Why Are People So Down On Gel Batteries?

[demonboy]

I'll warn you now, I am going near-mad trying to decide on what maintenance-free batteries to go for to replace our SLAs. I'm getting completely conflicting reports on battery types and their performance so I figured liveaboards are probably the best people to ask.

According to the figures, gel batteries appear to be the most obvious choice for a liveaboard. Their longevity is second to none, yet I am told I should be looking at AGMs. However according to the West Marine catalogue, AGMs can only be deep cycled 300 times, versus gels which can cycled 1,000 times.

The ever polite and comprehensive Charles Sterling said this of gels:

i would not use gel batteries as the are over sold, expensive and useless

Having recentlly bought one of his products I was very grateful for this really useful insight.

Assuming I have a comprehensive charging system and ensure I don't over-charge them, what is the reason not to go for gels? Someone on PBO has just told me he's done 12-15 years on his gels. Doesn't that say it all?

 

[macd]

I'm no battery expert, although there are some on the forums so I hope you get the advice you're looking for.

I've certainly read on here that Mr Sterling's notions on gel batteries are somewhat out of date (and possibly a little self-interested). He also seems to think that 'maintenance-free' as applied to batteries is an oxymoron. He is very clearly of the view that the only type of domestic battery that should be installed on a boat is a true traction battery (such as a golf-cart battery).

You might be interested in this thread, especially post #33: http://www.ybw.com/forums/showthread.php?p=2800787

 

[gavin_lacey]

Gel batteries like to be charged and discharged slowly. Most boat owners want to discharge batteries slowly but charge them fast. Large alternators, battery sensing alternators, Charge boost systems such as Sterling, all will reduce gel batteries life thus mitigating any cost benefit. Gel batteries also seem to be particularly sensitive to being incorrectly wired - parallel with positive and negative from opposite ends of the parallel lines is essential. Many boats (including proffesionally fitted) do not have this but if not so fitted the warranty is voided on some makes.

 

[vyv_cox]

I bought a three-year old motorhome with a gel domestic battery. This duty is pretty similar to that of a boat but the charging system is more sophisticated than many and the engine runs more often. The battery was totally dead. I realise that this is a long way from being a controlled evaluation but it is significant that the original flooded acid starter battery was perfect for some years afterwards.

 

[demonboy]

Well, having done further research since my OP, and also finding a possible supplier of AGMs, I think I'll knock gel on the head anyway and plmup for AGMs. I don't trust myself with this careful charging of the gels and it sounds like monitoring them would be as time-consuming and painful as topping up open lead-acids, which defeats the whole object. I guess I should go with what a lot of people are saying on these forums about AGM.

I do find Mr Sterling's responses aggresive and childish, especially as he knows I am a new customer of his having just laid out over two hundred quid for one of his bits of kit, but I digress...

 

[nathanlee]

Again, and opinion from me, as there are people on here that know far more about the finer chemistry of batteries, but I did do a fair amount of research before deciding on mine.

I ended up going for a 200ah AGM. It was a Lucas from the local battery shop. Not marine specific, and cost me 200 notes.

So, here's why I decided to go AGM.

AGM is a bit more robust. It has a lower internal resistance, so charges more efficiently. If you are using solar cells, this is obviously helpful as you don't want your precious charge being resisted. They can be used for big power draws, so you could, in needed, use any of your domestics to crank the engine. Finally, they have more "usable" capacity, so pound for pound, you get a bigger battery - i.e. if you needed to (probably not advisable) and AGM will discharge way further than a gel or flooded battery.

Somebody is probably going to come along and argue, as is the nature of a forum, but that's what a couple of weeks of pondering led me to understand.

 

[macd]

I do find Mr Sterling's responses aggresive and childish...

You're not the first. He can be nice as ninepence, but then...

 

[Blue5]

I do find Mr Sterling's responses aggresive and childish, especially as he knows I am a new customer of his having just laid out over two hundred quid for one of his bits of kit, but I digress...

Sounds like you spoke to him on a good day, he is very good on his subject sadly his customer service skills need to be honed.

The good thing about forums like this if you are pre warned about his nature you can make allowances....

 

[demonboy]

OK, thank you all for your comments. I appreciate the comparisons and the experiences too, it's reaffirmed what I said in my previous post. Despite wanting to carry on the discussion about a certain electronics manufacturer I think I have the answer I was after.

Thanks, all

 

[GrahamM376]

According to the figures, gel batteries appear to be the most obvious choice for a liveaboard. Their longevity is second to none, yet I am told I should be looking at AGMs. However according to the West Marine catalogue, AGMs can only be deep cycled 300 times, versus gels which can cycled 1,000 times.

If you want high number of cycles, traction batteries will far out perform gels. look at this range - http://www.exide.com/Media/files/Downloads/IndustEuro/Classic Solar.pdf

I've tried AGM and found they're not worth the extra cost, now back on bog standard 110AH leisure, cheap and easy to source. Wouln't put sealed or gel near my boat, want to charge quickly when the need arises and keep everything simple. Golf cart would be best but I'm restricted on "footprint" area to get them in.

