# how to check batteries/performance



## dave-rsvr (Aug 8, 2010)

Hi,i have burstner 748,i updated the 2 x 90amp batteries for 2 x 110 amp elecrosol battries in the summer. the performance of these seem to of dropped off alot recently.
i charge for a day or until the charge goes off,the burstner says charging at about 13/14 amps or what ever it is then shuts off when charged.
i do not have electrical epuipment to check anything.
what needs to be done to see what the issue is.
thanks
Dave


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## 747 (Oct 2, 2009)

You would need to be a bit more specific as your new Elecsols should be OK.

If you have the analogue ammeter and voltmeter on your control panel, then they are not accurate. Mine are about 1 amp and 1 volt out on the low side.

I believe the batteries are charged to 13.8 volts on hookup but the alternator appears to charge above that level. This should mean that your batteries are getting more or less a full charge.

All you can do is to put something 12 volt on (of known amperage) and drain your batteries to see how long they last. I would only do it to 50% capacity (or around a reading of 12.0 volts on your control panel. That should tell you something.


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## spatz1 (May 19, 2011)

To check the capacity...

I charge both my batteries to 14.7v...

split one off and use the other to power 60w of hab lights left on.

mine power the 60w for 12.5 hours and the battery volts drops to 11.9 v recovering to 12.2 when the load is taken off...

Repeat for other battery and compare results....


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## airstream (Jan 7, 2009)

*A/H?*

Hi,
First step is to check the amp hour rating of your Elecsol batteries 
Your 90 a/h may have had the same ah rating as the Elecsols

You need to find the "C" figure ie C20 C100 etc - the idustry standard is C20 but some sellers use C100 so a 90/100 a/h at C20 is then sold as a 110 a/h battery but the C100 rating is not mentioned

May also just have a model number in LARGE text ie 110 to give the impression of capacity but no actual rating stated

Once you know the battery rating at C20 a rough test is to fully charge the battery in doors or anywhere the tempereture is over 75F (not possible with most on board chargers)

Next put a fixed resistive load on the battery to reflect the claimed amp hour rating ie 110 a /h at C20 would be 110/20 =5.5 amps
for this I woud use a 12 volt 65watt headlamp bulb

Note start time and monitor every hour until the bulb dims note time and remove the bulb

Put battery back on charge

Actual capacity at C20 would be the total hours the battery managed to light the bulb multiplied by the load ie 10 hrs x 5.5 amps = 55 a/h

The above is only rough evaluation as the actual testing by the manufacturer is on a brand new battery under controled conditions with a fully charged battery and its voltage monitored to comply with the standard

Good Luck

Ray

Once fully charged


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