> I'll write a program which saves elapsed time & leave the machine on > continuously until it turns > off from low-power. By adjusting charging times, I'll figure out optimum > charge-time.
That sounds like a great way to do it, Philip. > They could have easily used the NEC charging method as it presents 8.4V to > pin 5 > of the connector (8201a). I'm speculating here but the only reason I can think of why they put together custom rechargeable packs with an external jack would be for the situation where they would want to have a surplus of extra packs all being charged separate from the NEC machine itself, and then they'd use them in the machines when fully recharged. But, who knows for sure. I've refurbished a couple of those weird packs in Brian's photos myself, soldering in the right 71.5K Ω resistor (hard to find part, by the way!) and jumper and putting in either NiCad or NiMH cells. My favorite is to use five of those small NiMH cells to get a full 6V. I'll be very curious what you find on the charging times and performance! Gary On Thu, Jul 23, 2020 at 10:55 PM Philip Avery <[email protected]> wrote: > > A-ha! Thanks Gary. Studying Brian's photos I see that wasn't originally > a rechargeable pack. My (8201a) pack has the 70K ohm resistor on the > "set" lines & Ni is bridged to positive. They could have easily used the > NEC charging method as it presents 8.4V to pin 5 of the connector (8201a). > > Slow charging Ni-MH is a black art so I figured I'll do some experiments > to see how long it takes to fully recharge. I'll write a program which > saves elapsed time & leave the machine on continuously until it turns > off from low-power. By adjusting charging times, I'll figure out optimum > charge-time. > > Philip > > On 24/07/2020 5:37 pm, Gary Weber wrote: > > They didn't. That tiny little battery pack with the external charging > > jack was an "aftermarket" thing. I think it was installed by a > > company that did VAR resales of 8300s into industrial label printing > > applications. > > > > By the way the 5-cell NiMH solution works really nice. Keeps the > > voltage way up in the acceptable range throughout the discharge cycle. > > I definitely recommend the solution Brian highlighted. > > > > On Thu, Jul 23, 2020 at 10:32 PM Philip Avery <[email protected]> wrote: > >> Why did NEC go with such a small battery for the PC-8300? > >> > >> I've just rebuilt my PC-8201a pack and it had 4 x AA Ni-Cd's originally. I > >> replaced these with 4 x Eneloop AA's (2000mAh) & lowered the charging > >> resistor value so it will charge them in a reasonable time-frame, ie > >> overnight. > >> > >> Philip > >> > >> On 24/07/2020 3:40 pm, Gary Weber wrote: > >> > >> Brian, > >> > >> Those are precisely the same batteries I've been using to build up > >> refurbished 5-cell rechargeable packs for my machines also. They've been > >> working very well. > >> I got my battery sets off of eBay and they arrived within 10 days or so. > >> They still sell them there so you'll be able to find 'em. > >> > >> Gary > >> > >> > >> > >> > >> On Thu, Jul 23, 2020 at 8:34 PM Brian K. White <[email protected]> > >> wrote: > >>> My PC-8300 came with a rechargeable battery pack that had a tiny 60mah > >>> battery originally, a 5 button cell nicd hot-glued in the middle, with a > >>> couple diodes & a resistor and it's own barrel jack to charge the pack. > >>> All corroded and dead of course. > >>> > >>> I determined that you could fit 5 x 1/2AA nimh cells in the same case, > >>> same voltage, same charger, and get 800mah instead of 60. > >>> > >>> 1/2AA is a size that exists, but is pretty hard to find. > >>> > >>> I found this on Amazon, welded tabs already, and even sold in sets of 5, > >>> exactly the number needed, perfect. > >>> http://amazon.com/gp/product/B07ZNZ535F/ > >>> > >>> Not so perfect, it took over 4 months to arrive (March 17 to July 21). > >>> > >>> But they did finally arrive, and the size worked out. > >>> > >>> Everything fits, and it's easy to replicate the original wiring just > >>> moved around. > >>> > >>> https://photos.app.goo.gl/JRVp71Govw49PXaM6 > >>> > >>> -- > >>> bkw > >> >
