Charging a Mobility Scooter off EHU

[Bilbo Baggins]

Sugestions please, as to how I could charge a 24v (2x12v) mobility scooter when no electric hook up is available.
Does anyone use an inverter whilst on the move? Ta

 

[Robert Clark]

We charge our electric bike batteries off our inverter, but only when driving, so that the leisure batteries are not drained.

 

[TheCaller]

Does anyone use an inverter whilst on the move?

That's what we do with the electric wheelchair (also 24V). In an emergency, I have given it a partial charge while stationary, but as the wheelchair is 2 x 56AH & the M/H is only 2 x 95AH, a full charge isn't a good idea! (although 200W of solar helps on a sunny day).

 

[hilldweller]

Does anyone use an inverter whilst on the move? Ta

Yes - a 300W sine wave inverter. Not a good idea to do it when not on the move unless you have massive leisure batteries.

 

[Bilbo Baggins]

Thanks for your replies. Thought that I would have to do it that way. I believe that the charger draws about 1.2 amps, so assume that would be about 288w, so a 300w inverter appears to be the one?
Didn't realise it would be from the leisure battery though, could someone tell me why that is. TIA.

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[hilldweller]

Didn't realise it would be from the leisure battery though, could someone tell me why that is. TIA.

Normally you wire an inverter to the leisure battery so that if you flatten it you still get to start your engine. Normally when the engine is running it charges the leisure battery. You may have heard "split charge relay", that's what does it.

However with a plug in inverter you may plug it into the engine battery using the cigar sockets in the cab or to the leisure battery using the sockets in the rear. Cigar sockets are more like 200W so not up to much for inverters.

 

[Bilbo Baggins]

Thanks Hilldweller, I did think that the power draw might be too much for the 'cigar sockets'
So if its connected to the leisure battery, yes it would not flatten the engine battery, but if we turned off the engine
and went for coffee, we would need to disconnect it first, otherwise it would continue to draw from the leisure battery.
However thats not a real problem if it meets our original aim of charging the scooter batteries.
And you think that a 300w inverter would be sufficient. TIA.

 

[Lenny HB]

Thanks for your replies. Thought that I would have to do it that way. I believe that the charger draws about 1.2 amps, so assume that would be about 288w, so a 300w inverter appears to be the one?
Didn't realise it would be from the leisure battery though, could someone tell me why that is. TIA.

You need at least a 500 W inverter advisable to run inverters at a max of 80% of their capacity also a 300w would probably trip out with the surge when you connect the charger.

 

[Snowbird]

If you are only going to use an inverter for charging your mobility scooter batteries whilst driving I would suggest hot wiring your inverter into your engine battery. The wiring on many motorhomes that charge the leisure batteries from the alternator is not designed to charge the batteries when having a constant pull such as an inverter running for long periods. The wiring from the alternator to the engine battery is much heavier.

 

[Bilbo Baggins]

Thanks for that Lenny HB. I'm no electrician so gratefull for that advice.

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[Bilbo Baggins]

And thanks, Snowbird. Something else I will consider befor putting this plan into action.

 

[TheCaller]

Didn't realise it would be from the leisure battery though, could someone tell me why that is.

If you are only going to use the inverter to charge the scooter & if you are only ever going to use it while on the move, then you could wire it to the starter battery. Otherwise, as Brian says, you are in danger of flattening the battery & not being able to start the engine. If you do connect it to the starter battery, it's even more important that you turn it off if you stop & go for a coffee.

Another consideration is where you are going to mount the inverter. It should be as close to the battery as reasonably possible. It doesn't matter how long the cable from the inverter to the charger is - the voltage drop at 230v & 1.2A will be insignificant, but the current between the battery & the inverter will be 25 - 30A. Then you have to consider how easy it is to get to the inverter to switch it on & off - unless you get one with a remote.

Snowbird makes a good point - not all motorhome leisure battery charging & wiring systems are created equal - some appear to use wet string. What is the make & model? Someone on here will know whether the charging system is up to replacing what the inverter draws.

I agree with Lenny - you probably need a 500W inverter. I use a 600W pure sine wave inverter wired to my leisure batteries, but then I use it for other things & when stationary.

