grid

[bobnwend]

I’m a newbie and I apologise if this has been asked before but can you charge two electric bikes when you are off grid or should we always plan to be on hookup to charge them? I have a 150 W solar panel, one leisure battery and no inverter at the moment.

As far as I can understand from my research a 4amp bike charger would drain a 100Ah leisure battery with a 1kw inverter in an hour and the Bosch battery in the bike requires 4.5 hours to charge fully, so can you help me with this please?

 

[TheBig1]

Looks interesting...how about sharing your ideas here with what we might need to use this type of charging successful..I for one are open to anything that makes eBike charging more user friendly...

This will take some basic skills, but nothing complicated

You can even source a cable with the cigar plug on, but very easy to solder on your own

Take the red and black wires to the input side of this (other similar boost converters available from a multitude of sellers)
<Broken link removed>

take a cable attached to the output side and fit to suitable plug or socket to fit the bike battery

DON'T CONNECT TO THE BIKE BATTERY YET!

Plug into the 12v socket and using a multimeter measure the output voltage. Using a suitable insulated screwdriver adjust the output voltage to your required 36v or 48v

Source a suitable project box to cover the converter and drill several air vent holes. Then install the bare booster into the box

As I say with basic skills this should pose no problems. The same system can be used to charge the batteries on a small mobility scooter or heaven forbid, an e-scooter

 

[LesW]

Looks interesting...how about sharing your ideas here with what we might need to use this type of charging successful..I for one are open to anything that makes eBike charging more user friendly...

Read my posts above.. this is what I use

12V Car Cigarette lighter invert to 42V 1.5A light duty Charger for 36V battery | eBay

Find many great new & used options and get the best deals for 12V Car Cigarette lighter invert to 42V 1.5A light duty Charger for 36V battery at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[Buzz67]

For anybody with Wisper bikes a 12v dc charger is available. 12V 10A input.

 

[Wabs]

Bike...thing to get about on with wheels.

Battery..makes getting about easier, makes wheels go round.

Charging..puts back energy into battery for next time you want wheels to go round.

Yep sorry, just come down a one way river facing the wrong way,how silly am I,

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[two]

This will take some basic skills, but nothing complicated

You can even source a cable with the cigar plug on, but very easy to solder on your own

Take the red and black wires to the input side of this (other similar boost converters available from a multitude of sellers)
<Broken link removed>

take a cable attached to the output side and fit to suitable plug or socket to fit the bike battery

DON'T CONNECT TO THE BIKE BATTERY YET!

Plug into the 12v socket and using a multimeter measure the output voltage. Using a suitable insulated screwdriver adjust the output voltage to your required 36v or 48v

Source a suitable project box to cover the converter and drill several air vent holes. Then install the bare booster into the box

As I say with basic skills this should pose no problems. The same system can be used to charge the batteries on a small mobility scooter or heaven forbid, an e-scooter

I would caution the use of an alternative charger.
A 36V battery should be charged at a higher voltage than 36V (nearer 42V) and this will vary according to the state of the battery.
The chargers I have come across have as many as five connectors (not just two) and I believe these extra ones are use by the battery BMS to communicate with the charger and control what happens.
The simple approach described may "work" but I'd want to be more careful about how I treat my e-bike battery, especially if it costs £700+ to replace.

 

[Paul Wilkins]

Its an interesting thread. I looked at trying to charge Bosch batteries via solar, would have thought that Bosch would have been all over this. I have read elsewhere that their eBike batteries need 48v DC AND a 5V DC 'signal' feed to charge.
Bosch's recommendation is that you use an inverter and then use the supplied Bosch step down transformer to charge the battery.. that's progress for you

 

[NASHMAN600]

We bought our first motorhome in 2017,s 2004 Chausson.
We purchased two Haibikes one with a 400wh battery and one with a 500 wh.
It came with one 110ah battery so I installed another and 200watts of solar and a victron inverter 1600watts.
This setup enabled the Nespresso coffee machine and hairdryer and to charge the 2 E bikes.
In four years we have never hooked up once on Cls and Cs sites, it does hammer the wet LA batteries but my Banners still lasted 3 years which I thought was more than acceptable. This applies to spring - autumn season.
I appreciate there was a considerable investment in equipment, no labour as I installed it all.
But this shows what works. The ebike batteries we topped up regularly or charged while driving.

 

[autorouter]

Its an interesting thread. I looked at trying to charge Bosch batteries via solar, would have thought that Bosch would have been all over this. I have read elsewhere that their eBike batteries need 48v DC AND a 5V DC 'signal' feed to charge.
Bosch's recommendation is that you use an inverter and then use the supplied Bosch step down transformer to charge the battery.. that's progress for you

I don't think many companies manufacture their own charger. They buy in a suitable one from a charger company. They may rebadge it and maybe get the company to tweak the product a bit if they're buying a lot of them. I think nobody was interested in developing a 12V to 48V DC charger with a 5V signal feed, so they don't supply one.

