Charging ebike in the boonies

[muttmaster]

Well, just spent my stimulus money on a Rad ebike. I am sure I will be much stimulated. Maybe even more so if congress approves ebike 30% tax credit. Before the ebike arrives, I am trying to figure out best ways to charge up battery while in the boonies for multiple days.

I have read RC Jim’s post on ebike, watched Utube on charging while camping. Seems like many options exist for me while out there in my FWC, and I like options and I like to explore what seasoned ebike and FWC owners have done.

I do have a Honda eu2200i, and some have posted that they charge the bike just fine, but I am not sure if the inverter on the eu2200i is a pure sine wave type specified by Radbike for charging the lithium 48 v. I do carry a 350 watts pure sine wave inverter on trips that I can use off the camper battery or the generator if needed.

I have 160 watts stock ZAmp plus 100 watts Renogy on top, which is more than I need as the AGM gets topped up by 10 or 11 in the morning. I can get more or bigger panels if needed to charge up to two 750 watts, 48 v batteries. I plan on getting extra ebike battery or built my own to extend range of the ebike. The battery are pretty expensive and I don’t want to ruin them while charging it. The Ideal set up for me is to be able to have two fully charged ebike battery for the days ride, while charging a spare battery during the day with solar and after getting back to camp, be able to top off the two used up battery with either generator or via inverter off camper battery. Double my needs if I bring a friend with Rad ebike too.

Some have used separate batteries and inverter to charge the ebike battery, and I may explore that option too if I DIY a 48v Lithium power center. But that maybe the most expensive option and it will have to wait.

I also saw on Utube ebike owners solar charging directly from panel to Victron mppt controller and plug into ebike battery directly without using the Radbike charger, which lead me think maybe I like a separate charging setup from FWC. So, I hope all the solar and electrical and ebike gurus on the forum can give me some advise on what is the best way to keep on riding.

 

[astropuppy]

Very interested.

 

[Vic Harder]

How many AH are the bike batteries?

 

[muttmaster]

I was hoping a guru would chime in. Vic, Rad bike battery is 14 ah for the RadRunner Plus. They also offer a slimmer profile one that is 10.5 ah.

There are aftermarket batteries that is 52 v but I have not looked into them yet. Below is info on the Lunacycle site.

www.electricbike.com/52v-battery-3077-fet/

 

[Vic Harder]

That web site you linked to sets off my computer's warnings.... I dug up this site RadRover 5 - Fat Tire Electric Bike | Rad Power Bikes

Looks like the battery is 48V, 15AH. The included charger is 48V, 2Amps = roughly 100Watts.

The thing that might be confusing (it got me, thanks to rando for pointing it out in a kindly way!) is that a 15AH battery is not just a 15AH battery. What do I mean? The amount of energy stored is 48V x 15AH = 720 WATT hours. A 12v x 15AH battery only stores 12*15 = 180WH.

So what? (sorry about that pun). In your camper you will need 4x as much power being generated to fill a 48V 15AH battery as you would to fill a 12V 48AH battery.

So using the factory charger that came with your bike, a fully depleted battery should take 7 hours to charge (7Hrs x 2A = 14AH). You want to do that 2-3 a day for your multiple batteries, right? So call it 14*3 = 42AH... at 48V. The 12V AH needed to make that happen is actually 4x that (plus a bit more because of electrical losses), so 42AH *4 = 168AH. If your AGM batteries are fully charged before dark and you are going to bed with the intent to charge all three batteries overnight, you will need 2x that to avoid depleting your AGM's below 50% (never mind running the fan/fridge etc). That's a 2* 168 = 336AH 12V battery! Huge and heavy....

If all that looks right, I would use your existing 350W pure sine wave inverter and plug the factory charger into it and charge during the day after your solar panels have already finished charging your camper batteries.

And keep monitoring your SOC on the camper batteries to ensure you are still good for the essentials overnight.

Make sense?

 

[muttmaster]

Planning on getting Victron mppt 100/30 soon. Some Brit on Utube demoed using Victron 150/70 and 300 watts panel to charge the battery directly without the stock Rad charger. Possible without damaging the battery?

Rad bike told me my Honda eu2200i should be able to charge 14a via charger. But they only recommend ac wall charging. I am not sure if I want to use generator if I don’t have to. Guess I’ll have to experiment a bit to see how long it will take to charge up one battery, then maybe get another factor charger if the needs arise.

Thanks for looking into it, and the good advise.

Found a forum specifically on e bike charging. I will spent some time on it soon.

If I get a bigger inverter, say 1500 watts, will it charge faster?

 

[Vic Harder]

The recommendations for charging Lithium batteries vary. For some reason, Rad bikes included a 2A charger. What do they say about your warranty if you charge faster?

Can it be done? Yes. Should it? Depends on how much battery life you want, I think. Faster charging is harder on the batteries.

 

[muttmaster]

It will be April delivery for my new toy. I don’t have any warranty info on the battery but will look into it.

 

[rando]

Planning on getting Victron mppt 100/30 soon. Some Brit on Utube demoed using Victron 150/70 and 300 watts panel to charge the battery directly without the stock Rad charger. Possible without damaging the battery?

Rad bike told me my Honda eu2200i should be able to charge 14a via charger. But they only recommend ac wall charging. I am not sure if I want to use generator if I don’t have to. Guess I’ll have to experiment a bit to see how long it will take to charge up one battery, then maybe get another factor charger if the needs arise.

