HP-9114B IL disk drive - how to prolong battery life?

[Craig Bladow]

Many years ago I acquired an HP-9114B disk drive and the battery was dead so I replaced it. Due to only using the drive sporadically this battery eventually failed, so with the next battery I left it plugged in all of the time, to an HP 82059D (output 8 vac) power adapter and now the battery is dead again (but it has been a few years). Anyone have a recipe for keeping the battery (perpetually ) healthy in this disk drive?

[trojdor]

I've found that most battery chemistry likes to be frequently 'stirred' by using/cycling it.
(If a secondary battery is sitting unused, it's slowly dying.)
And unless it's a lead-acid cell, it's almost always worse to leave the battery under a constant state of charge.

So my advice for longer battery life would be;
1. Don't leave it plugged into the charger all the time.
and, more importantly,
2. Simply use the device more often to drain it down, and cycle it.

Now, if it were LiON instead of NiCD or NiMH, I'd suggest storing the battery with a charge between 40% and 60% to maximize it's life.
But in all fairness, even LiON batteries like to be regularly used....otherwise capacity quickly goes down.
Good luck,

mike

[rprosperi]

I assume its the Panasonic/Powersonic PS-628 SLA battery, right?

If so, as an SLA battery, there's no way around it, it will need to be replaced every few years, just like the batteries used in UPS systems, emergency light fixtures, and even your car. On the good side, they're super easy to change and not too expensive. When I put a new one in, I just create a reminder for 3 years later to replace it again. It will need to be replaced regardless of how much you use it, or how you baby it.

[Martin Hepperle]

• Lead (Pb) batteries (e.g. the Panasonic block mentioned above) want to be kept at a relatively high state of charge. It is not good to drain a car battery completely.
  Usually it is good to regularly recharge them - e.g. for the HP 110 it is recommended to recharge when the indicated charge falls below 60-80%. One should never overcharge or leave them on the charger for long time.
  I regularly recharge my lead batteries every 2-3 months for about 6-14 hours, but not much longer. I do not actually have a timetable for this, but I do it regularly. If in use for more than an hour or so, I plug in the charger, especially the 9114 draws more current that the charger can supply.
• NiCd batteries on the other hand like to be cycled completely (but not deep discharged!). Otherwise they suffer from "memory effect".
• NiMH batteries seem to be close to NiCd but obviously don't need the cycling. They loose capacity slower than NiCd and Pb when not used.
  

Overcharged NiCd and NiMh batteries get warm - Pb batteries may open their pressure valve and you may hear them breathing. Both not good and charging should be stopped. Overcharged LiPos may halt and catch fire...

The HP chargers are primitive by today's standard.
Therefore I use, if possible, a small r/c model aircraft charger which has programs for NiCd, NiMH, LiPo and Pb batteries.
The best is to use such a special charger for the specific battery type. Mine was about 50$ - it is not necessary to spend 300+$. It operates on 12V, so I use my laboratory power supply.
For NiCd it also has a "cycle" option where you can specify 1...3 discharge/charge cycles).
These chargers "know" about the battery chemistry and when the battery is full. Usually the voltage increases and when the battery is full it drops slightly and the energy is converted into heat. These "intelligent" charger then switch off.

Some HP chargers have very simple diode rectifiers (sometimes a single diode), which leave a pulsating voltage and current, which is probably also not the best for charging batteries. In the best case they reduce charging current to a "trickle" for Pb batteries, but not as prcise as a modern charger.

I built me a small box with contacts which can take the refurbished NiCds or NiMH packs e.g. from the ThinkJet. For the 9114 disk drive I crated an adapter cable.

But even so, I agree that after maybe 5 - 6 years it may be necessary to replace batteries.

Martin

[Craig Bladow]

(01-11-2021 01:29 AM)rprosperi Wrote:  I assume its the Panasonic/Powersonic PS-628 SLA battery, right?

It's a generic SLA, 6V 1.3 Ah as was its predecessor. I have to gently bend one of the terminals to face the other way so it plugs in nicely.

[Craig Bladow]

(01-11-2021 01:13 AM)trojdor Wrote:  So my advice for longer battery life would be;
1. Don't leave it plugged into the charger all the time.
and, more importantly,
2. Simply use the device more often to drain it down, and cycle it.

I'm envisioning a 41C/71B programmed to wake up periodically to exercise the drive but now the problem extends to the NiCd battery in the 41Cs case .

(01-11-2021 01:13 AM)trojdor Wrote:  Now, if it were LiON instead of NiCD or NiMH, I'd suggest storing the battery with a charge between 40% and 60% to maximize it's life.
But in all fairness, even LiON batteries like to be regularly used....otherwise capacity quickly goes down.
Good luck,

mike

Two LiFePo4 cells would work........

[Craig Bladow]

(01-11-2021 05:13 PM)Martin Hepperle Wrote:  

• Lead (Pb) batteries (e.g. the Panasonic block mentioned above) want to be kept at a relatively high state of charge. It is not good to drain a car battery completely.
  Usually it is good to regularly recharge them - e.g. for the HP 110 it is recommended to recharge when the indicated charge falls below 60-80%. One should never overcharge or leave them on the charger for long time.
  I regularly recharge my lead batteries every 2-3 months for about 6-14 hours, but not much longer. I do not actually have a timetable for this, but I do it regularly. If in use for more than an hour or so, I plug in the charger, especially the 9114 draws more current that the charger can supply.
• NiCd batteries on the other hand like to be cycled completely (but not deep discharged!). Otherwise they suffer from "memory effect".
• NiMH batteries seem to be close to NiCd but obviously don't need the cycling. They loose capacity slower than NiCd and Pb when not used.
  

Overcharged NiCd and NiMh batteries get warm - Pb batteries may open their pressure valve and you may hear them breathing. Both not good and charging should be stopped. Overcharged LiPos may halt and catch fire...

The HP chargers are primitive by today's standard.
Therefore I use, if possible, a small r/c model aircraft charger which has programs for NiCd, NiMH, LiPo and Pb batteries.
The best is to use such a special charger for the specific battery type. Mine was about 50$ - it is not necessary to spend 300+$. It operates on 12V, so I use my laboratory power supply.
For NiCd it also has a "cycle" option where you can specify 1...3 discharge/charge cycles).
These chargers "know" about the battery chemistry and when the battery is full. Usually the voltage increases and when the battery is full it drops slightly and the energy is converted into heat. These "intelligent" charger then switch off.

Some HP chargers have very simple diode rectifiers (sometimes a single diode), which leave a pulsating voltage and current, which is probably also not the best for charging batteries. In the best case they reduce charging current to a "trickle" for Pb batteries, but not as prcise as a modern charger.

I built me a small box with contacts which can take the refurbished NiCds or NiMH packs e.g. from the ThinkJet. For the 9114 disk drive I crated an adapter cable.

But even so, I agree that after maybe 5 - 6 years it may be necessary to replace batteries.

Martin

Martin,

Thanks for the information, I should probably remove the battery from the 9114b when not in use (or use it more!) and then charge it with an intelligent charger on some schedule as you mention.

[Dave Frederickson]

I use a PowerSonic PSC-6500A-C 6V SLA charger. It does have fast and float charge modes but doesn't switch over to float very well.