Charge electric bike on the move

[Curly]

Is it possible to charge electric bike batteries on the move, I have an 1800 watt inverter and would like to use it whilst traveling, my thinking is the vehicle battery and my 2 x 110 amphr leisure batteries are not being drained, the batteries are never run flat only approx. 1/3 used and then recharged to full if that makes sense.

The inverter is used off EHU for the bosses domestic hair dryer etc. Going to charge them direct from leisure batteries and check the leisure batteries afterwards for useage.

 

Curly

[pagey]

i am going to do the same ..you will get some more technical answers im sure

[thebishbus]

I do that , The leisure batteries drive the inverter, the alternator charging the leisure batteries.

Brian B.

[aandncaravan]

Charging an electric bike battery on the move is feasible, but you need to understand the path of the electricity from the Alternator to the Leisure battery as this will almost always involve the Motorhome Charger/Controller and it's Electronics at some point.

Failing to appreciate the huge current that can pass and it's implications, might work out very expensive as an 1,800watt Inverter running flat out can draw up to 180amps from the batteries.

Remember no Inverter will be 100% efficient, we have seen them as low as 75%. Don't get taken in by figures of 'Peak efficiency of 90%' as this is a short term rating that drops off rapidly when running for longer than a minute is required.

 

I am guessing your Rapido is utilising CBE equipment where the main current from the Alternator passes through a Boite Securite relay which effectively controls the Split Charge.

This relay can handle up to 70amps for short periods, but longer periods of more than about 50amps will damage it. See photo of one starting to burn out.

 

Systems from the likes of Nordelettronica, Arsilicii, Sargent, Calira, some Schaudt, etc will pass the current through the unit/Fuse board.

Obviously trying to draw 180amps through wiring, connectors and the box itself can lead to big time burnout.

 

See our 'adding a second battery' web page for pictures of examples where the controllers have been asked to draw current they just weren't designed for : http://www.aandncaravanservices.co.uk/add-a-second-battery.php.

 

Obviously the draw of an Inverter is going to be far higher again.

 

The cabling will rarely be rated for the current either.

 

We had in a motorhome that had a 3,000 watt Inverter fitted to run the 230v aircon system in the roof when driving.

The Inverter was drawing almost 170 amps from the 2 batteries, the 140amp Alternator was doing it's best to put that back into the Leisure batteries.

You can imagine the fire damage.

 

 

Also, don't forget that charging your two habitation batteries and running the Inverters is not the Alternator's Day job. It is already supplying upto 15amps to the Starter battery 30 - 60 amps amps for the Engine ECU, Injectors, radiator/aircon fans, interior blower motor, wipers, etc. Plus about 20amps for the habitation batteries to put back the charge used the night before, etc.

That can be close on 100amps BEFORE you give it the Inverter load, which on a 'small' 600watt Inverter can be 60 amps.

Don't forget that a 180amp Alternator is rated at 180 'peak', short term loads only. It's safe continuous rating is about 2/3 the peak rating, so around 120amp. A 120 rating Alternator can safely deliver about 80amps, etc.

 

You can see why Alternator failure is becoming a bigger issue than ever before?

 

 

It is probably that your ebike charge draw won't be high, keep the current draw low and it might work well.

 

[sshortcircuit]

I sometimes charge when on move, but through a 150w inverter, which is more than capable. I did at one time have a 2000w inverter and it was very rarely used.

With all battery and inverter enquiries the first thing that is required is an assessment of energy needs and then purchase a suitable inverter other than the buy big method.

Back to OP yes.

[Billggski]

I just have a spare battery I charge up while I'm out, simpler, cheaper and it sounds as if it's safer.

12v->240v->36v ?

[colin]

Despite what it might say on the charger, odds are you will find it only draws 82w, which is why as above we only need a 150w invertor.

[Derek Uzzell]

aandncaravan - 2018-07-26 8:03 AM

 

...I am guessing your Rapido is utilising CBE equipment where the main current from the Alternator passes through a Boite Securite relay which effectively controls the Split Charge.

This relay can handle up to 70amps for short periods, but longer periods of more than about 50amps will damage it. See photo of one starting to burn out...

 

 

Although Rapido commonly employs CBE equipment for their motorhomes’ electrical system, I’m pretty sure Rapido does not fit CBE ‘boite relais sécurité” components. My Rapido does not have them and I can’t find anything on-line to suggest Rapido has used them historically.

[hallii]

I charge my two ebike batteries on the move using a 500w pure sine wave inverter and have no problems.

 

A pure sine wave inverter will be a lot more gentle on the switch mode chargers and will be more efficient.

 

H

[Curly]

Well what a response I’m really pleased with the comments I also have a 150 watt inverter and as an experiment have connected the elec battery to see how long it takes, engine not switched on, but out of 5 segments of charge the battery only needs 1 segment to be fully charged.

Also checking the vehicle battery as the charge is on going, so you techeees out there is this a reasonable test to do.

[Curly]

What I should have explained is that the Rapido is on a Merc chassi and has a dedicated 15 amp cigarette socket as well as the bog standard cigarette socket, at the moment the inverter is a little warmer than I would like, replies on this bit of info much appreciated.

[aandncaravan]

Derek Uzzell - 2018-07-26 11:18 AM

 

aandncaravan - 2018-07-26 8:03 AM

 

...I am guessing your Rapido is utilising CBE equipment where the main current from the Alternator passes through a Boite Securite relay which effectively controls the Split Charge.

