|
|
|
![]() |
|
|||||||
|
||||||||
![]() |
| Thread Tools |
Rating:
|
Display Modes |
|
#31
|
|||
|
|||
|
Re: Be aware of battery and charger inconsistencies!
we give them a charge and shelve them until needed again. though hey see periodic use throughout the year anyway
|
|
#32
|
||||
|
||||
|
Re: Be aware of battery and charger inconsistencies!
How long do they typically sit on the shelf without any maintenance, and is the shelving area air conditioned?
|
|
#33
|
|||
|
|||
|
Re: Be aware of battery and charger inconsistencies!
Quote:
The automotive chargers use charge currents that are appropriate for automotive batteries and they change charge currents and transfer to trickle charge mode based on the battery voltage. Since the voltage at full charge is related the same for all the 12 V (nominal) batteries, irrespective of their Ahr rating, the automotive chargers are able to properly charge all automotive batteries no matter what their actual Ahr rating is. Each week, where I work, we literally use tons of batteries just like the ones used in FRC (different Ahr rating) to build large Interruptible Power Supplies for industrial applications and data centers. These are sourced from one of the FRC legal suppliers. We CALCULATE our charging current based on the size and number of batteries in a battery bank and recommendations from the battery manufacturer. Neither we, nor any competitor that I know of, has the technology that would allow a charger to distinguish between batteries of different sizes and what charge rates are appropriate for that battery. |
|
#34
|
||||
|
||||
|
Re: Be aware of battery and charger inconsistencies!
Quote:
If so, you could multiply the RCM by (25/60) to get an Ahr rating (at 25 amps down to 10.5V). For many automotive batteries, the RCM rating is available. |
|
#35
|
|||
|
|||
|
Re: Be aware of battery and charger inconsistencies!
I'm still not sure how using a >6A charger after you've used some other charger adheres to the rules. But by all means, you should put in a Question on the Q&A to see what the answer is; that's absolutely the right approach. Good luck; I'm pretty sure I know who's going to process that question, and he's the one that tells the LRIs & his inspectors when he's the LRI to tell teams to remove chargers >6A.
|
|
#36
|
||||
|
||||
|
So to answer this another way, and avoid illegal chargers: what is it about this charger that is apparently improving the OP's robot performance? Is there a process to follow with the "standard" chargers that should achieve the same result, but safely?
|
|
#37
|
||||
|
||||
|
Re: Be aware of battery and charger inconsistencies!
There's no apparent competitive advantage. The issue is that charging over 6 amps is unsafe per manufacturer direction and can decrease the life of batteries.
|
|
#38
|
|||
|
|||
|
Re: Be aware of battery and charger inconsistencies!
Quote:
|
|
#39
|
||||
|
||||
|
Re: Be aware of battery and charger inconsistencies!
How do you know that? Have you tried this proposed process and measured the current?
|
|
#40
|
|||
|
|||
|
Re: Be aware of battery and charger inconsistencies!
the main issue we suffer from is inconsistencies, not necessarily any kind of improved performance over other good chargers. All of our previous chargers get different performance because they all charge the batteries to a different level. The max charge current is actually irrelevant to us, what matters is the state the batteries are in when they get taken off the chargers. These Stanly provide a consistent charge every time and every charger is the same. That is the key element we need, a consistent charge level that actually fully charges the batteries. We do not get that out of the 6 old ones we had(which there are three different types) but we do with these new ones.
|
|
#41
|
|||
|
|||
|
Re: Be aware of battery and charger inconsistencies!
Because the old chargers can't put out more than 6 so they will charge them as much as they can until hey reach a fully charged status(which isn't really fully charged it seems like). At that point we will move over to the stanly, there is actually a current readout of the charge rate so yes we did measure it and once it reaches a certain point it goes into float charge which documentation states is not more than a few amps. So we can indeed for a fact know and guarantee that we will always be within this rule. This is what we were going to do from the start anyway. Just because we have 15A chargers doesn't mean they will ever be charging at that unless we put a dead battery on which there is no need to.
|
|
#42
|
||||
|
||||
|
Re: Be aware of battery and charger inconsistencies!
Quote:
Also, 6A is pushing it for these batteries. You should charge your batteries at the lowest charging rate you can get away with to maximize the lifespan of the batteries. The only thing charging at a higher rate gives you is less time to charge. Last edited by Chris_Ely : 06-03-2014 at 17:16. Reason: correctness |
|
#43
|
||||
|
||||
|
Re: Be aware of battery and charger inconsistencies!
Quote:
Quote:
|
|
#44
|
|||
|
|||
|
Re: Be aware of battery and charger inconsistencies!
we are aware it will decrease the battery life but we don't care. From the information I found online here "http://www.powerstream.com/SLA-fast-charge.htm" there is absolutely no danger what so ever in using this charger with these batteries. Possibly through missuse or abuse but under normal conditions nothing dangerous should happen.
|
|
#45
|
||||
|
||||
|
Re: Be aware of battery and charger inconsistencies!
Quote:
The Ahr rating will increase if measured with a lower current. So be careful when comparing FRC Ahr to automotive Ahr computed from RCM*(25/60). I eyeballed some data from the discharge curves in NP-18-12 datasheet and plotted the actual Ahr of that FRC-legal battery vs discharge current. At the RCM 25 amp rate, the FRC battery appears to be less than 7Ahr, which would correspond to an RCM of about 17 minutes. |
![]() |
| Thread Tools | |
| Display Modes | Rate This Thread |
|
|