Expert battery advice needed - Aixam Mega City

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williambelow
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Expert battery advice needed - Aixam Mega City

Postby williambelow » Thu Aug 19, 2010 1:30 pm

Hi
this is my first post - I am looking for some advice about battery replacement for an Aixam Mega City.
The car currently has in it 8 x GNB M83CHP12V24 batteries. I have been told by Aixam's service agents that they need to be replaced, but that the cost of replacement will be £2,400 + VAT (i.e. £2,820) :shock: , which seems like quite a lot to me!

The service agents themselves have tried a cheaper option - which involves replacing with their own sourced batteries, rather than Aixam supplied ones - the cost of these is slightly better (but still not cheap) - at £1,500 + VAT, BUT (and here is the big but!) they don't work properly, as apparently the charging cycle for these batteries isn't matched by the charging programme in the car's charger. Aixam say that the only solution to this is to replace the entire "brain" of the car, which costs another £1,600 + VAT - so this "cheap" option turns out to be ridiculously expensive :shock: .

So, where does this leave me? As I see it, there are several options:

i) Go with the Aixam option for £2,820 - too expensive.
ii) Try to source replacements for the GNB batteries - the risk is though that this model is no longer made - though GNB tell me they have a replacement which should work fine (the AF12080XO) - though these are almost £200 each.
iii) Try to find an alternative battery which will work with the charging cycle already programmed into my car - any suggestions most welcome! :!:
iv) Try to find an alternative battery and find somebody who can adjust the charging cycle of my car without charging me £1,600 for the privilege - again, any suggestions most welcome! :!:

I am a rank amateur at all of this - so if anybody is able to suggest any expert to help me out (I am based in North London), that would be enormously appreciated. :wink:

with thanks and kind regards
WB

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Jeremy
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Re: Expert battery advice needed - Aixam Mega City

Postby Jeremy » Thu Aug 19, 2010 5:09 pm

This seems a bit odd to me. Those batteries are bog standard Exide (used to be GNB) valve regulated AGM lead acid deep cycle ones, so their charge regime would be just like any other AGM battery. The only factors to consider when using batteries of a different make would be the physical size, the connection type, the voltage and capacity. Quite why the charger needs changing for a change of battery is a bit beyond me.

The original batteries were rated at 92 Ah (20 hr rate), 80Ah (6 hr rate) or 70Ah (3 hr rate) and should be 260mm long x 174mm wide x 274mm high, with M6 bolt on terminations. The recommended charge regime looks standard to me, 1/5 x C to 2.37V per cell then hold at 2.37V per cell until current drops below 0.02 x C, then float at 2.55V with current below 0.02 x C for a maximum of 4 hours. This charge regime would be OK with any valve regulated AGM battery of the same capacity, I'm sure. I'm guessing that the replacement batteries that the agent tried weren't of the same capacity or type, hence the charging problems, although I would have thought that even a flooded battery like the fairly cheap Trojans would work OK with that charge regime.

The challenge will be to find batteries of the same size, type and rating that can be used as replacements, if the GNB ones are so expensive. If you can fit batteries of a different physical size, but the same rating, then you may have more options open to you. Price wise I would expect deep cycle VRLA AGM batteries of this capacity to be around £150 to £200 each, so around £1200 to £1600 for the set of 8 that you need. For example, Victron make a 90Ah VRLA AGM deep cycle battery that would electrically match the existing batteries, but is physically a different shape (they are 350mm long x 167mm wide x 183mm high, and the same weight as the GNB ones. They cost around £150 + VAT and delivery each.

Jeremy

Edited to add:

It seems as if this battery is now marketed directly as an Exide 'Element' industrial battery, with the same specification as the GNB. The Exide type number is AF 12 080 X O according to this link: http://www.industrialenergy.exide.com/p ... el=Element , here's a link to the data sheet: http://www.industrialenergy.exide.com/e ... 0Blocs.pdf (which still refers to the old GNB part number)

A bit of hunting around and I'm sure you will be able to find a direct supplier of these somewhere, most probably as a cost a bit below that from Aixam. The Exide listed sales outlet is:

CMP Batteries Ltd.
P.O. Box 1, Salford Road,
Over Hulton
Bolton BL5 1DD,
Lancashire
01204 661460 phone
01204 661479 fax
sales-uk@eu.exide.com

williambelow
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Joined: Mon Aug 16, 2010 9:35 am

Re: Expert battery advice needed - Aixam Mega City

Postby williambelow » Fri Aug 20, 2010 3:01 pm

Jeremy

thank you very much for your message - very much appreciated. I will check with the service agent what batteries they tried to install, and see if I can understand why they failed to work.

