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RedDevil · 01-09-2018, 10:12 AM

Don't panic just yet.
There are 120 NiMH cells in the pack, right?

They'd hold about 1.2 Volt each when not close to being topped off. 150 Volt under a mild charge seems OK.
When full they'd top out at 1.5 Volt each, again, 180 Volt for the full pack fully charged seems correct.

I cannot see how charging in the cold should damage them. These cells can handle close to 100 Ampere in short bursts. 310 milliAmpere is next to nothing.
I'd be careful when the voltage starts to climb as cells reach their top though 20 hours into the charge. But the pack should have warmed up by the charge by then, so even that.

You are underway with the charge anyway, if the pack is toast there is no harm in continuing, and if it isn't it is the right thing to do anyway.

I would never charge LiFePO4 batteries in severe cold, but that's another chemistry.
Talking about that:

http://batteryuniversity.com/learn/a...w_temperatures

The problem with cold charging NiMH batteries is that they appear fully charged when they're not; then you'd be at 180 Volt early, which is not the case. No worries then.

01-09-2018, 10:12 AM	#7 (permalink)
RedDevil Master EcoWalker Join Date: Dec 2012 Location: Nieuwegein, the Netherlands Posts: 3,999 Red Devil - '11 Honda Insight Elegance Team Honda 90 day: 54.23 mpg (US) Thanks: 1,714 Thanked 2,247 Times in 1,455 Posts	Don't panic just yet. There are 120 NiMH cells in the pack, right? They'd hold about 1.2 Volt each when not close to being topped off. 150 Volt under a mild charge seems OK. When full they'd top out at 1.5 Volt each, again, 180 Volt for the full pack fully charged seems correct. I cannot see how charging in the cold should damage them. These cells can handle close to 100 Ampere in short bursts. 310 milliAmpere is next to nothing. I'd be careful when the voltage starts to climb as cells reach their top though 20 hours into the charge. But the pack should have warmed up by the charge by then, so even that. You are underway with the charge anyway, if the pack is toast there is no harm in continuing, and if it isn't it is the right thing to do anyway. I would never charge LiFePO4 batteries in severe cold, but that's another chemistry. Talking about that: http://batteryuniversity.com/learn/a...w_temperatures The problem with cold charging NiMH batteries is that they appear fully charged when they're not; then you'd be at 180 Volt early, which is not the case. No worries then. __________________ 2011 Honda Insight + HID, LEDs, tiny PV panel, extra brake pad return springs, neutral wheel alignment, 44/42 PSI (air), PHEV light (inop), tightened wheel nut. lifetime FE over 0.2 Gigameter or 0.13 Megamile. For confirmation go to people just like you. For education go to people unlike yourself. Last edited by RedDevil; 01-09-2018 at 10:26 AM..