This relay can handle up to 70amps for short periods, but longer periods of more than about 50amps will damage it. See photo of one starting to burn out...

 

 

Although Rapido commonly employs CBE equipment for their motorhomes’ electrical system, I’m pretty sure Rapido does not fit CBE ‘boite relais sécurité” components. My Rapido does not have them and I can’t find anything on-line to suggest Rapido has used them historically.

 

 

Derek, thank you I wasn't sure on that model. hence defaulting to describing the more robust CBE solution.

In that case it will probably go through the CBE main board with quite a small split charge relay, as shown on the web pages, with even less capability.

 

[Alanb]

Derek Uzzell - 2018-07-26 11:18 AM

 

aandncaravan - 2018-07-26 8:03 AM

 

...I am guessing your Rapido is utilising CBE equipment where the main current from the Alternator passes through a Boite Securite relay which effectively controls the Split Charge.

This relay can handle up to 70amps for short periods, but longer periods of more than about 50amps will damage it. See photo of one starting to burn out...

 

 

Although Rapido commonly employs CBE equipment for their motorhomes’ electrical system, I’m pretty sure Rapido does not fit CBE ‘boite relais sécurité” components. My Rapido does not have them and I can’t find anything on-line to suggest Rapido has used them historically.

 

May I add to Derek's comment. Whilst Allan may have downloaded the picture of the "boite relais securite" in good faith, the original was posted on this forum by Mick Bajcar and relates to problems that Mick was having with the fridge drawing current from the habitation battery. The picture was attached to the following post by Mick. I might add to Mick's comments that in my opinion with over 70 years of soldering experience, some of the other soldering in the photo does not seem to be exemplary

 

Mick Bajcar - 2016-08-21 1:55 PM

 

Well, with many thanks to all who have given advice, it is now fixed!

 

When I removed the relay it is clear what a pathetic device this boite relais securite is. The pins of the relay had been cut so short that there was little chance of a decent contact. It seems perverse to me to need to bolt the high current cables together on the front of the Printed Circuit board, yet rely on feeble soldered connections underneath. The relay pins were coated, presumably in nickel yet they had not even been tinned for a decent connection. I replaced the relay with one from Maplin and now have a tad over 14v at the leisure battery with the engine running.

 

Thanks again for all the help

Note that on Image Boite 2 it shows the PCB discoloured around the offending connection, indicative of overheating

 

Mick

 

This is the thread from which the above quote was taken, and in which the image appears.

 

Alan

http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Chausson-Welcome-76-fridge-running-off-battery-Help/43400/

[aandncaravan]

Alanb, not exactly sure of the point you are making, but clearly the phrase "Allan may have downloaded the photo in good faith....." suggests I made a mistake. But I don't think I have.

 

I think you have misunderstood the fault. The thread was not about a fault involving a "Fridge drawing current from the habitation battery" because that is what they are designed to do. The fault was that the Alternator could not put back the current being taken from the Habitation battery by the Fridge because the Split Charge relay had an issue with a soldered joint being overloaded. Most likely failing after passing a lot of current.

 

The Poster writes,

"I have found that the battery has been getting flat as I drive and have established that the fridge is not switching to run off the alternator but flattening the battery instead. This suggests a problem with a split charge relay............".

 

So clearly the Fridge is working as designed (poor design though not going direct to the Starter battery), connecting to the Habitation battery to collect the Alternator current that should be arriving there. Just that the Alternator current is being 'blocked' from reaching the habitation battery by the burnt out relay unit.

 

However, the thread is a very good example of just how little capacity there is for taking current from the habitation battery for the Alternator to put back, by something like an e-bike charger.

The "boite relais securite" is a neat general purpose CBE relay with built in fusing. It is used by motorhome builders for everything involving a supposedly 'heavy duty' relay from battery isolation to Split Charging.

 

While they are specifically designed for split charging, the relay used is light duty.

In the Post referred to by Alanb, the OP refers to the relay by saying, " It looks as though it is a standard plug-in 30A relay that has been soldered in....... ".

 

 

So I stand by my perfectly appropriate photo used as an example to show that the alternator charge of one habitation battery at 15 amps + Fridge 15 amps + second habitation battery 15 amps + 11 amps of e-Bike charger (probably worst case) comes to 56 amps and a bit above the capability of this type of set-up.

 

If the CBE equipment installed is the 'lighter duty' version indicated by Derek, then have a look at the size of the very small relay highlighted on our web page.

 

Charging an e-Bike battery on the move from the habitation battery is almost equivalent to adding a 'third' habitation battery to the load of the alternator charge system.

It might seem 'only 82w' but throw in the inefficiency of an Inverter onto what you can see will already be an overloaded circuit, if a second habitation battery has been installed, and you can see the issues.

 

 

But then again, connecting the Inverter directly to the Starter battery circuit changes things completely and begins to make more sense.

See this thread : http://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Technical-Alternator-or-Inverter-charging-/48365/

 

Welted charges his habitation batteries on the move, using an Inverter and 230v charger, to very good effect and faster charging as a result.

The same approach could be used for any 230v charger, like the e-bike, Laptop, etc.

 

 

I would however advise caution if considering Cigarette Lighter Sockets to supply Inverters as they are normally light duty and for short term use.

Continuous long term running of an e-bike Inverter would suggest that a minimum 20amp socket/plug would be required to give a decent element of safety.