Data Logger info.

[Flying Scotsman]

Graham, try a X640 or a Y537/3.

Douggie

[Doug Smock]

Some guys report putting the cells in at 100 or 110 degrees... and having them come out at 95 or so...

It's a wonderful thing isn't it?

[G Doggett]

Hi Guys
To answer some of your questions -

The cells are Hyperion Litestorm VX 5000 25C , so they are top quality from Enerland.

I didn't actually observe the MAH being put into the cells at recharge , I was kinda busy between heats, but it did take just over 1/2 hour at 1C to complete.

The Logger starts recording as soon as it is connected to the batteries. I don't know if this can delayed by programming.

It is Autumn down here so the ambient temperature is a bit nippy, maybe I should figure out some way to warm the cells before the race. I certainly don't want to damage these expensive suckers.

Finally I have tried 'Reddys Prop' the Y537 but it cavitates too much, I think it is just too small in diameter for this hull.

Thanks for the input.

Graham.

[D. Newland]

David how low do you figure is two low? I have seen similar readings on my polyrc cells.

Sorry, Steve. I guess I didn't really answer your question.

I guess it's relative to how hard you're pushing your setup, how pre-warmed your cells are, quality of wire/connectors, etc.

IMO I would think that properly warmed enerland cells should hold 14 volts easily with the above setup. That's why I posted what I did when Graham originally saw low 13's. Maybe I'm all wet. I don't run a logger.

It would be great for Graham to run the same setup again with warmer cells at the start and see what voltage changes there are (if any). That would tell alot and be great info for this board.

It would be interesting to know what Buass or Harris's P Rigger SAW runs did to their voltage under load...maybe 12 volts??

The problem that I found out (the hard way) is that running too cold of cells too hard damages them badly...and they don't necessarily heat up or puff. They just get damaged. A logger would help at least pinpoint the problem in this scenerio...too late, but it would tell you what the load voltage dropped to!

[G Doggett]

So what method are you guys using to warm up your lipos on cold days?
I presume jamming them in your shorts is not recommended
Graham.

[Darin Jordan]

So what method are you guys using to warm up your lipos on cold days?
I presume jamming them in your shorts is not recommended
Graham.

Depends on how sunny it is outside...

Heating pads work great...

[Doug Smock]

Depends on how sunny it is outside...

Heating pads work great...

[G Doggett]

You'll have to excuse my ignorance, but what are heating pads and where do I get some ?
Graham.

[D. Newland]

They are what my wife uses when she's feeling crampy.

Look at a local drug store. They are like a small blanket (size of a big notebook let's say) that you plug into the wall and they heat up. I use a cooler and put the heating pad in it, then put my LiPo's in there and let them warm up.

[Mich. Maniac]

They are what my wife uses when she's feeling crampy.

Look at a local drug store. They are like a small blanket (size of a big notebook let's say) that you plug into the wall and they heat up. I use a cooler and put the heating pad in it, then put my LiPo's in there and let them warm up.

I have a small drink heater/cooler I can hook up to car jack.. truckers use them and I found in vacant apartment where I work. Maybe I will warm it up and check temp after a while. I was just gonna sell it in rummage but maybe it will stay here. It would be perfect. warm up my lipos and cool down a 6 pack for my way home!

[G Doggett]

I have a small drink heater/cooler I can hook up to car jack.. truckers use them and I found in vacant apartment where I work. Maybe I will warm it up and check temp after a while. I was just gonna sell it in rummage but maybe it will stay here. It would be perfect. warm up my lipos and cool down a 6 pack for my way home!

Good idea Mich.
I've got one of those heater/cooler things stashed somewhere in the garage, I don't think I have ever used it.
I must dig it out, dust it off, and make it part of my boating kit.
I need a bigger car.
Graham.