What is my range?

[toolongtoremember]

Hi there,

I have built an electric recumbent cycle and I was wondering whether anybody could help me out on calculating the range?

It is a 2 wheel recumbent, with a 50AH 48V, using 260 3.7v 18650 cells and a BMS.

The motor is a Bafang BBS02 750W.

The cycle weighs in around 30KG and I am 60KG.

I've attached some pictures.

Thanks in advance everybody!

 

[Nealh]

2400wh that is some an a bit more !!!
Only way of calculating poss range is by using wh per mile figure and everyone is different but starting at a poss 20wh/m it would equate to 120 miles but there are to many other factors, though bents are usually frugal and aerodynamic compared to an upright so would say range would be a lot greater and could be anywhere from 120 - 300 miles.
Terrain, wind are the two main factors and the assist level you use, Spec of cells will also play apart.

 

[egroover]

Wow, how long does that take to charge?

 

[Andy-Mat]

Hi there,

I have built an electric recumbent cycle and I was wondering whether anybody could help me out on calculating the range?

It is a 2 wheel recumbent, with a 50AH 48V, using 260 3.7v 18650 cells and a BMS.

The motor is a Bafang BBS02 750W.

The cycle weighs in around 30KG and I am 60KG.

I've attached some pictures.

Thanks in advance everybody!

Difficult.

There is no simple calculation that will do it for you....

The range is also dependent on the type of tyre(s) you have, their air pressure, the ups and downs of your route, does your motor brake and put power back in the battery (some do!), your wind resistance, the wind direction, your style and speed of riding, the list is endless.

My personal take is to always ride the same route and keep an eye on distance and S.O.C..

That way you will get a feel for average distance one charge will achieve.

Also, having two batteries, and taking a spare with you, will not only increase your distance dramatically, but is (in spite of what they say) better for the battery, as you can change it out immediately and not risk going too far in the direction of under charged - particularly bad for a Li-ion battery.....which can cause it to eventually not take a charge anymore!

Though the electronics are supposed to prevent that!!

A S.O.C. indicator is a must have, so that you don' t get caught out!!!

Remember, that all batteries have basically a fixed number of recharges, period. By careful usage, you can increase this number, with poor usage, you can reduce this number!

Regards

Andy

 

[wheeliepete]

You could fit a watt meter between the battery and controller to record Ah and watts used then ride a set distance and calculate the power used per mile to give you an idea.

https://www.ebay.co.uk/itm/Digital-Monitor-LCD-Watt-Meter-60V-150A-DC-Ammeter-RC-Battery-Power-Amp-Analyzer/113242016808?hash=item1a5dc00c28:m:mtVi3NY781paAUX5QcBEyGQ:rk:9:pf:0

 

[trevor brooker]

if you have got a multi meter you can calculate as per thread

https://www.pedelecs.co.uk/forum/threads/how-do-i-calculate-watts-used-per-mile.31067/

 

[toolongtoremember]

Wow, how long does that take to charge?

10 Hours, so overnight.

 

[toolongtoremember]

You could fit a watt meter between the battery and controller to record Ah and watts used then ride a set distance and calculate the power used per mile to give you an idea.

https://www.ebay.co.uk/itm/Digital-Monitor-LCD-Watt-Meter-60V-150A-DC-Ammeter-RC-Battery-Power-Amp-Analyzer/113242016808?hash=item1a5dc00c28:m:mtVi3NY781paAUX5QcBEyGQ:rk:9:pf:0

That I will be doing! Will order one ASAP

 

[scott gaza]

Hi toolong. With 50ah even flat out you have 3+hrs min power supply when drawing a constant 750w. PS: How does you're bike handle with a 12.5+kg battery at your back?

 

[toolongtoremember]

Hi toolong. With 50ah even flat out you have 3+hrs min power supply when drawing a constant 750w. PS: How does you're bike handle with a 12.5+kg battery at your back?

Have just been for a cycle on high assist, 60 miles and the battery still shows as full on the BBS02 screen... this might take some doing to see how far it will go.

It handles just fine at anything above 3mph, but anything less like all two wheel recumbents it's a pain in the ass to cycle.

 

[scott gaza]

Cool! I imagine you will hardly ever need to recharge it as the battery will recover some of the voltage loss its self by the time you use it again.

 

[Nealh]

Have just been for a cycle on high assist, 60 miles and the battery still shows as full on the BBS02 screen... this might take some doing to see how far it will go.

It handles just fine at anything above 3mph, but anything less like all two wheel recumbents it's a pain in the ass to cycle.

Although voltage drop isn't linear so not a good way to try and calc range just out of interest what was/is the SOC after 60 miles ?

 

[toolongtoremember]

it took an hour and a half to charge back up, I have no idea what the SOC was as I have no way to test that. It was on a 5 amp charger.

 

[Nealh]

By the sounds of it your 60 miles used up 15 - 20% of the voltage range/capacity.
In an earlier thread you said 10 hrs to full charge and 1.5hrs to top up full charge so about 15% or so used up. I would be inclined not to charge up every time unless you are doing far more miles. My guestimate is that you will see possibly 250 - 300 miles range or eve a bit more from such a massive battery, with that you could do a LEJOG or JOGLE with one charge along the way so massive range.
As I mentioned earlier as well an unpowered bent is so much more economical to ride then an upright so given the fact yours is assisted mileage should be verrry good.
I would be inclined to run it just once to see it's actual capability and not recharge until you see about 3.5v per cell.
A simple £5 millimeter will tell you the SOC.

 

[anotherkiwi]

A reply to the original question: Insane!

At my current strength I would get 400 km from your battery.

 

[toolongtoremember]

Going to try a much longer run tomorrow. See what happens! Also does anybody know a chainring that will fit a BBS02 with 52T? I don't think the chainring on the BBS02 originally is up to much good.

 

[wheeliepete]

You can get a standard Bafang chainwheel in 52T, but as you say they are not great. I don't think anybody makes and after market one in that size, but an adapter is an option. Lots of nasty cheap ones out there, but this one is decent quality.
http://precialps.com/uk/accessories-bafang-bbs01-bbs02/19-adaptateur-130bcd-bafang-bbs01-bbs02.html

 

[toolongtoremember]

OK I put the battery to the test yesterday. 120km round trip using full assist, 50kmh all the way (also with a fair bit of stop start due to gates I had to pass through), pretty much pedaling for the aesthetics. I got the battery down to 30 percent remaining with some noticeable voltage sag at the 115km mark. 7 hours to recharge supported my theory there. So now I have a base minumum range I can work with .

I also found a newly released 52t Lekkie bling ring for a bbs02, I will purchase one of those as soon as a I wear out my 52t bafang one (I had a 46t ring which came originally with the kit and it only lasted a few 100km).

The recumbent is finally working reliably, trouble free. So many years of happy cycle touring to come!

 

[wheeliepete]

I also found a newly released 52t Lekkie bling ring

Great, do you have a link?

 

[Nealh]

Tonking along at 50km/h and top assist will have an affect on cells, demanding high amps constantly.
Which cells did you use ?
Range will be even better probably at least triple in PAS 2 and about double in PAS 3, for longer cell life use the lower PAS and save high PAS for inclines.
On shared paths hopefully you are respectful of other users as you must know you are affectively riding a moped in the guise of a bent.