Can anyone recommend a charger?

GRIZZ

1 mW
Joined
Aug 26, 2021
Messages
16
Location
Mass., US
I'm about to buy this used battery without a charger.
https://em3ev.com/shop/50v-14s7p-rectangle-battery-pack/
Capture.JPG

It has an Anderson connector and is 52V.

I'm looking for something a little better than a dumb charger, preferably something with an option to extend the battery life by not charging it to full and I don't need a fast charger. I am in North America.
 
You want a charger whose CV setpoint can be adjusted between 57V and 59V, which includes from below 4.10Vpc up to 4.20Vpc.

The latter may be needed for occasional maintenance like top balancing and precise cap test benchmarking.

For normal usage cycling, choose between 4.10 and 4.15Vpc to get better longevity while sacrificing very little capacity.
 
What is the total Ah capacity the pack is rated for?

A 0.3C charge rate would be the lowest I would recommend. 0.2C would mean up to 5hours needed to refill from "empty"

For longevity purposes stay below 0.4C.
 
The dumbest "charger" is no charger at all, just a PSU or DC-DC converter without any stop-charge functionality.

A simple LVC circuit / relay that cuts off its input when the pack leads reach the desired voltage setpoint is really all that's needed for LI cells.

For balancing purposes, a timer control that gives the ability to hold at that CV for X minutes may help if using a standard cheap BMS for that function. Ideally also the ability to limit current, lower than the usual rate.

But if you use an active balancer that can do so at any voltage range, separately from the charging process, none of that is needed.

If you do get a true charger, it will hold CV / Absorb for a certain time according to its own internal algorithm, hopefully before trailing current drops below 0.1C for longevity.

On a good one that AHT (Absorb Hold Time) will be adjustable as well as the voltage setpoint.

With the best chargers, all these parameters can be controlled "live" via CAN control signaling, but they usually cost hundreds more, plus the BMS / other device doing the signalling
 
There are relatively cheap chargers that have a basic A/B switch for charging level

often claiming 80% vs 100% SoC but that is rarely accurate.

Need to actually log the V&A for each setting with a DMM and ammeter to see what's what

and personally I would only buy that type if the precise voltages used were still tweakable by the user.
 
john61ct said:
lots of things

I appreciate the support, I understood only a little of it all though. I'm new to the hobby and most of it went right over my head.
 
john61ct said:
What is the total Ah capacity the pack is rated for?

Here is the text from the seller.

"20.7Ah Panasonic PF"

I have in excess of 12 hours to charge so longevity of the battery investment is more important to me.
 
Have you asked Em3EV for recos on specific chargers?

My reco is Grin's Satiator, user friendly and super flexible! Their model #4808 "24V-52V" output, actual range is 24-63V @8A (manual states 12-63V)

Many say these are good, apparently what Ping sells:
https://kingpan.m.en.alibaba.com/productlist.html?wx_navbar_transparent=true&type=search&SearchText=14S&pageType=productList

Luna has also been pretty reliable
https://endless-sphere.com/forums/viewtopic.php?t=105307
https://electricbike.com/forum/forum/knowledge-base/chargers/38871-how-to-adjust-the-luna-charger-mini-and-advanced

This has been reco'd by Pajda, mad respect

https://m.aliexpress.com/item/1005001412497599.html

And finally, check out "Ovar" and

"Dongguan Yalan"

for cheaper possibilities.
 
You do not need to understand everything I discussed, but it is pretty basic level

Parse it slowly, do some googling for terminology,

then feel free to ask specific questions

read past threads here you'll pick up a lot, it just starts to sink in.

Beside the right gear, good knowledge is required for you to get best value, help make your pack last years rather than murdering it in months.

Is the pack already on its way? Do you know what BMS it includes?

GRIZZ said:
"20.7Ah Panasonic PF"

OK so, 6-9A will be enough if current is not adjustable, up to 20A if it is, for when you want to refill in an hour.

Do not go lower than 4A that would be up to a 5hr charge cycle.
 
john61ct said:
Have you asked Em3EV for recos on specific chargers?

My reco is Grin's Satiator, user friendly and super flexible! Their model #4808 "24V-52V" output, actual range is 24-63V @8A (manual states 12-63V)

Many say these are good, apparently what Ping sells:
https://kingpan.m.en.alibaba.com/productlist.html?wx_navbar_transparent=true&type=search&SearchText=14S&pageType=productList

Luna has also been pretty reliable
https://endless-sphere.com/forums/viewtopic.php?t=105307
https://electricbike.com/forum/forum/knowledge-base/chargers/38871-how-to-adjust-the-luna-charger-mini-and-advanced

This has been reco'd by Pajda, mad respect https://m.aliexpress.com/item/1005001412497599.html

And finally, check out "Ovar" and "Dongguan Yalan" for cheaper possibilities.

I sent Em3EV an e-mail with questions. Their chargers sale page are full of dead links and not linked to from the homepage so I'm not sure they sell them separately right now.

I'm interested in Luna Mini not because its cheaper, but because it does have the switch and looks portable which is handy for trips. I'm assuming I'd need to make or buy a XT60-To-Anderson adapter to use it though? It is only 3A and @john61ct recommended against going lower than 4A.
 
I've had excellent service from Luna chargers (in fact, my 52V one still operates perfectly after six years) including a new 52 V that I purchased since it can provide 80%, 90% or 100% SOC. The only thing you would need to do (assuming Luna doesn't have an Andersen to XT-60 connector) is replace the Andersen on your battery with an XT-60. Usually they have connectors with "pigtails" to facilitate this.
 
Which charger did Luna rebrand as their own?

