while i have the HV battery out of my gen1

Personally, I would just charge to 8.0 and wait for the three to arrive.

Bob Wilson

 

The battery modules will not be harmed by shaking or turning upside down. They are effectively sealed units although they do have pressure relief valves. Damage by bending, dents or cracks in the plastic cases is a different matter.

John (Britprius)

 

USPS would never do that.

 

Necessary no, but it will tell you if any modules are low capacity (worn out) so those should be replaced before you put the pack back together.
Original modules have 6.5 Ah capacity. It has been reported that some Prii ran fine even though the capacity was severely reduced, but I would consider replacing modules that have very low capacity before putting in too much effort rebuilding the pack, so this test will tell you if any have very low capacity. I think you said that the tail light was drawing like 2.7 Amps (?) which would mean that a 10 min load test will draw almost 0.5Ah from the module.
If the voltage drops below 7.2V during that test then the module has at least one bad cell and you might consider replacing those that do not even survive the 10 mins.

 

Although this is true, it appears that scotman27's battery did not start from a discharged state. If, after resting for a few hours, the parallel battery still measures 7.94V then I would say he should stop, since the nominal battery module voltage is 7.2V.

I agree that 8V per module is a good target voltage to strive for. 8V x 38 modules (when connected in series) = 304V compared to nominal battery voltage of 273.6V.

It is not necessary to fully charge the traction battery; it is sufficient to get the battery to the point where it will comfortably spin MG1 to start the gasoline engine.

 

While the nominal voltage is 274V, that is also the level that the battery is "empty", the normal operational voltage on the Prius HV battery is around 300V. If you want to reach fully charged, that will be around 330V, depending on temperature (higher temp = lower voltage, that is also the reason the you might be able to charge to close to 340V when the HV battery is cold, but it will drop to 330V when you continue to charge at a low current, of course, otherwise you will gas the electrolyte out of the cells)
So, I find that you can see a constant current charge safely taking the modules to 8.7V (while compressed, as they will build up some pressure). At 300V the modules are about half-full, so the Prius will happily start with that level and will put a bit of charge into the pack, so 8V per module is a safe medium-charge level. Hope this clarifies.

 

Standalone, using my MRC989, I've seen voltages above 8.0V but not much above. More importantly, they are not holding nearly as much charge per volt above 8.0V as below. With 6 cells per module, 8/6 = 1.33V.

Let me suggest reading the Panasonic datasheet on NiMH batteries: NI-MH HaNdbook - Panasonic

• 1.5-1.62V maximum charge - 9-9.72 V peak shown at start of dV/dt drop (DANGER!)
• 1.4V highest discharge voltage - 8.4 V the safest, highest voltage I would EVER go.
• 1.33V - 8 V a safe target that provides 5% volt, safety margin.

My MRC989 detects the dV/dt drop and stops charging. But as soon as it does, the voltage decays. The extra energy pushed into the module goes away (probably heat) and not much at all. Stop at 8V per module and you are in a good, conservative state. Go higher and your starting to play with risky voltages. These NiMH batteries do not take kindly to overcharging . . . even a little bit.

Bob Wilson

 

3157 bulbs are spec'ed as a 27W + 7W dual filament bulb.
7W as running taillight,
27W as brake/turn light.
This light is also used in trailers and pickup trucks, since you
need only a single red enclosure to provide all mandatory lighting functions.

 

Oh and since 12V, 27W means that 2.25Amp is drawn in normal application, I suspect that at 8V they will draw just under 2A for the heavy filament and just under 1/2A for the light filament, so I would not be surprised that the total current is 2.3 Amp at 8V.
BTW, is your meter switched to "hold" mode so it continues to display the last measured value even when disconnecting the load?

 

Scotman I am a little concerned about the current drawn with your tail lamp bulbs. You say this is around 2.7 amps. This seams very high for a tail lamp as these are rated (at leased in the UK) at 6 watts and turn signal bulbs at 21 watts, this translates to 0.5 amps and 1.75 amps at 12 volts. At the module voltage of 7.2 volts the current drawn would be nearer half those figures. Could you confirm the wattage and rated voltage of the bulbs used, or the exact type of bulb.

John (Britprius)

 

Hi John,
Incandescent lamps are *not* resistors. Their current is almost independent of the voltage, because the higher the voltage, the hotter they get, the higher their resistance.
Since those bulbs are spec'ed (in the US) for 7+27W (34W total) the 2.27 Amps reported seems to match pretty well at 8V, since they are supposed to draw a nominal 34/12 or almost 3 Amps total at 12V.

 

Did the other 2 packages that the USPS said were on the way arrive in the mean time?

If you want someone else to look at your pack, that is an option. Did you ask Mark what he can do for you?
If you prefer to do this yourself (it is not difficult - I already explained the basic procedure - just some work and time spent) then the modules from Bob sound like an alternative. I do not know how money is, sometimes you need to do things yourself because money is tighter than time, sometimes it is the other way around - you could do things but don't want to spend the time. Do you have enough vacation to take a day without affecting your pay check, or would taking a day off cost you?