Hey Jason, thanks for the info. Yeah I was considering just doing a add on BMS but I think there are a number of reasons it is better to just go with a full on battery:
- Most important is safety. Having to periodically access the internal battery chamber to charge, with lots of exposed conductors is risky. If we added an external connector and BMS to the existing enclosure, the only difference is that you would be able to reuse some parts. Then you effectively have an end user assembled battery, with highly variable quality.
- I also don’t think you could probably add a BMS with the features I am shooting for to the existing enclosure - there wouldn’t be quite enough space. My design relies upon high electro-mechanical integration to fit it in.
- I think external quick disconnect connectors is also crucial. If you are cycling a critical seal (the battery enclosure O-ring) every charge then that increases the likelihood of failure over time.
- I feel like surface power is not always the best option too. The cost of those Outland technology units is really high. $6200 top side unit + $2200 tether + $6400 vehicle side unit = $12800. So this battery setup could be an order of magnitude less expensive. If you need a very thin tether that could be an issue too. Or if you don’t have a generator.
Thanks for the feedback!