OK guys,

My Impact is my first foray into larger electric models so a few words of advice wouldn't go amiss from you seasoned electric pros!

How do many of the large lipo packs do you own? How do you charge them? How long do you get from each pack?

I was speaking to a FlightPower (lipo producers) guy on Saturday who said that their new cells can be charged at up to 2.7C which makes things more bearable at the field - not having to wait 60-90 mins for a recharge will be nice!

Now, can I charge my packs from my car battery with the engine running? I know Schulze (my charger manufacturer) doesn't recommend it but this is more to do with an unregulated power supply to their charger than anything else?

I don't fancy having to buy and transport a generator and even a large leisure battery is not going to give me a days flying is it???

So, how do you guys do it when I hear you say you had a good days flying/practising on your latest electric models!!!

Thanks,
Mark

Not sure mow many charges you would get at 2.7C

3 sets of cells and a generator for a days flying.

I'm prepared to top off a partially discharged battery from the car without running the engine but as for routinely trying to recharge from flat from the car forget it. Apart from anything else that sports job in your atavar will not take kindly to being idled for hours at a time. I once had a Lotus Elan Sprint which would routinely break piston rings if you treated it this way due to oil being washed from the cylinder walls.

Malcolm

Hi Mark.
Assuming a 5Ah battery pack, at 42V, being charged at 2.7C, that is a charge current of 13.5A and a net total of 5x2.7x42=567W.
Does such a charger actually exist?
Also, you could not do it from a normal leisure battery, the load would be too high.

I can charge max. 3 times from a 110Ah leisure battery, at 1C (6000 mAh packs.) The last charge cycle may even have to be done at a lower current (less than 1C) to avoid that the charger terminates the charge due to low source battery voltage.
Typically you can only take about half the rated capacity out of a 12V battery, i.e. a total of approx. 55Ah from a 110Ah battery.

Magne

Thanks guys. As I thought - no real 'all round' solution

So a generator is really the only way to go I guess?? Oh, and the small issue of 3 sets of cells GULP!!! [X(]

Malcolm, which do you use? BTW, hope the house move went well.

@Mattyd, At 2.7C they were saying 150 charges would be the norm.

150 charges sounds ok

We have 2 sets of TP5300 and started out with one TP1010 charger. We found that to speed up the charging process an additional charger would help more than an additional set of batteries, and costs much less than additional set of batteries. We now have two sets of batteries and two chargers. Charge time is 45 minutes per set of batteries.

Go to the field with 2 charged batteries, fly, put on charger, fly second pack, put it on second charger, first pack will be through in about 20 additional minutes. We did find it necessary to buy a generator to power the chargers at fields without electric available. The heavy liesure batteries will not sustain the load and the charger will quit due to low input voltage.

Mike

I bought one of these 1kVA jobs brand new from an Ebay seller last year for under £200. So far it has proved fine. Move not until next month but stuff starting to get packed away so modelling a bit restricted.

Malcolm