Lithium upgrade - is my current charger / setup OK?

[Mad dog]

Hi all, my 2 x 100ah Banner lead acids are about knackered, so looking at fitting a 200ah lithium instead. I've no solar, it's just a 2019 Rapido Dreamer D55 based on a Ducato with a Nordelettronica NE287 17A charger.

I think the charger might be a bit under spec for a 200a battery? It's supposed to handle lithiums by altering the dip switches. I could order a 150ah battery instead, but if it's handled 2 x 100ah lead acids for 4 years, will it do?

The van split charges from the alternator to charge both engine & hab batteries, will this be OK for a big lithium battery please?

I've tended to find that despite rarely using a hookup when away, our regular driving keeps the batteries topped up, so I've never bothered with solar. We tend to drive each day, I previously found that the lead acids would last 3+ days with our usage.

Cheers all.

 

[Guigsy]

Having relatively low power chargers just means it'll take a long time to charge.

I've got a 280Ah lithium. My mains charger is 20A. Which is fine because generally when I'm using it, it'll be plugged in all night.

I'm still running the (not lithium friendly) charger from my alternator. It only gives about 15a. I will upgrade it to a 30a at some point.

 

[Mad dog]

Thanks Guigsy, I'm not bothered about it taking a long time to charge. We don't normally use too much power, but it's nice to have a reserve if we do. A long drive ought to put a fair bit back in them, we often drive a couple of hours a day on our long trips. If it gets low, I can always find a hookup for the night.

 

[Steve N Tracy]

I have a 17 amp 287 on my 2019 Rollerteam charging 2 100 amp lifepo 4's set to lead acid and it charges them ok though takes a while, and with the engine running while driving the alternator puts in between 14.2 to 14.5 volts so no issues there.

 

[AdrianChen]

Thanks Guigsy, I'm not bothered about it taking a long time to charge. We don't normally use too much power, but it's nice to have a reserve if we do. A long drive ought to put a fair bit back in them, we often drive a couple of hours a day on our long trips. If it gets low, I can always find a hookup for the night.

I think the charger may complain if the batteries are low and it has to run for a long period at max output - but I wouldn't rush to replace it if it has Lithium settings, just see how it goes. Seems like the b2b might be a higher priority for you since you drive frequently, and 15amp isn't much. The 2 points to check will be the size of your alternator (which may very well be big enough for a larger B2B someone on here is sure to know), I'm sure I've heard that the B2B should be under 40% of the alternator output so as not to stress the thing but I stand to be corrected on that figure, and the cable size fitted to the existing B2B or SCR, which may require upgrading if you double the output.

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[Guigsy]

I've got 280Ah... it's total overkill for us. The fridge runs on gas. We don't have any mains powered devices, so I don't run an inverter. We've got a lot of electronic gizmos, but they all charge on USB. Even my 15" laptop will run on a 30w USB C PD socket. The result is that the battery will last us the best part of a week even in the depths of winter with no sun on the solar, and if we don't drive anywhere.

 

[Gromett]

Hi all, my 2 x 100ah Banner lead acids are about knackered, so looking at fitting a 200ah lithium instead. I've no solar, it's just a 2019 Rapido Dreamer D55 based on a Ducato with a Nordelettronica NE287 17A charger.

I think the charger might be a bit under spec for a 200a battery? It's supposed to handle lithiums by altering the dip switches. I could order a 150ah battery instead, but if it's handled 2 x 100ah lead acids for 4 years, will it do?

The van split charges from the alternator to charge both engine & hab batteries, will this be OK for a big lithium battery please?

I've tended to find that despite rarely using a hookup when away, our regular driving keeps the batteries topped up, so I've never bothered with solar. We tend to drive each day, I previously found that the lead acids would last 3+ days with our usage.

Cheers all.

A battery charger should not burn out or blow up if given a big battery. The problem is the duty cycle and the installation location. A charger will be designed to get a battery of a certain size up to full charge within a certain period of time. If you put a bigger battery on it then it may exceed the duty cycle and will probably run hotter than designed for longer. If it is a quality charger then it will just shut down if it gets too much for it. BUT I have had one fail on me and when I looked at it the white paint on the metal had significantly browned and was flaking due to the extended periods of over temps.

The second thing to consider is if you are running it a longer time than designed ensure it has good ventilation for cooling.

Personally I would upgrade the charger at the same time as this will ensure you get a full charge as it may take 14+ hours for a 17A charger to charge up a 200AH battery. I spec based on an 8 hour charge period as a baseline. So 200Ah / 8 hours = 25Amp charger, preferably bigger.

 

[Lenny HB]

As the mains charger has a Lithium it should be OK but if charging from low level it may get a bit hot and overload it.

You really need to fit a B2B it is really not a good idea to charge a Lithium from a split charge relay. You risk damage to the alternator and the battery will never get a proper charge profile.

One of the biggest advantages of Lithium is its ability to charge fast always best to fit as much solar as you can get on the roof.