2old said:
I've had excellent service from Luna chargers (in fact, my 52V one still operates perfectly after six years) including a new 52 V that I purchased since it can provide 80%, 90% or 100% SOC. The only thing you would need to do (assuming Luna doesn't have an Andersen to XT-60 connector) is replace the Andersen on your battery with an XT-60. Usually they have connectors with "pigtails" to facilitate this.
 
The usual shot at Luna as if nobody else has other companies manufacturing parts for them. The six year old one is their 2 amp charger, the other is the blue 80/90/100 unit. Over the years I've purchased from them probably 25 times for myself and friends. The one problem was rectified promptly.
 
GRIZZ said:
It is only 3A and @john61ct recommended against going lower than 4A.
If you're OK with the fastest from-depleted recharge session being 6-7hrs, go for it

but I'd bet you'll regret it, IMO closer to 8A the better.

Keep in mind if holding CV/Absorb, you should be stopping at 2A, and since that is only 1A lower than the starting maximum

higher risk of "overcharging" in the sense of losing some pack longevity.

Compared to the Satiator, **so** much better, how much are you saving? IMO just save your pennies a bit longer.
 
GRIZZ said:
I sent Em3EV an e-mail with questions. Their chargers sale page are full of dead links and not linked to from the homepage so I'm not sure they sell them separately right now.
They used to be stellar, **much** more consistent than Luna, run by a Brit living in China.

Lots of bad reports in the past year

many members think maybe he sold out and moved on.

Again, have you finalised your order sent payment already on its way?

 
john61ct said:
If you're OK with the fastest from-depleted recharge session being 6-7hrs, go for it

I'll have 9+ hours because it will be overnight or during a work shift.

I'm driving into Boston to meet the seller in person tonight.
 
No I really would like to know, just interested is all.
They could have done a custom run, who knows.
Or a semi-custom run by adding a voltage display to the case or the 70/80/90% switch or added silicone to failure components.

2old said:
The usual shot at Luna as if nobody else has other companies manufacturing parts for them. The six year old one is their 2 amp charger, the other is the blue 80/90/100 unit. Over the years I've purchased from them probably 25 times for myself and friends. The one problem was rectified promptly.
 
After appropriate battery capacity for your needs, your next criteria is a reliable, adjustable, relatively fast charger according to the battery C-rate. You just don’t know yet, how important it is. Once you started to ride, you don’t want to miss your bike a week for a fried charger. See where I am going?
You need a backup if it is not available locally. So you are in the need of two chargers, one of them fast, ideally. :wink:
 
MadRhino said:
After appropriate battery capacity for your needs, your next criteria is a reliable, adjustable, relatively fast charger according to the battery C-rate. You just don’t know yet, how important it is. Once you started to ride, you don’t want to miss your bike a week for a fried charger. See where I am going?
You need a backup if it is not available locally. So you are in the need of two chargers, one of them fast, ideally. :wink:

Two cheap chargers is an option. A slower one that charges to 100%, and a faster one, adjusted to charge to 90% (or whatever). Unless you have multiple packs of varying voltages, then get the satiator.
 
E-HP said:
MadRhino said:
After appropriate battery capacity for your needs, your next criteria is a reliable, adjustable, relatively fast charger according to the battery C-rate. You just don’t know yet, how important it is. Once you started to ride, you don’t want to miss your bike a week for a fried charger. See where I am going?
You need a backup if it is not available locally. So you are in the need of two chargers, one of them fast, ideally. :wink:

Two cheap chargers is an option. A slower one that charges to 100%, and a faster one, adjusted to charge to 90% (or whatever). Unless you have multiple packs of varying voltages, then get the satiator.
The second advantage to have a backup, is that it doesn't have to be a backup. One solid state that you can mount on the bike, and a charging station at home. :idea:

The most practical charging security is to be able to charge by any means available locally. If you can find junk and build one yourself, you’ll never be stocked without a charger. Once you know your cells requirements, it is easy to feed them satisfied.
 
So, if the seller has no charger, how did he keep the batteries bms from ruining itself. If it sat long enough, it will have dead cells in it, and it won't work anymore.

If he's just not selling you his charger, thats different. But bear in mind the value of used batteries is zero dollars. This is not for silly reasons, batteries that sit long enough have the bms discharge one cell group till it dies, if not recharged periodically.

This is not bullshit, I used to answer the question why is my battery dead now a lot every spring. I worked for a bike kit company, and we told every customer to charge the battery at least once each winter. Few did. Many batteries could stand this in year one, but not in year two. Big reason the battery warranty was one year, not two.
 
"Roughly 1 year old, stored for 7 months at 40%"

He only had one charger and kept it for himself. He topped off the battery for me when he sold it to me last night so I can test the mid-motor after I install it while waiting for the charger to arrive. Hopefully the smart BMS can give me more information when I figure out how it works this weekend.
 
markz said:
No I really would like to know, just interested is all.
They could have done a custom run, who knows.
Or a semi-custom run by adding a voltage display to the case or the 70/80/90% switch or added silicone to failure components.

2old said:
The usual shot at Luna as if nobody else has other companies manufacturing parts for them. The six year old one is their 2 amp charger, the other is the blue 80/90/100 unit. Over the years I've purchased from them probably 25 times for myself and friends. The one problem was rectified promptly.
Sorry if I misinterpreted your response. I've never seen anything on Luna's site to identify their supplier(s). They claim to manufacture some batteries in the US, but ????? I purchased a 52V 10 ah battery from them about five years ago that looked like it was from UPP (based on external characteristics); it was fantastic and used for a BBS02 or 1000w, 48V DD over the five years; I gave it to someone who is still using it AFAIK. Maybe UPP makes some of their products.
 
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