I’m 67 and retiring in April so moving south is going to happen very soon methinks!
[quote=bgeery;23896]But on the subject of money, it’s not as much as people seem to think. If you want equivalent range to the lead pack, a lithium conversion on an '02 GEM can be under $2K, and you can expect 2-3k cycles out of the LiFePO4 pack.
[/quote]
What battery are you suggesting can be purchased for under $2K? I can’t find 100ah batteries for that. I assume we’re talking about 24 batteries.
And what range are you suggesting one might enjoy with these batteries?
Don
[quote=OLD HOUSEBOATER;23921]REALITY: Over 92.34% of us don’t have range problems. We plug them in and drive them.
In almost all cases the GEM is a descretionary toy and is not our primary mode of transportation. [/quote]
Yep, my GEM is a discretionary toy. I use it like I use my Harley - nice days only and never intentionally in the rain. FWIW, I also drive it like a motorcycle in that I’m very aware that I have zero protection in case of an accident and think about that when I’m in the GEM.
I live about 7 miles from downtown and would like the range to wander down there and back without range anxiety. 25 miles would be plenty for me, but that’s about twice what I currently get.
[quote=OLD HOUSEBOATER;23921] I believe that the majority of us don’t even Golf.
Hmmmm Do you use yours to Golf?[/quote]
I don’t Golf or Bowl. I found I couldn’t break a hundred in either and gave up.
Don
If your carts unmodified you should get a solid 21 miles range with good batteries. More with T1275 Trojans.
I get a solid 20 without going below 50% and I am using Inexpensive East Penn 31’MDC’s. My cart is back to stock and pushes freely.
Have you changed out anything from stock? I carry 32 pounds of air in stock 12" tires.
[quote=OLD HOUSEBOATER;23945]If your carts unmodified you should get a solid 21 miles range with good batteries. More with T1275 Trojans.
I get a solid 20 without going below 50% and I am using Inexpensive East Penn 31’MDC’s. My cart is back to stock and pushes freely.
Have you changed out anything from stock? I carry 32 pounds of air in stock 12" tires.[/quote]
I addressed this in post #10:[quote=Laslonimne;23890]A couple of years ago I replaced my 12.44:1 gear with a 6:1. While I can now easily cruise at 40 mph, my range has dropped to 12 or so miles. I would like to see 30 or more miles per charge. [/quote]
I’m also running 205/40R16 tires which are just a bit taller than the stock tires. I have made no changes to the controller.
Don
[quote=Laslonimne;23943]What battery are you suggesting can be purchased for under $2K? I can’t find 100ah batteries for that. I assume we’re talking about 24 batteries.
And what range are you suggesting one might enjoy with these batteries?
Don[/quote]A 60AH LiFePO4 pack will give the same range as a fresh stock OEM lead pack. 25 cells x 60 Ah x $1.25 = $1875. The price may be closer to $1/Ah now. CALIB in California is CALB’s factory warehouse in the US.
Zivan charger reprogramming $80. J bolt battery tie-downs and deck board $25. Additional battery interconnect cables $15.
That’s the minimum parts to convert over to lithium. All that comes out to $1995 (not counting any shipping or sales tax.) A 2000 cycle LiFePO4 pack, vs 300 cycle lead pack (assuming [B]good[/B] deep cycle rated lead). Lithium already beats the lifecycle costs of lead.
Will CALIB sell retail? There website makes it seem they’re more attuned to OEM & wholesale. Also not sure about shipping costs unless you are in CA or can find a local distributor.
[quote=ARandall;23963]Will CALIB sell retail? There website makes it seem they’re more attuned to OEM & wholesale. Also not sure about shipping costs unless you are in CA or can find a local distributor.[/quote]AFAIK, they will sell to anyone, any quantity. Unless something changed recently. In any case, there are plenty of dealers that sell the CALB CA series (grey) cells, so finding a source is easy enough.
A pack of 25 60 Ah cells only weighs about 110 lbs, so shipping is probably not expensive.
Get the cells strapped together into batteries, and try to get the copper cell interconnects and hardware included free. They run about $3 each otherwise.
Thanks. I didn’t see a “dealer locator” option on their website so I’m not sure about retail locations. I think shipping lithium from CA to OH might get pricey since I believe there quite a few regulations on shipping lithium batteries due to fire hazards.
Hmm, AH is a battery rating system showing the capacity of the battery providing a certain level of amperage over a given time period. The GEM doesn’t “care” about the battery rating or chemistry involved of course (other than the charging algorithm), it simply pulls the power from the pack until the pack can’t provide sufficient power. How then can a lower rated AH battery provide equivalent power to a higher rated AH battery? This makes no sense at least from the perspective of LA technology given the same power loading.
I understand of course that the chemistry of the LI pack is completely different than LA and has other advantages such as an improved life-cycle, less weight, no self-discharge but I’m a tad skeptical of your assertion of power equivalence for a lower AH rated system.
Can you expand on this a bit more so that I might understand better?
Al
Effective capacity of lead is much lower than stated, in EV use, due to the Peukert effect. Lead is rated at the 20 hour discharge rate, lithium is rated at the 1 hour rate. You are lucky to get half the Ah rating of lead in EV use.
The other factor is depth of discharge allowed. You can use 90% of lithium capacity, but only 80% DoD is allowable on even the best lead acid batteries.
That’s how my 160Ah LiFePO4 pack provides about 80 miles of range, having only a slightly higher Ah rating vs the OEM lead pack.
You will get a better price direct from CALIB, but if you want to find CALB dealers, Google for “calb ca 60ah ca60 batteries”.
