Charging e-bike batteries

[pentland]

We have just bought a couple of folding e-bikes to provide a bit of help to our aging bodies.

The problem now is how to keep them charged up. There are two issues as I see it.

1. The batteries (which will always be kept in the saloon) need a charging supply of 42v 2A & and my initial reaction is that it seems less than ideal to use an inverter to take Storyline's 12v supply to 240v only then to use the supplied charger to reduce it back down to 42v. I have not got time to address this issue right now unless there is an 'off the shelf' solution ?? but will deal with it over the winter.
2. This is the pressing issue which I have just a few days to sort before our last cruise of season. A 2022 lifestyle with a fridge full of cold beer & NZ Sauvignon Blanc (plus a bit of milk & food) together with a mass of USB charging cables, not to mention incidentals such as VHF, radar/plotter, autohelm etc etc means our 3 x 115Ah batteries are already worked hard.
As we sail off the west coast of Scotland the name of the game is to spend as much time as possible at anchor in pleasant surroundings and only visit places that have shore power when we need supplies. Therefore these two bike batteries will have to be charged by the 12v system. All we have to charge this is a beefy uprated alternator (c80A) and a wind generator (1-3 amps in F3-F5). I have long lusted after portable power units like Jackery and numerous others on Amazon but they don't really get us anywhere as they are just another battery which will also need charging.
I now think the answer must include the boat's battery bank but we need another way of charging it and so finally I get to the question. Would it be best to get a lightweight non-thirsty petrol generator (do they exist?) or a largish solar panel (we have an unused solar input on the controller that manages the wind generator - this can handle a panel with <100W).

What do you think - it seems a bit of a backward step to increase the amount of petrol we carry from the 5L needed for the o/b - as a guesstimate based on zero experience the bike batteries will take c4 hours of charging every other day to be kept in that 60-80% window that lithium batteries like. The amps needed are modest so it would only need the smallest generator to run for say 25 hours over a 2 week cruise. Does anyone know a model of generator that might suit and roughly how much petrol would we need ?
I am going to ring the super helpful (& friendly) guys at Marlec who made our Rutland wind generator for advice on solar panels but would also be very interested to read anything that sailors here can offer based on the reality of having a solar panel on a sailboat (I realise some kind of gantry would he best but I need something pro tem to use now).

Sorry to be so long winded - it's an age thing I reckon ?

 

[sarabande]

Lots of 12v chargers for ebikes

12 charger ebike at DuckDuckGo

I'd add a solar panel as a first step.

 

[dunedin]

Not quite the answer you are perhaps looking for, but we tend to stop off at a pontoon (Mallaig, Salen, Lochmaddy etc) perhaps once a week for a major restock - of food, water, etc. But also mass recharge of all battery devices whilst on shore power. Quite a long list of things to remember now.
How often do the bike batteries really need charged? And how often do you take the bikes ashore by dinghy (we find tend to use bikes more from pontoon days anyway)?
PS. Solar a must anyway for fridge etc.

 

[Stemar]

I'd add a solar panel as a first step.

Me too. As much as I could fit within my budget.

Mine are fitted under the boom, on the hatch garage, which means one is part shaded much of the time, so I fitted two, rather than one big one, as a bit of shade tends to bring down the whole panel, but the other one is still going full blast. This arrangement worked well for years on Jissel, so far so good on Jazzcat

 

[ylop]

We don't have ebikes but have pondered the idea (I'm really waiting for the UK to make its mind up on private e-scooters as they would be much more space efficient on board!). There are 12V ebike chargers around - the "RV" community love an ebike and the eMTB people love a campervan so there is definitely a market! What's the longest trip you are likely to make without the opportunity for shore power and how many bike charges might you need? would a second (or even third) set of bike batteries you charge at home or one night a week on shore power actually be easier/cheaper than engineering the power to do it at sea?

 

[West Coast]

Similar issue to charge my electric outboard battery - although suspect this will need charging much less frequently. I have only had the outboard a month or so, with 2 weeks cruising, so time to discharge/charge requirements are still a learning curve. My thought at the moment is to buy a larger portable inverter from amazon/ebay to suit the units mains charger which was supplied with the outboard.

