Bosch 36V fatpacks opened up

[Eclu Lardbut]

Anyone found their Bosch charger gets a bit hot if charging six FPs?
I wonder if there's a weakness in these chargers, for I see quite a few busted ones for sale on the 'bay - perhaps they overheat.
I was thinking of getting another type, like this one...
http://www.all-battery.com/TenergyBatte ... 01310.aspx
Which would take it to 41.6V, still OK for FPs, as far as I know.

[ambroseliao]

Actually, you DO NOT want to use that charger since it would take your pack to 51V which would destroy your packs. The one you want is this one which tops out at 42V which is a bit high but better than 51V. You could put a diode on this to drop the V a bit...

http://www.all-battery.com/TenergySmart ... 01338.aspx

[docnjoj]

Anyone found their Bosch charger gets a bit hot if charging six FPs?
I wonder if there's a weakness in these chargers, for I see quite a few busted ones for sale on the 'bay - perhaps they overheat.
I was thinking of getting another type, like this one...
http://www.all-battery.com/TenergyBatte ... 01310.aspx
Which would take it to 41.6V, still OK for FPs, as far as I know.

I use my Bosch charger on six fatpacks all the time and have for at least 2 years. It works great and shuts off fully at 41.5. One of the most consistent charges I have. My Fatpacks hold their chare for weeks on end too even though i once let them drop to zero by leaving them connected to my controller. Best batteries made still, IMHO!
otherDoc
Ambrose is spot on regarding the charger from Tenergy. Don't use it! I does not seem to be adjustable. It looks like a typo when they say 41.5 since it is listed in the documents as a 51 volt charger. That is too high for fatpacks which are 10s2P Konions and shoud only be charged to 41,5 or so. The bosch chargers have cooling fans. Are yours working?

[John in CR]

I had 6 of them. Only one failed in 3.5 years. They do get hot in there. Each has 2 mosfets each on a fairly large finned heat sink, and that heat sink gets toastly. They have internal fans that suck air in through the white rubber thing, which as designed sucks air through the pack too. I run 20s, so I run mine 2 chargers in series. I took 2 out of their case and made a case out of thin plywood housing both into a smaller form. I installed 2 high volume 12V computer fans to give the boards much better ventilation than stock. The little centrifugal blowers from the Bosch charger make great fans for ventilating controllers.

It doesn't get very hot here, but if it did, then I would put an exterior fan blowing on my chargers running stock. Those heat sinks inside get way too hot to touch for more than an instant. Once I found that out, I did run a fan on my stock ones before cannibalizing to make a smaller better ventilated portable 20s charger.

I picked up some Greentime chargers that work great. I told Leo I wanted an 83V cutoff and they came tuned perfectly. My Bosch's now collect dust as backup or multi-bike charging only.

John

[999zip999]

John what's the green time charges ?

[John in CR]

John what's the green time charges ?

Chargers I got from Leo. I picked up a 4A and a 6A from him, and both work perfectly. The only thing odd is on the 4A you turn it on first before making the connection to the battery to avoid the spark. ON first precharges the caps. The 6A has something to eliminate that so connecting whether on or off makes no difference. It's no big deal, just different. Solid units with nice fat wiring, 7mm OD on the input and output on the 4A and over 8mm on the 6A. My cheapie welding machine only has an 11mm cable on its input cable. I like overkill on wiring just like on my dropouts. They get only warm, not hot like the Bosch chargers and greater current too, so they must be more efficient, which is always nice. Plus they're smaller, so better to bring on the road for opportunity charging.

John

[pwbset]

Sure wish someone could source V & VT cells new in bulk... if they even still make them new... such a great ebike cell.

[John in CR]

Sorry, I thought everyone knew about Leo. chinagreentime@gmail.com

[John in CR]

Sure wish someone could source V & VT cells new in bulk... if they even still make them new... such a great ebike cell.

I'm hot on the trail, but still nothing yet. I thought I had a source that made cheap replacement packs that fit Makita tools, but the cells weren't them. Sony US18650V or Sony US18650VT are the exact cells we want, preferably already tab welded in 2p4s blocks They've been in production long enough that they should be dirt cheap by now. At the $1-1.50/cell that they should be I'd figure out how to buy a container full. I bet they're in some of the LiMn ebike packs.

[pwbset]

I'm hot on the trail, but still nothing yet.

I thought you might be especially since you're getting "into the business" more and more. Count me in for a few hundred at least if you ever do source them new.

Would also rock to source the 26650VTs like drewjet did that one time...

[docnjoj]

I'm hot on the trail, but still nothing yet.

I thought you might be especially since you're getting "into the business" more and more. Count me in for a few hundred at least if you ever do source them new.

Would also rock to source the 26650VTs like drewjet did that one time...

+1 to buying Konions new. It is just that I have gotten spoiled by the A123 20 Ah pouches, and I haven't even assembled my 12S battery yet. Soldering all those connections is now a pain in the butt! Maybe cheep Fatpacks! Dream on!
otherDoc
edit: Hey Pwbset
What is the capacity of the 26650 konions?

[pwbset]

Soldering all those connections is now a pain in the butt!

That's why I tab weld! Soooo easy!

edit: Hey Pwbset
What is the capacity of the 26650 konions?

2.5ah I believe. They aren't quite the powerhouse of the 18650VT, but are still at least a legit 5-8C cell if I remember right.

[docnjoj]

Thanks pwbset!
otherDoc