Lithium Parallel In Harmony With Lead Acid

OK, time to get off of the fence. It is folly to install a Lithium battery, as an auxiliary/Leisure battery if the standard set up (the majority of motorhomes) has been installed.

Connected in series with a standard 30amp automotive (12 volt) relay, connected across terminal number 87 & 30 using a piece of wire with an indefinable length, and a (normally) inadequate gauge, normally again with a 20 amp in line fuse.

Apart from the fact that there will be issues, which I simply refuse to go into again, it would be a complete waste of money.

Like any battery, yes it would work, but given the price it would be a complete and utter waste of money.

You really should not buy a Lithium battery unless you have the correct charging procedure in place. Not because it wouldn't work, just because you would be wasting your money not getting the real benefit of Lithium batteries ability to fast charge and deep discharge, which you simply cannot get when the battery is connected into the system with a wire the thickness of a boot lace.

If anyone is thinking about this, go to Halfords and buy the cheapest leisure battery that they can, get free fitting and donate the difference to Jims charity
 
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Hi,

thanks for all your contributions to the thread. There are some really valid ideas here that are always worth considering before deciding which batteries to buy. We'd just like to clarify that mixing chemistries could be regarded as having a possible benefit in that for those wishing to enjoy the benefits of TN Power LiFePO4 batteries but not wishing to bin healthy lead acid batteries to make room for TN Power, the TN Power product can replace individual batteries within the bank temporarily. The benefit of weight saving is obviously immediate. The benefit of deep discharging is something that can be later enjoyed when the whole bank is TN Power LiFePO4. Meanwhile, the depth of discharge should be set no lower than 50% to ensure no damaging deep discharges occur on the lead acid battery in the bank until such a time as it reaches its natural cyclic limit and needs replacing.

This approach not only ensures lead acid batteries aren't wasted but also spreads the cost of switching to TN Power which is, in its category, excellent value for money but obviously still represents a significant investment for the end user. At the end of the day, Lithium is now becoming popular for use in myriad applications from superyachts to IT UPS systems and even mobility scooters. Why should a motorhome enthusiast miss out because their vehicle has a lead acid starter battery that is sometimes connected in parallel to the house bank?
 
So which is it...

At first we thought of this .
bike1.jpg


Then re discharge we discover its more like this

bike.jpg



Maybe even this

bike2.jpg


Bust most likely adding an expensive battery to an existing FLA setup is like this

bike4.png
 
BatteryMegaUK said:
Hi,

thanks for all your contributions to the thread. There are some really valid ideas here that are always worth considering before deciding which batteries to buy.
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You come across as a really nice person, and I genuinely think that your heart is in the right place and having a battery supplier as a member/contributor is a good thing.

I think you'll glean more about motorhome electrical installations and how they impact and differ from "normal" auxillary batteries, say in cars for ICE (In Car Entertainment systems)

BatteryMegaUK said:
Why should a motorhome enthusiast miss out because their vehicle has a lead acid starter battery that is sometimes connected in parallel to the house bank?
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This is an example, the engine and leisure batteries are always connected in parallel when the engine is running, unless a B2B is, or has been installed, and I am not aware of a single European van chassis that doesn't still use Lead Acid as a stop start engine battery
 
The advantage (at least for me) would be the ability to fit an inverter and not worry so much about over working a lead acid bank (current draw I mean, not overuse /voltage drop).
Lets be honest here with regards worries about sizing of standard MH cabling... it's 12v! There is NOTHING on the 12v system that would over power that design anyway.
Anyone fitting a lithium MUST be looking at the opportunity to have 240v "on tap" without having to have EHU. And with that in mind you would be wiring ADDITIONAL suitably sized cables in at the same time as the inverter install..
on top of this, wiring the inverter into the MH's 240v circuit is absolutely up to the job of supplying 240v from the inverter to the standard MH 240v sockets without any issues with MH's standard cable sizing.

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eddievanbitz said:
You come across as a really nice person, and I genuinely think that your heart is in the right place and having a battery supplier as a member/contributor is a good thing.

I think you'll glean more about motorhome electrical installations and how they impact and differ from "normal" auxillary batteries, say in cars for ICE (In Car Entertainment systems)

This is an example, the engine and leisure batteries are always connected in parallel when the engine is running, unless a B2B is, or has been installed, and I am not aware of a single European van chassis that doesn't still use Lead Acid as a stop start engine battery
Click to expand...

When the batteries are connected in parallel (engine running or perhaps landline charger/solar on) the issue of deep discharging is not so much of an issue (nor is battery size or type really). The size of wiring may need upgrading for the quick recharge of Lithium, but the main benefit of lithium (weight and cycle rates) can be achieve with the same charging speed as the current charging system has (provided the voltages are adequate). Where the voltage is inadequate, obviously sticking with lead acid is best unless the owner wants to invest in the right charging equipment to suit the desired upgrade.

I guess there is no one size fits all answer and if folks are interested in lithium, they should say what they individually have so that experienced fitters like Eddie can advise on what is possible and the pros and cons of each option, allowing them to make an informed decision specific to their vehicle. If they choose lithium, the key is to choose a genuinely safety tested one with a real UN38.3 test certificate, rather than a self-certified one. TN Power has the real deal but is still cost effective.
 
PeteH said:
How about This ? :- https://www.motorhomefun.co.uk/forum/threads/what-do-you-think-of-this-lithium-batteries.204006/

I make absolutely no comment.
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Correct, you shouldn't comment as that is a completely different chemistry battery and I'm not surprised he had to rip everything out and custom design it. This is completely different to what this thread is about despite his title having the word iron in it. The voltages suggest its nothing of the sort.
It would be similar to suggesting running your car on 9v tv remote batteries ?
 