 

[TheBig1]

the other option is get an electrician to do what I did on a previous van.'

run a separate 100amp split charge relay to an anderson plug and make up a wiring harness that you charge the batteries direct from the alternator. you would need to lift the battery cover and pull the battery connector plugs out and plug into the connectors on the harness.
most 240v mains chargers are 4amp output so you need many hours to recharge. An 8amp charger will recharge twice as fast and if you search ebay or go to your local mobility shop they are easy to obtain but not cheap

 

[Snowbird]

There is of course this option, which is much easier than messing about with inverters.
Amazon product ASIN B00EZ53JH2

 

[Snowbird]

Or if you want a foolproof one that switches off when the engine is not running and gives a more powerful charge, at a cost.
Amazon product ASIN B00CBGEVJM

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[SUGGY]

Send a PM or conversation to G8SYN , he used to run a generator to supply power for his wife's scooter and her rechargable breathing unit but sorted out his MH to charge everything via solar and engine charging ,

 

[tonyidle]

One of these set to 27v or 28v output would be an ideal solution. Quiescent draw 15mA.

 

[TheBig1]

One of these set to 27v or 28v output would be an ideal solution. Quiescent draw 15mA.

that circuit will take more than a little work to get right and produce a lot of heat

 

[Don Quixote]

I'm I great believer in "KISS" and as @hilldweller has suggested the 300watt inverter is what you want and will do the job. Hard wired to your LB's and NEVER to your VB.

 

[Bilbo Baggins]

Thanks for all these replies. Certainly given me some options to consider. Only running a small van, a Autocruise Rhythm and carry the scooter on a rear mounted platform. The battery pack is easily removed and usually charges within an hour, with it's mains charger. Thanks again

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[Bobby22]

Could always get a genny.

 

[Bilbo Baggins]

Could always get a genny.

Afraid I'm short of space!!

 

[Snowbird]

Thanks for all these replies. Certainly given me some options to consider. Only running a small van, a Autocruise Rhythm and carry the scooter on a rear mounted platform. The battery pack is easily removed and usually charges within an hour, with it's mains charger. Thanks again

If the battery pack is easily removed for charging as our Auto-go ones are, then without doubt if it was me I would go down the 12volt-24volt route, just remove your battery pack and plug in whilst driving.

 

[Bilbo Baggins]

If the battery pack is easily removed for charging as our Auto-go ones are, then without doubt if it was me I would go down the 12volt-24volt route, just remove your battery pack and plug in whilst driving.

Ah but..... the 2 x 12v batteries are in series, in the pack, which is not easy to access.

 

[Snowbird]

Ah but..... the 2 x 12v batteries are in series, in the pack, which is not easy to access.

I know that, exactly the same as mine. I put you a link up earlier of a 12 volt in, 24 volt out charger. Keep it simple, all you do is take the battery pack off the scooter and plug it into the cigarette lighter socket.

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[Bilbo Baggins]

I know that, exactly the same as mine. I put you a link up earlier of a 12 volt in, 24 volt out charger. Keep it simple, all you do is take the battery pack off the scooter and plug it into the cigarette lighter socket.

Yes, I saw your link, and would like to keep it simple. I am no electrician but was worried that 24v will not charge the batteries as they are around 25.4v when fully charged. however if this is something that you have used, and works well, then i'll probably go for it. Thanks

 

[TheBig1]

to charge 2 batteries in series you need about 27v

 

[TheCaller]

The chargers @Snowbird linked to are for charging 24V batteries. That doesn't mean that their output is 24V. In fact they are three stage chargers, which means their output will vary between nearly 29V at peak, down to around 27V float charge.

Neither of them charge very fast though. If the scooter needed a full charge, you would be driving for hours before it had finished. At least with the inverter & your existing charger, you will get the performance you are used to. Having said that, it sounds as if your existing charger doesn't charger very much faster than the more expensive one Snowbird linked to.

 

[Bilbo Baggins]

Thanks TheCaller,
I'm collating all this information and will make a choice later.
This all came about because last week-end we spent on the seafront at Exmouth. Our forays into the town
over two days, resulted in flat batteries. We've known for a while that they are not as efficient as they were
when new, and considering they were new in 2008, the've lasted well. We will be replacing them very shortly and making plans to facilitate their charging, whilst on the move.

 

[ColinandDawn]

Hello @Bilbo Baggins

I have an electric wheelchair 24v I use for trips away in the camper.

The camper has two 110ah batteries, powering an inverter and a 12v 5 amp charger(24v).

I also have two extra battery boxes - this is a good solution because I can leave a box charging and still be out and about in my wheelchair using an extra battery box.

We set off with all batteries fully charged and have the equivalent of six charges whilst away without power.

I have also been known, when out and about, to plug into the mains socket at a library or cafe when necessary and with their permission.
I have never been refused permission.

I do have a 200w solar panel kit in the garage waiting to be fitted (to the new RV now). I hope this setup will provide a continuous solution (through the summer at least).

Anything is possible - it's just how much it costs...

Regards

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