 

[NormanS]

After a couple of bad (say catastrophic) incidents with Marlec wind generators, I turned to PV panels. Now have a theoretical 180 watts, and in a normal year on the West Coast, with fridge and all the usuals, never go near a pontoon. As you may know, this year there hasn't been a summer on the West Coast, but the PV panels still produce a surprising amount of safe and silent power. That's the way I would go.

 

[Concerto]

I have an ebike onboard and have not yet had to charge it from 12V. I only use it when on a pontoon and have shore power. You do not mention the type of ebike you have bought as there are some major differences between the cheap ones and the more expensive ones. The cheaper ones made abroad usually have fairly poor quality batteries and have only 3 gears. Mine is a Volt ebike that has 8 gears and a much larger capacity battery with longer overall life. They quote 40 to 50 miles range and I have done 45 miles and still had 40% charge left. Because of the range I do not charge it every time I use it, but on 240V it charges in a couple of hours. One general word of warning, lithium batteries can catch light is subject to a shock like dropping, so ensure they cannot move in rough weather.

Your best bet would be to add as much solar power to your boat. I currently have a 10 year old solar panel that cannot cope with running the fridge, instruments, autopilot, lights, USB charging of phone and laptop, etc. without a lot of engine use. New batteries were fitted this year but still get hammered when not charged within 3 days. A new larger solar panel and wind generator are now going to be a added.

 

[dunedin]

I have an ebike onboard and have not yet had to charge it from 12V. I only use it when on a pontoon and have shore power. You do not mention the type of ebike you have bought as there are some major differences between the cheap ones and the more expensive ones. The cheaper ones made abroad usually have fairly poor quality batteries and have only 3 gears. Mine is a Volt ebike that has 8 gears and a much larger capacity battery with longer overall life. They quote 40 to 50 miles range and I have done 45 miles and still had 40% charge left. Because of the range I do not charge it every time I use it, but on 240V it charges in a couple of hours. One general word of warning, lithium batteries can catch light is subject to a shock like dropping, so ensure they cannot move in rough weather.

Your best bet would be to add as much solar power to your boat. I currently have a 10 year old solar panel that cannot cope with running the fridge, instruments, autopilot, lights, USB charging of phone and laptop, etc. without a lot of engine use. New batteries were fitted this year but still get hammered when not charged within 3 days. A new larger solar panel and wind generator are now going to be a added.

To be fair you are choosing to go almost entirely pontoon to pontoon with shore power, with no overnight anchorages - which is fine as each has different preferences, but almost the opposite from what the OP stated as their preference, which is “the name of the game is to spend as much time as possible at anchor in pleasant surroundings and only visit places that have shore power when we need supplies”.

However, I do suspect that weekly shore power may be sufficient anyway

 

[Fantasie 19]

To be fair you are choosing to go almost entirely pontoon to pontoon with shore power, with no overnight anchorages - which is fine as each has different preferences, but almost the opposite from what the OP stated as their preference, which is “the name of the game is to spend as much time as possible at anchor in pleasant surroundings and only visit places that have shore power when we need supplies”.

However, I do suspect that weekly shore power may be sufficient anyway

Well also to be fair... if the OP is at anchor why would he need to charge electric bikes??? As Dunedin mentioned above - is the plan to take them ashore by tender often? Could you take the charger with you and plug in while enjoying coffee/beer/dinner/lunch in a shore side establishment??

 

[NormanS]

Well also to be fair... if the OP is at anchor why would he need to charge electric bikes??? As Dunedin mentioned above - is the plan to take them ashore by tender often? Could you take the charger with you and plug in while enjoying coffee/beer/dinner/lunch in a shore side establishment??

When we used to carry (folding) bikes aboard, they were invariably taken ashore by dinghy. If there were "shore side establishments", we wouldn't need or want the bikes. They came into their own when, as usual, we were far away from towns or villages.

 

[Alex_Blackwood]

We have just bought a couple of folding e-bikes to provide a bit of help to our aging bodies.

The problem now is how to keep them charged up. There are two issues as I see it.

