John, If you’re using the Turnigy charger you have the option of bulk charge or balance charge.
Bulk charge you only connect the large red and black leads ie the xt90
Balanced charge you connect the xt90 and the small connector.
I would recommend balanced charge. That way you ensure all four cells get the same voltage.
Similarly, when you’re using the battery, you can connect a battery monitor to the multiway connector. It will alarm if any of the cells drops below a preset voltage. The instruction manual for the Turnigy charger details the minim voltage for different cell types.
There’s a much wider range of really sophisticated chargers available nowadays. Look at other RC hobby suppliers rather than just Hobby King. It’s usual to use the main discharge leads in combination with the balance leads. After all any decent charger will be capable of supplying many Amps and that could get interesting with just the skinny balance wires!
Yes… and make sure you have a fuse in line. On one occasion I wasn’t concentrating and accidentally disconnected my battery at the 4mm plugs! There was quite a flash!
That’s one thing I think is poor with many older chargers. Many now (e.g. ToolkitRC) use an XT60 for the output which is so much better. I cannot understand how anybody ever thought those 4mm plugs were appropriate. Asking for trouble!
I always balance charge with both leads connected. Check the recommendations for storage - I believe for LifePo4s there are no special storage requirements. I have never kept them at anything other than full charge and I have one coming up to four years service with no ill effects. YMMV.
There is a recommended storage charge for LiFe batteries. One of my caravaning friends is meticulous with this. I suspect it’s because he spent £600 on his battery!
…it’s all in the excellent Turnigy charger manual John.
Probably worth doing your own research but I’m sure that I read somewhere that although LiFePO4 chemistry is much more forgiving than LiPo it is still preferable to store at about 50% charge. (How to Find Happiness With LiFePO4 (Lithium-Ion) Batteries - Solacity) The link applies to much bigger installations ( Anyone running 400w from the summit? ) but the chemistry is the same. If there is an issue it is determining what half charge looks like as the charge graph is so flat. I tend to have mine sitting at 13.1 or 13.2 v which providing I am reasonably organised the night before a couple of hours gets them up to full charge (I tend to use a low charge current to avoid any problems - so under 1A). I will have to wait a few years to find out if this approach is effective long term but so far so good!
Really liked the reference in the article to a “RUD” event if charged above 4.2v.per cell…worth reading the article to find out about the acronym!
73 Paul
I do the same. My old LiPo cells (4000mHh 3S1P) were charged with a simple balance charger limited to about 200mA / cell. It could take a long time to charge a pack up from flat. But I think this gentle charge regime is why these 11 yr old packs still work so well. That and maybe some luck in what I purchased (I think £9 ea inc carriage from Hong Kong!) They do seem to have lost some capacity over the years but for the cost and number of uses not an issue.
I’d always suggest more gentle charging wherever possible.