Battery help

[big_gems]

Hi, looking for guidance for a new battery. Jimmy from Insat has suggested the following options. We have tried one battery but current too high and it died rapidly
Really appreciate your expertise

The battery is to power a kids ride on truck. So needs to be safe.

The current demand could be as high as 50A, then the cells I would have used would have been Sony VTC5 (2600mAh 30A), VTC5A (2600mAh 35A), VTC6A (3120mAh 30A), Samsung INR18650-25R (2500mAh 20A), LG HE2 (2500mAh 20A)

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[IR772]

Is there enough space to use Lead Acid, as that would be the low cost option.

If you want Lithium the parallel part of the series parallel connection in the battery is to provide the current and capacity so 4 of any of the above cells in parallel will easily peak 50 AMPS.

But that is a high current really as a short peak, you need very good connections and cables for that current.

No getting away from the better the cells the more it costs.

The more cells in parallel the more current it will give and the longer it will last.

 

[Deleted member 4366]

Is there a question there? If so, what is it? Any type of cell can give 50A if you use enough of them. What's the size limitation? What's the voltage.

 

[OldBob1]

Powering a kids ride on truck 50 amp load demand?
Is it to break a world record, a powered hand drill could power one of them and climb brick walls

 

[Nealh]

Lithium ion cells give the lightest battery and one of the safer technologies offering good discharge rates,
there aren't many that can handle high amp discharge and
maintain a good discharge with out massive battery sag.
Jimmy's suggested cells are the best there are with current technology.
Sony's in particular are rated as the best at this level how ever they all have draw backs which is their life span most will only manage 300-400 complete discharges before capacity suffers and you could lose up to 60% over that period as a single cell.
As mentioned more cells wired in parallel the better 3 is the minimum for large amp draws 5,6,7 or more is the way to go, in your case 4P or 5P is more then ample

A cell rated 20a discharge and wired 4 cells in parallel will have discharge of 80a, 5 = 100a, 6 = 120a etc, etc.
Cells don't like heat and most manufacturers have an upper temp limit which cells can be safe at when discharged which is about 70/75 oC. Again cells will run cooler the more in parallel you have.

The VTC5A is the pick of the cells it handles the 25a very well and sits at nearly 45 oC on discharge also it handles 30a nicely though is near to its upper cut off temperature level, amost all of the other cells at there intended discharge ampage are above the temp cut off level.
LG's HE2 is also a good cell and can handle 20a per cell and holds voltage discharge well also but can find little info on cell heat.
VTC6A shows no improvement and gets hot at 15a (80 oC) and ven hotter att 20 & 30a discharge.
Samsung 30Q's 15a rated and Sanyo PF and GA cells 10a rated are also very good cells if enough are in parallel or ask jimmy about Boston cell.

 

[big_gems]

Thanks, aim is to make 15-18ah so should be 5p.
Current is only high at start off then drops away but was enough to impress jimmy and fry his first battery!

Will go with Sony

Thanks again

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[Nealh]

What cells did the battery have that died quickly ?

 

[big_gems]

I think they were Panasonic NCR18650A

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[Nealh]

I think they were Panasonic NCR18650A

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Not surprised then they are only rated 6a max, would need 9 minimum in parallel for them to be any good.

 

[big_gems]

Thanks again.

I think Jimmy and I totally underestimated the power of a peg perego gator truck!

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