Is It Worth Changing ?

[Alan de Enfield]

I currently have 6x 200Ah batteries, one has died (internal short), another is not in the best of health so may end up needing to replace the lot at a cost of around £1200, or

I could replace with these at £5000

“12V bank Nickel Iron NiFe Battery 1200ah 10 x 1.2V cell - In Stock - Ex demo set, special price”.

http://www.bimblesolar.com/index.php?route=product/product&product_id=1016

Would I really gain anything ? (heavy - months - ‘leisure’ user)

Existing batteries rarely get below 75% SoC

I could buy a lot of fuel for the Generator for the £4000 difference, and, will I also have the additional cost of new alternators, battery charger etc ?

[Richard10002]

My first thought is that, if 2 have died, you have 4 left, so 800Ah subject to reduced capacity. You could just disconnect the failed ones and get some, or a lot, more time out of the 4 which haven't failed?

Which batteries would you be planning on buying at £200 each if you replace like for like? El cheapos, good brand??

You could buy 8 or 10 Trojan T105s for similar money, (although these can be destroyed just as fast as el cheapos with the wrong useage and charging regime  ).

Will you need to make major/minor adjustments to your battery box to accommodate a different type of battery?

[Alan de Enfield]

27 minutes ago, Richard10002 said:

My first thought is that, if 2 have died, you have 4 left, so 800Ah subject to reduced capacity. You could just disconnect the failed ones and get some, or a lot, more time out of the 4 which haven't failed? That's what I have done for now (will review in Spring)

Which batteries would you be planning on buying at £200 each if you replace like for like? El cheapos, good brand?? Varta

You could buy 8 or 10 Trojan T105s for similar money, (although these can be destroyed just as fast as el cheapos with the wrong useage and charging regime  ).

Will you need to make major/minor adjustments to your battery box to accommodate a different type of battery?  No - Plenty of space

 

[Richard10002]

I have 4 more or less dead Trojan T105s which I have been considering replacing for several months. However, i have just fitted 500w of solar so, (based on advice here, particularly smileypete ), am planning to eke out the Trojans until Spring when a new set will get a good start with what I hope will be a good useage and charging regime.

Procrastinating will also give time for other ideas and solutions to rise to the forefront of my brain

[Sea Dog]

That's quite a large bank Alan, is your electrical fit out quite demanding? Even ditching the 2 duffers would still see you at about double the typical domestic bank capacity which I'd have thought is about 440 amp hours, and many manage on a much smaller capacity. Your 75% remaining capacity lowest discharge figure suggests a maximum use of 300 amp hours between charges - are we talking one day's usage there followed by a daily full recharge?  Depending on whether you reveal anything very unusual, I'd have thought your remaining 800 amp hours of capacity would be quite comfortable, and you could potentially save yourself a fair bit of money.

As for the Bimble offering, I'm not sure batteries are something I'd choose to buy second hand.  Even if Lithium batteries are more forgiving, you still don't know whether they've been treated well. You may also need to change your charger if it's settings can't be adjusted for compatibility. 

Just my two pennorth to help in your thought process.

[Alan de Enfield]

22 minutes ago, Sea Dog said:

That's quite a large bank Alan, is your electrical fit out quite demanding?

Average 100-120Ah per day

Even ditching the 2 duffers would still see you at about double the typical domestic bank capacity which I'd have thought is about 440 amp hours, and many manage on a much smaller capacity. Your 75% remaining capacity lowest discharge figure suggests a maximum use of 300 amp hours between charges - are we talking one day's usage there followed by a daily full recharge? 

Like to occasionally stop for 3 or 4 days without needing to run the engines, on most occasions would only be stopping 1 or 2 nights.

Eberspacher is 10a (continuous) Blown air heating so uses a bit at this time of year.

220v Freezer, 12v Fridge, Occasional 220v microwave, usual LED lights, TV, chargers, PCs etc

Depending on whether you reveal anything very unusual, I'd have thought your remaining 800 amp hours of capacity would be quite comfortable,

Ahhh - but what is their capacity today ? 700 / 600 / 500 Ah ?

and you could potentially save yourself a fair bit of money.

As for the Bimble offering, I'm not sure batteries are something I'd choose to buy second hand.  Even if Lithium batteries are more forgiving, you still don't know whether they've been treated well. You may also need to change your charger if it's settings can't be adjusted for compatibility. 

Just my two pennorth to help in your thought process.

Appreciate it.

 

[cuthound]

Nife batteries are almost indestructible, and extensively used in the rail industry. They have a life of around 40 years. However they operate at a lower cell voltage of around 1.2 volts per cell and have a much wider voltage range beetween dis charged and charged.  

https://en.m.wikipedia.org/wiki/Nickel–iron_battery

Edited November 10, 2017 by cuthound
To remove a letter masquerading as a space

[keith.]

With thanks to this forum and a little reading elsewhere I have learnt loads about batteries since owning a boat.

In an ideal world the load, battery and charging system are designed to power the load as required, not taking more than 50% battery capacity and being recharged to 100% in that cycle (24hrs). 

In the real world of fuel costs, running restrictions and no mains lead some compromises have to be made. I think that your requirement to not run the engine for 3/4 days is possibly the deal breaker assuming that on other days you are charging to at least 80%. Therefore if I was you I would replace the bank for 4 x 110AH (Varta, Exide or Banner) or 4 x Trojan T105 (if you are prepared to keep them topped up). On no cruising days run the engine/generator early on in the day to recharge the bulk and allow solar to top them up. In winter the power has to come from a mains lead or you accept prolonged running times.

[Sir Nibble]

NIFE batteries are less efficient than lead acid at about 70% so that makes them need much more charging.

[smileypete]

My usual thought with unusual battery brands, novel battery types, desulphators etc etc is 'let someone else be the guinea pig'

Sometimes after a thorough look there are a few guinea pigs already...

[Horace42]

Unless there is a compelling reason to use nickel iron such as the need to reduce weight  (for the same power output) you might find it better to stay with lead-acid, as I did when faced with a similar decision. But that was largely because it meant all my existing automatic charging and management  system becoming obsolete due to incompatible volts/amps/time characteristics.

I settled for another set of 4 x 100ah  lead-acid batteries - and maybe again in a few years.

[MtB]

3 hours ago, Richard10002 said:

I have 4 more or less dead Trojan T105s which I have been considering replacing for several months. However, i have just fitted 500w of solar so, (based on advice here, particularly smileypete ), am planning to eke out the Trojans until Spring when a new set will get a good start with what I hope will be a good useage and charging regime.

Procrastinating will also give time for other ideas and solutions to rise to the forefront of my brain

 

Given the apparent need to charge batteries daily to avoid serious degradation, if you can eke out through the winter by charging daily, there seems no point in buying new batteries come the spring. After all you'll still need to charge them daily so why shell out on extra capacity you won't use? 

With my Trojanoids down to about 80AH (estimated, at 24v), I charge them every night and they rarely fall below 75% on the high reading SG, or 61% on the low.