 

[Clive Mott]

Charging one 17ah 42v lithium battery requires 714 watt hours of energy. At 12 volts that is, 59.5 Ah. Now add at least 10 % more for charger and inverter inefficiencies and that is 65.45 Ah. Two bikes then double it. Many people get away with it because they only partially discharge the leccy bike battery. That is the simple maths bit.

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[Landy Andy]

Charging one 17ah 42v lithium battery requires 714 watt hours of energy. At 12 volts that is, 59.5 Ah. Now add at least 10 % more for charger and inverter inefficiencies and that is 65.45 Ah. Two bikes then double it. Many people get away with it because they only partially discharge the leccy bike battery. That is the simple maths bit.

What does that mean.

65.45 Ah. So what?

So you have two 110Ah batteries and you are going to use a quarter of what you’ve available??

I'm assuming not.

Not being rude, I don’t know.

Also most people aren’t charging flat to full, isn’t that the same with most of these things. No different to your car, where you don’t drive it until it runs out of fuel.

 

[two]

It's true, not to assume that e-bike batteries will be flat when you charge them.
But you should not assume that your habitation battery will be fully charged, either.
For some, the capacity of the two will be very similar and 'exercising' the habitation battery that much is likely to reduce its life.
That is why you should try to assist it by charging on the move, using your alternator to provide the power.

 

[Chrisboyo1]

Great post so much info
I have been looking at installing an additional 12 volt battery with a 350 amp inverter for the bike battery charger this would be separate from the liesure battery but charging from the solar panel. I have 2 feeds from the solar panel one of which goes to the vehicle battery I am thinking of using a toggle switch to allow charging of either battery as required
I would be interested in any comments

 

[rupert]

eBay item number:
173772977403
I use this when driving or mid day sun shine cost £50

 

[the1andonly]

I have 2 feeds from the solar panel one of which goes to the vehicle battery I am thinking of using a toggle switch to allow charging of either battery as required

To clarify : the 2nd battery charging on a dual charge controller is typicaly only a trickle charge (definitely on a Votronics duo Mppt)
you intend to toggle the primary charger.
The perceived wisdom would be to use one large bank and monitor usage. If lead acid again perceived wisdom would be to only add same size age and type so a separate battery is a good ploy as an interim measure with the intention to consoladate in the future.

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[Chrisboyo1]

To clarify : the 2nd battery charging on a dual charge controller is typicaly only a trickle charge (definitely on a Votronics duo Mppt)
you intend to toggle the primary charger.
The perceived wisdom would be to use one large bank and monitor usage. If lead acid again perceived wisdom would be to only add same size age and type so a separate battery is a good ploy as an interim measure with the intention to consoladate in the future.

I have 2. Lead acid 100amh liesure battery's The additional battery is an AGM

 

[TheBig1]

I have 2. Lead acid 100amh liesure battery's The additional battery is an AGM

You do know that you should never mix battery types?

 

[Chrisboyo1]

You do know that you should never mix battery types?

The batteries are not connecting they're independent of each other.
2 liesure battery's wired in parallel . 1 vehicle battery. Independent. 1battery for charging the bike battery independent

 

[jumar]

I believe I now have an eBike charging system that works for us...

We ride most days, using 40% each ride minimum....each battery on our YT Decoys is 540ah

The Hymer has a 90ah Leisure battery, a 1000w Pure sine wave inverter connected, I have just upgraded my Roof mounted Solar Panel to 200w, I have a backup of a 150w folding panel which is about the size of my windscreen, also a Battery bank which now connects to either panel.....
A test in non perfect conditions this afternoon harvested 105w from the roof panel, forgot to add that this panel now has a tilting setup.
my aim is to be able to have my van in the shade (We live in Spain) and the portable setup charging the bike batteries, during this time our van battery will be left undisturbed, and providing power to the vans internal workings. Outside the heat of the summer, the van will be parked in a position to harvest the solar energy, via both panels.
I don't claim to have done this on the cheap, but provided a system to keep the bikes charged and the riders happy. Thats all.

 

[Jimbohorlicks]

Can you show a photo of your tilting panels please ,for info.

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[jumar]

Can you show a photo of your tilting panels please ,for info.

Sure, but as my left hand is currently restricted in movement I can send you the lowered position only...also the diagram from Amazon..

 

[Jimbohorlicks]

Thanks, relatively simple then. I saw one on a van that had a motor and operated by remote control,but it spanned over his whole roof and covered his top vents untill it was raised.

 

[TheBig1]

Sure, but as my left hand is currently restricted in movement I can send you the lowered position only...also the diagram from Amazon..

Thanks, relatively simple then. I saw one on a van that had a motor and operated by remote control,but it spanned over his whole roof and covered his top vents untill it was raised.

Basically some nuts and bolts and 6 short lengths of dexion. I would be concerned that the knurled plastic encapsulated nuts would degrade and fail driving down the road

 

[jumar]

Basically some nuts and bolts and 6 short lengths of dexion. I would be concerned that the knurled plastic encapsulated nuts would degrade and fail driving down the road

Then it's my duty to ensure that these are well maintained and renewed periodically, in the meantime may I suggest you don't drive too close to a Silver Hymer on the roads of Spain..