HandyAndy said:
Correct, you shouldn't comment as that is a completely different chemistry battery and I'm not surprised he had to rip everything out and custom design it. This is completely different to what this thread is about despite his title having the word iron in it. The voltages suggest its nothing of the sort.
It would be similar to suggesting running your car on 9v tv remote batteries ?
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Yes, But as one commenter said, He is either a Genius or a fool. But on the surface it allegedly works for him and for a LOT less that £1000 per Battery Pack.

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PeteH said:
Yes, But as one commenter said, He is either a Genius or a fool. But on the surface it allegedly works for him and for a LOT less that £1000 per Battery Pack.
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In fairness to BatteryMegaUK they are selling LiFePO4 batteries for a lot less than £1,000 too.
 
Just to chuck something else into the mix Hymer offer a Lithium battery that you just couple straight to your existing Pb battery, there is a guy in the Hymer hall at Dusseldorf telling people all about it, one of his arguments was for using the Pb battery to warm the Lithium when it’s too cold to charge.

Martin
 
funflair said:
Just to chuck something else into the mix Hymer offer a Lithium battery that you just couple straight to your existing Pb battery, there is a guy in the Hymer hall at Dusseldorf telling people all about it, one of his arguments was for using the Pb battery to warm the Lithium when it’s too cold to charge.

Martin
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I think you will find that they are not just coupling a Li battery to a Pb one. The system is described as a smart one that intelligently charges the different battery types and controls which is used as a source, according to conditions. Indeed it appears to be an expensive bit of sophisticated kit that is needed to combine the two, costing £2,350 (including 1 Li battery).
 
Pausim said:
I think you will find that they are not just coupling a Li battery to a Pb one. The system is described as a smart one that intelligently charges the different battery types and controls which is used as a source, according to conditions. Indeed it appears to be an expensive bit of sophisticated kit that is needed to combine the two, costing £2,350 (including 1 Li battery).
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Any control and I don’t doubt there is some is all built into the Lithium battery I believe as the guy said it just connects.

Martin

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Pausim said:
In fairness to BatteryMegaUK they are selling LiFePO4 batteries for a lot less than £1,000 too.
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ERR? the last word was? Pack. Most users I know, have at least two batteries (yes I know. Grandads tin hat is ready for the incoming). So you are convinced that only ONE LiFeP04 will out play 2 Gels?.
 
PeteH said:
ERR? the last word was? Pack. Most users I know, have at least two batteries (yes I know. Grandads tin hat is ready for the incoming). So you are convinced that only ONE LiFeP04 will out play 2 Gels?.
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His pack appears to be 100 plus individual cells in an uncased pack giving 28V, which might work well for him but probably is not what most of us would consider convenient. I have not suggested that one LiFePO4 will out play 2 Gels. Not sure what you are getting at here but the size of battery bank needed depends on individual needs. I use 30 to 40 Ah per day and plan around that.
 
Pausim said:
His pack appears to be 100 plus individual cells in an uncased pack giving 28V, which might work well for him but probably is not what most of us would consider convenient. I have not suggested that one LiFePO4 will out play 2 Gels. Not sure what you are getting at here but the size of battery bank needed depends on individual needs. I use 30 to 40 Ah per day and plan around that.
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Yes, but will one LIFEPOP outplay 2 gels? I dont remember suggesting anything else. As for the guy with his 2nd hand laptop batteries, only he know what suites him? And I dont think for a moment he would challenge the LIFPOP`s. he just wanted a CHEAP solution to HIS issue. I reckon he may be playing with fire, But that His issue, so long as he isn't parked next to Me!!
 
PeteH said:
ERR? the last word was? Pack. Most users I know, have at least two batteries (yes I know. Grandads tin hat is ready for the incoming). So you are convinced that only ONE LiFeP04 will out play 2 Gels?.
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We replaced 6 Varta lead acids with 2 Lithium
Our last van had 4 gels which had less umph than the 6 lead acids
 
Robert Clark said:
We replaced 6 Varta lead acids with 2 Lithium
Our last van had 4 gels which had less umph than the 6 lead acids
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My Last R-V had SEVEN Lead Acid. 4 Hab; Up front 1 Hab in the rear, and 2 Starter battery 2. 400W solar on the roof. along with a 2KW inverter. But then we used to Marshall Festivals, and where "off grid" for up to 10 days, and using the 4KW LPG generator was not universally popular, once the Site filled up..

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PeteH said:
Yes, but will one LIFEPOP outplay 2 gels?
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Does it need to? They have different characteristics and it is not as simple as 2 of one type equals 1 of the other. If you had one of each at 100Ah you could probably get 90Ah out of them both occasionally, but if you did it regularly one would wear out and lose capacity a lot quicker than the other. The answer depends on many factors including your discharge and recharge rates. Sorry no easy answer.
 
X2 140AH Exide gels, coupled with solar 120, original batteries van March 2005, that will do for me.
 
Currently I can have 4.7 £105 "wet" batteries for the price of one LI-Po. When/if the price comes down It may then be worth consideration.
 
Bouncing this to ask whats the stated max and continuous amp draw of these things BatteryMegaUK ? Your spec sheet online doesn't seem to show it?
 
Generator for me.... same price as 1 lithium and runs the heating, microwave, kettle and cooker ring. Can't do that with a lithium
 
HandyAndy said:
Bouncing this to ask whats the stated max and continuous amp draw of these things BatteryMegaUK ? Your spec sheet online doesn't seem to show it?
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Hi Andy,

The max charging current is 50AH the max discharge current is 100AH.
 

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