Re: another Tahoe hybrid no start thread
 

Never heard of them. Very unimpressed with their website and even less impressed by their boastful claims.

Great system, but improperly used Prolong can damage modules. Modules made between 2007 and 2009 have a higher likelihood of leaking, but it can happen with any year.

I do recommend Bumblebee. I know the owner, and I know their process. They've also been at it for 10 years.

The GMs destroy their batteries. Completely. I've posted test data on this site, and it's very common for the entire battery to be at less than 10% state of health as the battery management is so permissive, it will drill a pack into the ground before it triggers a failure. It doesn't help that the cooling system is marginal.

When one has to replace 40 modules 100% of the time, it makes ZERO sense to use reconditioned modules. It can't be done profitably. When I get a call on one, I offer to rebuild their batteries with brand new modules harvested from Generation 2 Prius batteries. I won't do anything else.

The only way for you to get a brand new set of modules is to buy a brand new pack. The only source for modules is Toyota, and they only sell whole packs.

Re: another Tahoe hybrid no start thread
 

thanks for your help,

I took off a few busbars and didn't see anything more than 0.001V and I checked from the neg and pos again and they are at like 0.002V now, not sure if maybe the voltage decayed a bit in the cells sitting all day and the leakage stopped. Still won't start though so I am wondering if its an unrelated problem, going to have to take it to the dealer for now.

Hopefully I can get this current pack working for a least a little while I have some trips coming up and need this back on the road for the time being.

Just wondering what are your thoughts on the new lithium ion battery cells from Nexpower? they sound pretty interesting and aren't really any more than new NiMH, since this thing is just a giant money pit now anyway maybe I'll try some lol

also on the Prolong charger/discharger, what would cause it to damage the cells? I went through the 3 discharge/charge cycles on their website and the last one I left it on about 30 hrs to balance.

thanks

Re: another Tahoe hybrid no start thread
 

If you measured essentially 0V between each module (-) and the case bottom, you likely do not have a leaking module.

I can't account for your small voltage measurements to ground when the battery is assembled. That is very atypical.

I have VERY strong opinions on the Nexpower product. I will summarize with the following:

1. A GM Hybrid would absolutely destroy them.
2. I would not own one unless it was given to me for testing.
3. It is a horrifically poor implementation that took a major shortcut.
4. They will likely appear to outperform NiMH for the first 3 years, but will deteriorate steadily if actually measured.
5. They will likely not last anywhere near as long as the original NiMH packs.

Concerning the Prolong, battery cooling is absolutely critical and long soak charges are not beneficial to prismatic modules like they are to Honda "D" cells. Excessive charging pressurizes the cells, and they can vent. If they vent, which you may or may not hear, electrolyte is permanently lost, and internal resistance has increased.

Did you charge with the cover in place? I don't remember the exact way it flows, but IIRC, if the cover is removed, cooling is disabled.

Re: another Tahoe hybrid no start thread
 

thanks, yes I charged with the cover in place and I checked the battery fan was running and had the windows all down and the back open to try to keep it from getting too hot but it has been fairly warm out lately.

Good info on the new batteries, curious what the major shortcut is with the Lithium ones, so it looks like you would recommend either new NiMH cells or reconditioned ones from Bumblebee only, how are Electron Automotive?

I left the Tahoe with the dealer today to hopefully find out if the codes and no start are from a bad battery pack or something else is fried. If its bad I'll probably get something from one of these guys and cross my fingers I can get my money back on the reconditioned ones I just put in

also what are your thoughts on the cylindrical ones? they looked popular for a while but I am not seeing them advertised as much lately.

Re: another Tahoe hybrid no start thread
 

IIRC, HA recommends to not charge when it's about 90°F.

The major shortcut? Lithium Iron Phosphate, LiFePO4, (LFP) is not NiMH. The LFP cells will be managed as though they were NiMH because they didn't develop an intercepting BMS to feed the car the NiMH parameters analogous to the desired LFP parameters. The voltage performance of the two chemistries is substantially different, and they also have different temperature influences. The net effect is that a much larger % of the battery capacity will be used with more EV driving, but 1.4kWh is not an EV capacity (maybe 2 miles of EV range). They're going to cycle them to hell and cook them to hell. Another issue is that LFP can't be charged below freezing, or it sustains permanent damage. Yttrium can be part of the LFP mix to improve that, but even then charging needs to be very carefully done. NiMH doesn't like to be charged at cold temps either, but it's more tolerant than LFP.

I have no direct experience with Electron Automotive, but I've watched a few of their videos, and they seem competent.

Cylindrical cells? They are pure unmitigated sh!t of epic proportions. They're the Chinese made garbage that's been pervasive in Honda replacement packs for over a decade. You either get good cells, or garbage depending on the supplier and where they are in the production run. Even the good cells are markedly inferior to the Sanyo/Panasonic cells of ages past. With the Hondas dying off, and the pool of suckers drying up, the Chinese have been looking for new markets, and they've developed these abominations. I call them CCAP, Cylindrical Cell Abomination Pack.

The manufacturer's perpetuating this lie should be shot or at least maimed in some fashion.

You know how I feel about the Lithium option. I would BEG for lithium before I'd install a CCAP because I've already done so. Horrible performance, lasted barely two years, performed worse than a ragged out Prius pack I slapped together from marginal modules AND the bastids leaked like old corroded "D" cells.

Eff 'em.

Re: another Tahoe hybrid no start thread
 

thanks for the info, just thought I should update the thread here, finally got my Tahoe running again, had to get the dealer to clear those codes, they said that is all they did, not sure why clearing them myself with the Torque app did not work. Everything else seems fine, I will run my reconditioned batteries for a while and see how bad they are and then decide if its worth it to get new ones or not. In conclusion those couple of codes seem to have been set by either my Prolong charge/discharging or by disconnecting the 12V battery and the only fix was to get the dealer to reset them.

One other thing I was curious about, does GM provide a way for anyone to actually modify the battery management software or do we have to wait 20 years for the patents to expire or something? Would be pretty cool if someone wanted to actually take one of these trucks and make it work with a different battery, maybe a large lithium ion or something. I wonder if it had a big enough battery that could handle the current if the electric motor is big enough to actually drive around in low acceleration situations or if its just not big enough

cheers

Re: another Tahoe hybrid no start thread
 

it would be way easier to just swap the body panels to a 4.8l you could get about the same mpg as the hybrid (swapping the powertrain could prove to be too pricey )
https://cimg5.ibsrv.net/gimg/www.gre...5db8e2985b.jpg
https://cimg3.ibsrv.net/gimg/www.gre...2d2f466e2e.jpg