The 2 Seater Gem car does not have the room to make it easy like the 4 seater to
upgrade to lithium. I have lots of pics for those that want to attempt it. It came
with the old Zivan charger which according to their main Sacramento location
can be reprogrammed though I haven’t done it yet.
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Under the seat; much tighter than 4 seater setup. 5 LEAF MODULES UPFRONT IN SERIES,
3 MORE UNDER SEAT IN SERIES AND 4 IN PARALLEL
Leaf modules were from a 2013 model with 45,000 miles on them. Nissan was sued and had
to settle over the lack of range/weak battery pack on the 2012 and earlier battery pack. I STILL HAVE LEFT OVER
CELLS I WILL PROBABLY END UP SELLING. This was the reading after installation before I ever drove
or charged the cells ie the Leaf modules were in great shape.
to settle over the lack of range/weak battery pack on the 2012 and earlier battery pack. I STILL HAVE LEFT OVER
CELLS I WILL PROBABLY END UP SELLING. This was the reading after installation before I ever drove
or charged the cells ie the Leaf modules were in great shape.
Front connections view. 5 Leaf Modules fit perfectly without endplates though. The bottom of the battery
compartment is nicely/well insulated.
compartment is nicely/well insulated.
I LEFT 2 DISCONNECTED TROJANS IN FOR BALLAST. 1 UNDER THE SEAT AND 1 IN THE FRONT COMPARTMENT. NOBODY HAS FOUND AFTERMARKET SHOCKS THE CORRECT DIMENSIONS?
PROOF OF CONCEPT. MAKE SURE THE DOG IS LOCKED UP! Dogs love Gem cars
though they sometimes try to bite the front tire. Had to keep her away from the
exposed battery pack; would have singed her hair big time!
If I understand correctly, you have 120ah batteries in series with 60ah batteries?
If, yes. What is your thoughts, or purpose?
Much better to use Leaf cells for ballast. IMO
With 20 total, you could have a 120ah pack rather than 60ah.
I mean 8 in series, 4 in parallel
On Fri, Feb 10, 2017 at 2:38 PM, Gillette Jeffreynakedwaterskier@yahoo.com wrote: 20 on series then 4 in parallel…keeps voltage the same but more current
NOTICE I TRIED TO WHITE OUT THE LAST S! Sorry, been taking many antihistamines; bad allergies lately.
I might use 20 cells ie 2x10 w an a vs b battery switch but then i would need a more expensive bigger bms…same if i do the 2 x 10 series packs in parallel…bigger bms and bigger charger…i can always reconfigure…but mine is only a 2 seater.
The test drive was 10 in series but not what i ended up running
I hate to disillusion you, but it doesn’t work that way.
No good can come from that configuration. Possibly no harm either, just not a good idea. IMO
Picture adding a 12v battery to only one of the Gem batteries. It works, but is unbalanced.
Meaning, charging and discharging thru the string is thrown off. No way to keep in balance or to use the extra energy.
Same bms for 20s no matter how many are in parallel.
See picture of a typical leaf configuration.
2 in-series pairs in parallel.
Adding more in parallel doesn’t change the number of cells to monitor or balance, as they are locked in step by electrical connection.
I’m working now with a guy connecting 4 sets in parallel 24 in series. They are Volt batteries but same theory.
He will have 200ah and 88v nominal. 100 volt peak.
Using a single bms-24.
I will bounce it off my electrical engineer if he ever wakes up!
Meanwhile don’t run it like that.
Also, be careful not to parallel cells after this, as they will be out of balance.
Make sure modules are within 100mv or so. When connecting unbalanced cells in parallel, current is only limited by connecting strap, and internal resistance.
See if your engineer agrees.
As always. IMHO
I am afraid to go up to 88 Volts. I am set up 60 to 80V, 12x500= 6000W capacity; 88V to 100V would require
more alterations to the Gem system? Stock is 72.
With 20, 21, or 22, you don’t need a modification. Just charge a little over what Gem likes. It sags quickly.
I finally had someone copy my 98v 24s setup. So far so good. Keep an eye on him in forum. Only issue was electric heater got too hot. I never use mine.
It’s only the unbalanced system I take issue with. To work properly all series packs must be the same, or use separate bms and charging.
Only way bulk charging works, is by dividing evenly between all packs in the series string. If one or two packs are greatly different capacity or voltage, it’s not good.
If all packs in string are doubled it’s fine.
Joe Engineer wants to read over the BMS manual before deciding what to do. He thinks
bms might be able to be setup to compensate.
See if this link works.
Even if it can be compensated, there is no advantage to having the extra 2 modules.