Norm;
Just seeing this, a clear warm
DRY night had me enjoying the patio last night til bedtime.
I've kind of done this part already so I'll put up what I've seen.
I'm now building my larger unit at 14.4 which is nice since it uses an even 12 Sub-Cs and they stack real nice.
These are rated at 1300mA each and I don't think I've shipped any out that are less than 70% of the original rating of 1.3Ahr, mostly percents higher than that.
The real cool thing about NiCds is they try their darnedest to keep the voltage at the same level until about 90% dead then, they drop off like a zener going into conduction.
A good test or even better a good battery pack would be one that built at 14.4Vdc 1.3Ahr should be able to show the voltage to be stable and 900mA of use.
A better test would be to run the battery until it drops and take note of the watts used. If you're running the watts-up meter just off the batt pack, you might hook up the alternate power source, I did this using an old PC Hard Drive connector and 4 AA NiCds in series. This way you can let the pack drain as low as you want, even to zero if you wanted to
or needed to. that way you can read the results without worrying about trying to read the numbers and doing work at the same time.
IF for some reason you have a pack that drops to 0, then you have a cell that is toast and will drag the rest of the pack down with it.
I've done this on Amy's e-bike that uses 48Vdc and the watts-up meter is the fuel gauge for me since the meter built into the bike is for acid-based batteries.
I have caught some of my home built packs doing this and wish I had a meter on each pack, it would make figuring out which pack has gone bad quicker.
I have GHURD controllers on each of the e-bike 14.4Vdc 16Ahr packs and charge them via 4 separate HF 15watt panels. This way they get the charge they need individually instead of one large pack like they SLA used to get.
A small note, once the packs pass the first 3 tests of charge/discharge cycles, I've not had any show up later with a bad cell. I have overcharged a pack (or 2
) and had them pop, but that's a different post.
I know I got a little long winded-- <o_o>
NORM Does this help?
Bruce S
For others reading this, the reason I chose 14.4 is the voltage "dip" that occurs when a load is put on these. I've seen this dip happen on the Wattups meter and saw a nice 900watt inverter go into LVD when I tried using a 12Vdc or 10-cell batt pack. The 14.4Vdc packs still have a voltage dip, but it is well within the rated limits.
A 14.4Vdc NiCd pack fully charged will read up in the 16V range, I have not had any problems with the MSW inverters going into high-voltage alarm.
The units I mess with range from 150watt up to 1000watt, the ones I do most of my testing with are 300 & 750 watt vector units, the 900 watt unit came with a 700watt Microwave and has no other outside markings on it.
The little 150 & 300 watt inverters run just fine --mostly-- on the 12Vdc 10-cell packs too, so if you have a bunch already built I wouldn't tare them apart.
