Richardfast

My Feedback: (15)

I am charging my Thunder Power 2S 1310 LiPo pack using my Hobbico Quick Field Charger Mk II. The voltage is only 7.9 volts when the Mk II quits charging. According to the info that came with my Thunder Power pack, a fully charged 2S pack should be 8.4 volts. Appears to me I am losing a lot of capacity by using the Mk II charger. What are you getting for fully charged voltage? Thanks.

jaofos

Actually I think Li-Po's are 3.7v per cell, so 7.4v would be fully charged.

DaveG55

Mine generally top out at a shade under 4.2v/cell Usually in the 4.17 or 4.18 area. I've got one 2s pack and 1 3s pack and that holds true for both packs. It doesn't seem to matter which charger I use (I've got 3 that will do lipos) or if they're charged with a balance charger or through the discharge leads.

guver

My Feedback: (325)

Yes, you are losing some capacity and "full" shlould be 4.2 as stated above. I consider "empty" to be 3.5 volts resting. Lots of chargers will terminate around 4.1, the MKII is originally a li-ion and is intended for 4.1, but yours is quite a bit low.

DaveG55

It's my understanding that the voltage lipos are rated at is just above 1/2 way between their fully charged and safe discharge voltages.
1 cell is rated at 3.7v, a bit above 1/2 way between 3.0v and 4.2v. 3v/cell being the minimum safe voltage and 4.2 being the maximum charge voltage. So a 2s battery would have a minimum safe voltage of 6v and a full charged voltage of 8.4v and be rated at 7.4v. A 3s battery would be rated at 11.2v and have a minimum voltage of 9v and a fully charged voltage of 12.6v.
In the real world the maximum charged voltage will vary a few hundredths of a volt but it's never a good idea to discharge below the 3v minimum.

Richardfast

My Feedback: (15)

Thanks all of you for the replies. I think I can conclude that since my MkII was originally for LiIon cells it is not charging my LiPoly's to full capacity (4.2 volts).

For info, I replaced the 8 cell NiMh GWS pack that I had in my GWS Formosa with a Thunder Power 1310, 2S pack and it now performs quite a bit better. I noticed that the GWS pack voltage dropped to 6.6 volts under a 10 amp load, whereas the LiPo's only dropped to 7.2 volts. That gives me quite a bit more RPM under full throttle. Also, I saved 1/2 oz in weight and gained several minutes in duration. Price difference is $20 though.