Leisure battery charging problem

[gerry mcg]

Ive got a problem… perhaps related to by B2B install.
I’ll come back to that.
ive got an EBL119, 200Ah lithium battery, a Votronic 1212-50 B2B And a Victron BMV700.

now today i noticed the BMV was showing a 3A load current when i turned the ignition from O to ACC - i thought that was odd! - the leisure battery shouldn’t know about the starter load. When i cranked the engine and started it, there was >10A load showing on the BMV… Very Odd!!

now i noticed the liesure battery is not charging from the alternator, and hte BMV was not showing Alternator current. the plot thickens!

im not confident the B2B has been properly installed into the EBL - so i have have taken it out of the loop and reinstated the wiring as it was before - and the EBL still is not charging hte leisure battery.

ive put a multimeter across the terminals at the back of the EBL. there are 3, from L to R, we have (1) Starter battery + (red), (2)Ground -ive (2x Brown) and (3) Leisure +ive (Black)
when the engine is off, if i put a multimeter across 1 and 2, i get 0.00V, if i put a multimeter across 2 and 3, i get 13.35v (lithium hab battery)
when the engine is running, if i put a multimeter across 1 and 2, i get 13.35v, and across 2 and 3, i get 13.35V as well.

the BMV stays 0A going in

if i plug into hook up, teh BMV is showing 17A current going in, and i get 0.00A across 1and 2, and 13.8V across 2 and 3.
if i pull the 20A charging fuse in the front of the EBL, the current drops to 0A and the voltage across 2 and 3 drops back to 13.4V

any idea why i am seeing starter load on the BMV and why the alternator is not charging the Leisure batteries?

Ive disconnected the B2B at the moment (it only has a 5A protected starter voltage signal cable, 5A protected Leisure battery signal cable, -ive leisure battery temp sensor and D+ cable attached, but it is not connected to main stater battery cable or EBL at hte moment, so shouldn’t be messing with things.

the van is above 5C inside, so it is not the Lithium BMS preventing charging

could there be a blown fuse somewhere ? A stuck relay? Any ideas?

 

[gerry mcg]

Found a blown 50A maxi blade fuse in the starter battery area.

 

[autorouter]

a Votronic 1212-50 B2B

If the starter battery wire that has the 50A fuse is also the same wire that was feeding the B2B, then that's probably why the fuse blew. You will need to increase it to maybe 70A. and satisfy yourself that the wire is capable of carrying 50A continuous current. It probably is, but worth double-checking.

The wire might have the cross-sectional area (CSA) printed on it. If not, it is often embossed into the cable sheath, and is visible using a torch at a shallow angle. If not, the diameter of the wire (including the insulation) can be used to look up the CSA.

I presume the B2B is connected between the starter battery and the Starter Battery Input at the back of the EBL. So the voltage at that Starter Battery Input will no longer be the voltage of the starter battery.

The EBL119 will still charge the starter battery when on hookup, because it uses the Fridge 12V supply that comes via a separate wire from the starter battery (with a 20A fuse near the starter battery).

 

[gerry mcg]

Thanks. I've replaced with a 50A maxi fuse for the moment and will monitor the situation.
I replaced the Starter battery last week, so it is possible it blew when this was being replaced.
All working now

In still a bit surprised the BMV700 that is connected to the leisure battery is seeing a 3A current draw when the ignition is switched from 0 to ACC (presumably the glow plugs) and then a 10A+ current draw as the engine cranks.... This doesn't seem right, but I confess I can't recall looking at the BMV as I started the engine before

 

[the1andonly]

BMV showing draw on starting!
Something doesnt sound right to me. I know nothing about the EBL units but something isnt correct. I need to read you post again. Hope someone with a bit of nouse wakes up.

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[gerry mcg]

BMV showing draw on starting!
Something doesnt sound right to me. I know nothing about the EBL units but something isnt correct. I need to read you post again. Hope someone with a bit of nouse wakes up.

I've got a battery Master fitted, so it is likely there is a flow of current from the leisure battery to the Starter battery as the starter battery voltage drops momentarily on starting.

 

[the1andonly]

So many different ways of dealing with the 12V systems on Motorhomes. Ive Got CBE and a Votronics duo charger so no Knowledge of how a Battery master works but a 10A draw, is this normal? A question for the cognicenti.
edit
Does this question the state of the Starter battery?

 

[gerry mcg]

So many different ways of dealing with the 12V systems on Motorhomes. Ive Got CBE and a Votronics duo charger so no Knowledge of how a Battery master works but a 10A draw, is this normal? A question for the cognicenti.
edit
Does this question the state of the Starter battery?

it is a brand new starter battery and i spoke with Ash at Vanbitz and he said it was Ok. The drain is instantaneous and not sustained… it reverses to charge as soon as hte engine fires

 

[the1andonly]

Thanks. I've replaced with a 50A maxi fuse for the moment and will monitor the situation.
I replaced the Starter battery last week, so it is possible it blew when this was being replaced.
All working now

is it still all working?

 

[gerry mcg]

The 50A fuse blow was probably due to the load from the B2B and the 50A fuse being under size. Should be 80A
I plan to rewire with thicker gauge wiring and fit 80A fuse

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