 

[AdrianChen]

A battery charger should not burn out or blow up if given a big battery. The problem is the duty cycle and the installation location. A charger will be designed to get a battery of a certain size up to full charge within a certain period of time. If you put a bigger battery on it then it may exceed the duty cycle and will probably run hotter than designed for longer. If it is a quality charger then it will just shut down if it gets too much for it. BUT I have had one fail on me and when I looked at it the white paint on the metal had significantly browned and was flaking due to the extended periods of over temps.

The second thing to consider is if you are running it a longer time than designed ensure it has good ventilation for cooling.

Personally I would upgrade the charger at the same time as this will ensure you get a full charge as it may take 14+ hours for a 17A charger to charge up a 200AH battery. I spec based on an 8 hour charge period as a baseline. So 200Ah / 8 hours = 25Amp charger, preferably bigger.

Agree - I think i've seen 15% of the battery AH as the min spec for a charger, as opposed to a maintainer type device, my old classic car is maintained on a 0.8amp jobby

 

[Gromett]

Agree - I think i've seen 15% of the battery AH as the min spec for a charger

Depends on the manufacturer as well. A cheap chinese one I would want a much higher rating than say a Victron. It was a cheap chinese 25Amp one of mine that looked toasted to heck and back.

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[Mad dog]

Thanks for the replies, really helpful. Just been having a peak under the bonnet, any idea how to find the spec/output of the alternator? Perhaps ask my Fiat dealer...

 

[Mad dog]

As the mains charger has a Lithium it should be OK but if charging from low level it may get a bit hot and overload it.

You really need to fit a B2B it is really not a good idea to charge a Lithium from a split charge relay. You risk damage to the alternator and the battery will never get a proper charge profile.

One of the biggest advantages of Lithium is its ability to charge fast always best to fit as much solar as you can get on the roof.

Thanks Lenny, you're probably right, but I'm going to try & find out my alternator output. I think the battery could zap up to 100A, some people say they've got 200A alternators fitted. If that's the case, then surely it can handle it?? Apparently my alternator isn't one of the variable output types, but might be more like 80A +?? I guess that means that the starter battery could get neglected if the lithium wants it all??. I'm not sure how the vans decide how to allocate their output.

 

[LithiumConvert]

Thanks Lenny, you're probably right, but.....

He is most certainly right. Having lithium without a B2B is not a good idea.

I guess that means that the starter battery could get neglected if the lithium wants it all??

With the B2B, you decide what power you want to direct to the lithium battery whether your vehicle has a smart alternator or not.

 

[jumar]

B2B with Lithium Battery is the perfect partnership, increasing or installing Solar completed the task....
As the OP claims to drive every day....the Solar isn't top of the list...but the B2B would be..

 

[Mad dog]

I've found out from my Fiat dealer that my alternator is 150A output. I'm trying to find out now what the maximum amount amps the battery can imput at one time. Apparently our van is 'lithium ready' ie they've put a chunky cable from the alternator to the hab battery, but how much it can take, I don't know.

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[Lenny HB]

Depends on the Lithium a 100ah often only 50amps but larger batteries can be 100 to 200 amps, if you have 2 batteries in parallel you can double those rates.
The battery spec will tell you.

 

[Mad dog]

Depends on the Lithium a 100ah often only 50amps but larger batteries can be 100 to 200 amps, if you have 2 batteries in parallel you can double those rates.
The battery spec will tell you.

It's 1 x 200A battery, I'm pretty sure it can suck 100A but I'm checking for sure. If that's the case, do I need a B2B?

 

[AdrianChen]

It's 1 x 200A battery, I'm pretty sure it can suck 100A but I'm checking for sure. If that's the case, do I need a B2B?

I would - Even with a 150amp alternator sucking up to 100amps through it especialy when at low speed traffic jams etc the alternator will get pretty hot I would think, yes it will work to a degree depending on what the "chunky" cable size is, but for example 100amps over a 16mm cable of 6m run will give 1.5v drop reducing the alternators charge voltage from 14.2v to 12.7v, so the actual charge current will not get to 100amps, but quite a bit down from that and a fair bit of heat! Much better to size the cables, B2B, and fusing to get a predicatable result, and less wasted heat/wear and tear on the alternator and its drive belts etc.

 

[peterc10]

The main reason for using a B2B is to protect the alternator from overheating whilst charging lithiums, which have low resistance and therefore will take whatever the alternator can provide. Lead acid batteries develop high resistance as they get charged, and therefore prevents the alternator using high currents.

 

[autorouter]

There's another reason to use a B2B with a lithium battery - it should not be charged when the temperature is very low. A B2B will have a temperature sensor input, and you can put a temperature sensor on the battery. The B2B should have a lithium profile, which will ensure it is never charged when the battery temperature is very low.

Also a B2B will probably have provision for voltage sensor wires. These are thin wires that connect directly to the battery terminals, and measure the exact voltage of the battery. The B2B uses this information to compensate for any voltage drop along the B2B output wires, so that the battery always gets the correct voltage charging profile.

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[Mad dog]

I've found out that the battery apparently accepts a max of 50 amps. I'm looking at adding heating plates to it (very little extra) so it always charges at the correct temperature. It'll be located next to the hot water tank which is always on if we're travelling & using the battery.

 

[Mad dog]

This is the spec sheet... It looks like 100A max input to me?