# Battery quick drain.



## Raygris (May 14, 2013)

Hi, this is my 1st post. My vehicle is for special events and will not be street driven except for parades. It will pull a passenger trailer. 10mph max. All the equipment was bought used.

Parts: Warp 9", Kelly 1000 amp controller, Albright sw180 Main contactor, albright dc182 reverse contactor. cutis pb-6 throttle. chinese dc-dc converters. 72 volts. Older discovery agm batteries.

Symptoms: 78.2v at 'key on'. Reverse down driveway, 76v. 100 yards more, 72v and the safety disconnect actuates. Voltage climbs back up at about .1 v every 3 seconds at first and then slows to about 75v. at this point each individual battery reads about 12.2-3 except one at 12.7.

My guess is the batteries or one of them anyway. Before I spring for a new pack, I was hoping for some advice. What do you think about the cause? How do I check for the bad battery (or batteries) Battery recommendations?

Thanks for your time,


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## major (Apr 4, 2008)

Raygris said:


> Hi, this is my 1st post. My vehicle is for special events and will not be street driven except for parades. It will pull a passenger trailer. 10mph max. All the equipment was bought used.
> 
> Parts: Warp 9", Kelly 1000 amp controller, Albright sw180 Main contactor, albright dc182 reverse contactor. cutis pb-6 throttle. chinese dc-dc converters. 72 volts. Older discovery agm batteries.
> 
> ...


Do you mean Discover Battery? I looked at those a while back. They suck. http://www.diyelectriccar.com/forums/showthread.php?t=32677&highlight=discover+battery Your symptoms sound like bad batteries (badderies). You test the battery under load to determined its SOH, State of Health, and capacity. Monitoring battery terminal voltage and current draw in the application is a good indicator. Also see that your charger is functioning correctly.

Look for a better battery when you replace them 

major


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## Raygris (May 14, 2013)

Thanks Major, I found some panasonic AGM 120 amp-hr at $200 each and some odyssey AGMs at a VERY low price. (so low it worries me) What do you think. Worth looking at, or back to Trojans?


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## EVfun (Mar 14, 2010)

I don't think your application is a good fit to Odyssey batteries. They need to see high rate charging on a regular basis to maintain capacity. They are sealed batteries that benefit from a shunt regulators, because they cannot withstand much overcharge. They shine in applications where high peak currents are demanded. 

It sounds like several of your current batteries are dead. Make sure your charged is capable of fully charging them, you need to take a 72 volt pack up to about 87 volts and hold it there until the current falls. Based on your use description I think the best fit would be flooded lead acid batteries.


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## Raygris (May 14, 2013)

Now I have a new set of trojan 1275 batteries and the same symptoms. My next thought was the dc-dc converter output was low. I tried two different 10 amp units and a 20 amp (rated not tested) with the same result. Now I'm wondering about controller programing. Does anyone have some ideas?


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## major (Apr 4, 2008)

Raygris said:


> Now I have a new set of trojan 1275 batteries and the same symptoms. My next thought was the dc-dc converter output was low. I tried two different 10 amp units and a 20 amp (rated not tested) with the same result. Now I'm wondering about controller programing. Does anyone have some ideas?


Hi Ray,

You post up with a title of quick battery drain. Your symptoms are fuzzy, but could very well be due to crappy batteries. You replace the batteries and now say the symptoms are still there. Do you know that your new batteries are in fact good? Is your charger good?

I think you need to instrument with at minimum a voltmeter on the battery and ammeter for the battery. Also, at least temporarily, a voltmeter on the motor. A tach or speedometer is good. Now record actual numbers during the performance test and report back.

I had mentioned previously my opinion of Discover battery. I have even a less flattering opinion of Kelly controllers. It is too soon for me to blame Kelly for your problem, yet  

I do like your motor and contactors though 

Regards,

major


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## TEV (Nov 25, 2011)

Hi, 
I don't have experience with lead batteries, but I think that your problem is the setting of the "safety disconnect" at 72V , I guess that you have 6 batteries , you have to find the lowest battery voltage under load recommended for your battery , multiply that with 6 and set the controller to that number. I am sure that the voltage will be less than 12V , maybe as low as 10.5V (10.5V*6=63V).

Please don't use the 10.5V setting, unless you verify it with your battery manufacturer or other authorized source.


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## TEV (Nov 25, 2011)

Also if your battery cables and/or battery connections are not rated for your application can be another reason.


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## Raygris (May 14, 2013)

Thanks, I have ordered an amp-meter. I have a dash mount volt-meter and a hand held for the motor. The short cables are 1/0 and the long ones 2/0.
I didn't think to test shiny new trojan batteries but I'll do that now.

My battery experience is limited to off-grid homepower (since 1989) and 4 years with a GEM car. With the homepower there was never a load that could pull the battery voltage down so fast and the GEM car instruments don't show that. What I knew was that at 2v per cell there isn't much juice left. So I had the controller set at that. 

Does anyone have a good Idea of what the low voltage safety should be set at with these batteries? My dealer just said he would have to talk to someone.


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## major (Apr 4, 2008)

Raygris said:


> Does anyone have a good Idea of what the low voltage safety should be set at with these batteries? My dealer just said he would have to talk to someone.


I don't understand "low voltage safety". Is that a setting on the Kelly?


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## Raygris (May 14, 2013)

Sorry Major, I'm not familiar with EV (or electronics) terminology. In home power charge controllers, there is a top and bottom voltage limit. When the voltage goes down to a pre-set voltage, the circuit to the load is interrupted to prevent damage to the battery bank. The Kelly motor controller has a setting that appears to have the same function.


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## major (Apr 4, 2008)

Raygris said:


> Sorry Major, I'm not familiar with EV (or electronics) terminology. In home power charge controllers, there is a top and bottom voltage limit. When the voltage goes down to a pre-set voltage, the circuit to the load is interrupted to prevent damage to the battery bank. The Kelly motor controller has a setting that appears to have the same function.


Hi Ray,

The 72 volt pre-set you're used to is likely a no-load or at least a light load battery voltage limit. With EVs, the load can be hundreds of Amps and this will cause a droop in battery voltage due to the internal resistance in the battery as well as the the resistance caused voltage drop in the wiring between the battery and controller. I'd set the controller "low voltage" to like 60 Volts to get it out of the equation, at least for the time being.

major


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## Raygris (May 14, 2013)

Success! After re programming the low voltage limit, all is well. Thanks for your help!


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