1. The batteries (which will always be kept in the saloon) need a charging supply of 42v 2A & and my initial reaction is that it seems less than ideal to use an inverter to take Storyline's 12v supply to 240v only then to use the supplied charger to reduce it back down to 42v. I have not got time to address this issue right now unless there is an 'off the shelf' solution ?? but will deal with it over the winter.
2. This is the pressing issue which I have just a few days to sort before our last cruise of season. A 2022 lifestyle with a fridge full of cold beer & NZ Sauvignon Blanc (plus a bit of milk & food) together with a mass of USB charging cables, not to mention incidentals such as VHF, radar/plotter, autohelm etc etc means our 3 x 115Ah batteries are already worked hard.
As we sail off the west coast of Scotland the name of the game is to spend as much time as possible at anchor in pleasant surroundings and only visit places that have shore power when we need supplies. Therefore these two bike batteries will have to be charged by the 12v system. All we have to charge this is a beefy uprated alternator (c80A) and a wind generator (1-3 amps in F3-F5). I have long lusted after portable power units like Jackery and numerous others on Amazon but they don't really get us anywhere as they are just another battery which will also need charging.
I now think the answer must include the boat's battery bank but we need another way of charging it and so finally I get to the question. Would it be best to get a lightweight non-thirsty petrol generator (do they exist?) or a largish solar panel (we have an unused solar input on the controller that manages the wind generator - this can handle a panel with <100W).

What do you think - it seems a bit of a backward step to increase the amount of petrol we carry from the 5L needed for the o/b - as a guesstimate based on zero experience the bike batteries will take c4 hours of charging every other day to be kept in that 60-80% window that lithium batteries like. The amps needed are modest so it would only need the smallest generator to run for say 25 hours over a 2 week cruise. Does anyone know a model of generator that might suit and roughly how much petrol would we need ?
I am going to ring the super helpful (& friendly) guys at Marlec who made our Rutland wind generator for advice on solar panels but would also be very interested to read anything that sailors here can offer based on the reality of having a solar panel on a sailboat (I realise some kind of gantry would he best but I need something pro tem to use now).

Sorry to be so long winded - it's an age thing I reckon ?

Be extremely careful with chargers for e-bikes. The fire services are warning, as they do, about the increase in the number of fires caused by use of non standard e-bike chargers. Your boat, your life! Sorry if that seems harsh but it is a fact of modern life.

 

[KompetentKrew]

Suspect you're going to want the petrol genny, @pentland, or to use marinas more often.

I have an AGM battery bank about the same size as yours, and I can barely last a week at anchor on the battery, even with a bit of solar (although I must test to see if I may be able to increase its output). After the second or third day I must turn the fridge off for part of the day to preserve power. It looks like I may be forced to buy a larger battery bank sooner than expected, but I am also buying a genny.

On most boats the fridge consumes the most electricity. Older laptops or ones with a gaming GPU may consume a bit more, most laptops sold within the last 5 years should consume a bit less. A1 or A2 Apple laptops should consume quite a bit less - barely more than a tablet. Mobile phones and Kindles consume the least. Charging your bikes will significantly increase your leccy load.

Your wind genny and 100W of solar will barely put a dent in this - if you're running the fridge I doubt they'll be enough to keep your battery bank from depleting, never mind charging the ebikes.

Most cruisers I see using gennies are using one of about 1kW - often cheap ones from Screwfix, Homebase or wherever. A neighbour of mine bought a new Honda EU10i - he thinks they're great; his previous one looks abused but lasted 20 years (or nearly). But the Honda is significantly more expensive, so the cost is hard to justify. The Honda EU20i is better still - in fact I think it may be the only high quality generator in this size still being made - but your charging is unlikely to get it properly loaded. Read this article. It might well be the case that a cheap 750W - 800W genny from the DIY store is more suitable than either of the Hondas because it'll be running with a proper load and, hence, more efficiently.

EDIT: matey with the Honda EU10i says it "sips" petrol, but I'd guess all small petrol pennies are more or less about as efficient as each other, and that this is true of all of them.

