Batteries / Power Systems: January 2009 Archives

Li-Po batteries have the best power/weight performance of all of the mini battery sizes. If only they'd come down in price more, they'd have more utility. In any case, I'm using small Zippy brand 11.1 volt (3S) 2200 mAh battery packs. The only problem I found is that the balancing connectors on them aren't nearly long enough to reach from my Turnigy charger to my bomb-proof charging container (an old army-surplus ammo case). I tried to see if anyone sold 3S lipo battery connector extensions, but no luck.

Also, my Turnigy charger requires two connections for LiPo balancing -- the main Dean's connector and the balancing connector. This is a pain in the waddle since you can do it with only one connector -- as long as you remain within the relatively low amp constraits of the balancing connector (likely < 5 amp).

To make life difficult, there are apparently four (4) different LiPo balancing connectors in use. My Zippy batteries use the Align standard, which is a JST XH connector. Here's a very handy chart describing the various connectors and which batteries use which connector: http://www.rcaccessory.com/pdf/Battery%20Tap%20Configuration%20Guide.pdf

Now that I know that both my Turnigy charger and my Zippy batteries use JST XH, I just had to go to Digi-Key and order the right parts:

1	10	455-2249-ND	CONN HEADER XH TOP 4POS 2.5MM	JST XH SHROUDED HEADER	0	0.13500	$1.35
2	10	455-2267-ND	CONN HOUSING 2.5MM 4POS	JST XH HOUSING	0	0.05700	$0.57
3	100	455-2261-1-ND	CONN TERM CRIMP XH 26-30AWG	JST CRIMP CONNECTOR	0	0.03340	$3.34
4	10	455-2219-ND	CONN HOUSING 2.5MM XH 3POS	JST XH HOUSING 3 PIN	0	0.05700	$0.57
5	10	455-2248-ND	CONN HEADER XH TOP 3POS 2.5MM	JST XH HEADER 3 PIN	0	0.10000	$1.00

Once the connectors arrive, I'll have enough to play around with them for quite a while!

p.s. Bonus, the same connectors can also be used to create extensions for my LiPo battery monitors.

I just had a nice conversation with one of the staff at BatterySpec.com, which is where I bought my Tempest TR22-12 sealed-lead acid (SLA) battery. I had inquired about a warranty exchange. They denied it but they gave me a really good reason why -- which is why I'm giving them two thumbs up.

The reason my TR22-12 died on my Piaggio is because I had it in a 2 serial 2 parallel configuration with slightly lower capacity Rhino batteries. I had them configured as a bank of Rhinos and a bank of Tempests. The internal resistance of the Tempests is lower than the Rhinos, so the Tempests were discharging faster and this is why one of them failed.

If anything, I should have done a mixed bank of Rhino-Tempest paired with another Rhino-Tempest. This would have protected the Tempests. But in general, mixing different capacity batteries is a big no-no -- which is why my warranty claim was denied.

In any case, my TR35-12 should be good for its purpose so we'll see where to go from there!

All in all, I'm very happy with BatterySpec and glad that they took the trouble to call me to tell me why my warranty claim was denied and why I shouldn't be doing what I had been doing.