 

[ccscott49]

AGM's are good all rounders. But before we go any further, there is no such thing as an "use for everything battery"
But and its a big but, flooded lead acid batteries for domestic use are without doubt the best way to go, especially the ones designed for the job, ie rolls, or traction type batteries. They can be discharged well down and re-charged quickly, you only need to keep an eye on the electrolyte levels and traction and rolls have large electrolyte reservoirs. They are initially expensive, but so are AGM's ( I havent mentioned gels here as IMHO they are just not what we as liveaboards need). I have AGM's as I got a good deal on them and they fulfil all my needs, when they go belly up, (which oif course they will) I'll replace them with rolls of the same size (125ah) with re-combiner caps, which allow you to not check levels so often, at a price. They also last a long time! Leave the gels for airplanes etc.

This is experience of 16 years permanently living aboard and a bunch of batteries.

 

[Sybaris]

We have two 12V banks (6 x 2V lead acid fork truck batteries) connected parallel giving a total domestic bank of (12V) 960Ah.

They were installed in 1996 and are still going strong. Easy to maintain (top up water once every few months), can take a lot of beating, and very cost effective in the long run.

I strongly believe the best way of making sure your batteries last is to have your bank well oversized so that you never discharge below around 50% and most of the time stay around 80% or above.

Most of what I understand about batteries and how to maintain them I got from Nigel Calder; Keep it simple, keep it over-dimensioned, and never discharge too much on a regular basis.

 

[Sandyman]

We have two 12V banks (6 x 2V lead acid fork truck batteries) connected parallel giving a total domestic bank of (12V) 960Ah.

They were installed in 1996 and are still going strong. Easy to maintain (top up water once every few months), can take a lot of beating, and very cost effective in the long run.

I strongly believe the best way of making sure your batteries last is to have your bank well oversized so that you never discharge below around 50% and most of the time stay around 80% or above.

Most of what I understand about batteries and how to maintain them I got from Nigel Calder; Keep it simple, keep it over-dimensioned, and never discharge too much on a regular basis.

Spot on.

Whats wrong with the good old lead acid's ? Never a problem. Maintenance is just part of your routine.

 

[demonboy]

Colin, you know I value your opinion! Thanks for that.

I strongly believe the best way of making sure your batteries last is to have your bank well oversized so that you never discharge below around 50% and most of the time stay around 80% or above.

This is also true of my experience from seven years as a liveaboard. However it's taken me that long to work this out! Our 315aH domestic bank was constantly being pulled down to 50%, especially over the long trip to India with months at anchor and running water-makers with little sun to top up via solar.

I've knocked gels on the head and since AGMs in India are cheap (comparatively speaking) I will give them a go. They do seem to be getting an all-round thumbs up here and on PBO. If these don't work, then it's back to lead-acid.

 

[Plevier]

Well, I think there's a lot of consistency here with the answers you're getting on your simultaneous thread on the same question on PBO!

 

[ianj99]

Can't say I blame Charles Sterling for being grumpy. He must get fed up with being asked for advice and then having it ignored.

The general advice about not discharging below 50% and also using a 4 stage charger or alternator regulator to ensure as close to 100% charging as possible is what will determine the life of your batteries.

Manys a boat owner who has spent a fortune on batteries and nought on the charging facilities and then moaned when the batteries have died prematurely.
Ian

 

[nathanlee]

Did Charles Sterling say that the best batteries are standard flooded...? I vaguely recall somebody in the boatyard telling me that once.

Anyway... battery technology has come on leaps and bounds since the 40's. The 80's even, or 90's. You get the idea.

If you tried using you mobile phone battery from 10 years ago to run your mobile phone today, it'd last perhaps an hour.

There's a massive commercial battle on out there to improve battery technology. Energy is money. If you stand in the camp that flooded lead acid is better because it's familiar, I dare call you a luddite.

I don't dare enough to hang around for the response though.

 

[Conachair]

The general advice about not discharging below 50% and also using a 4 stage charger or alternator regulator to ensure as close to 100% charging as possible is what will determine the life of your batteries.

And therein lies the problem for cruising batteries. Close to 100% takes an awfully long time, unlikely that many cruiser's batteries ever get fully recharged apart from maybe a once in blue moon equalization.

 

[Sandyman]

There's a massive commercial battle on out there to improve battery technology. Energy is money. If you stand in the camp that flooded lead acid is better because it's familiar, I dare call you a luddite.

I don't dare enough to hang around for the response though.

Looks like I'm a luddite then No worries. Been using lead/acid in one form or another for more years then I care to remember. Relatively cheap & easy to maintain. Never let me down. See no reason to change, unless someone can give me some very good reasons why I should.

 

[nathanlee]

Looks like I'm a luddite then No worries. Been using lead/acid in one form or another for more years then I care to remember. Relatively cheap & easy to maintain. Never let me down. See no reason to change, unless someone can give me some very good reasons why I should.

Well, yeah, I do understand why people would opt for the simple technology. KISS, and all that.

However, the newer stuff has benefits, like not needing to be topped up with water, better charge and discharge characteristics etc. If you go for the currently REALLY expensive lithium batteries, you get even better performance, but at a trade off of simplicity and wallet damage.

I suppose it depends on your needs. If you have a boat that's unlikely to get wet, has little need for high capacity (i.e. you have readily available charging), and is unlikely to get too bashed around, then flooded is probably a better choice, simply because it is simpler.

However, I'm a firm believer in vorsrpung durch teknik.