Yes, great info. Those specs say that the lithium profile is perfect for 21s.
With that information I can build a custom battery for the r4f super charger.
Either of the ones pictured. Tote battery or Samsung module -1.
@INWO I don’t know if they come with F5 activated or not. They kind of said, or at least strongly alluded to in the literature that it doesn’t come with it turned on unless you ask for it. I suppose if they don’t you can send it back and just tell them to turn on the default for F5. I also no longer have my R$F co-branded SCO7210 to check if it existed on there or not.
@AssyRequired If I hadn’t owned a used one, and wasn’t trying to figure out what to use it for, I probably never would have spent the time to hunt down the important stuff like the charge curves, that were basically inadvertently hidden from view.
Thanks for all that info. Slowly wading through I’m gaining knowlwedge and understanding. Thats what is great about this forum.
It looks like my R4F super charger can be reprogrammed to charge lithium batteries.
Quike Charge literature says for F5 ,lithium batteries, the charger must be pre-programed at the factory. (I gues the turn on default for F5 @Inwo referrs to)
From @Inwo response he can build a pack for “21s” because of the lithium profile indicated.
F 1-4 charge profiles can be done following their adjustments except for F5, the lithium, which required factory pre-programing, as above.
If I understnd the charge curve graph, that is what @Inwo would use to build a custom battery - to match the charge curve of the charger.
So I gues this is for both of you, how would that work? I send the charger back to them them to pre-progrm it to certain specs then @Inwo would build a battery pack to those OR Build the pack and then send charger to get pre-programmed?
Is there another option?
I’ll call Quick Charge on Monday and ask them their thoughts too.
It sure would be easier (and < $) to use my present charger, if it can charge the lithium batteries. Then just have @Inwo build a pack.
Then its install, hook up and ready to go!
Your thought?
Thanks again men.
Barry
Don’t worry about the charger. Any 72v charger will work with my 21s battery.
I think you are overthinking it. You won’t need to change anything.
Connect two wires. Pos and neg that were connected to old batteries. Download the app from qr code on bms. Turn on battery.
On reflection, just go with Dave’s suggestion. It’s simpler.
Original post follows:
@barry1 just for shits and giggles, drive the gem around until you are at like 70% battery remaining then disconnect one output lead and try setting the charger to F5. If it does take, get a voltage read on the lead pack, write it down, then reconnect the charger to the batteries and if you have alligator leads hook them up, then plug the charger in. Write down what your meter is showing with the charger on and also look at the led display on the charger and see what percentage it is shows.
If you send it back to be turned on, I’d send it to quick charge, skip R$F because they are probably just going to send it to quick charge.
I think what Dave is saying is that the default F5 profile is fine. 24s lifepo4 cells charge to the same finish voltage as 21s SDI cells. Best not to confuse the person on the other end of the phone or you might get a charger back that stops at the finish voltage for 21 lifepo4 cells.
Thanks Dave that sure seems simple enough.
I noticed on the reprograming video for quick charge, that jrjava mentioned, it showed them pushing the buttom going through F1-5, so it at least gets to the F5. But if I understand what you are saying there is no need for me to do that.
Their video say the “d setting,” done after the F setting is established, controls the last 20% of the charge. I dont need to do that? I just leave it on what ever setting it is on and just conect the batteries?
I’m already having trouble with my lead acid batteries holding charge so what jrjava is saying to do might be problematic.
Thnaks again
Barry
The one they used got to F5. Others, including yours, might or might not, Or, they might but it might not do anything.
The BMS will protect the batteries if your charger gets frisky.
But, out of curiosity and a possible answer as to why your batteries went to shyt, could you go into the programming mode and check what all the settings are?
You should be on F3-d2 with flooded Trojan batteries. If it’s set anything else, that’s the problem. Your batteries were undercharged continuously and that caused the premature death.
Thnaks I’ll that out.
The Trojans I have were purchased in 2018. They are the third set in about 12 years. The second set on this charger.
I called Ray with Quick Charge in tech supoort. Based on my R4R charger being more than 3 years old he said I should just place in in the F4 mode which is the closest mode to F5, and it would charge the lithiums with no problem.
He also confirmed your staement that the BMS would protect the batteries if too much charge. The BMS appears to be key.
He said that F1-3 are too aggressive of a charge rate for lithium.
He said the F4, even when it drops to the fload mode, which lithiums do use, is the setting to use.
Seems pretty straight forward as Dave indicated too.
I think Im going to move it that direction, with Dave’s battery pack after I check measurements again.
I’ll have to do some fabrication on rear cowling to get the box to fit.
I’ll try to find the thread in this forum again, on someone doing that with their 2002 Gem.
You guys, your knowkedge, and willingness too share it are terrific !
Thanks,
Barry
Looking forward to this, I haven’t seen anyone using the Quick charger with lithium. His comment was funny about F1-3 being too aggressive, Lithium can handle way more charge current then lead. 21s for a Gem is a good setup.
The “too aggressive” could be my misunderstading of his comment but he definatly said to use the F4 setting for the Lithium’s charging. The whole point of my call. With my thimble full of knowleged I didn’t pursue further discussions on it.
I did notice on their charging curve graphs the lithium at higher VPC than others.
Do you have resevations about the Quick Charge use?
I have to make mesurments of compartment space for Mike’s battery pack then I’ll go from there. The cart is at a vacation home so won’t get to it til June.I’m accually looking forward to the conversion.
I’ll have to check with Mike to see if he still has a set up pack that he feels would work.
Thanks to all again.
Barry
The charge graph for lithium is the 25a charger, it is way too high at the end of a charge cycle. But most chargers for Gems are the 10amp charger so it will probably be ok. You will have to run an active balancing bms for sure to handle it. Shunt balancers would not work at all with this. The BMS INWO uses is a good one and can handle this charge curve. 4.11v per cell for 21s nmc is a little to high but bms can cut it off at the preferred lower level. Looking forward to following this.
My preferred method. Faster charging.
It should work well with NMC lithium but can you imagine using it with LFP? It would never fully balance. The full output of the charger is nowhere near the charge capacity of the Samsung cells, they could take 5 of the Gem chargers charging at once!
No, but then lfp never balance in any case. They are cheap and tough, at least usa made ones are tough, but basically a poor choice for EV use. IMO
So because, according to Ray at Quick Charge, if on the F4 setting the charger “drops into the flood mode for the last part of the charge” that is what guards against a “too high of a charge at the end of the charge cycle.?”
So Dave by using the BMS in your Samsung 21s, NMC, battery pack these batteries should have no probelem being charged with the Quick Charger? Is that a correct understanding on my part? Sorry for not being a quick on the uptake as you guys.
Thanks again.
Bary
I don’t think I can say it any differently.
Do what you want.
Thanks Dave,
I think you were right earliry in my over thinking it.
As you mentioned you can build a custom battery for the r4f super charger.
Because any 72v charger will work with your 21s battery.
I won’t need to change anything.
“Connect two wires. Pos and neg that were connected to old batteries. Download the app from qr code on bms. Turn on battery.”
You are right, pretty clear and no need to say it differently.
Thanks.
I’m going to take the mesurments in June, which was the only concern you had, to make sure of fit. Then I’ll hook back up with you about getting your batteries. You’ve been very helpful! Thanks.
Barry
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you will be assimilated
Which dash lcd do you suggest?
@Oldschoola - Have you decided on a pack yet?
If you were looking at the JK BMS and asking about the display options, I would pick the larger display.
But that is just me.