EBike charging - what are my options?

[Pablo79]

I’m trying to decide the best way to charge 2 ebikes in MH garage.

 

I have 215w solar, Victron MPPT and 160ah gel battery power.

 

Each bike has a 36V 4A charger, so the power draw is quite low. It seems over the top to get an inverter to step up from 12v to 230v, only for the chargers to step down to 36v, but I dont know of any other way apart from getting a battery power bank.

 

What different options do I have? How do you charge yours?

[Ocsid]

I don't agree with the thought that a 36 Volt Lithium battery, 4 Amp E bike charger is low powered.

The Actual charging volts of a 36 Volt Lithium battery is 42.3 Volts[??], so we have a 169.2 Watt need if driving right up to 4 Amps, which at zero conversion losses is over 14 Amps at 12 Volts, in reality being 18 odd Amps.

 

So, the more practical bike charging is going to need to settle for a lower charging rate than replicating that mains charger's 4 Amps.

I have played mentally with just this issue but whilst we found we did not need to go that route.

 

I thought buying one of the offerings for wheelchair, or golf carts, like this :

 

https://www.ebay.co.uk/itm/12V-Car-Cigarette-plug-to-36V-42V-1-5A-Lithium-Charger-E-Bike-Scooter-Wheelchair-/173772977403

 

Other issue are that some e-bike batteries are not just simple generic Lithium, but feature a "handshake" protocol between the battery and charger. More than a two pin plug might hints at this with your bike.

The other issue, is the capacity of our e-bike battery is 600Whr, more than the usable 540Whr of energy stored in our 90 Ah 12 volt battery.

 

We found we were on EHU frequently enough that actually we did not need to go further in 12 VDC recharging them. Could do a week off EHU at a time with our bikes 100 mile range.

[Pablo79]

I’d definitely be happy with a 12v option, even if it’s slower.

 

Also, I see there are 12v pure sine wave inverters than run off a 12v socket. That could also be a workable solution.

[Ocsid]

Pablo79 - 2021-03-21 8:00 AM

 

I’d definitely be happy with a 12v option, even if it’s slower.

 

Also, I see there are 12v pure sine wave inverters than run off a 12v socket. That could also be a workable solution.

 

With the replacement cost of our Kalkhoff charger I would not entertain using other than a "pure sine wave" inverter if going the inverter route.

The first step in considering this is to read the AC input info off the charger, to know the peak load you might encounter so you buy an adequately rated inverter.

If you go that route then it will not be "slower" as that charger is a 4 Amp unit, come what may. But for the time it takes to recharge them as much as needed, the currents from the 12 volt system will be "significant", as suggest expect something over an eighteen Amps drain. Not "healthy" IMO, if you are not driving, unless it is a short recharge you need to undertake.

 

However, powering that charger from an inverter plugged into a standard 12 vDC jack socket is way above the vehicles standard socket rating. It will require dedicated wiring.

 

Your "options" depend on what batteries these e bikes are fitted with, as I have already said some feature a "handshake" protocol where only "their" charger can recharge their batteries.

 

Others, simply use generic Lithium batteries, these can be recharged with any source developing, in this case 42.3 Volts DC.

 

Knowing more about the charger you have and the batteries you have, answers can be more targeted.

[Alanb]

I am not qualified by experience to offer advice on Ebike battery charging. However may I make the following observations.

 

1. In my x244 Ducato only the cab power socket is fused at 20A. Other outlets, including the cigarette lighter will be fused at 15A, or even 10A.

 

2. I find it refreshing to see someone not dashing headlong into the inverter route.

 

Alan

[ColinM50]

Far be it for me to suggest that this might be better handled in a different format, but I'd seriously look at the model aircraft market. It's very sophisticated and knowledgable about lithium charging and there's several companies that have in depth expertise in this filed. I have a few lipo chargers, my most recent one I'm sure would fit the bill of variable input voltage etc. Cost about £75 though was a Xmas pressie so not 100% sure

 

https://www.overlander.co.uk/chargers.html

 

Overlander have been in the market since before Pontius started lekky flying and a bit like A&A of yore, give excellent impartial advice. I'd suggest a phone call would be in order

[thebishbus]

If you want to go down the 12 volt cig/socket route, look at the range of chargers from " Powatechnic " at Sheffield .

Brian B.

[colin]

We charge one bike at a time with through a Aldi invertor into the standard Bosch ebike charger, absolutely no problems, I would have preferred a 12 to 36(42) in car charger but at time we set up there where none available for Bosch, you may however find one for your bike.

[Pablo79]

I've decided to go down the inverter route and am installing a 1000w PSW. Gives me options if I want to use other things in future.

 

I will keep the bikes charged from EHU as much as possible, not let the bike batteries deplete too far, and will aim to use the inverter when the solar is producing some decent power.

[Ocsid]

Pablo79 - 2021-03-24 11:57 AM

 

I've decided to go down the inverter route and am installing a 1000w PSW. Gives me options if I want to use other things in future.

 

I will keep the bikes charged from EHU as much as possible, not let the bike batteries deplete too far, and will aim to use the inverter when the solar is producing some decent power.

At that 1000 W rating, if ever asked for long, the resulting current drain will probably do a 160 Ah GEL technology battery no favours.

[Pablo79]

I agree. Even though it's capable of 1000w, It won't be drawing near that charging the bike. It's more about giving me options for the future should I need more power AND wish up the battery capacity.