Batteries~

[Mk.32]

Hello we are prepping for our first regional and got some last min question.
How long does the kit charger take to fill a battery?
and how many batteries do you general need?

[PAR_WIG1350]

I would say three or four minimum (you MIGHT be able to do it with 2, but you will have to run some matches on a less-than-full battery), those that are not in use should be kept on a charger, use automated chargers that switch to float or trickle charge automatically.
As far as time is concerned, I'm not sure, but it depends on the current used to charge the batteries. Higher current = faster charge but fewer cycles so it should only be used if you have to.

[Dale(294engr]]

When 5A Quick Charge lamp goes out it is ~80% charged

Time to get there depends on the degree of discharge, batt age, temp
(SLA batts should ALWAYS be on charge to prolong life maintain lowest internal resistance = max delivered performance)

the 20% balance occurs in trickle mode usually ~.1A so takes 2-3hours..

Responding to earlier commenter. Quick charge does NOT reduce battery life
that's why it is programmed to cut off early (charge heating is culprit)
Battery life can be greatly extended (years) by charging ASAP after each use and remaining on trickle at all time

good news full top off is rarely needed
unless your robot draws above average current during 2m15s match
due to lots of robot pushing.. or inefficient drive train

cant have too many SLA's..
I advise my team to save least 1 Batt that had a full overnight trickle
for critical playoff use expect pushing matches of extra speed power

I will be RI at SanDiego & will bring Flash Drive with my Battery Workshop
I have Dynamic Battery Discharge curves that illustrate V vs I for constant load ~50A (18AH is valid only at .8A, at 50A it is a 6min batt! before the Vout drops quickly)

[DonRotolo]

A 6 Amp quick charge is not as good for the battery as a 2A slow charge. But, if you expect that your batteries will last only 2 or 3 seasons, it hardly matters.

It IS very important to always keep your batteries as fully charged as possible, since being in a discharged state causes irreversible damage (sulphation). Keep this in mind as you put them away after the robot season, especially over the summer.

Team 1676 brings ten batteries and six chargers to a regional, this is enough for qualification and eliminations all the way to the Finals. If you make it into the eliminations, I am sure several teams will be happy to loan you fully-charged batteries. Considering that, 4 or 5 should be plenty for a basic stock, with 2 or 3 chargers. 2 would be a bare minimum, but possible with care.