There's a fella who lives on the south coast who likes to try and help boaters out. Coming up to 77 years old he says hes not as fit as he used to be but is happy to drive up and help us fit out the engine room electrics on NB Ernest as long as we pay for his petrol and sort him out with a B and B. Pretty generous I think. He also drives up to London to help out with electrical issues for the women boaters of London and has even started running hands on training courses for them.
Not many people around like Graham.
With our battery bank and charging we're having a major change from the norm. We're investing substantially in a Lithium (LiFePO4) system. Probably.
There are some massive selling points for LiFePO4 battery systems...
If I was to explain it as batteries are a bath, the stored power is the water. My batteries now, and nearly all others in narrowboats (and camper vans and caravans) take a long time to fill and the fuller they get the slower the water needs to go in. So back to the bath. Both taps are full on for the first twenty minutes or so, then they get shut down to about 1/3rd open and steadily closed the more the bath gets filled. When the bath is about 80% full the taps get turned down even further to a very slow trickle. That last 20% takes hours and hours to fill. Now you can just fill the bath to 80% full and crack on having taken only a few hours, but if you don't fill the bath 100% full at least once a week, maybe twice, the bath quickly starts to fail (well the batteries do, losing irreplaceable capacity). So lots of us use solar panels to put that last 20% in to save diesel and engine wear/service money. On Ernest we don't want lots of solar panels, it's going to spoil the look we think. There will be a clear roof policy, just poles/planks/ropes as needed. This would mean with more standard batteries, charging for about 25 hours a week for what we'd use, probably as 3 hours a day and one day of 7 hours per week. That costs both in diesel and maintenance and engine life.
So how long does the LiFePO4 'bath' take to fill. Well forget turning the taps on, there is now a fireperson with large bore hoze (no pun intended) standing over your bath, he/she will fill your bath at maximum pressure (techy peops we're looking to limit to 200a) until you say that's enough ta. You don't have to worry about filling to 100%. Ever. In fact LiFePO4 prefer to be between 20% and 90% full for longer life. So charging wise were talking about 3 or 4 hours a week instead of 25. Thats a saving of about 1000 litres of diesel and 4x engine services at maybe £100 each.
The time well looked after LiFePO4 batteries last compared to the cheapest chandlers special offers are immense.
Cheapest Cheapo Charge Cycles = as low as 70 cycles
LiFePO4 Charge Cycles = as many as 5000!
No we're not going to be able to achieve that figure as we'll be cycling to a lower state of charge, probably 30% empty and that's about 2500 to 3000 charge cycles. Depending on what size we get that's probably about 15 years as opposed to cheapo ones at maybe 2 years if you're lucky.
The downside is of course the cost. The difference between a decent lead acid set up providing maybe 1000 cycles and what we're planning on doing is somewhere in the region of £5000 for the same usable capacity. Yikes, said it was an investment!
No comments:
Post a Comment