1998 Prius turtle light on hills

One reason I will never buy a grey import.
I don't think this is normal. Others will come along with more information soon I suspect.
By the way, welcome to PriusChat. Did you search PriusChat for an answer to the question?
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Just a guess but there may be corrosion on battery bus bars.

Try going a little slower up the hill, that might work, I don't know.
I hope I'm allowed to comment, I haven't got a bladder in my fuel tank. <sorry, funny to me only

 

You have the first Prius model produced and I would recommend reviewing the Wiki entry to understand some of the design characteristics:

• lowest power engine - maximum 4,000 ICE rpm
• least efficient transaxle - internal seals to keep oil from motors
• oldest traction battery architecture - strings of "D" cells

I would suggest trying a series of tests at lower entry speeds to find the fastest, sustained speed up a given grade. With my NHW11 2003 Prius on a 6% grade:

• 55 mph (88 kph) - fully engine powered
• 60-65 mph (96-104 kph) - maximum engine power, some battery charge drain
• 70+ mph (112+ kph) - heavy battery drain that can exhaust the charge

I suspect that somewhere under 88 kph you'll find a constant speed that works ascending hills. Any faster or any steeper and you'll have to ascend even slower. But one word of caution.

We are finding heat is the enemy of the traction batteries and descending hills heats them a lot. As the batteries heat and are charged, the internal pressure builds up and they can vent a small amount of the gas. This ages the traction batteries and leads to their failure. About the only mitigation is to use "B" when descending large hills. Also, try to park in the shade to minimize heat-soak.

I would recommend visiting the YahooGroup "Mk1_Prius", which is one of the best group of NHW10 model Prius owner/operators.

GOOD LUCK!
Bob Wilson

 

Welcom 1st time poster. If your HV battery is showing its age, and the yahoo goup Bob mentioned cannot help, I think this particular Prius may have a limitation we cannot improve.

In general, I think that HV battery temperature management in hilly driving is better done with the air conditioning on full, in flow through mode. The battery's fan system cannot always mange the heat load on its own. But in this context I don't know if the 1998 came with A/C, and for sure its belt would take a few horsepower from that engine not producing very many to begin with. But my personal rule was battery temperature first, hill speed after.