would this Lithium battery be ok for my electrics

Tranona said:
You don't say what type of relay you have and how the batteries are connected. The engine battery should not be connected to the house as seems to be happening
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Should have a connection when he starts the engine, if he has a VSR, which could account why the heater starts with the engine running, it's drawing power from the engine battery. Could be a dodgy domestic battery or dodgy wiring/bad connections.

Doesn't explain why the engine won't start after the heater has started. Unless a dodgy domestic battery has pulled the engine battery down.
 
Refueler said:
Surely this would not draw battery down enough to prevent engine start if all wiring is correct ?? What is its running amps ?? 4A or so ?? OK start up will be more - but not so high that engine is affected.

I have a 'gut feeling' the fault lies around that relay setup ....
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I only mention it's a new install, rather than an old install with a new problem, to hopefully save some guesswork for people.

If i was looking into this i would start my getting the heater to work on its own battery, before muddying the water with engine batteries/starting.

Keep the domestic battery separate, check connections, check battery etc.
 
ill get picks of all my wiring the weekend. thank you. i did notice after my post that the engine battery fuse had tripped, could be why i couldnt start the engine after. i also have a battery disharge protection device on the house battery which can disable it if it gets below a curtain amount, or too high,
 
UK-WOOZY said:
ill get picks of all my wiring the weekend. thank you. i did notice after my post that the engine battery fuse had tripped, could be why i couldnt start the engine after. i also have a battery disharge protection device on the house battery which can disable it if it gets below a curtain amount, or too high,
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What voltage does it cut out at ?

Try moving the heater connection straight to the battery, not through the protection device, as a test.
 
PaulRainbow said:
What voltage does it cut out at ?

Try moving the heater connection straight to the battery, not through the protection device, as a test.
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As I understand it most of these heaters whether chinese or Eber etc. - have low voltage cut-off ... usually at 10.5V ... too low of course to start an engine - but high enough to prevent serious damage to battery.... as long as charged up asap.
Why would a domestic need a LVC / HVC unit ? I can understand if the start battery is also connected to non engine related items.
 
UK-WOOZY said:
ill get picks of all my wiring the weekend. thank you. i did notice after my post that the engine battery fuse had tripped, could be why i couldnt start the engine after. i also have a battery disharge protection device on the house battery which can disable it if it gets below a curtain amount, or too high,
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Information "Drip Feed" once again. Why don't posters include all of this sort of info when first posting? I refer the Gentlemen to post #4 and give up!
 
We've all been prodding for more info - prodding to get OP to look deeper into his wiring ...

Not an unusual scenario on forums ... frustrating at times - but about par for the course.

I'm sure we are all guilty of it at times ....
 
The talk of "dragging the battery down" implies high current drain which would, in many cases, be apparent by something dissipating the energy by heat or smoke. I think this is a case of a loose connection presenting resistance to the heater start circuit. When a load is place on it by the heater starting, the voltage drops. Check all the connections, or as Paul says, start isolating components to fault find by jumping the heater straight to the battery first.
 
here are pics of my electrics

Domestic-

~This is the device on the domestic battery-

Dometic PerfectBattery BR 12 - Battery refresher, 12 V


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engine batt

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So i have two solar controllers with twin battery terminals. both batteries are connected to both controllers. i have removed the larger panel during winter because the NOA mount and panel is like a sail in the current winds. So atm there is a 60w panel on the coachroof. The alternator is connected to the relay. and the relay is connected to both batteries too. I started the heater on sunday remotely from the autoterm modem app. and it started the heater fine. when i got to the boat, the engine started fine too. (before the fuse was tripped so i had tried to start off the domestic battery , this time nothing had tripped and the engine started fine. the heater is now directly connected to the battery terminals. the domestic battery went down to 12.0 volts. and today typing this out on the forum the heater diagnostic returns this voltage.

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I think also it need to check the panel on the roof is working poperly. I know they dont last for ever, its been on the boat 4 years.

the battery charges quickly with the engine running and gets to 13v but always goes down to around 12v
 

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