How to rebuild Currie 24v RTMB pack?

Batteries, Chargers, and Battery Management Systems.
Post Reply
User avatar
7tronics   100 mW

100 mW
Posts: 35
Joined: May 14 2010 11:19am

How to rebuild Currie 24v RTMB pack?

Post by 7tronics » Jun 14 2013 10:21am

For our family's own Currie Via Rapido, we've noticed after a couple of years of at least a few times a week riding in spring, summer, and early fall, the Li pack has degraded noticably in peformance and range. The standard RTMB 24v 10Ah performance and range were fine when first acquired (used) but the replacement pack now runs about $400.

Now I have several other biking options as noted in the signature line, but this is my daughter's favorite e-bike. Several times she has ridden the Mtn Trailz and it is similar Peddle Assist and with a newer 24v 10Ah SLA pack has similar range to the aging RTMB pack on the Via Rapido. However it does weigh about 16lb more and is far less "stealthy" = there is no mistaking the other Currie Mountain ebikes with the prominant motor and battery packs and ebike labels.

? Are there any ideas out there for rebuilding the Currie RTMB pack with Li batteries that would be larger capacity or less expensive than the $400 replacement 24v 10Ah Li pack?
Mark Smith, @W4CHL W4CHL Wiki
Light Electric Vehicle Assn
eBikes: 2001 Currie eFolder, 2001 Currie Mtn, 2005 Giant LaFree Lite, 2008 & 2010 Currie Trailz, 2010 iZip Via Rapido, 2011 Powabyke Shopper, 2007 Optibike 600, 2010 Marin Bikes BionX MTB
Other LEVs: 2007 Currie Tech eZip 500 eScooter, 2013 OT ELF (4Q2013), 2014 OT Naked ELF, 2019 Segway/Ninebot GoKart

dnmun   100 GW

100 GW
Posts: 16190
Joined: Jun 09 2008 1:32pm
Location: portland, or and loveland, co

Re: How to rebuild Currie 24v RTMB pack?

Post by dnmun » Jun 14 2013 11:02am

why not repair the lithium pack you have now. the performance should not degrade in 2 years. something is wrong and if you fix it then the battery should work as it once did.

lithium is not like the SLA battery

User avatar
7tronics   100 mW

100 mW
Posts: 35
Joined: May 14 2010 11:19am

Re: How to rebuild Currie 24v RTMB pack?

Post by 7tronics » Aug 08 2013 4:13pm

Sorry for delay in reply. Before opening up the RTMB plastic wrapped Li-Ion pack inside the aluminum housing, I decided to check with a GT Power A8 charger. It hadn't dawned on me that the A8 could test these larger ebike packs as I got the charger for much smaller nominally 12v ham radio Li and NiMH battery pack testing.

I set to 8S and went through charge/discharge for Li-Ion. After one cycle the resting voltage jumped from 28.4+v to 29.2v after allowing the pack to settle for a few hours. First pass discharge after full charge with Currie Li-Ion charger measured only 8.1Ah, but after one cycle with the GT Power A8, it was up to a bit over 9.3Ah. With the GT Power A8, I have to cycle twice on charge or discharge as the max capacity setting is 5Ah. Perhaps the best thing to do is charge with the GT Power A8 charger instead of the Currie charger!

I am looking forward to putting this on a West Mountain Computerized Battery Analyzer (CBA) so I can keep tabs on this pack over time. Under 1A load (which is all the GT Power A8 can manage at 29v peak) and with a full charge according to the GT Power A8 settings, my daughter had more range on the bike yesterday than before I did this. She is good about backing off when the Currie indicator shows all "Red" and performance drops. She didn't take the exact same path to church event, so only real way to tell is to put this RTMB on the CBA and get snapshots over time.

Thank you for suggesting I investigate the existing Li pack before turning to an alternative!
Mark Smith, @W4CHL W4CHL Wiki
Light Electric Vehicle Assn
eBikes: 2001 Currie eFolder, 2001 Currie Mtn, 2005 Giant LaFree Lite, 2008 & 2010 Currie Trailz, 2010 iZip Via Rapido, 2011 Powabyke Shopper, 2007 Optibike 600, 2010 Marin Bikes BionX MTB
Other LEVs: 2007 Currie Tech eZip 500 eScooter, 2013 OT ELF (4Q2013), 2014 OT Naked ELF, 2019 Segway/Ninebot GoKart

User avatar
dogman dan   100 GW

100 GW
Posts: 35399
Joined: May 17 2008 12:53pm
Location: Las Cruces New Mexico USA

Re: How to rebuild Currie 24v RTMB pack?

Post by dogman dan » Aug 09 2013 5:17am

Maybe you should be leaving it on the currie charger longer than you have been, to get balanced better. Also, it's possible your charger just doesn't put out the same voltage as it did two years ago. Several of my chargers have done that, drop a volt or so over time. Some can be adjusted back up.

Post Reply