Help with a 48 V battery and charger

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captjack6
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Help with a 48 V battery and charger

Hi
I am new to this forum but I am glad I found it. I hope you can help me. Its starting to get expensive...
I have a 48V 5Ah Lead acid battery pack I constructed to work with a 48V Hand Pruner The pruner works and I measured the output of the pack. I used the pruner for about 10 hours total time. I am testing this pruner from China. My problem is trying to get a charger that will be compatable with my battery. I got a charger that is for a 48V 20Ah Lead acid battery is says model DC48v-2 AC voltage: 110-220/60Hz Output specs 2.6-2.7A
I want to know if this will work with my battery. The last charger (different but still a 48V 20Ah charger) I hooked up to this battery promply burned up. I had to change the connector I thought I checked which terminal was + and-.
I am not real knowlagble in electronics and its hard and expensive to keep killing stuff. I have to prune about 1000 more trees and need to figure this out soon.

captjack6
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Re: Help with a 48 V battery and charger

Really hope someone can help me

proton
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Re: Help with a 48 V battery and charger

I have a 48V 5A SLA charger if u want it - Hp brand -
$160
email me direct to talk, via website

The LiFepo4 BattMan www.falconev.com

captjack6
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Re: Help with a 48 V battery and charger

Thanks for your reply. I would take you up on your offer but this configuration is only temporary. I am in the USA testing a power prunner for a company in China. They sent me the pruner but did not want to send the batteries and charger. At the time I didn't think I would have an issue getting a small 48V battery pack and charger. When in production, the factory will go to a Li battery pack and charging system.
I need to know if the charger I have now will suffice for a time.

The charger a DC48v-2 AC voltage: 110-220/60Hz Output specs 2.6-2.7A. It was made for a 48V 20Ah Lead acid battery I have a 48V 5Ah battery pack. Not knowing too much about electronics I would like to know if it will charge my battery pack before I hook it up and blow a charger.. I have marked your web page and keep you in mind for a Li system. Thanks again If you could comment on my system I would really appriciate.

Spaceangel
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Re: Help with a 48 V battery and charger

I have a 48 volt 7 AH battery pack that I charge with any type of charger that I have laying around. From Iota 48 volt 15 amp charger to scooter chargers from TNC those blue ones that do roughly 2 amperes on a 48 volt pack. Just as long as you don't exceed 58 volts and it continuously maintains 55 volts you are great, fine , good. A nice three step charger is nice but maintaining 55 volt is very critical.

My problem is trying to get a charger that will be compatible with my battery. I got a charger that is for a 48V 20Ah Lead acid battery is says model DC48v-2 AC voltage: 110-220/60Hz Output specs 2.6-2.7A
I want to know if this will work with my battery. The last charger (different but still a 48V 20Ah charger) I hooked up to this battery promptly burned up. I had to change the connector I thought I checked which terminal was + and-.

Didn't the pruner come with a charger? Wow! Carrying around four batteries of 5 AH to make 48 volt pack is rather heavy? Mine is on my back pack for my radio and it kills me. The reason why a big 48 volt Iota charger doesn't ruin battery pack is charges up fast and doesn't have time to boil, cook or melt. Those ones from TNC scooter are nice, low cost, tested and actually work. They even sell connectors to make your own charging circuit. What burned up on 20 AH charger? Mine is 15 real amperes from Drake and works A, OK on any of my packs. I even run 48 volt pack 7 AH Yuasa NP7-12 pack on charger while at camp grounds straight from IOTA + Battery pack for radios. Also if you use a big enough regulated charger you can use your pruner as a corded device also.
It won't do any damage to either battery or charger. So your hedge trimmer should work fine. So again What burned up? Battery pack should be at least 13 x 4 = 52 idle, sitting voltage for many hours. So to try and answer your question 2 to 2 1/2 amperes is good, perfect for you scenario.