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Brent,
If I’m getting 12 miles on a full charge with GEM AGM, could I expect to double that with 100AH LeFePO4? Or do you think I’ll need 180AH?
Don
Only 12 miles on GEM batteries? Seems awfully low to me unless they’re “shot”. I’d think you’d get something closer to 20-25 miles on a good set of lead acid batteries unless you have a lot of hills and/or hot-rod your cart.
Don’t know about LiFePO4 but according to Brent who is the resident LI “advocate”, you should get much better miles per charge with that technology. Especially w/ 180AH batteries.
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[quote=ARandall;23996]Only 12 miles on GEM batteries? Seems awfully low to me unless they’re “shot”. I’d think you’d get something closer to 20-25 miles on a good set of lead acid batteries unless you have a lot of hills and/or hot-rod your cart.
Don’t know about LiFePO4 but according to Brent who is the resident LI “advocate”, you should get much better miles per charge with that technology. Especially w/ 180AH batteries.[/quote]
Al,
I guess you’ve forgotten or ignored my earlier posts in this thread.
Reread post 10 where I replied to YOU how I manage to get this range.
Don
Don
No need to get snippy. I’ll just ignore your posts from now on!
Al
[quote=bgeery;23975]Effective capacity of lead is much lower than stated, in EV use, due to the Peukert effect. Lead is rated at the 20 hour discharge rate, lithium is rated at the 1 hour rate. You are lucky to get half the Ah rating of lead in EV use.
The other factor is depth of discharge allowed. You can use 90% of lithium capacity, but only 80% DoD is allowable on even the best lead acid batteries.
That’s how my 160Ah LiFePO4 pack provides about 80 miles of range, having only a slightly higher Ah rating vs the OEM lead pack.
You will get a better price direct from CALIB, but if you want to find CALB dealers, Google for “calb ca 60ah ca60 batteries”.[/quote]
Common figure manny of us use for DOD is 50% it’s possible to go lower than that but you sacrifice life.
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[quote=Laslonimne;23995]If I’m getting 12 miles on a full charge with GEM AGM, could I expect to double that with 100AH LeFePO4? Or do you think I’ll need 180AH[/quote]The best way to find out, would be to hook up an Ah meter, and record the actual Ah usage over that 12 mile range. The Cycle Analyst (CA-HC model), with 0.25mOhm, would be an excellent device for this job, and needed as a “fuel gauge” for a lithium pack anyway.
Another way to get an accurate estimate, would be to find out the Peukert number for your model of battery and do the simple calculation to determine the effective Ah capacity of your AGM battery pack.
An educated guesstimate on my part, would say the 100 Ah CALB cells would approximate the stock pack range with your hot rod GEM. The 180 Ah cells would probably get you a range of 55 miles or so.
You may also be able to tame some of that power demand by reprogramming the motor controller and tweaking some of the settings.
Lastly, if you are thinking about the 180Ah CALB cells, make sure you can actually fit them into place. It’s easier on the older GEMS, but from what I’ve been told, the newer GEM’s battery boxes are a much tighter fit in general. 100 Ah cells will probably fit with little problem (but again, check the measurements to confirm.)
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[quote=OLD HOUSEBOATER;23999]Common figure many of us use for DOD is 50% it’s possible to go lower than that but you sacrifice life.[/quote]Right. The cycle life rating for deep cycle lead is based on 80% DoD. You certainly can baby the pack and increase it’s life. 2k cycles for CALB cells will dramatically increase with shallower discharge cycles. That’s one of the reasons I went with a larger pack.
At some point we start running into the issue of the cycle life of the cells exceeding the calender life of the cells. It’s unclear if there really is a calender life for LiFePO4, as there is with lead. But if you want to be safe, plan to use the cycle life of the lithium pack within 8-10 years or so. That seems to be within the range of the sparse anecdotal evidence regarding LiFePO4 calender life.
A good idea I’m sure and I’d love to have one, but at around $200 I think I’ll put off the purchase until I decide to definitely convert.
The GEM Gel comes in a plain brown wrapper - actually off-white - and there is no indication of Ah rating, much less a Peukert number. Non-GEM-branded replacements are generally 130Ah. Of course, I have no idea what any of this means.
[quote=bgeery;24000]An educated guesstimate on my part, would say the 100 Ah CALB cells would approximate the stock pack range with your hot rod GEM. The 180 Ah cells would probably get you a range of 55 miles or so.
You may also be able to tame some of that power demand by reprogramming the motor controller and tweaking some of the settings.[/quote]
I can live with a 25 mile range.
I have not reprogrammed the motor controller. You’re probably correct that I could see a range improvement by doing this. But I have no idea where to start.
The 180Ah CALBs are about two inches taller than the stock GEM AGMs. I don’t think there is any way they will fit.
I really appreciate your input Brent. I’m giving serious thought to the 100Ah Lithium batteries.
Don
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[quote=Laslonimne;24004]
The GEM Gel comes in a plain brown wrapper - actually off-white - and there is no indication of Ah rating, much less a Peukert number. Non-GEM-branded replacements are generally 130Ah. Of course, I have no idea what any of this means.[/quote]You can probably also find a generic Peukert number for AGMs to do the calculation. I’d guess the usable Ah of the AGM pack to be about 50.
I can live with a 25 mile range.
I have not reprogrammed the motor controller. You’re probably correct that I could see a range improvement by doing this. But I have no idea where to start.
Contact Marlon in California. Info I have for him is mgrd@yahoo.com or WMGRD@COX.NET or 619-247-4044. Let me know if none of those work, and I’ll look for current info. He will rent out a controller programmer, and let you know what you change and how.