Anton Bauer Hytron 50 Re-cell.

[Robert Hart]

I have been re-celling an AB Hytron 50 battery which uses NiMh cells. I used to do my CP16 batteries with no issues and this one is fine afterwards as well.

I got lazy this time and had a battery place stitch the new cells together. I am over cutting strips of shim and soldering and hoping the solder does not get hot and melt under load.

I reserved the dismantlement and re-assembly of the case for myself as I am a bit wary of letting people "have a go" when they have not worked this particular battery previously. Those logic series PCBs deserve care and respect. A stab in the wrong place with an overshooting screwdriver and its all over.

However, inside the case which was partially dismantled when I got it, there was a stiff leaf spring clattering around loose inside. It is about 28mm long by about 9mm broad. The two ends are curved over, obviously as keys to fit loosely in grooves in a channel and retained by whatever it is that loads against it.

For the life of me, I cannot find anything inside the battery case that could possibly use this piece. I opened up another battery pack which has not entirely died to look for where this spring is meant to be. It unfortunately turned out to itself be a previously re-celled pack. There is no sign of such a spring or where it might go. It may have had one or maybe not - no way of knowing.

The newly re-celled battery pack works fine, reports its time remaining under the given load correctly and mounts up to the camera without falling off or anything catastrophic happening which might suggest a missing spring somewhere.

If anyone has a clue as to whether this is a stray piece that has come loose inside or is a total foreigner which might have fallen in whilst the case was in a box or wherever, any advice would be appreciated.

Why not have a proper tradie do the deed? This is Western Australia. We don't have everything in the colonies and I also have a penchant for doing as much for myself as I can. Knowing how something operates is a lifesaver in the field sometimes when the ordure hits the McCauley.

 

[John Ritter]

Hi Robert

Some how that extra part got in there, The standard Hytron 50 pack does not contain any springs. (BTW: non of the Anton Bauer packs use springs)
Just discard it and use the battery

Regards John Ritter
www.ritterbattery.com

 

[Robert Hart]

QUOTE: "Just discard it and use the battery." - John. - Thanks for your quick reply. Your suggestion is the plan. The Hytron 50s are a bit small for the SI2K and yield 30-45 minutes operating time. I have been having a possible overvoltage problem with generic 240Watt batteries. After the recorder unit laid down ( definition "bricked" in RED-speak ) again, the issue seemed to be local to a power regulator chip on the upper motherboard. Both times it has gone down it was with a fresh battery. I put a meter on one and it was showing 18volts, the other 17volts, both a bit on the high side for my comfort. These may be the same style of batteries that some Epic/Scarlet owners are having problems with until the batteries are partially discharged. They are rated for 240watts. Maybe the builders have achieved the power endurance by brute force - adding more cells. That's the next investigation. If that is how they have gone about it, I shall be a bit disappointed. In the meantime, thank you for your advice.

 

[John Ritter]

Hi Robert

You may have a faulty battery charger if your packs are being charged to 18 volts. (could also be a faulty charge controller (PCM) in the battery as the battery control circuit should limit the charge voltage also).

The charger should be limiting the voltage to 16.8 volts, depending on the accuracy of voltmeter you are using this can be read as 17 volts.

The cell design standard is to use 4 cells (or banks of multiple cells i.e. 2, 3, 4, 5 to increase capacity) each cell should not be charged higher than 4.2 volts and the 4 cells in series will max out at 16.8 volts.

When the 16.8 volt battery pack is first used the voltage will drop very rapidly to the 16-15.8 volt range and then discharge to 14-13.5 volts at which point the voltage will drop of sharply.

see the attached graph example:


Regards John Ritter
www.ritterbattery.com

 

[Robert Hart]

Thanks again for your further reply John. As this is your bread and butter you are generous in even sharing this information.

I should have clarified that the two 240watt packs are generic batteries out of China that have their own "travel charger" and are not related to Anton Bauer except that they have the AB fixture to enable them to mount to the camera.

The cases are of the "fluted waist" style seen in some aftermarket V-Mount batteries. The cases are interesting in that whilst the surfaces are hard black plastic, they have some sort of composition finish that is grippy like rubber. You would have to be very careless to drop one.

They can be ordered in either AB or Sony V-Mount. I shepherd them when charging and charge in several shorter periods to make sure they don't get hot. I do not like "travel chargers" which feed via D-Taps on the sides of the batteries. The batteries do have excellent working endurance on the camera.

I imagine their initial "high" state in use lasts longer, which may be enough added time for the voltage regulator chip on the camera motherboard to become stressed on a hot day.

The motherboard is of an industrial standard normally applied to critical military, medical or other applications like train control systems. In fairness, the camera was a demo unit before I got it and there were signs people had been opening it up for a look.

In its past life it has been powered by external sources as diverse as 12v truck batteries or IDX power supplies off generators, so the problem may not be the bigger batteries alone but something awry that is provoked by them.

The two AB Hytron 50 batteries are normally used piggyback on a Titan Tandem70 on the back of the camera. They have been fine but of shorter and shorter endurance. Given they were used when I got them and that was three years ago, that is not a bad innings at all.

Each had a few dud cells when I opened the cases and tested the cells after allowing a self-discharge period. To get me by until a second set of replacement cells come in, I recombined the best of the two sets which has to be ultimate in being plain cheap.

I don't expect the recombined cells to last much longer as there were a couple of warmer ones among them when I checked them during a charge cycle before closing the rear case back up.

The pattern and castwork of the cases is impressive with good internal finish on the flat surfaces, no signature of the sandpaper marks on the original patterns you will see on a lot of plastic products. The dies or molds look to have been maintained as well, testament to AB's aspiration towards quality I guess.

The only thing I might cry in my cups about is that the lower ridge of the slot into which the PCB locates in the rear cover will sometimes bind on the edge of the PCB which warped and hung about 1/16" high. That one case is more beat up than the other.

I ended up dressing the upper edge of the slot in the rear cover to a small chamfer to match the existing chamfer in the small end-guides and the PCB then slid in just fine.