Thanks for looking into it, and the good advise.

Found a forum specifically on e bike charging. I will spent some time on it soon.

If I get a bigger inverter, say 1500 watts, will it charge faster?

A couple of points - you can only charge direct from your solar panels if they are wired such that their output voltage is above 50V or so. For that you would likely need 3 panels in series, and I think you only have 2, so that is a no go.

For charging from your camper battery, the limiting factor would be the 2A charger. A bigger inverter won't help, so it will take 7-8 hours to charge a completely dead battery. Is there a faster (higher current) charger available? You should be able to fully charge these in 2 hours without damaging them.

With the 2A charger, the generator option seems like the worst of all (for you and those around you). You would still need to run the generator for 8 hours to charge one battery, and it would be incredibly inefficient. At that point you may as well buy a dirt bike!

 

[rando]

That web site you linked to sets off my computer's warnings.... I dug up this site RadRover 5 - Fat Tire Electric Bike | Rad Power Bikes

Looks like the battery is 48V, 15AH. The included charger is 48V, 2Amps = roughly 100Watts.

If all that looks right, I would use your existing 350W pure sine wave inverter and plug the factory charger into it. Just keep monitoring your SOC on the camper batteries to ensure you are still good for the essentials overnight.

Using the factory charger, a fully depleted battery should take 7 hours to charge (7Hrs x 2A = 14AH). You want to do that 2-3 a day for your multiple batteries, right? So call it 14*3 = 42AH

Your roughly 360W (actual is likely more like 300W) of solar can produce 360W/15V = 24A. I doubt your stock ZAMP solar controller can actually put out that much (a Victron 100/30 could)... if you could get that full power into your batteries/charger in 8 hours of sunshine you could recharge 8Hr * 24A = 192AH.

You should be good to go.

Make sense?

You may want to check these numbers, thinking in Watt-hours. If the batteries are 15Ah at 48V, that is 720Wh or 2160Wh for 3 batteries. That is a lot of Ah at 12V!

 

[muttmaster]

Just checked Lunacycle website. They have many chargers. I better call Rad bike for possibility of 4 amp charger.

I won’t be charging three at the same time. Only one at a time. But maybe if I get the bigger inverter, and another charger, will I be able to charge two at the same time if the sun is high up?

Got a dirt bike. Ebike for shorter day trips and for more tranquility. I probably should not worry about it too much. Once it arrives, I will have plenty of time to ride and experiment. The range expected in stock battery is 20 miles or more, but range test was probably done on flat pavement, low elevation. riding downwind and tires fully inflate, etc. My rides will be in high elevations, dirt and sandy terrains. Just lowering tire pressure for soft stuff will use more juice.

I should just jump on the Lithium wagon and DIY a 280 ah pack and just run the inverter all night and charge the bike batteries without worrying about running out of juice.

Just ordered a Victron mppt 100/30. Thanks Vic, you convinced me to spent more stimulus money.

 

[Old Crow]

Food for thought! I like how this guy (Kyle at Bolton Electric Bikes) explains things...

 

[muttmaster]

Now I am really glad that I did not order the second stock battery when I ordered the bike. The video is for a different model bike, but their website shows a new 52v/16ah available for preorder at cheaper price, with a 3 amp charger include. I will get more power and save some money. I am on it. Thanks OldCrow!

 

[Vic Harder]

You may want to check these numbers, thinking in Watt-hours. If the batteries are 15Ah at 48V, that is 720Wh or 2160Wh for 3 batteries. That is a lot of Ah at 12V!

ho boy.. yah, that makes a difference. Good thing I am taking a break from posting on the "how to " thread. Brain isn't working as it should! Thanks for the kindly prod and correction!

I will go back and fix the calculations...

 

[Wallowa]

Have read about off road motorcycles that went from AGM [no spilling] to Li batteries to save weight...BUT temperature became an issue...low overnight temps to below freezing [many of my off road motorcycle trips have ice on the bikes in the AM] stopped the possibility of just starting the bikes and charging them in the morning..

What I am speculating about is will low temperatures limit the use of your batteries in terms of charging them...if they can be kept above freezing then I assume all is good..do not know if your ebike batteries have BMS features...

 

[muttmaster]

I doubt that I will be charging the battery outside or below 32F. I believe they have built in BMS. They cost plenty, $500+, I am sure they are protected.

 

[muttmaster]

Thanks Vic, Rando, OldCrow and all, I knew I could count on you to steer me in the right direction. I signed up on Electricbike.com forum with same topic and got many reply post since last night. Lots of ebike nerds been doing this for years and I am sure I will find my way there. Cheers.

 

[Vic Harder]

Let us know what you find out!

 

[muttmaster]

I will try. Getting many post on best way to juice up.

I watch few Utube video on DIY Lithium. 280 ah with four cells plus BMS for $500 or so China. What do you think? I like to just use battery charger provide by Radbike and even charge two battery over night. I will have plenty of ah left in the AM.
My two AGM in Grandby is five years old now, doing fine, but planning on getting more juice.

 

[Vic Harder]

I will try. Getting many post on best way to juice up.

I watch few Utube video on DIY Lithium. 280 ah with four cells plus BMS for $500 or so China. What do you think? I like to just use battery charger provide by Radbike and even charge two battery over night. I will have plenty of ah left in the AM.
My two AGM in Grandby is five years old now, doing fine, but planning on getting more juice.

I'm not the expert here on DIY batteries.... sorry.