I have three 90Ah AGM batteries (giving 270Ah for house use) and one separate 90Ah AGM battery to start the Yanmar 3GM30 (27HP) engine. They are all identical in specs (Absorbed Power AGM GT12-90C), each weighs 29kg and all 9 yrs old. I deliberately chose the start battery to be identical to the house batteries.
The start battery is having trouble maintaining charge so I'll replace all four of them.
I'll still have to buy three smallish batteries for house use because there is no room under the sole for one big one.
Question (1): Any current recommendations on a brand to select ?
Question (2): Is there any reason why I should NOT continue with using a deep cycle start battery rather than a, supposedly, high discharge type start battery? (It's only a small engine remember).

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zilla said..
I have three 90Ah AGM batteries (giving 270Ah for house use) and one separate 90Ah AGM battery to start the Yanmar 3GM30 (27HP) engine. They are all identical in specs (Absorbed Power AGM GT12-90C), each weighs 29kg and all 9 yrs old. I deliberately chose the start battery to be identical to the house batteries.
The start battery is having trouble maintaining charge so I'll replace all four of them.
I'll still have to buy three smallish batteries for house use because there is no room under the sole for one big one.
Question (1): Any current recommendations on a brand to select ?
Question (2): Is there any reason why I should NOT continue with using a deep cycle start battery rather than a, supposedly, high discharge type start battery? (It's only a small engine remember).

All the batteries are 9 years old and your asking us about batteries! I would buy the same again. I only use deep cycle start batteries.

Can't buy the same again since the manufacturer/supplier no longer exists.

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zilla said..
Can't buy the same again since the manufacturer/supplier no longer exists.

9 years is pretty amazing, I'd be very happy about that.
Start battery should have a very high cold craving number. The house batteries and the start battery do very different jobs and as such need to be different types of battery.
The anchor winch can be attached to the start battery as the motor in a anchor winch is for all intents a starter battery.

www.mysailing.com.au/news/update-boat-batteries-from-lead-acid-to-lithium

Not a a bad article if you want to got that route

My mate is getting very good service from Century Marine batteries. He says they seem to be a hybrid of start and deep cycle. At about $240 each are good value.

Though your Yanmar 3 GM is only a small engine, being a diesel it still needs plenty of grunt to spin it. I think 660 CCA is the minimum you should have.

Regarding CCA..... yes the current start battery I use (an Absorbed Power AGM GT12-90C) has a CCA of 700. That has served well.
I intend to only use AGM batteries as well, not any wet cells.

Cisco... is your mate using the same battery type for a dual battery system like mine (that is, is he using the same type of battery but for both engine starting and a second battery bank for house deep cycling purposes)?
I have set up my dual battery system so that once the engine has started and the alternator has charged up the starting battery the starting battery is then isolated and the alternator then only charges the house battery bank. The start battery is always charged first.

^^ I think so zilla.

I am currently in the process of setting up my battery box and battery use. For simplicity's sake I am setting it up the same as in your average automobile as a single battery system and using a double pole isolator switch.

For local use of the boat I will just have a single battery. For going cruising I am fitting a second double pole isolator that will remain disconnected while local. For emergency back up I will carry a portable power pack. While moored a 7 watt solar panel is used to maintain a floating charge to the battery.

When going cruising a second twin battery is installed and connected into the system. Battery management is manual with day by day alternating use of each battery.

For battery monitoring I am fitting one of these. https://www.baintech.com.au/baintech-voltage-amp-meter

At the price they are good value and simple and easy to fit plus I already have the hole from the old defunct volt meter.

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cisco said..
^^ I think so zilla.

I am currently in the process of setting up my battery box and battery use. For simplicity's sake I am setting it up the same as in your average automobile as a single battery system and using a double pole isolator switch.

For local use of the boat I will just have a single battery. For going cruising I am fitting a second double pole isolator that will remain disconnected while local. For emergency back up I will carry a portable power pack. While moored a 7 watt solar panel is used to maintain a floating charge to the battery.

When going cruising a second twin battery is installed and connected into the system. Battery management is manual with day by day alternating use of each battery.

For battery monitoring I am fitting one of these. https://www.baintech.com.au/baintech-voltage-amp-meter

At the price they are good value and simple and easy to fit plus I already have the hole from the old defunct volt meter.

Better off buying the Chinese version at $16 rather than $160.


www.banggood.com/Car-DC-12V-24V-Voltmeter-Ammeter-LED-Display-Digital-Voltage-Meter-p-1130496.html?rmmds=search

For battery isolation these are hard to beat.

www.banggood.com/Brass-Battery-Disconnect-Cutter-Blade-Switch-Top-Post-Marine-Terminal-Cut-Off-p-1139052.html?rmmds=search

These are particularly good when you have two or more batteries, easy to switch over and make sure you keep connected. I have had a couple of the rotary switches fail.

Looked at the same issue for the same engine.
Best compromise with price a big factor and knowing I have shore based charging.
Century Marine AGM from Supacheap.
$249.00 each
Not all stores stock them.
12 months on, perfect performance.

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Ramona said..
Better off buying the Chinese version at $16 rather than $160.
www.banggood.com/DC-12V-24V-Car-Voltmeter-Ammeter-LED-Display-Digital-Voltage-Meter-p-1130496.html?akmClientCountry=AU&rmmds=search
For battery isolation these are hard to beat.
www.banggood.com/Brass-Battery-Disconnect-Cutter-Blade-Switch-Top-Post-Marine-Terminal-Cut-Off-p-1139052.html?rmmds=search
These are particularly good when you have two or more batteries, easy to switch over and make sure you keep connected. I have had a couple of the rotary switches fail.

