Currie izip transplant and overvolt

[roadstar]

I dismantled an old izip and transplanted the motor, controller, throttle and battery rack onto a Saracen Aluminium bike. The izip MY1018 motor (200 watt version) is fitted between the pedals in a mid drive setup. I’ve a freewheeling crank bought from Eclipse bikes 48T, 48T, 32T and a dicta 14 tooth freewheel on the motor.

The battery pack is SLA two 12volt 12AH batteries.


The bike gets a top speed of 19 mph on the flat and I use the bike for a 4 mile commute to work. It’s acceleration is disappointing

The battery pack just about gets me to work before losing all power.

Tonight I tried overvolting the bike. I added another SLA battery to make my battery pack 36 volts.

The bike now goes like the clappers!! Top speed is now 23+mph, and it climbs hills really great, the acceleration is fantastic. Only took it for a short spin.

I noticed the motor did heat up a bit on full throttle whizzing up and down my road. I wonder what the range of the bike might be as the Izip battery indicator on the thumb throttle did not seem to go down. Also the starting level on the indicator was on ‘High’ where as on 24 volts fully charged it only show half way.

 

[e-beach]

Sounds like your new setup will go about 1/3 farther and 1/3 faster. Putting an RC watt meter on the system will give you more detail. They can be had on ebay. Or if you want a really nice bicycle computer get a CA from gren tech:
http://www.ebikes.ca/shop/ebike-parts/cycle-analysts/ca-sa.html

Over volting your motor will make it warmer. Get to know your new setup, because if your motor gets too hot, you can burn it up.

As for your old sla's it also sounds like they are not in "like new" shape. So I expect them to degrade faster then your new sla thus causing your whole range to degrade faster then if you put 3 new sla on your bike at the same time.

It is always better to make sure all your batteries are new when changing e-bike batteries.

Mixing old and new batteries is generally considered bad practice. It is easier to get away with if you are using sla's, but highly discouraged if you use lithium batteries unless you know what you are doing.

If you have the budget, seek out information on lithium batteries which are lighter, longer lasting and may have a higher C rating depending on what type you use.

Meanwhile... please follow these instructions:

 

[roadstar]

Thanks,

just updated my profile, will complete it shortly.

you're spot on, one of the batteries is new the other two are old. Range now gets me back from work and a little further, whereas before on two batteries it struggled. Top speed is 25mph on throttle, 27mph with me pedaling, before on 24 volts 19 to 20 mph top speed. Ohh and the top speed test was across country going slightly up hill at 36 volts and it accelerates like a banshee and the gears now actually are useful.

The motor does heat up and I'll have to be careful of it, I keep stopping to check the heat.

I think you're right, the batteries won't last, I get lots of SLA's from work and this is why I've been using them. The SLA's come from UPS's, alarm batteries (admittedly some are bad), I've also a supply of Lithium batteries from laptops and emergency lighting and I'm researching into how to make battery packs from these. I am on a budget and I want to learn how to make and maintain my own stuff - rather than buy it. I've made my own bike and I think I now have a bike which is discreet, easy to change flats on the road and easy to replace parts if they fail - and is inexpensive.

I now have 3 unite my1018z motors from old IZIP's I've bought (great motors for mid drive builds) - I only wish they were the 450 Watt version that you get in the USA, but they are the 200 watt ones we get in the UK - but overvolting makes them usable whereas on 24 volts they were wanting -so I've spares to burn up whilst I learn..

 

[DrkAngel]

See -Homemade Battery Packs for laptop cell recycling into usable battery packs.
Page #1 has a handy index and links to great mods for the eZips etc.

I've fit 33.3V 31.2Ah into the eZip-iZip rack mount battery packs. .

 

[DrkAngel]

Sounds like your new setup will go about 1/3 farther and 1/3 faster.

Adding a 12V SLA (24 >> 36V) should move you 1/2 further or 1/2 faster ... not at the same time though!

Good idea to add a volt meter ... as a fuel gauge.
You can tap into the throttle leds for a volt meter connection.
3 SLA would be full near 42V and empty near 31V.

SLA are likely Sulfated, you might like to try a desulfater, rejuvenates most older batteries ... to some degree.

 

[DrkAngel]

Top speed is 25mph on throttle, 27mph with me pedaling, before on 24 volts 19 to 20 mph top speed. Ohh and the top speed test was across country going slightly up hill at 36 volts and it accelerates like a banshee and the gears now actually are useful.

I would guess that you are running a 450w motor.

See my graphs for a crank drive MY1018z 450w @ 24V and (625w @) 33.3V. - Crankin' It - Mid-Mounted Crank Drive
Graphs are for motor only!
I added an Epoch DNP 34, ... 15, 13, 11T 7 speed for higher pedal assist speeds.

If an actual 200w motor ...
Your gearing up the motor (9 >> 14T motor sprocket) combined with (probably?) a higher amperage controller, (20A >> 35A+?) is greatly adding wattage at the lower (less efficient) rpms.
See - Vetting the XYD-16 the helically geared variation of the MY1018z
... overheating will likely be a problem!