Robert Cracknell

Since my original post about cycling Rx packs I have bee experiencing some rather strange problems with my Overlander D100V2 charger. I was cyclng a 4 x AA Rx square pack and the display showed ‘D’ for discharge and a start voltage of 4.14V. As the cycling went on I noticed that the pack voltage began to rise. From a start of 4.14V it slowly rose to 4.23V. As I had set the cell cut off at 4.0V (1.0v/Cell) I thought there is no way this is going to finish so I cut the process short. I recorded the latter part of the rise by videoing the display. A couple of days later I was cycling a 4 x AAA 800mah flat pack with a discharge of 1.0A and a charge of 0.5A and, foolishly, went into the house to make a cuppa leaving the pack discharging. When I came back about 10 minutes later I could smell something hot and within a few seconds one of the cells on the pack split open and was extremely hot. I am sure it was still on the discharge part of the cycle but even if it wasn’t 0.5A is below 1C and should not have caused the cell to rupture, I raised this with Overlander Support (the charger is just over 3 years old) about 2 weeks ago and apart from being told that they have reported this to the manufacturer I have no answers. Given the volatility if LI-Po cells I am not going to risk putting any of these near this charger! Has anyone had any similar experiences with a D100V2…?

E.D. The consensus on this thread seem to point to Eneloops......

Nigel The batteries are described as 'Racing Battery' at 2600mah. See photo.... Rob

John Isn't 500ma too low for a Rx and 4 servos? Rob

Thanks Simon Perhaps I'll repeat the procedure but at 0.1A charge which is as low as the charger will go.. Thanks Rob

I have been cycling some of my Rx packs to check on their condition and capacity and I have come up with a few points which I feel could warrant input from the forumites. The packs in question are all 4.8v, 2600mah Rx square packs made up from welded Vapex AA Ni-mh cells. They range from less than a year old to some at 6 years old. The charger is an Overlander D100V2, and the settings for this exercise are; Discharge Rate 1.5A Charge Rate 1.5A (57% C) Cut off voltage 4.0v (1.0v per cell) The first point is that none of the cells took anywhere near the rated capacity of 2600mah, The best I could achieve before voltage cut off was reached was 1960mah. The others varied between this figure at best at 1550mah at worst. The discharge figures more or less mirrored these. Secondly, discharge times varied as well with the newer pack discharging the fastest. This was not measured but simply an observation from the side by side display on the D100V2 This raises a question or two…. The full capacity of the cell clearly cannot be extracted unless the 1.0v/cell limit is breached, i.e. the remaining capacity is only available by taking the cell to damagingly low levels. How do we assess the working capacity of these packs? Maybe we should be looking for ‘Real World’ ratings, perhaps expressed as a percentage of the claimed maximum. The voltage drop was also noted and at a 1.5A load the voltage dropped quite quickly to around 4.3/4.5V. What is considered to be the minimum operating voltage? The voltage would hold at this for much of the discharge cycle. All input and comments appreciated….

Sign of things to come.....? S/H Laser 100 just sold on EBay for £510...!

Chris You might find that your crystal is a Fleet (FCS = Fleet Control Sytems), 73 being the frequency and R for Rx. I have some similarly marked.

Like the time an American tourist visiting Windsor Castle said how convenient it was that the Queen had the castle built so close to Heathrow Airport.

Must be a regional thing as I live in North Essex and my local Lidl do not have it....

Anyone know a friendly lottery winner...?

I have a number of Ni-Mh cells that I would like to check out more thoroughly. Sure, they seem to charge OK but you are correct in that they might collapse under load. What is the consensus on what the load should be and the best way to apply it? Has anyone designed a simple circuit that will apply a constant load while the voltage is checked? What can be used as the load - bulb, resistor..? What is your favourite method?

Why has 'stutter' got all those t's...?

If you download the Lidl app you are able to see the special offers leaflet a week in advance.

Dick If you pm me your postal address and I can post you a copy. Rob