View Full Version : Multiple Batteries from one charger
Venkatesh
27-02-2003, 17:49
Our 6A charger from this year is not acting fully normal (releasing "strange smells", etc) but we have 4 competetion-legal batteries. With only one charger (the old 4A heat-sink charger), we have a minor problem. Is there any method by which one charger can simultaneously charge multiple batteries?
:] -Venk
Team 30: We have High-Octane Lines
Gadget470
27-02-2003, 17:51
Originally posted by Venkatesh
Our 6A charger from this year is not acting fully normal (releasing "strange smells", etc) but we have 4 competetion-legal batteries. With only one charger (the old 4A heat-sink charger), we have a minor problem. Is there any method by which one charger can simultaneously charge multiple batteries?
:] -Venk
Team 30: We have High-Octane Lines
How do you have 4 Competition Legal batteries? You were given 2 in your kit. Only those two are legal
kevin.li.rit
27-02-2003, 17:58
He's right the ones from last year look the same, but they are not the same model. If you really needed another charger buy one from sears or something.
First, it is not legal to use any charger other than the 6A one provided this year. Second, you should never plug multiple batteries into one charger. Not only does it do you no good (4A / two batteries = twice the charging time!), but it also runs some serious risks of things releasing gas due to overcharging. In short, you're going to have to buy one (or two) new chargers that are exactly the same model as the one in the kit.
Venkatesh
27-02-2003, 18:17
how are the batteries this year different from past ones? I have seen no difference in robot operation with either year's batteries, but we've not been carefully looking into it.
I guess we'll resort to another charger. Sniffle.
Also thanks for informing me of the illegality of the old batteries (one more thing we dont have to make room for!)
sanddrag
27-02-2003, 18:26
From section 3.1.1
You may use additional battery chargers as long as their charging rate is no greater than the one provided in the Kit of Parts.
Originally posted by sanddrag
From section 3.1.1
You may use additional battery chargers as long as their charging rate is no greater than the one provided in the Kit of Parts.
Odd. Rule C20 says it has to have "equivalent charging characteristics," which would imply to me that a lower amperage wouldn't be acceptable. Oh well. I suppose it doesn't really matter as nobody is going to stop you from using a slower charger.
Josh Hambright
27-02-2003, 20:43
wait last years batteries are different from this years?
I didn't notice any differences but i suppose i didn't look very closely...
Now i have to figure out which ones are which.
Are there any differences to look for to tell the difference?
Originally posted by oneangrydwarf
wait last years batteries are different from this years?
I didn't notice any differences but i suppose i didn't look very closely...
Now i have to figure out which ones are which.
Are there any differences to look for to tell the difference?
Check the model numbers. The newer one's are model ES18-12 (http://www2.usfirst.org/2003comp/Specs/Exide.pdf).
kevin.li.rit
27-02-2003, 21:09
The battery is a different model.
Josh Hambright
27-02-2003, 21:43
doh
Steven Carmain
28-02-2003, 16:50
It says the charge current is 5.34A, but the charge rate is 6A. Will we fry batteries?
DougHogg
28-02-2003, 17:57
Originally posted by Venkatesh
Our 6A charger from this year is not acting fully normal (releasing "strange smells", etc) but we have 4 competetion-legal batteries. With only one charger (the old 4A heat-sink charger), we have a minor problem. Is there any method by which one charger can simultaneously charge multiple batteries?
:] -Venk
Team 30: We have High-Octane Lines
Last year, I bought a charger called a BatteryMINDer.
It is not a high speed charger (only 1 amp) but it specifically states that you can charge up to 4 batteries. Its other claim to fame is the fact that you never have to disconnect it. It actually maintains the health of the battery by preventing sulfination which is the formation of sulfer compound crystals when the battery gets too low, or over charged. The batterMINDer also claims to break up the crystals (which degrade battery performance), and even has a special button you can push to activate a special frequency to do that.
While not the right charger for quickly charging your batteries at a competition, it is great for in between events for your extra batteries. I kept last year's batteries plugged in all year. I attach the batteries together in pairs and then jumper the pairs together, and attach the charger. Our batteries seem to be in good shape.
I found this link for the BatterMINDer on google.com:
http://www.batterymart.com/batteryminder.php
Al Skierkiewicz
02-03-2003, 19:09
OK here is the real poop on chargers...
1. Never try to charge two batteries from the same charger. Batteries have this bad habit of supplying current to each other (when connected in parallel) until they discharge and/or short.
2. This years batteries are slightly different from last years (new and improved) but can use last year's charger. First came out with a statement early on, that this year's battery could be charged with any previously supplied FIRST 12 volt charger.
3. Venkatesh, this years charger acts differently than previous ones. The lights on the front panel tell you that it is alternately charging and discharging/testing to determine battery charge condition. Read the manual for a complete explanation. The smell may just be the contaminants from internal components evaporating with heat. If it charges a dead battery in less than four hours it is working.
4. DougHogg, another engineer also found this Battery Minder charger but we both felt that the claims were too far fetched to be real. I am still waiting on a better test, but we chose not to buy one. "If it sounds to good to be true, it probably is."
kevin.li.rit
03-03-2003, 20:44
I think I'll buy several of those!
DougHogg
03-03-2003, 22:26
Originally posted by Al Skierkiewicz
OK here is the real poop on chargers...
1. Never try to charge two batteries from the same charger. Batteries have this bad habit of supplying current to each other (when connected in parallel) until they discharge and/or short.
4. DougHogg, another engineer also found this Battery Minder charger but we both felt that the claims were too far fetched to be real. I am still waiting on a better test, but we chose not to buy one. "If it sounds to good to be true, it probably is."
Al, thank you for your post on batteries.
On point #1, can you expand on that. I have been charging our batteries in parallel for a year, and haven't personally observed a problem. I am not an engineer, but I am trying to understand how the problem you mentioned could occur. If both batteries have some charge, why wouldn't they flow from the most charged to the least until they balanced each other and then stop flowing (like a full bucket of water flowing through a hose into a partially full bucket until they were at the same level.)
On point #4, I did a search on Google for "BatteryMINDer" and "Review" and found positive feedback on the BatteryMINDer, but no scientific testing from an independent source. I will keep my open for more info.
Gary Dillard
03-03-2003, 23:39
Originally posted by Jnadke
Check the model numbers. The newer one's are model ES18-12 (http://www2.usfirst.org/2003comp/Specs/Exide.pdf).
Actually, the newer ones are EX18-12. Look on the battery and in the kit of parts list. The specs FIRST provided are for the ES18-12. Also please read this thread
http://www.chiefdelphi.com/forums/showthread.php?s=&threadid=16942
that refers to the posts on the FIRST Forum - you can only use the batteries provided by FIRST (EX18-12) during competition.
I see the link to the FIRST forum doesn't work anymore, but Gadget470 quoted the text of it further down.
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