Reading the battery discussion it seems like split charge would do away with any concerns of having two different batteries. It makes sense for the application to have a leisure batt for the fridge but I can see simply connecting them in parallel would be wrong.
"Both batteries must be the same type"?
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Oldfogey
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I think this link may give some ideas, and suggests that there is more to a split charge relay than just a switch:
Kemo Lead Acid Battery Split Charge Module | Maplin
To quote: "Using this module it is possible to charge two 6-24V lead acid batteries (e.g. car batteries) from the same power source. The charging current is distributed in such a manner that a discharged battery is charged more intensively than a battery which is almost charged. Ideal for use in motor homes, boats or caravans where the TV, radio, etc. is operated from one battery and the second battery must remain charged for starting the motor."
This suggests that replacing your manual switch with the correct automatic relay may be a good idea, not only being automatic, but also good for the batteries.
This is what would be used in a motorhome - and fits with the use you are describing.
At the price (other sellers are available), it looks a good idea to me!
Kemo Lead Acid Battery Split Charge Module | Maplin
To quote: "Using this module it is possible to charge two 6-24V lead acid batteries (e.g. car batteries) from the same power source. The charging current is distributed in such a manner that a discharged battery is charged more intensively than a battery which is almost charged. Ideal for use in motor homes, boats or caravans where the TV, radio, etc. is operated from one battery and the second battery must remain charged for starting the motor."
This suggests that replacing your manual switch with the correct automatic relay may be a good idea, not only being automatic, but also good for the batteries.
This is what would be used in a motorhome - and fits with the use you are describing.
At the price (other sellers are available), it looks a good idea to me!
Discussion? You asked a question. I answered it. No discussion.
If you don't want to accept it, that's fine by me. I have no obligation to help you. You decide if you don't want to accept it. Unless you need to ask your mummies permission.
Very rude. Odd guy.
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FFS ..... 5 posts and you're already deciding who's worth reading.
PS, you're wrong ..
bushwwacker
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Eh?!? :confused2::confused2::confused2:
Pikey
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I have twin batttery setup with Aux battery been interconnected thru an ignition switched 200Amp relay. As well as having a manual switch to disconnect if necessary.
Main Batery is a 750CCA 100AH jobby, Aux Battery is a smaller 550CCA 70AH (IIRC) Leisure battery.
Both have been in situ for over 16months and neither have failed to hold a charge or failed to start 1st time every time. Even in winter.
Main Batery is a 750CCA 100AH jobby, Aux Battery is a smaller 550CCA 70AH (IIRC) Leisure battery.
Both have been in situ for over 16months and neither have failed to hold a charge or failed to start 1st time every time. Even in winter.
Oldfogey
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I like the idea of the manual cutoff for the secondary battery in addition to the relay. In fact I think motorhomes and caravans can do this from thier leisure electrics control panel.
Hey MHM, I read all the thread. popotla probably appreciated your advice and was just asking for clarification, maybe not very well expressed. "Discussion? No discussion ....... mommie's permission"???? So let's move on.
When you say "must be same CCA", do you mean exactly the same, or can 750 go with 800, 800 with 850, etc.?
When you say "must be same CCA", do you mean exactly the same, or can 750 go with 800, 800 with 850, etc.?
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MHM was answering the question correctly with reference to two batteries simply connected with a switch. The simplest way to do it using two different batteries was also said early on in the thread and that's to use a split charger.
technically the batteries should be identical, but some disparities are always present so it is quite usual to use two batteries that are similar .. model changes between years maybe, so yes, 750 and 800, 1000 and 1100 .. and yes, technically they'd still equalise down but if you keep the difference small it's unlikely to hurt.
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Ideally both batteries should be identical, however that is unlikely in the real world. The greater the difference the greater the load on the system and the shorter the life of each battery. What that life is, is subject to many variables and is in the lap of the gods.
The more sophisticated the control system, the more chance you have of extending the life of both batteries. Look in the CFAQ section for a simple but effective split charge system.
The more sophisticated the control system, the more chance you have of extending the life of both batteries. Look in the CFAQ section for a simple but effective split charge system.
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I think not - certainly not if you read his PM.
Pikey
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I never made it clear in my post but the Aux battery does not run anything that the main battery runs. it is only for CB, Car radio, HAm Radio, interior Light, Invertor, work lamps & spot lights, All of which are wired thru a separate fusebox. The batteries are only connected together when the engine is on and the Alt is charging.
With regard to having in parallel two batteries of different specifications, I read the following:
"They can be very different, as long as they are the same chemistry. The same chemistry is match a flooded with a flooded. AGM with AGM, Gel with Gel, etc. Otherwise you are good."
"They can be very different, as long as they are the same chemistry. The same chemistry is match a flooded with a flooded. AGM with AGM, Gel with Gel, etc. Otherwise you are good."
popotla
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captainbeaky
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In that case, differing battery specs will be fine ( previous caveats still apply though).
captainbeaky
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Yup, looks good - I would go with that.
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