For me it is never about cheapest price.

It is always about good quality at a value for money price, and, where possible, buying Australian made and owned.

I have been looking at all that is on the bay and regardless of price, the Baintech unit is the only one so far that comes close to what I want.

What I want is a combined volt/amp meter to fit an existing 50 mm hole, that will indicate up to 50 amp charge or discharge and has a Hall Sensor to eliminate the need for an exposed shunt.

If you can find such a thing for less than $50 I will greatly appreciate it.

I want to know what my alternator is charging as well as what my ship's load is.

The trouble is lots of these supposedly Australian made electronics are just rebranded Chinese items. A search on Alibaba will often find the same item with even the propriety brand on them or the packaging. Good example is GM engine sensors supposedly made in the USA by Delphi and available for over fifty dollars or off Alibaba in the same packaging for $11! Just fitted a new fuel pump to my race car for $28. Same pump from an Australian supplier is $330, they have the cheek to use exactly the same catalog photos! Then a few days later I get a message from eBay to say the new price for the pump is $21 including postage so I still got screwed! The Australian agent wanted more than that for just postage.

I know what you are saying. So far, the Baintech item comes closest to what I want but I am still circling the field.

I wouldn't mind having seperate volt and amp meters but what I really want is an amp meter that displays charge and discharge.

The VDO 60+/60- amp meter is outrageously priced and I do not like VDO's repair policy. They refuse to supply parts without they do the repair.

I am still looking so if you come across what I want, please post a link.

Using current clamp probes is good idea compare cutting the cable and inserting shunts.
Measuring DC current, display will show polarity of the current, it's obvious charging - discharging.
My ideal set up would be a couple of clamps probes, one on alternator output to monitor charging
and second on the house line to monitor battery bank. Use one current meter and switch
clamps probes over or two current meters, they cheap and I can have different colours.

Having a proper ammeter means having a shunt with the full current running through it. That's a little dangerous on a boat. Better of using Charriot's idea with portable meters for the odd time you want to check. If you just wire in a cheap Chinese voltmeter and get used to what voltage your system operates when charging correctly that should be ample. This is what I use in my race car but I bought it from China for about $4.
http://www.ebay.com.au/itm/DC-12V-Mini-Blue-LED-Digital-Display-Volt-Monitor-Voltmeter-Voltage-Gauge-AUS-/322512588367?epid=2159359515&hash=item4b173f8e4f:g:BkIAAOSwq1JZE97d

Thanks Charriot and Ramona. Good advices.

I don't like the idea of having a shunt in the system which is why I am looking at the Baintech unit. It is a bit pricey though.

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cisco said..

For battery monitoring I am fitting one of these. https://www.baintech.com.au/baintech-voltage-amp-meter

At the price they are good value and simple and easy to fit plus I already have the hole from the old defunct volt meter.

I've got one of these installed - seems to work OK

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Lazzz said..

cisco said..
For battery monitoring I am fitting one of these. https://www.baintech.com.au/baintech-voltage-amp-meter

I've got one of these installed - seems to work OK

Thanks Lazzz. Which cable/cables do you have passing through the Hall Sensor??

Does it read charge and discharge or only one of them??

This is the wiring diagram that it comes with.

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cisco said..
Thanks Charriot and Ramona. Good advices.

I don't like the idea of having a shunt in the system which is why I am looking at the Baintech unit. It is a bit pricey though.

I would go crazy and buy one of these!

www.tomtop.com/p-e2452.html?mid=10000007372&utm_source=EDM&utm_medium=Normal EDM&utm_campaign=E2452&utm_design=2430&utm_content=2958&aid=TTEDM170831

$2.98 US dollars with free postage.

Yes ridiculously cheap but the current range is only up to 10 amps and they don't show any wiring details.

The 2 wire socket to + and - to power the instrument and I assume with the 3 wire socket, the blue and the red break the main power line and feed the current through the instrument to measure amps and the black goes to earth to measure volts. The shunt I assume is integral to the unit.

Ships load will exceed 10 amps quite often and charging amps nearly always.

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cisco said..

Thanks Lazzz. Which cable/cables do you have passing through the Hall Sensor??

Does it read charge and discharge or only one of them??

This is the wiring diagram that it comes with.

From memory (which isn't always right) I have the main +ve lead from the House bank, which is like the lead from the starter motor & just fits through the sensor, to my main +ve load bus.

The main read out is the voltage of the bank & the other is the amps. I don't have my fridge, auto pilot or anchor winch running through this - separate circuits.

To tell you the truth I don't take a lot of notice what the amps are anymore but I've never seen it go negative as my solar panels keep it up & it just gets lower with a load on.

I'll try to remember to take notice of what goes on next time on the boat. Everything was doing what it should when I installed it so I haven't taken much notice lately.

errrr, back on topic any other recommendations for a battery brand apart from Century Marine ?

I just bought a set of lion battery's 4 golf cart 6v and 1 marine starting I have used (abused) lion`s before in industrial applications and after deciding to go for wet cells I new what to buy

Does anyone use Seamaster brand?

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zilla said..
errrr, back on topic any other recommendations for a battery brand apart from Century Marine ?

errrr, yes, whatever cheap brand suits your pocket.

Batteries are one of those items where price and quality are directly related.

Sorry for being the one having to enlighten you to the facts of life.

The more lead in a battery, the longer it will last and the more money it will cost.

If you want to go lithium, go buy a mine or a bank.

I would just buy a suitable sized lead acid battery off eBay.

Hi, I have been using Supercharge FLA batteries and have been very happy with them so far. Perhaps they have something in their range that would suit.
Cheers.