Hi Paul, yes, I smiled at the thought of using one of those fluffy asbestos things that used to be everywhere (I do know that isn’t what Richard had in mind). Maybe an old radium bed warmer to keep the battery warm too
Thank you both for your comments, probably time for me to relax and let common sense prevail!
As my SLAB has come to the end of its life (it will not power my new HF radio) I was inspired to look at these LiFePo batteries. Unfortunately the seem to be permanently out of stock at Hobbyking.
Has anyone successfully received one on backorder, or found another suppllier for a high capacity 4S type?
Otherwise is it OK to buy 2 smaller capacity ones and parallel them up?
Any precautions needed with this?
thanks.
I have been paralleling 2 X 3cell 5AH Lopos for 3 years, I only parallel immediately before use by completing a Y connection and have 20A auto spade fuses in the positive leg immediately off each battery. I break the Y connection prior to charging. This method also gives me an indication which battery has been used. Sparks are not necessary for this activity. I use X40 connectors rather than power pole. These have proven to be reliable when drawing 20A peak.
May be of use to anyone looking for powerpole connectors pre-made, I was at my local halfords today and came across some for £2.50, I couldn’t resist at that price and bought 2 packs.
May I offer a word of warning having just goosed an almost virgin LiFePO4 battery. I stupidly left mine connected to my 817 after coming back from holiday; the resulting current drain from the switched-off radio resulted in a totally ruined pack
I actually use quite a number of LIFePO4 batteries in my model boats, especially when the SLABs I have used in the past have shuffled off this mortal coil, which is why I am so annoyed at myself for forgetting to disconnect it from the 817
Hmm, that’s surprising Barry. I am fairly certain the 817 switches off when the voltage gets too low to sustain it.
On one occasion I forgot to switch out my 4AH 3S LiPO when I came off a summit. I didn’t realise that I hadn’t disconnected it until I tried to switch on the 817 later in the day on another summit. Unfortunately the spare battery had been left in the car, so I had to use my 2m handheld to qualify the summit. I was able to recharge the battery which had around 2.8V per cell rather than the recommended minimum for a LiPO of 3.7V and it is still working fine.
There is no power switch between the drains of the FETS in PA and the supply, only the digital and small signal sections are switched. It’s possible for some current to flow when the set is switched off.
Yes, the same conclusion here. To quote the article - _“If rechargable batteries are installed, the '817 trickle charges the pack at 10-15 milliamps”. Multiply that small 0.015AH rate by the 8 week stay Barry had in the Seychelles and yes that battery would be flattened.