 

[Refueler]

A look at chargers used by RC modellers ..... we have Programmable chargers that cater for NiCd through to LiPo ... from 1 cell NiCd up to 12S Li ( 12cells = 50.4V) ....
E-bike will have one of the Lithium based batterys and an RC charger can easily be found that will work both from mains 240 and 12V.
If its 42V ... then if its LiIon (HV) or LiPo then that is 10S ... 2A rate is easily achieved.
Not only will it charge the e-bike ... but any other battery including Lead Acid ....

One aspect that I do not see anyone mention ... depending on what Li form the batterys are - they may need to be stored at reduced ( 30 - 50%) charge level to avoid damage. Only charged up for use ...

 

[sailaboutvic]

Solar probably his best option ,
We use to have 780 W and it kept everything going although unless there a lot of deck space a frame is needed.
As a temp measure we have a 150w flex panel .
On this boat , the disadvantages of a flex is they don't last as long as the frame panels .
The advantages is you can move them around to get the best out of them .

 

[ltcom]

Another vote for solar.

 

[Minerva]

My last solar panel purchase cost iro £0.75 per watt - that is absolutely the way to go these days. With 200w of solar and a ~360ah battery bank, I can regularly charge at 7-8Amps (west coast too). Over a long Scottish summers' day, that's a good few Ah's into the battery bank.

The days of ruining the peace with an ear shattering Genny should be behind us these days.

 

[William_H]

As said solar is the way to go. However it entirely depends on arrangements to mount the solar panels. This will dictate size and number of panels. However for best bang for buck look at domestic solar PV panels by they are usually 40v no load so will need an MPPT controller for 12v battery. about 300w about 180 by 100cm.
As said be very careful of lithium charging. It is critical that charging stops when battery is fully charged. I would tend to feel safest with the original charger supplied with the bike run on an inverter. But even then monitor charging. (or do it remote from boat) House fires seem to occur around here regularly from bike and scooter chargers. ol'will

 

[StefanSG]

as a guesstimate based on zero experience the bike batteries will take c4 hours of charging every other day to be kept in that 60-80% window that lithium batteries like.(

I bought an older (Giant) Ebike that had been recelled with Lithium batteries. It’s pedal assist and has approximately 40 mile range. But I can leave it in the shed for a fortnight, or a month, and the battery will still be in the same state of charge as when I left it. So I don’t leave it on charge, I let it get to 10-15% before I charge it. That AFAIK is the point of Li-ion batteries, that they retain their charge extremely well, and 100% of their capacity is available to use ( ie the voltage stays near 12v -or whatever working voltage is, until the last 10-15%). Unless you need the full range for emergencies at a moments notice, I would stick to solar for charges when required.


SSG

 

[Refueler]

I bought an older (Giant) Ebike that had been recelled with Lithium batteries. It’s pedal assist and has approximately 40 mile range. But I can leave it in the shed for a fortnight, or a month, and the battery will still be in the same state of charge as when I left it. So I don’t leave it on charge, I let it get to 10-15% before I charge it. That AFAIK is the point of Li-ion batteries, that they retain their charge extremely well, and 100% of their capacity is available to use ( ie the voltage stays near 12v -or whatever working voltage is, until the last 10-15%). Unless you need the full range for emergencies at a moments notice, I would stick to solar for charges when required.


SSG

Lithium are one of the lowest Self Discharge batterys available over counter. BUT therein lies their Achilles Heel.

People think to leave them in high states of charge expecting them to perform later. That's fine for a while ... then user starts to notice performance duration getting progressively shorter .....

Reason ? Its not so much as capacity degradation as some say - its mostly due to increasing Internal Resistance. As that increases - the battery has to basically fight harder to deliver ... this causes heat ... the voltage drop increases ... battery fights harder. In effect the battery appears to be less charged / less able to deliver ... but when you let it rest - the battery voltage level recovers and you think its ok. Try using it again .. voltage derop ... less performance ... same scenario. Eventually cells puff / die. In extreme - they can burst and flame.

The 70 - 80% level given by some manuals is a compromise of useable charge level and reduced damage as a result of staying charged. It is NOT ideal storage level. It is designed for a user who is going to use it often and regularly. But if user is not going to use and store away - then it should be discharged to 30 - 50% level, 30% being best.

I have over 70 models with 65 powered by Li based tech. The investment in batterys is significant and if I do not take care of storage - then I have serious costs to replace.