A good charger.

[Sekra]

I have a turnigy mega 400W v2 and its working like a charm! I also use the hobbyking 540W psu without à single complaint!

Go for it - its cheap and good!
Sebastian

[cjcj1949]

Be careful with the parallel charging. When you go for series or parallel you loose the basic protection that's designed into the charger. I've just vaporized a balance lead when doing series charging by connecting the balance connectors in the wrong order. Connecting batteries in parallel will mean that the more charged batteries will charge the less charged ones. The charge currents can be very large and won't do the batteries much good. Lots of people do parallel charge and many use the more expensive fused board from Revoelectric.

[aamacgregor]

Hi Sabastian, I've already ordered the charger as mentioned in my previous post.

Not sure what I'm going to do about the PSU, but I'll most likely modify a computer PSU as suggested by dani_r.

cjcj1949, thanks for the warning. I have looked into parallel charging a little and realise that there is a lot of potential to get things wrong. I guess this I would only parallel charge when all of the following conditions are true:

1) when the cell voltages on all packs are very close
2) when the packs have the same capacity (just to make charge rate/time calculations match)
3) when the packs have been balance charged before hand (or at least no more than two charge cycles ago)
4) when I'm at the field and it makes sense to do so (i.e. I wouldn't do it at home... I don't think)

If there are any other points that I should consider please let me know.

[cjcj1949]

You only really need to think about what you are doing. I would have a slight modification for the initial connection and have some small resistance in there to limit the initial charge current between cells. A 0.1 ohm on each balance connector will limit the amps so that the volts don't have to be too close. After a few minutes the resistors can be switched out. It is better to have all the batteries the same and new and at the same temperature to get good current sharing, again small resistors in series, as used with diodes, will help to even out the current. They will also act as fuses if you do something wrong. Parallel charging at the field is a problem unless you are very strong or like using lots of car batteries or have mains or a generator. The main thing is to make a tidy rig that will force you to connect up all batteries in the right way. You then have to decide on connecting the balance leads first or the main connectors. I prefer balance leads as they act as fuses and save the lipos from damage. If you don't make mistakes the order doesn't matter.

[aamacgregor]

Thanks cjcj1949. Hmm, maybe I won't bother attempting to parallel charge, at least, not in the short term... it seems that there are aspects that I haven't appreciated. I think I should make sure that I know completely what I am doing before attempting it. I guess if I can charge a battery at a high rate (not that I'll be planning on doing that often even though my new Gens Ace battery is rated at a 5C maximum charge rate), then there isn't much point in me parallel charging... especially considering I couldn't do it even if I wanted to, since I only have one good battery! Anyway, thanks for your input, I really appreciate it.

[brummycraig]

I used ElectriFlyer.co.uk

+1

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