CTEK mx5 with a 220Ah bank?

fergycool

Member
Joined
2 Nov 2013
Messages
144
Location
Cambridge
I’ve just added a second battery to my domestic bank to give 2 x 110Ah.

I’ve only just realised that my current charger is a CTEK MXS5.0 which is rated for a maximum of 110Ah batteries.

It outputs 5A.

According to the Calder Bible a lower rated charger will just take a much longer time to charge a larger battery bank (and be beneficial to the battery!).

Is that OK or should I really upgrade the charger? It’s always plugged into shore power, except when in use! So time is not an issue!

It has gone through a full charge cycle and is now at the maintenance stage. However, the batteries were charged when fitted. It spent about 18 hours on the bulk charge stage. At no time was it too hot!

Am I being naive?

Cheers
Ferg
 

VicS

Well-known member
Joined
13 Jul 2002
Messages
48,093
I’ve just added a second battery to my domestic bank to give 2 x 110Ah.

I’ve only just realised that my current charger is a CTEK MXS5.0 which is rated for a maximum of 110Ah batteries.

It outputs 5A.

According to the Calder Bible a lower rated charger will just take a much longer time to charge a larger battery bank (and be beneficial to the battery!).

Is that OK or should I really upgrade the charger? It’s always plugged into shore power, except when in use! So time is not an issue!

It has gone through a full charge cycle and is now at the maintenance stage. However, the batteries were charged when fitted. It spent about 18 hours on the bulk charge stage. At no time was it too hot!

Am I being naive?

Cheers
Ferg

Unless your power usage has gone up or you intend recharging less frequently it wont take significantly longer to recharge your enlarged bank than the old bank

However you are now using the charger outside the manufacturer's recommended limits


I would see how it goes. Replace with a larger model if you see the need or if it becomes necessary to replace the MXS 5 anyway.

when the enlarged bank starts to age you may find a more powerful charger desireable.
 
Last edited:

Alpha22

Active member
Joined
22 Sep 2003
Messages
1,400
Location
Cambridgeshire
The CTEK is a quality bit of kit, it will be fine. As you read, it will just take longer to charge.... as long as you have the time it should have no problem.

A fair few years down the line, as the batteries move into old age, you may have an issue with the charger never getting to the float stage...... but by then they will be knackered anyway!!!
 

Poecheng

Well-known member
Joined
16 Aug 2013
Messages
2,174
Location
East Coast
I have 3 x 85ah = 255AH service bank and I have charged them with that charger a number of times.

Takes a while and I place the charger so that it dissipates heat as best it can (it gets a bit hottish) but it does the job and goes through all the stages.

Treated myself to a bigger and marine version a few weeks ago ! Thats why I always recommend CTEK
 
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