Crystalyte help

[tomv]

Hi,

I'm an electric bike newbie and just finished installing Crystalyte 408 kit on my bike. Works great and I can't get enough of it!

But now I have a bunch of questions and I hope you guys can help me out. I can't find answers to anywhere

- I'd like to build 48V battery. It would let me go faster and it looks like motor efficiency is higher at 48V then my current 36V. The question is what else do I have to change besides my battery? I know the motor can handle 48V. Do I have to buy a new controller? How about the throttle? Both controller and throttle are marked 36V on my kit. Controller is 20A.

- Can anyone recommend decent 36-48V Nimh charger? I only found $300 fancy multichannel variable voltage chargers, but I'd rather buy something simple and inexpensive.

Thank!

 

[Ypedal]

Welcome to the group !

You are in the right place for Ebike info. that's for sure !

The crystalyte 36v controller will take 48v .. no problem there.

Is you throttle the LED type or no LED ? ( Battery power indicator )

 

[tomv]

Yes, the trottle has three LED lights - power and battery high/low. It's ok if low never lights up because battery will always stay above the level that's low for 36V. I'm only concerned that throttle works and that I don't burn out anything.

I guess low voltage cutoff would be a bit of an issue too. 36V controller cuts off power at 20V (I think). That would be overdischarging for a 48V pack. For this reason I'm thinking to get a separate metter like Watts up or similar.

 

[Ypedal]

A 36v controller custs out at 29v.

So yes. you controller will not cut out at 40v like it should using a 48v pack but that's ok. monitor it manually.. you know how far you can go on a charge after a few rides, and it's as simple as " Stop using throttle when the battery power is no longer there.. "

You can remove the LED wire from the conector and use it as a regular throttle at 48v. Or get a non-Led throttle, they are fairly cheap.

Very good idea on the Monitor. watts'up or Cycle Analyst meters are a great thing !!!

 

[xyster]

- Can anyone recommend decent 36-48V Nimh charger? I only found $300 fancy multichannel variable voltage chargers, but I'd rather buy something simple and inexpensive.

Haven't tried one, but the Nexcell chargers like these (half-way down the page) are popular:
http://www.ebikes.ca/store.shtml
All-battery.com, another reputable vendor, carries a 48v 1 amp NiMH charger for $46:
http://www.all-battery.com/index.asp?PageAction=VIEWCATS&Category=349

 

[tomv]

Thanks for the links!

The 1A charger is not very practical. 15+ hours to charge 15Ah pack.
The Nexcell might be ok, but also there's no info on how they work. I wonder what end-of-charge condition do they use?

I'm thinking about using Soneil charger to charge Nimh. It's designed to charge SLA and charges thme at constant current to a certain voltage (55.2V for 48V charger) and then maintains that voltage. Could that be a problem for Nimh? I know fast Nimh chargers use dV/dt and temperature, but for say 1/5 C charging, would that be necessary?

I'm looking at this one here:
http://soneil.com/Completesets/4804SR.pdf

 

[Ypedal]

The Nexcell chargers from ebikes.ca use Dv/Dt, do your packs currently have a 10k NTC in them ?

 

[tomv]

Well, I don't have a pack yet! I'm just planning to build one from 40 F cells. I suppose I could put in a thermistor, but I would not know if I did it right. I might be very wrong about this, but I think if I'm only charging at 1/5C batteries would not heat up enough to trigger tempereature cut-off. On the other hand I'd like to never get them to a condition where they're overcharged/venting/warmng up.

 

[Ypedal]

Fast charging is worth it on Ebikes.. you don't want to have to wait overnight for a full charge.. my 72v 8ah bike is fully charged in 2.5 hrs and ready to ride..

This of course depends entirely on your needs. F cells at 13 to 15ah should be charged in 4 hrs max imo.

 

[tomv]

That sounds like a mighty mighty charger! 72V 4Amps? Which one is it? The biggest thing i see on ebikes.ca is 48V 2A

 

[Ypedal]

oh.. i thought you were going 48v.

With the 48v setup.. i'd say go with 2 x 24v 4 amp chargers.

If you go 72v.. then a 3rd charger would be in order...

I do not know of any 72v chargers out there.. but that would not be advisable anyways.. too many cells in series for safe charge termination.

 

[NickF23]

I'm thinking about using Soneil charger to charge Nimh. It's designed to charge SLA and charges thme at constant current to a certain voltage (55.2V for 48V charger) and then maintains that voltage. Could that be a problem for Nimh?

My 48 volt (2 x 24 volt) pack charge voltage goes higher than that so I don't think it will fully charge them.

One of my charger is a 1 amp drill charger which has a temp cutoff. This works well with the 13AH F cells, they still get warm so even c/13 is enough to heat them up.

Another option is to use drill chargers, some of which charge at up to 10 amps. I'll start another thread on that.

 

[numberonekiwi]

Hi I have the same setup as you on 36v
The one thing I am concerned about running at 48V apart from the led indicator as mentioned it is easy to disconnect but my main concern is the controller that has the 3205 FETS which have a breakdown voltage of 55v a fully charged 48v NiMH pack will be around 56v which is slightly higher however if you accidentally leave the battery power switched on to the controller you could possibly have up to 60v across the battery terminals while charging

Caculations worked out from 36V battery

Battery on charge (max before charger switched off/trickle)=45v
Battery on trickle =43v

so if you divide those figures by 30 then multiply by 40 should give you the specs of the 48v pack