Charging Parallel packs

[oatnet]

OK, it would have been obvious to someone smarter. I have two LiFe packs on a TF, in parallel, without a Schotty because of regen. I thought that by flipping the power switch and interrupting the circuit, I was isolating them - WRONG!

Last month I noticed that my next-to-last Flintstone charger died, and was apparently dead for a while. Even
though the Flintstone was charging the cells individually, the sum charge was ALSO being applied to the parallel pack... Even though the main circuit was interrupted, the charger itself was completing the circuit -duh!

I had noticed a while back that charging seemed to take longer, so I figure I went 50-60 cycles like this. Even worse, this was the cheap chinese "Ocean Cheer" pack with 100+ charge cycles (<70% DOD) on it already (chinese life dies in 3 months my A$$, Harmon/Goldberg). I realized that this was a great opportunity to compare bulk/single cell charging.

I measured cell voltages at peak charge and cells in both packs are all within .01v of delivered voltage (although there is a wide variety between the cells) so I don't see significant wear. I am sure that it helped that these are large format cells (15ah) instead of a bunch of little cells, and running < 70% DOD kept me out of the most damaging zone. This has me thinking about bulk charging a bit more, but just to be safe I, each night I alternate which pack is connected to the charger.

-JD

 

[Toorbough ULL-Zeveigh]

(chinese life dies in 3 months my A$$, Harmon/Goldberg).

You mean talking outta their a$$.
The two of them must be sh!#'n bricks cuz the two of them do nothing now but trash talk Ping over at PA.
Goldberg hasn't had any credibility since friction drive was the standard.

I agree larger format cells are what's needed.
Less stress on the plates, better heat dissipation means longer life.
But where to park them in the limited space on a bike.
Smaller cells can be tucked in more nooks & crannies but are a PITA to deal with.

 

[safe]

Eyeballs Needed

This thread was left in a rather ugly state, so I'm going to hijack it for my own purposes. Over in the photo's section for my Safe Project #001 I posted this:

...and I'd like people to take a look at it and see if anything jumps out at you as being wrong.

It's always good to get extra eyeballs to make sure you haven't made some dumb error.

This will allow me to switch from parallel to series with the use of a small connector in between the batteries. Depending on how it's hooked up it will behave differently.

Just look at it and see if you see any problems...

 

[TylerDurden]

Just look at it and see if you see any problems.

If the goal is a crude and incomprehensible image taking up serverspace; I think you nailed it.

 

[Toorbough ULL-Zeveigh]

:lol: :lol:


You ripped the same thought out of my head, only you said it better.

Depicting parallel with crossed lines.
I can envision newbies reading this in the years to come pulling their hair out trying to follow it.
Seriously safe, is this deliberate to spread unenlightenment?
I know you're a bright enuf guy, (not as bright as you think you are) but this is not genius level output.
I think we've been had, it's gotta be a monkeyteaser.

 

[safe]

I think we've been had, it's gotta be a monkeyteaser.

Go to the "Safe's Project #001" thread for the full technical write up. It's not a joke. What I'm doing is orienting the cells in the way they will look on the bike, so they will sit backwards and the positive and negative will be reversed.

It might be a good idea to redraw the circuit the other way... hmmmm.... the main point is that the circuit is correct... but I suppose presentation is important. :?

This revised version flips the wires around... can you read it now? (see how the wires cross in the upper right corner now)

I mean, I know this is probably right, but it's always good to get some extra review to catch any errors that I might have not seen.

 

[Toorbough ULL-Zeveigh]

Electrically both diagrams are right.
Now that it's redrawn for some bizarre reason it's suddenly cleared up the difficulty I was having;

those red things are supposed to represent deans connectors.

At first they looked like little batteries.
Yeah, there are conventions for electrical drawings designed to make reading them a little less confusing than tracing the actual spagetti.

I thought you already were up on this but one small thing you can do that would help out is when wires cross paths, draw a small arch on one of the lines to indicate it's passing over the other & they're not connected.
Wherever wires are connected place a reinforcing dot at the intersect point.
The arch thing is the old convention but for a hand drawn diagram it's best to be as unambiguous as possible.

Sorry for the over-reaction but Tyler perfectly captured my frustration at that moment while I was tilting my head from side to side trying to make head or tail of what you were going for. :?
Next time I'll ask for clarification first.

 

[fechter]

Fuses might be a good idea. :wink: