Thursday, 27 October 2016

Release the Hydra!

It should be the Kraken, of course, but ive never found mythical sea monsters to be particularly useful in bulk charging batteries!

The Hydra in this case is a simple multi-headed trickle charging solution! Ive found that many deeply discharged batteries will recover, but the Accucel-8 cannot detect them! So, by sticking them on a 15v supply with a suitable series resistor, in this case 120 ohm, I can bring them back up to around 11-13v terminal voltage, and the charger will then detect them and go into the recovery cycle.

The 'Hydra' trickle charger!

With quite a lot to get through, I set up the 'Hydra' to allow me to bring up half a dozen or so batteries in one go.

Ive now run around a dozen through a pair of full Discharge/Charge cycles, and they all seem to have come up to sensible capacity. Around another 50 have passed basic on-load voltmeter testing and should recover when given the cycle charging. About a dozen have failed completely to recover at all

I can now at least dispose of all the known failures, and concentrate on those that show promise. As such, I am also now in a position to separate the 600mAh packs from the bulk of the 550mAh packs! I want to retain around ten good packs for my own use. All the rest can be sold on. Two lots of untested packs have been sold, thats 20 batteries. Im slowly clearing the space in the workshop!

Very kindly, one of the BVWS forum members, Tony, has sent me some 5p6 ceramic capacitors of the type I need to complete the PF8 refurbishment.

I shall get on to that shortly. It now requires some serious dismantling to change these capacitors, due to them being very close to the chassis edge.

The Ultimate 3S is coming along, slowly. Ive not yet heard from Hans regarding the missing inductor, but theres no rush. Ive completed the 10m LPF, this time without getting my wires crossed!

28MHz LPF, L1 (10t) fitted
28MHz LPF L1 and L3 installed and glued down
28MHz LPF complete
Ive also made up the RF coax connection header. This is using my TNC pigtail at present but will do for testing. I dont wish to power the unit for testing until I can have the output fed to a dummy load

RF coax header connection
Ive been hearing a lot recently about 'Parrot Repeaters', otherwise known as a Simplex Repeater, a type of Voice Store And Forward system. These are used on 70MHz where there is insufficient bandwidth for duplex repeaters, and generally seem to be much simpler to build. Im wondering if there is any such machine im my area, and if not, what the requirements would be for me to instigate one...

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