KB1UKU

captjack6
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Re: Help with a 48 V battery and charger

The pruner shears did not come with a charger or battery They said just to get a battery and charger here. I didn't realize how much trouble it was going to be to get them.. I am happy they wanted me test it for the americian market. The battery pack is heavy about 20lbs.After testing they will go into production with a LI battery and charger which will be half the weight.
I need to get this resolved so I can again start pruning trees. I have about 2000 left to do. I need to get it completed before the bud form on the trees to keep the blight from spreading. Its called "Eastern Philbert Blight" it will kill my orchard if I don't get it under control. It is going to be nice weather next week and I would like to get to work..
I took my battery pack and showed someone today. He is not an expert but more knowledgeable than me. He said I did everything right with the hook up and it should not have burned up the charger. It did and I want to make sure everything is correct before I toast another charger. Anyway the charger I have is DCC48v-2 AC voltage: 110-220/60Hz Output specs 2.6-2.7A
he said I might need a Diode to stop the current in the battery flowing back to the charger. He said that the current in the battery was greater than the current in the charger. Does this sound right to anyone. When I tested the last charger there is still voltage in the battery back.

After I get this thing working I will play with the charger I smoked..
Thanks

Spaceangel
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Re: Help with a 48 V battery and charger

Well, putting in a diode might be helpful but it shouldn't make it better. The charger should be current regulated to 2 to 2.5 amperes all day and all night till it gets battery pack up to snuff. I guess it doesn't sound right. I used a 10 amp charger once to charge up T-145 battery pack. It took me a week. So it never burned up. So charging a 5 AH with 2.5 amperes is a piece of cake. There are some battery chargers that sort of blow smoke after a while but most can do rated current for 100 hours straight and if the battery pack isn't charged then pack is toast. Actually there is some energy from battery pack into any charger for sensing battery voltage to charger. Maybe only a milli ampere or so. Maybe less.
Get something cheap on eBay or my favorite TNC scooters. Also LOAD test the pack or each individual battery to see if it can make 1 ampere for 2 hours. A number 93 auto light bulb draws one ampere so it should last a couple of hours on a 12 volt battery. If you have a portable tool like that then how about using 5500 MAH NiMH model race car packs taped together making 48 volts. I have a 24 volt pack that I use from ALL BATTERY and charge them with there 24 volt NiMH charger. It is Tenergy Brand. I use it for radio use in my GO bag. Charge at 24 volt and swith to 48 volt into a 48 to 12 volt converter. There are just too many choices to do in your case. Battery pack is Superpower 5300 mAh SC7.2VNI-MH

KB1UKU

mybridgetochina
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Re: Help with a 48 V battery and charger

Hello ,

Your battery capacity is 5Ah , but the charing current from the charger is 2.7A -so the charging current is about 0.5C ( means , in therory , it will take about 2 hours to charge the pack fully) -

Generall speaking , the charger should be OK for the pack -

However , for any kind of cells , either lead acid or lithium battery , the smaller the charging current , the better for the battery pack in terms of cycle life etc -

0.5C is a little higher even for lithium battery but it should be OK for short run time -

colin9876
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Re: Help with a 48 V battery and charger

Yes the chargers are interchangeable, because the capacity of the battery is less is not really important, its the voltage it charges to that is.

Purists would say that it would be better to charge a smaller battery at a slower rate, but 2.6amps is still only C/2 charge rate which you should get away with!

To extend the life of the pack if you ocassionally charged each batt seperately with a 12v charger then this would keep the pack balanced.
In a string of 4 batts balancing could be a problem as its only the total voltage that the charger looks at!

captjack6
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Re: Help with a 48 V battery and charger

Thanks to all that have replied. I talked to the tech Cliford from TNC scooter (great folks) he spent a good deal of time with me and assured me also that my charger would work. He also told me that I should hook up the battery to the charger before plugging in to the power source. not doing so might cause a voltage spike back to the charger (that must be what happened). He said I didn't need the Diode but it would not hurt. As a guy who wears suspenders and a belt I think I will put in the diode to be sure..Thanks again everyone I will let you know how it turns out.

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