Page 1 of 1

super caps in a NHW10

Posted: Sat, 02 Dec 2017, 20:29
by antiscab
So a recent battery issue in a friends NHW10 had me thinking

The original battery has a voltage range that spans roughly 280v - 380v

144 2.7v 500F caps and balance boards are around AUD$1100 brand new ... eLevelAB=5 ... eLevelAB=5

The NHW10 can also charge the HV battery from the 12v battery, for when the caps inevitably go flat (after a couple of days, if not less)

144 x 500F caps gives 3.47F, with a 100V operating window, that gives 347 As (or just shy of 50A for 7 seconds, assuming the little leads don't melt first)

I'm thinking it may be a cheap way to replace the original battery (comparatively speaking). I would only consider this in a hybrid (the caps might only weigh 10kg, but at a cost of $34500/kwh)

Then I realised 400v or 450v caps out of variable frequency drives are a thing. usually high frequency ESR goes up as these things age, but if your discharge time scale is measured in seconds, that's probably not going to matter.
Does anyone know of a stash of caps out of variable frequency drives?
My VLT5042 has 4 x 450v 3300uF caps. I would only need 1000 of them to match the super caps in capacity

I have two NHW10 prius that currently have no battery.
I'm shortly to have 320 x headway 10Ah cells that are a few years old - they will get one of them going (prototype 3 lithium conversion), though I'm tempted to test out the super caps.
I might put a 9 series 500F set (55F) in parrallel with one of the weak cell blocks. 5V operating window at the block level gives 265As

Re: super caps in a NHW10

Posted: Wed, 22 Aug 2018, 12:31
by Aevzer
any updates on this?

Re: super caps in a NHW10

Posted: Wed, 22 Aug 2018, 14:16
by antiscab
The caps I bought didn't meet spec, 300F instead of 500F, with wide variation and really high internal resistance.

I could retry with larger maxwells, but it's cost prohibitive