I will also look into the other options you suggested.

Again - enormously grateful for you sharing your expertise.

Kind Regards
Anthony

jonathan jewkes
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Location: Bristol

Re: Expert battery advice needed - Aixam Mega City

Postby jonathan jewkes » Fri Aug 20, 2010 8:46 pm

I agree with Jeremy - they are just AGM batteries, and any other brand of AGM batteries of similar Ah capacity should need an identical charging profile.
Some years ago I had a set of the same batteries as yours (though my vehicle was not an Aixam). I replaced them with Powersonic batteries which are actually gel batteries rather than AGM, but I didn't change the settings on the Zivan charger. My impression was that the Powersonics performed better than the GNB.
Do other people think that it would be OK to do a similar swap in the Aixam?

6 months ago I bought some more Powersonic PS121000 batteries (which are100Ah and an identical physical size to your GNB) from "The Battery Company Limited" in Rochford. Cost was £ 110 per battery including VAT and delivery.

Seems that your Aixam dealer needs to do a bit of net surfing
Jonathan Jewkes
Daily EV user for 10years - an enthusiast and also a realist

williambelow
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Joined: Mon Aug 16, 2010 9:35 am

Re: Expert battery advice needed - Aixam Mega City

Postby williambelow » Mon Aug 23, 2010 9:51 am

Thanks Jonathan also for your advice.

I am waiting to hear from the service agents today, so will mention that option to them.

Does anybody happen to know any good/reliable people or service agents who I could contact in the North London area who might be able to help me with an electric car? I'd be quite happy to go elsewhere, but am struggling to find anywhere with any real expertise!

Best Rgds
Anthony

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ChrisB
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Re: Expert battery advice needed - Aixam Mega City

Postby ChrisB » Mon Aug 23, 2010 5:39 pm

williambelow wrote:
Does anybody happen to know any good/reliable people or service agents who I could contact in the North London area who might be able to help me with an electric car?


Your here already 8) are you a paid member of the BVS ? if you are then you should be able to find like minded souls in your area (All part of the BVS service :wink: ) once you have located your like minded soul then your service problems will be no more :wink:

ChrisB
I reject reality and substitute my own !!!!!!

williambelow
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Re: Expert battery advice needed - Aixam Mega City

Postby williambelow » Tue Aug 24, 2010 8:47 am

Thanks Chris.

I have just joined and paid up! How do I go about finding some clever local people to talk to? I'm actually really keen to learn more about how to do things myself to the car, so would be great to meet up with somebody with some more knowledge.

Best Rgds
Anthony

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ChrisB
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Re: Expert battery advice needed - Aixam Mega City

Postby ChrisB » Wed Aug 25, 2010 6:38 pm

Contact our membership Sec Rob and he should be able to locate like minded souls or at the very least folks in and around your area who are also members.

Welcome to the BVS 8)

ChrisB
I reject reality and substitute my own !!!!!!

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MaryRCrumpton
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Re: Expert battery advice needed - Aixam Mega City

Postby MaryRCrumpton » Thu Aug 26, 2010 9:07 am

williambelow wrote:Thanks Chris.

I have just joined and paid up! How do I go about finding some clever local people to talk to? I'm actually really keen to learn more about how to do things myself to the car, so would be great to meet up with somebody with some more knowledge.

Best Rgds
Anthony


Welcome to the Society!

I am often humbled by the number of clever people we are lucky enough to count among our members. I am sure (as Chris says) that our membership sec will help you to make some contacts in your area.

We don't have an active North London group yet, though there is one in South London - get in touch with the Treasurer to find out more about their meetings.

Good luck in your quest!

Mary.
BVS North-West Coordinator, based in Manchester.
Contact via Text/Phone on 07751 696 055

CarlFuss
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Joined: Sat Aug 28, 2010 8:14 pm

Re: Expert battery advice needed - Aixam Mega City

Postby CarlFuss » Mon Aug 30, 2010 7:50 pm

Hi

just saw on the forum that you have a Mega City, well we have one also and have owned it for approx three years. We've had most major components replaced, luckily under warranty, and have some experience with sorting out problems. We've had the batteries replaced but I'm sure that in the future we'll be looking to upgrade them. Generally we're happy with the car, looks better than a G-Wiz, but the range is limited. Hopefully between us we can get the most out of these cars. I would like to replace the batteries with lithnium ion but cost is a big factor. There is one member who has converted a standard Aixam to electric power so he may be one to talk to, I have his details if you're interested.

Best Wishes

Carl


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