HV25 State of Health (SOH)

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reef
Posts: 101
Joined: Sat Sep 09, 2023 10:06 am
Location: East Yorkshire

What sort of State of Health values are other HV25 users seeing on their batteries after having them a while?

I've had mine around 15 months now and have done 280 cycles in that time. However the SOH as reported in the Fox App says it is now only 96%? This seems quite low and is a bit worrying as they're supposed to be good for 4000 cycles before hitting 80% SOH.

I'm curious what others are seeing? The SOH reading can be found in the v2.0 app under Battery > Info > detailed parameters. The cycle count can be found in Me > Data with the reporting method as "standard" and in the excel csv file it is cycle count.
Dave Foster
Posts: 1148
Joined: Thu Oct 13, 2022 7:21 pm

The SoH seems to only be available to the batteries which have the V2 BMS such as HV25, HV2600V2, ECS-V2, EP etc.. my V1's doesn't have it so unfortunately don't have any direct experience, but from what other users have said that is in-line with their observations for example one user with a 6 battery HV25 installed just over 14 months shows 96%.

I have been told LFP batteries have higher degradation during their early cycles which becomes flatter as they age - I haven't yet found a research paper which confirms that as they are typically investigating other affects when they compare (such as high or low temps).
reef
Posts: 101
Joined: Sat Sep 09, 2023 10:06 am
Location: East Yorkshire

Hopefully the initial degradation steadies off as you mention, otherwise I'll be hitting 80% SOH in about 5-6 years and 1400 cycles! I wonder where we'd be warranty-wise if that did happen?

The figure seems to be relatively accurate at least. As a year ago I could get about 10.5kWh from or into the batteries but that is more like 10.1kWh now.

I guess long-term data on these batteries is somewhat lacking still.
reef
Posts: 101
Joined: Sat Sep 09, 2023 10:06 am
Location: East Yorkshire

Thought it might be worth an update as at the ripe old age of 18 months since installation and only 390 cycles, it has just dropped to 94% SOH yesterday.

I'm starting to get a bit worried now. If the drop continues in a linear fashion Ill be at 80% SOH in 1300 cycles and under 5 years. I'm also struggling to get any more than about 9.7kWh into 12.28kWh of batteries.

Current total throughput on the 5 batteries is 8.24MWh. The Fox warranty document on the HV25 says they cover 8.9MWh throughput per battery down to a minimum of 60% SOH, so I'm about a fifth of the way there on both.

Anyone else with these batteries have figures for comparison? It feels like they're wearing quickly to me but for all I know it could be normal!
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